AU5410501A - Process for lining a borehole - Google Patents

Description

S&FRef: 556018D1

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Mintech Pty Ltd 3E, 1-7 Unwins Bridge Road St Peters New South Wales 2044 Australia Geoffrey Ronald Robbins Spruson Ferguson St Martins Tower,Level 31 Market Street Sydney NSW 2000 (CCN 3710000177) Process for Lining a Borehole The following statement is a full description of this invention, including the best method of performing it known to me/us:- BP Australia Documents received on: 2 8 JUN 2001 C-tch No: 5845c PROCESS FOR LINING A BOREHOLE Technical Field This invention relates to processes for lining a borehole.

Background Art Boreholes which contain sulphide minerals which are exposed on drilling and on exposure to oxygen in air start to oxidise and get hot. Frequently hot spots develop in such boreholes making it difficult to later load explosives into the borehole.

Objects of the Invention It is an object of this invention to provide processes for lining a borehole.

Disclosure of Invention Disclosed herein is a process of removing oxygen from or reducing oxygen in a borehole, said process comprising: placing oxygen affecting means selected from the group consisting of oxygen removing means and oxygen reducing means in the borehole to remove or reduce the amount of oxygen in the borehole; and i closing the borehole to substantially prevent air from entering the borehole.

This process has been previously described in Australian provisional patent application no. PQ7320 and Australian complete application no. 43754/01 the contents of both of which are incorporated herein.

20 The step of placing may comprise a step selected from the group consisting of flushing the borehole with a non oxygen containing gas or vapour, placing solid carbon dioxide in the borehole and allowing it to vaporise thereby flushing oxygen :.from the borehole, forming steam in the borehole and flushing oxygen from the borehole with the steam, placing and reacting an acid and a carbonate containing alkali in the presence of an aqueous medium in the borehole and flushing oxygen from the borehole with the carbon dioxide, placing at least one oxygen absorber in the borehole, placing at least one oxygen scavenger in the borehole, placing an oxygen absorber/scavenger in the borehole, and placing at least one oxygen absorber and at least one oxygen scavenger in the borehole.

[I:\DayLib\LBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM The step of placing may comprise placing said oxygen affecting means in the borehole in an amount sufficient to substantially remove all of the oxygen in the borehole or in an amount sufficient to reduce the oxygen concentration in the borehole whereby sulphide material (such as sulphide minerals) and/or other oxidisable material in the borehole is not oxidised to the extent whereby excessive heat is generated in the borehole as a result of an oxidisation reaction between oxygen and the oxidisable material.

The step of placing may comprise placing said oxygen affecting means in the borehole in an amount sufficient to substantially remove oxygen from the borehole whereby sulphide material and/or other oxidisable material in the borehole is not substantially oxidised. The step of placing may comprises placing iron or reduced iron in the borehole. In one form the step of placing may comprise placing reduced iron in a form selected from particles, powder, granules and any mixture thereof into the borehole. Typically the step of placing comprises placing reduced iron in the borehole in an amount sufficient to substantially remove all of the oxygen in the borehole. In another form the step of placing may comprise placing reduced iron in a form selected from particles, powder, granules and any mixture thereof in the borehole in an amount sufficient to substantially remove oxygen from the borehole whereby sulphide material in the borehole is not substantially oxidised.

20 There is further disclosed a process of removing oxygen from or reducing oxygen in a borehole, said process comprising: removing oxygen from or reducing oxygen in the borehole; and closing the borehole to substantially prevent air from re-entering the borehole.

Usually by these oxygen removing or reducing processes the amount of oxygen is 25 reduced in the borehole at least to the extent whereby sulphide material and/or other oxidisable material in the borehole is not substantially oxidised or is not oxidised to the extent whereby excessive heat is generated in the borehole as a result of an oxidisation reaction between oxygen and the oxidisable material. Typically this is achieved by removing >80% by volume of oxygen from the borehole, more typically >90vol% or >95vo1%, and even more typically >99vo1% of oxygen from the borehole.

[I:\DayLib\LBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM The step of removing or reducing may comprise a step selected from the group consisting of flushing the borehole with a non oxygen containing gas or vapour, placing solid carbon dioxide in the borehole and allowing it to vaporise thereby flushing oxygen from the borehole, forming steam in the borehole and flushing oxygen from the borehole with the steam, forming carbon dioxide in the borehole by reacting an acid and a carbonate containing alkali in the presence of an aqueous medium in the borehole and flushing oxygen from the borehole with the carbon dioxide, placing at least one oxygen absorber in the borehole, placing at least one oxygen scavenger in the borehole, placing an oxygen absorber/scavenger in the borehole, and placing at least one oxygen absorber and at least one oxygen scavenger in the borehole.

The step of removing or reducing may comprise a step selected from the group consisting of flushing the borehole with a non oxygen containing gas or vapour, placing solid carbon dioxide in the borehole and allowing it to vaporise thereby flushing oxygen from the borehole, forming steam in the borehole and flushing oxygen from the borehole with the steam, placing and reacting an acid and a carbonate containing alkali in the presence of an aqueous medium in the borehole and flushing oxygen from the borehole with the carbon dioxide, placing at least one oxygen absorber in the borehole, placing at least one oxygen scavenger in the 20 borehole, placing an oxygen absorber/scavenger in the borehole, and placing at least one oxygen absorber and at least one oxygen scavenger in the borehole.

The step of removing or reducing may comprise placing said oxygen affecting means in the borehole in an amount sufficient to substantially remove all of the oxygen in the borehole. Typically, the step of removing or reducing comprises placing said oxygen 25 affecting means in the borehole in an amount sufficient to substantially remove oxygen from the borehole whereby oxidisable material in the borehole is not *substantially oxidised. More typically, the step of removing or reducing comprises placing said oxygen affecting means in the borehole in an amount sufficient to substantially remove oxygen from the borehole whereby sulphide material in the borehole is not substantially oxidised. The removing or reducing may comprise placing iron or reduced iron in the borehole. Typically the removing or reducing comprises placing reduced iron in the borehole in an amount sufficient to substantially remove all of the oxygen in the borehole. The reduced iron may be in a form selected [1 :\DayLib\LIBxX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM from particles, powder, granules and any mixture thereof. In one form the removing or reducing comprises placing reduced iron in a form selected from particles, powder, granules and any mixture thereof in the borehole in an amount sufficient to substantially remove oxygen from the borehole whereby sulphide material in the borehole is not substantially oxidised.

The step of removing or reducing may comprise removing or reducing the amount of oxygen in the borehole whereby oxidisable material in the borehole is not oxidised to an extent that excess heat is generated in the borehole at a time selected from the group consisting of before said closing, after said closing at the same time as said closing, before and after said closing, and before, at the same time and after said closing.

Typically, the borehole is closed to substantially prevent air from re-entering the borehole by closing the borehole with a borehole plug located at an appropriate location in the borehole. Typically, but not always, the borehole plug is placed at or near the top of the borehole. The borehole plug may be fitted with a conduit having a one-way valve which conduit passes through the borehole plug or is otherwise associated with the borehole plug a conduit hose attached to the side of the S borehole plug to allow the escape of gas from the borehole without allowing air to i enter the borehole). Thus the invention further provides a borehole plug having a conduit fitted with a one way valve to allow gas to escape from the borehole and to prevent air from entering the borehole when the boreplug is positioned in the borehole so as to close the borehole. The invention further provides a conduit fitted with a one way valve which conduit is capable of being located between a borehole plug in a borehole and the wall of a borehole to allow gas to escape from the borehole and to 25 prevent air from entering the borehole when the boreplug is positioned in the borehole 000* 00so as to close the borehole. Alternatively, the borehole may be capped to substantially prevent air from re-entering the borehole. The cap may be fitted with a conduit passing through the cap, the conduit having a one-way valve so as to permit the escape of gas from the borehole but at the same time substantially preventing influx of air into the borehole. The step of closing may comprise placing a borehole plug, fitted with a conduit having a one-way valve which conduit passes through the borehole plug to allow the escape of gas from the plugged borehole, at an appropriate location [I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM in the borehole so as to close the borehole thereby preventing air and liquids from entering the plugged part of the borehole.

The oxygen may be removed or reduced by flushing the borehole with a non oxygen containing gas or vapour a gas or vapour such as nitrogen, steam, carbon dioxide, argon, helium, or a mixture of two or more of the foregoing). Flushing may be accomplished by placing a conduit connected to a source of non oxygen containing gas or vapour into the borehole and flushing the borehole with the non oxygen containing gas. Typically the end of the conduit is placed at or near the bottom of the borehole and the borehole is flushed with a sufficient flow of non oxygen containing gas or vapour for a sufficient time to reduce or substantially remove oxygen from the borehole and thence the borehole is closed to substantially prevent air from reentering the borehole. Alternatively, a sufficient amount of solid carbon dioxide may be placed in the borehole and allowed to vaporise and after a sufficient amount of the carbon dioxide has vaporised to reduce or substantially flush the borehole of oxygen, the borehole is closed to substantially prevent air from re-entering the borehole. In a further alternative, water may be placed in the borehole and heated to boiling point by placing an electric heating probe down the borehole into the water) such that 9.a sufficient amount of steam is liberated to substantially flush the borehole of oxygen and thence the borehole is closed to substantially prevent air from re-entering the S 20 borehole. In yet a further alternative, water already present in the borehole may be :heated by placing an electric heating probe down the borehole into the water) such that a sufficient amount of steam is liberated to substantially flush the borehole ooooo of oxygen and thence the borehole is closed to substantially prevent air from reentering the borehole. In another alternative, sufficient amounts of an acid and a 25 carbonate containing alkali may be placed in the borehole (typically in substantially 2;.stoichiometric amounts or alternatively the acid may be in stoichiometric excess to the alkali or vice versa) so as to react to liberate carbon dioxide in a sufficient amount to substantially flush the borehole of oxygen and thence the borehole is closed to S"substantially prevent air from re-entering the borehole. Water normally has to be present to enable the acid and carbonate containing alkali to react with each other.

Water may be already present in the bottom of the borehole or alternatively, it may be added to the borehole separately from the acid an acid such as citric acid, tartaric acid, a mineral acid such as HC1, H 2 S0 4 or HN0 3 an organic acid such as acetic acid, [I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM formic acid or other suitable acid, or a compatible mixture of two or more thereof) and carbonate containing alkali an alkali such as ammonium bicarbonate, sodium bicarbonate, potassium bicarbonate, potassium carbonate, sodium carbonate, ammonium carbonate, or a mixture of two or more thereof). The acid may be added in solid form, gel form or in liquid form such as in the form of an aqueous solution.

The carbonate containing alkali may be added in solid form, gel form or in liquid form such as in the form of an aqueous solution. Normally the acid and the carbonate containing alkali are added separately and sequentially so that the liberation of carbon dioxide does not take place until the acid and alkali come into contact with each other at the bottom of the borehole.

There is also disclosed a closed borehole from which oxygen has been removed or reduced in accordance with the above described methods.

The oxygen removing means or reducing means may be an oxygen absorber such as, for example, an oxygen absorbing composition, an oxygen absorbing element, an oxygen absorbing molecule, an oxygen absorbing compound, or a mixture of any two or more of the foregoing. The oxygen removing means or reducing means may be an oxygen scavenger, such as, for example, an oxygen scavenging composition, an oxygen scavenging element, an oxygen scavenging molecule, an oxygen scavenging !compound, or a mixture of any two or more of the foregoing. The oxygen removing 20 means or reducing means may be a mixture of one or more oxygen absorbers with one or more oxygen scavengers. The oxygen removing means or reducing means may be an oxygen absorbing material, an oxygen scavenging material or an oxygen absorbing and scavenging material, a combination of an oxygen absorbing material and an oxygen scavenging material, a combination of an oxygen absorber with one or more S 25 of the foregoing materials, a combination of an oxygen scavenger with one or more of the foregoing materials or a combination of an oxygen absorber and an oxygen scavenger with one or more of the foregoing materials. An oxygen absorbing material °for an oxygen scavenging material may be a plastic coated with iron particles, for example. The oxygen removing means may be a mechanical means such as a gas pump or a conduit linked to a source of non oxygen containing gas a gas such as nitrogen, carbon dioxide, argon, helium, or a mixture of two or more of the foregoing) or a conduit linked to a source of non oxygen containing vapour such as steam.

[I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM The oxygen absorber/scavenger typically comprises iron. Typically, the iron is in particular form. Advantageously, the iron is in reduced form. The iron may be in the form of iron granules or iron powder or iron filings or mixtures thereof. Typically the iron is in the form of powder, particles such as filings or granules and the iron is substantially pure iron, steel, pig iron, sponge iron, sponge steel, reduced iron, electrolytic iron, cast iron, scrap iron, scrap steel, reduced scrap iron, reduced sponge iron, reduced electrolytic iron, reduced pig iron, reduced sponge steel, reduced steel, reduced scrap steel or a mixture of any two or more of the foregoing. The finer the powder, particles or granules of iron, the faster the rate of oxygen absorption and/or scavenging. Typically, the powder, particles or granules of iron are in the range of one mesh to 1000 mesh, more typically five mesh to 800 mesh, even more typically mesh to 600 mesh, and still more typically, 100 mesh to 350 mesh.

The oxygen absorber and/or oxygen scavenger may be admixed with (or in the form of a composition) with other components such as an oxidation accelerating agent (e.g.

a salt which when dissolved in water forms an electrolyte solution which activates the oxygen absorber or oxygen scavenger such as iron, suitable salts including, for example, magnesium sulphate, potassium carbonate, potassium sulphate, potassium chloride, sodium sulphate, sodium chloride, magnesium chloride, calcium chloride or mixtures of any two or more of the foregoing), a filler such as, for example, activated charcoal, diatomaceous earth, oxidised steel, oxidised iron, sand, activated alumina, gravel, or a mixture of any two or more of the foregoing. Typically when the oxygen absorber and/or scavenger is an admixture or composition, iron is present in the .oe..i admixture or composition in an amount in the range of 5 to 98wt%, 10 to 98wt%, to 99wt%, 50 to 99wt%, 75 to 98wt%, 80 to 98wt%, 90 to 98wt%, or 90 to with the remainder of the composition being made up of filler, oxidation promoter and .oxidation promoter aid if required. Examples of oxygen absorbing compositions are disclosed in US patent No. 5,262,375 and 5,725,795 the contents of which are incorporated herein by cross reference.

S.

Typically, the oxygen absorber and/or oxygen scavenger is added to the borehole in an amount sufficient to substantially absorb or scavenge substantially all of the oxygen in the borehole. Thus, if iron is used as the oxygen absorber and/or oxygen scavenger the amount of iron typically used is at least a chemically stoichiometric amount relative to the amount of oxygen anticipated to be present in the borehole [I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM (typically determined by estimating the volume of the borehole from the depth and cross sectional diameter of the borehole and determining the approximate amount of oxygen present in such a volume by assuming that the oxygen makes up a certain proportion of the total volume of air in the borehole (typically, about 15 volume percent to about 30 volume percent, and more typically, about 15 to about 25 volume percent, and still more typically, about 21 volume percent), and determining the amount of iron required to react with such a volume of oxygen. Alternatively, a less than stoichiometric amount of iron relative to the amount of oxygen anticipated to be present in the borehole may be used if desired 10 mole percent, 20 mole percent, 30 mole percent, 40 mole percent, 50 mole percent, 60 mole percent, 70 mole percent, mole percent, 90 mole percent, 95 mole percent, or 98 mole percent of the estimated stoichiometric amount of iron required may be used if required). Typically, however, an excess of the stoichiometric amount of iron relative to the amount of oxygen estimated to be present in the borehole is used 110 percent, 120 percent, 130 percent, 140 percent, 150 percent, 160 percent, 170 percent, 180 percent, 190 percent, 200 percent, 220 percent, 250 percent, 270 percent, 300 percent, 325 percent, 350 percent, 375 percent, 400 percent, 425 percent, 450 percent, 500 percent, 550 percent, 600 percent, 650 percent, 700 percent, 750 percent, 800 percent, 850 percent, 900 percent, 950 percent, 1000 percent, 1200 percent, or 1500 percent). One way of 20 estimating the amount of iron required is by considering the following equations: Fe 0.502 FeO (1) :FeO 0.2502 Fe 2 0 3 (2) The molecular weight of iron is 55.85. The molar volume of oxygen at room temperature and pressure (25 degrees C, one atmosphere) is 24.465 1/mole and at 25 standard temperature and pressure (0 degrees C, one atmosphere) is 22.414 1/mole.

Assuming iron reacts with oxygen in the borehole in accordance with equations (1) and above then one gram of iron reacts with about 0.33 1 of oxygen gas at degrees C. Thus, if it was estimated that the borehole contained about 658 1 of oxygen gas then about two kilograms of iron would be required to be added to the borehole if a stoichiometric amount of iron was desired to be added to the borehole.

[I:\DayLib\L[BXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM The number of moles, n, of oxygen in a typical cylindrical borehole can be readily estimated as follows. Number of moles of oxygen in borehole can be estimated from the formula n PV/RT where (for Si units) P is the pressure of oxygen in the borehole in newtons/m 2 (1 atmosphere 1.013 x 10 5 newtons/m 2 V is the volume of oxygen in the borehole in inm 3 R is the universal gas constant (8.3143 joule/°C-mole), and T is the temperature in The volume of oxygen in the borehole can be calculated from V 7nr 2 h x 0.21 where r is the radius (in metres) of the borehole, h is the height of the borehole (in metres) filled with air (as opposed to water) and 0.21 is derived from the fact that dry air comprises of about 21% by volume of 02.

Usually the level of oxygen is reduced in the borehole at least to the extent that any rise of temperature in borehole as a result of some oxidation reaction therein is not excessive to the extent that it is dangerous to put explosives into borehole or is such that flammable gases in borehole catch on fire or are in danger of catching on fire.

The upper tolerable level of temperature in the borehole will depend on the nature of the explosives that are required to be used in the borehole and the nature of the flammable gases. Usually the oxygen level in the borehole is reduced at least to a level such that the temperature in the borehole as a result of an oxidisation reaction between any remaining oxygen and any oxidisable materials in the borehole is less than about 70'C, more typically less than 65°C, 60'C, 55°C, 50'C, 45 0 C or 45 0

C.

Examples of borehole plugs are described in Australian Patent Numbers 579 395 and 595 887 the contents of which are incorporated herein by cross-reference. Other examples of borehole plugs include mechanical type plugs, wherein such plugs comprise a contained mass of appropriate material such as polyurethane beads, sand or sawdust. Another example of a borehole is a sheet-like barrier device which is 25 affixed to the top of the borehole, and such a sheet may be made of a material which is substantially oxygen impermeable, such as plastic or polyurethane. Alternatively, *.an inflatable borehole plug assembly, may comprise a sealed gas-tight inflatable container containing a pressurised vessel having pressure releasing means, said pressurised vessel containing an inflating substance and a time delay liquid, adapted so that on operation of the pressure releasing means said time delay liquid is discharged from the pressurised vessel, thereby causing a time delay between said operation of the pressure releasing means and release of said inflating substance from said pressurised vessel, and (ii) the discharge of the inflating substance is delayed by [I:\DayLib\LIBX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM the time delay liquid whereby on discharge of the inflating substance the inflatable container is inflated to form a borehole plug; characterised in that the inflatable container is adapted so as to allow for operation of the pressure releasing means before the inflatable borehole plug assembly is dropped, lowered or pushed into a borehole. The inflating substance may be discharged after the time delay liquid is discharged from the pressurised vessel or simultaneously during the discharge of the time delay liquid.

In one form, an inflatable bore hole plug may comprise an inflatable bag having an inlet, and an optionally flexible conduit having one end of said conduit coupled to the inlet (by means of a one-way valve) in an optionally releasable fashion and the other end of the conduit being adapted to be connected to a source of pressurised gas or an inflatable substance which can inflate the bag, or a pressurised source of a co-reagent which can react with a further co-reagent in the bag to produce an inflatable substance which can inflate the bag. Typically the source of the pressurised gas or inflatable substance which can inflate said bag is an aerosol container which typically has pressure releasing means. The pressure releasing means is typically a nozzle coupled to an aerosol container via a conduit, with the other end of said conduit coupled to the inflatable bag via a one-way valve in an optionally releasable fashion. Descriptions of examples of the variations of 20 combinations of co-reagents that can react together to create an inflatable substance and the means to enable said reactions to be started when required are described in Australian patent Nos. 579395 and 595887 and Australian patent application no.

S•93295/98 the whole contents of which are incorporated herein by cross-reference.

Alternatively, the borehole plug assembly may be a combination comprising 25 an inflatable gas-tight container or bag, and a substantially non-elastic outer support for said inflatable container or bag. In this form the inflatable container may be a bag comprising multiple layers of plastic. The outer support for said bag may be "•-*constructed of a material selected from a group consisting of woven polyethylene and woven polypropylene. Said outer support may comprise a hole through which the conduit passes.

Inclusion of an outer sleeve in the borehole plug assembly is particularly advantageous, wherein for example, the inflatable container of the borehole plug assembly is prevented from bulging and stretching when inflated inside the outer [I:\DayLib\LBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM sleeve, causing the inflatable borehole plug to be retained particularly securely against the sides of the borehole (compared to inflatable plugs which lack a non-elastic woven outer support) and enabling a longer retention of internal pressure.

Additionally, when the inflatable container is disposed within the outer supporting sleeve, the rough texture of the woven material of the support provides an efficient frictional grip between the inflated borehole plug and the sides of the borehole.

Further, when the material of the outer support is white or opaque any temperature rise inside the pressured vessel is minimised when assembly is left in the sun. Still further, the outer support can protect the inflatable container against damage when the assembly is inserted in a borehole.

Preferably, the inflatable container of the borehole plug assembly should be able to withstand 10 to 300 kPa internal pressure and to maintain that pressure for up to six months. More typically, the inflated borehole plug will be required to retain a pressure of from 100 kPa to 170 kPa for up to four weeks. In this way, when the inflatable borehole plug assembly is inflated in a borehole, it is typically capable of supporting a direct weight of up to five tonnes, more typically up to three tonnes, loaded on its upper surface.

-Typically, the inflatable container of a borehole plug is dimensioned for °o o dropping or lowering down a borehole and is adapted for containing an inflatable 20 substance or pressurised gas after it is released from the pressurised vessel.

o o The processes of the invention reduce the propensity for certain minerals which are exposed on drilling a borehole, on exposure to air, to oxidise and become too hot. The walls of a borehole from which oxygen has been removed or in which oxygen has been reduced by a process of the first or second embodiments may still be at an elevated temperature, however. By inserting a borehole lining in the borehole, a explosive can be thereafter placed in the lined borehole and the so-placed explosive is facilitated in travelling unrestictedly to a desired depth in the borehole without S- interacting adversely with the walls of the borehole. Therefore, the processes of the invention include lining at least part of the borehole with a borehole lining.

Optionally, the borehole lining may be supported in the borehole by one or more support means located in the borehole to support the borehole lining in the borehole, typically to substantially prevent slippage of the borehole lining in the borehole.

Thus, the invention provides a process of lining a borehole, said process comprising: [:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM placing oxygen removing means or oxygen reducing means in the borehole to remove oxygen from or reduce oxygen in the borehole; lining at least part of the borehole with a borehole lining; and closing the borehole to substantially prevent air from entering the borehole.

The invention further provides a process of lining a borehole, said process comprising: removing oxygen from or reducing oxygen in the borehole; lining at least part of the borehole with a borehole lining; and closing the borehole to substantially prevent air from re-entering the borehole.

The invention still further provides a process of lining a borehole, said process comprising: placing oxygen removing means or oxygen reducing means in the borehole to remove oxygen from or reduce oxygen in the borehole; lining at least part of the borehole with a borehole lining; locating support means in the borehole to support the borehole lining; and closing the borehole to substantially prevent air from entering the borehole.

The invention yet further provides a process of lining a borehole, said process :comprising: removing oxygen from or reducing oxygen in the borehole; lining at least part of the borehole with a borehole lining; locating support means in the borehole to support the borehole lining; and closing the borehole to substantially prevent air from re-entering the borehole.

S•In another embodiment, the invention provides a process of lining a borehole, said process comprising: removing oxygen from or reducing oxygen in the borehole; positioning means to support a borehole lining in the borehole at a predetermined depth; and, before or after step lining the borehole with a borehole lining, such that the means to support the borehole lining supports the borehole lining in the borehole.

In this embodiment, the process may further comprise the steps of, maintaining an excess length ofborehole lining proximate or above the mouth of the borehole; and supporting the borehole lining proximate or above the mouth of the borehole with a means to support the borehole lining.

[I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Speci fcation ]Oxygenrem4.doc:JFM Optionally, in this embodiment of the invention the means to support a borehole lining is a first borehole plug and the method of lining a borehole further comprises the steps of inserting a second inflatable borehole plug in a borehole prior to lining the borehole with the borehole lining; inflating the second inflatable borehole plug before the lining is inserted in the borehole; charging the borehole lining with a required amount of explosive; inflating the borehole lining before or after step and inflating a first inflatable borehole plug after inflation of the borehole lining, wherein the inflated first borehole plug is located proximate the mouth of the borehole and substantially seals the borehole.

In still another embodiment, the invention provides a process of lining a borehole, said process comprising: removing oxygen from or reducing oxygen in the borehole; positioning means to support a borehole lining in the borehole at a predetermined depth; inserting an inflatable borehole lining, having a closed end and an open end, in the borehole such that the closed end of the borehole lining is in contact with said means to support; and inflating the borehole lining with inflating means; wherein the means to support the borehole lining supports the borehole lining in the borehole.

In one form of this embodiment, the process may further comprise the step of °oo° charging the borehole lining with a required amount of explosive and 25 sealing the inflated borehole lining with sealing means to substantially prevent the :ooo *ooo *borehole lining from deflating.

In yet another embodiment, the invention provides a process of lining a borehole, said process comprising: removing oxygen from or reducing oxygen in the borehole; inserting an inflatable borehole lining in a borehole to a predetermined depth; charging the borehole lining with a required amount of explosive; inflating the borehole lining with inflation means; [I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM sealing the inflated borehole lining with sealing means to substantially prevent deflation of the borehole lining; positioning a means to support the borehole lining proximate or above the mouth of the borehole; and supporting the borehole lining with the means to support.

In this embodiment the means to support may be a borehole plug and the method may further comprise the step of inflating the borehole plug sufficiently to substantially seal the mouth of the borehole.

According to another embodiment of this invention there is provided a process of lining a borehole, said process comprising: inserting an inflatable borehole lining in a borehole to a predetermined depth; charging the borehole lining with a required amount of explosive; inflating the borehole lining with inflation means; sealing the inflated borehole lining with sealing means to substantially prevent deflation of the borehole lining; positioning a means to support the borehole lining proximate the oo* mouth of the borehole; and %at% 20 supporting the borehole lining with the means to support.

00oo In this process the means to support may be a borehole plug and the process may further comprise the step of: inflating the borehole plug sufficiently to substantially seal the mouth of the borehole.

In the processes of lining a borehole in accordance with the invention the step of removing oxygen from or reducing oxygen in the borehole typically includes removing or reducing oxygen in the borehole by flushing the borehole with a non *oxygen containing gas or vapour, and/or placing oxygen removal means or oxygen reducing means in the borehole, as described herein above. The step of removing oxygen from or reducing oxygen in the borehole is typically in accordance with the first or second embodiment of this invention.

In the processes of the invention the means to support the borehole lining in a borehole may be a borehole plug. The borehole plug may be an inflatable borehole [I:\DayLib\L[BXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM plug assembly and the borehole plug may be inflated prior to inserting the borehole lining in the borehole.

A process in accordance with this invention which includes a step of lining a borehole may further comprise the step of inserting a spacer element in the borehole lining so as to permit explosive to be placed in the borehole adjacent the spacer element. The spacer element has an overall density less than the density of the explosive in the borehole and is expandable from a substantially lay flat configuration. The spacer element may further include means for expanding the element with an expanding material less dense than the density of the explosive. The means for expanding may comprise means for providing an inflating substance located with the spacer element.

Optionally, in these forms of the invention, the support means may also function to close the borehole to substantially prevent air from re-entering the borehole. Thus, the support means may be located at or near the mouth of the borehole. Alternatively or additionally, support means may be located below a bottom end of the borehole lining within the borehole so as to support the bottom end of the borehole lining. This support means is usually, but not necessarily, located :substantially at an end of the borehole.

0@60 o o Borehole lining

S

20 A borehole lining for use in the processes of the invention may comprise a •o substantially liquid impermeable sleeve adapted to substantially line a borehole, which sleeve has an open end, a closed end, an outer surface and non sticking inner surfaces thereby allowing explosive material inserted into the open end of the sleeve ode° owe* in situ to travel substantially unrestrictedly to the closed end.

The sleeve may further comprise means proximate the closed end for -facilitating the lining of a borehole with the borehole lining.

The closed end may include reinforcing means to reinforce the closed end.

The reinforcing means may comprise layers of reinforcing material such as plastic, woven plastic such as woven polyethylene, woven polypropylene, canvas, nylon, etc., for example. One method of filling such a lining is to insert a hose and drive or push the lining down into a borehole and through any water in the borehole to a predetermined position in the borehole, typically the bottom of the borehole. The lining can then be filled with explosive via the hose.

[I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM Alternatively, the borehole lining may comprise a substantially liquid impermeable sleeve adapted to substantially line a borehole, which sleeve has an open end, a closed end, an outer surface and inner surfaces and means proximate the closed end for facilitating the lining of a borehole with the borehole lining.

Advantageously, the means proximate the closed end for facilitating the lining of a borehole with the borehole lining is means proximate the closed end for supporting a weight to facilitate lining a borehole with the borehole lining. The means proximate the closed end for supporting a weight to facilitate lining a borehole with the borehole lining is selected from the group consisting of a fixed pouch disposed proximate the closed end, a removable pouch disposed proximate the closed end, and means to which a weight may be attached proximate the closed end. The means to which a weight may be attached proximate the closed end may be one or more eyelets, particularly, one or more reinforced eyelets located at or proxo.

The means proximate the closed end for facilitating the lining of a borehole with the borehole lining may be profiled, shaped or tapered to facilitate lowering of the bore lining down a borehole.

The borehole lining may further comprise means to substantially protect at least a part of the outer surface from damage as the borehole lining is lowered down a borehole, the means to substantially protect being disposed over at least a portion of 20 the borehole lining. For example, the liquid impermeable sleeve may be a waterproof ""polyethylene lining and the means to substantially protect may comprise woven polyethylene. Optionally, glue may be used to adhere the polyethylene lining to the woven polyethylene. A typical thickness of the liquid impermeable sleeve is approximately 15-30[tm, more typically about 20 tm, and a typical thickness of the means to substantially protect is 100tm-300jtm, more typically about 150tm.

Alternatively, an integral liquid impermeable sleeve/means to substantially protect could be used. Further illustrations of materials are given elsewhere in this .*.specification. For example, one could use 250-500jtm, typically about 300tm thick waterproof polyethylene lining to form the closed end and 2 to 3 metres of the sleeve adjacent to the closed end, 150-250 tm thick waterproof polyethylene lining for the next 2 to 3 metres and the remainder 100-150tm thick waterproof polyethylene lining.

[I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM The means to substantially protect at least a part of the outer surface from damage may be an outer sleeve or alternatively could be a plastic frame or a natural or synthetic rope frame. The outer protective sleeve may be sprayed, dipped or painted on the liquid impermeable sleeve, or the outer sleeve may be placed over the liquid impermeable sleeve. Where the outer sleeve is placed over the liquid impermeable sleeve it may be affixed to the liquid impermeable sleeve with adhesive, double- or single-sided sticky tape, iron-on tape, or a combination thereof, or any other suitable affixing means.

The outer sleeve may be disposed over at least the closed end of the waterproof lining so as to substantially protect the closed end from damage as the borehole lining is lowered down a borehole. Alternatively, the outer sleeve may be disposed over the closed end and over at least a portion of the borehole lining proximate the closed end so as to substantially protect the outer surface of the borehole lining at and proximate the closed end from damage as the lining is lowered down a borehole. As a further alternative, the protective outer sleeve may be disposed over at least a portion of the borehole lining proximate the closed end so as to substantially protect the outer surface of the borehole lining proximate the closed end from damage as the lining is lowered down a borehole. As another alternative, the outer sleeve may be disposed over the closed end and substantially over the borehole 20 lining so as to substantially protect the outer surface from damage as the borehole "••lining is lowered down a borehole.

*The means to substantially protect at least a part of the outer surface from damage may be disposed over the borehole lining at least proximate the closed end and may further comprise means proximate the closed end for facilitating the lining of a borehole with the borehole lining. The means proximate the closed end for facilitating the lining of a borehole with the borehole lining comprises means for supporting a weight to facilitate lining a borehole with the borehole lining. The means proximate the closed end for supporting a weight to facilitate lining a borehole with the borehole lining is selected from the group consisting of a fixed pouch disposed proximate the closed end, a removable pouch disposed proximate the closed end, and means to which a weight may be attached proximate the closed end. The means to which a weight may be attached proximate the closed end may include one, two, three, four, five or more eyelets. The eyelets may be located evenly or unevenly across the closed end or adjacent the closed end, for example, or some eyelets may be [I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM across the closed end and some may be adjacent the closed end. Alternatively, the means to which a weight may be attached proximate the closed end may include one, two, three, four, five or more hooks. The hooks may be located evenly or unevenly across the closed end or adjacent the closed end, for example, or some hooks may be across the closed end and some may be adjacent the closed end. A combination of hooks and eyelets may be employed. A pouch or net for supporting a weight may be attached to the eyelets or hooks. Alternatively, the means to which a weight may be attached proximate to the closed end may include one, two, three, four, five or more clips or shackles. The clips or shackles may be located evenly or unevenly across the closed end or adjacent the closed end, for example or some clips or shackles may be across the closed end and some may be adjacent the closed end. Any combination of clips, shackles, hooks or eyelets may be employed.

The means proximate to the closed end for facilitating the lining of a borehole with the borehole lining may comprise means proximate to, but disposed below, the closed end for supporting a weight to facilitate lining a borehole with the borehole lining.

The means proximate to the closed end for facilitating the lining of a borehole *."*with the borehole lining may be profiled, shaped or tapered to facilitate lowering of the bore lining down a borehole.

20 In the processes of the invention, the step of lining a borehole with a borehole lining may comprise taking a borehole lining having means proximate to the closed end for supporting a weight to facilitate lining a borehole with the borehole lining and a weight; ~placing the weight in the means proximate to the closed end for supporting a weight to facilitate the lining of a borehole with the borehole lining; and lining the borehole with the borehole lining to a required depth in the borehole.

Alternatively, the borehole lining may comprise a plastic sleeve adapted to substantially line a borehole, which sleeve has an open end, a closed end, an outer surface and non sticking inner surfaces thereby allowing explosive material inserted into the open end of the sleeve in situ to travel substantially unrestrictedly to the closed end of the sleeve.

Alternatively, the borehole lining may comprise a plastic sleeve, which sleeve has an open end, a closed end, an outer surface, non sticking inner surfaces thereby [I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM allowing explosive material inserted into the open end of the sleeve in situ to travel substantially unrestrictedly to the closed end of the sleeve, and means proximate to the closed end for facilitating the lining of a borehole with the borehole lining.

The means proximate to the closed end for facilitating the lining of a borehole with the borehole lining may be means proximate to the closed end for supporting a weight to facilitate lining a borehole with the borehole lining. The means proximate to the closed end for supporting a weight to facilitate lining a borehole with the borehole lining may comprise a pouch disposed either fixedly or removably proximate to the closed end; means to which a weight may be attached either fixedly or removably proximate to the closed end.

Alternatively, the borehole lining may comprise a liquid impermeable sleeve adapted to substantially line a borehole, which sleeve has an open end and a closed end, and an outer surface and non sticking inner surfaces thereby allowing explosive material inserted into the open end of the sleeve to travel substantially unrestrictedly to the closed end of the sleeve, said borehole lining having at least one pouch or other means for suspending a weight capable of holding one or more weights, disposed proximate to the closed end.

Generally, the pouch is located on the outer surface of the borehole lining.

Generally, in use the total mass of the one or more weights added to the pouch is at 20 least sufficient to facilitate the lining of a borehole with the borehole lining to a particular depth in a borehole, more typically to the bottom of a borehole. Hence the i pouch is of a size and is strong enough to hold the one or more weights. The total mass of the one or more weights is typically in the range of 1-50kg, more typically 2- .oooo 20kg, even more typically 5-12kg, advantageously 3-10kg, more advantageously 2- Usually, the closed end of the liquid impermeable sleeve is profiled, shaped or tapered to facilitate lowering of said sleeve down a borehole. Typically the closed end of the liquid impermeable sleeve is heat sealed. Typically the closed end of the liquid impermeable sleeve is V-shaped or U-shaped or a rounded-shape or circularshape or cylindrical shape or tapered shape. In one form the desired shaped end is made by folding or cutting the closed end and taping or welding heat welding) or adhering with adhesive) it into place. If necessary an insert can be included inside the end of said sleeve to provide said end with the required profile, shape or taper to facilitate lowering of said sleeve down a borehole.

[I:\DayLib\L[BXX\Backup\My Documents\Docs\My Documents\Speci fi cation ]Oxygenrem4.doc:J FM Advantageously, the closed end of the liquid impermeable sleeve is heat sealed. Typically the closed end of the liquid impermeable sleeve is V-shaped or Ushaped or may be formed in any manner or shape described for the liquid impermeable sleeve described hereinbefore. The "V"-shape or "U"-shape or preferred shaped closed end of the liquid impermeable sleeve can be made by folding or cutting the closed end and taping or welding or adhering it into place. The outer sleeve has a closed end which is "V"-shaped or "U"-shaped or a rounded-shape or circular-shape or cylindrical shape or tapered shape to facilitate lowering of the lining down a borehole when said outer sleeve is adhered to the liquid impermeable sleeve to protect the closed end of said liquid impermeable sleeve when said lining is lowered down a borehole. Typically the outer sleeve closed end "V"-shape or shape, or other suitable shape described hereinbefore formed by cutting it or folding it to form the appropriately shaped flaps and sewing, welding or adhering them together to form the appropriately shaped closed end and at the same time forming a pouch proximate said closed end. Generally the shape of the outer sleeve is substantially the same as or sufficiently similar to the shape of the end of the liquid impermeable sleeve it is intended to cover. Advantageously, the outer sleeve has at least one pouch (optionally two, three or four pouches) capable of holding one or more weights disposed proximate the closed end of the outer sleeve. Generally the pouch is located 20 on the outer surface of the outer sleeve. Typically the outer sleeve is secured to the liquid impermeable sleeve with adhesive and/or adhesive tape. Advantageously tape S•is used to secure the outer sleeve to the liquid impermeable sleeve. Generally, in use, the total mass of the one or more weights added to the pouch is at least sufficient to facilitate the lining of the borehole with the lining to a desired depth, typically to the bottom of a borehole. Hence the pouch is of a size and is strong enough to hold the one or more weights. The total mass is typically in the range of 1-50kg, even more typically 3-10kg, advantageously 5-12kg, more advantageously 5-10kg.

Typically, the outer sleeve is substantially non-elastic. Typically, the outer sleeve is a non-elastic woven outer sleeve. Typically, the outer sleeve is constructed of woven polypropylene, woven polyethylene, a coat of hyperlon, cloth reinforced PVC, tarpaulin, canvas, or other suitable material.

Typically the outer sleeve is in the form of a bag, sleeve or other suitable receptacle within which the liquid impermeable sleeve is at least partially disposed.

The outer sleeve typically is scuff resistant. The outer sleeve is typically abrasion [I:\DayLib\LIBXX\Backup\My Documents\DocsWMy Documents\Specification]Oxygenrem4.doc:JFM resistant. Typically, in use, the outer sleeve acts as an abrasion and puncture barrier for that portion of the liquid impermeable sleeve disposed within it. The construction and materials used for the outer sleeve is such that it resists tearing even on contact with sharp edges or points. The outer sleeve is generally constructed of a material and is dimensioned with respect to the borehole lining so that it imparts strength to that part of the borehole lining it covers. Generally the outer sleeve is disposed over at least the closed end of the borehole lining. More typically the outer sleeve is not only disposed over the closed end of the borehole lining but covers a length of the borehole lining extending from the closed end towards the open end. Typically the length is in the range from 1% to 100% of the borehole lining extending from the closed end towards the open end. More typically the length is in the range 5%-10%, 10%-15%, 15%-20%, 20%-25%, 25%-30, 30%-35%, 35%-40%, 40%-45%, 45%-50%, 50%-55%, 55%-60%, 60%-65%, 65%-70%, 70%-75%, 75%-80%, 80%-85%, or 90%-95% of the borehole lining extending from the closed end toward the open end. More typically the length is 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 26%, 27%, 28%, 29%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 80%, 85%, 90%, 95% or 100% of the borehole lining extending from the closed end toward the open end.

20 Typically the length of the protective outer sleeve is in the range 0.5-30, 25, 0.5-20, 0.5-15, 1-30, 3-15, 1-12, 1.5-10, 2-9, 2-8, 2-7, 2-6, 2-5, 2-4, 3-7, 3-6, 3-4, 4-9, 4-8, 4-7, 4-6, 4-5, 5-9, 5-8, 5-7, 5-6, 6-15, 6-10, 6-9, 6-8 or 6-7 metres.

Typically the outer sleeve is 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 17, 18, 19, 20, 25 or 30 metres. More typically the outer sleeve is six metres in length.

Typically the borehole is drilled to a depth of approximately 15-100 metres, more typically 20-70 metres, even more typically 30, 35, 40, 45, 50, 55. 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69 or 70 metres and is approximately in the range of 0.05 to 2 metres, more typically 0.2 to 0.5 metres in diameter. The borehole *9 is generally drilled at an angle and left unattended until the results of analyses of the contents of the borehole are completed. Occasionally the borehole may be partially filled with water.

The liquid impermeable sleeve is typically a plastic sleeve and is generally an elongated, flexible sleeve. The length of the sleeve varies depending on the length of [I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM the borehole. The length of the sleeve is at least as long as and is generally longer than the borehole (typically liquid impermeable sleeve length borehole length or depth (0.5 metres to 10 metres longer). The closed end of the sleeve is generally heat sealed, but may be sealed by other methods. The closed end may be sealed in a straight line or in a variety of shapes described hereinbefore.

The liquid impermeable sleeve or the outer sleeve may be weighted by using stones or sand or soil or any other like material. The weights may be placed inside the liquid impermeable sleeve but are generally added to the pouch of the outer sleeve.

The pouch may be formed by adhering or including integrally as part of the same material as that forming the liquid impermeable sleeve, or may be a pre-construed pouch proximate the closed end on the outside surface of the outer sleeve. The closed end of the pouch may be sealed or sewn in a variety of shapes, typically those described herein on page two. Alternatively, prior to sealing the closed end of the liquid impermeable sleeve, the pouch may be formed by folding one end of the sleeve back onto itself and adhering said end to the outside surface of the sleeve to form the desired shaped end and pouch which, as already mentioned may be a tapered shape.

The sealed closed end of the liquid impermeable sleeve may be reinforced to withstand any downward pressure as a result of the explosive travelling down the sleeve after the sleeve has been lowered down the borehole. For example, the 20 reinforcement may be in the form of strong adhesive tape to the closed end of the sleeve.

Typically the liquid impermeable sleeve is a liquid impermeable plastic sleeve. Generally one or more anti blocking agents are included in the plastic and thus a substantially liquid impermeable sleeve fabricated from such plastic has non sticking inner surfaces thereby allowing explosive material inserted into the open end of the sleeve in situ to travel substantially unrestrictedly to the closed end.

~The liquid impermeable sleeve is preferably formed from high tensile strength plastic and it is light in weight. Hyperlon could be used to coat the plastic instead of a separately attached outer sleeve. Usually the outer sleeve is a thin film in the range 50-500pm thick, typically 50-300gm thick, or 50-150pm thick, or 150-300gm thick, or 150-500pm thick, or 300-500gm thick; thicker films of 2 to 10mm thick, preferably 2 to 6mm thick may be used if desired) of a polymer such as polyolefin

(C

2

-C

10 olefin), copolymers of different polyolefins, terpolymers of different [I:\DayLib\LIBXX\Backup\My Documerts\Docs\My Documents\Specification]Oxygenrem4.doc:JFM polyolefins and blends of polyolefins. Examples of such polymers include polyethylene, polyethylene polymer with C 3 to C 10 alkenes, polyethylene/butadiene, polyethylene/vinyl acetate, different types of polyethylene including high density polyethylene (HDPE), low density polyethylene (LDPE), linear-low density polyethylene (LLDPE) and mixtures and blends of different types of polyethylene with each other and other copolymers, polypropylene, copolymers of polypropylene and blends with polyethylene and blends with polyethylene and polyethylene copolymers, propylene/butadiene, polyethylene polypropylene block copolymers and ethylene propylene C 4

-C

6 diene terpolymers. Other suitable polymers include polyurethane blends, poly(vinylchloride), polyvinylchloride blends (see flexible polyblends listed in Table 1 page 46 1-463 of "Encyclopedia of Chemical Technology"', Kirk Othmer, 3rd edition, Volume 18, John Wiley Sons 1982, incorporated herein by cross reference), and poly(ethylene-terephthalate). The major materials for the sleeve are coextrusions, usually layers of polyethylene types over a nylon core (trapped nylon). Combinations of grades of polyethylene could also be effective depending on strength required. Typically, the liquid impermeable sleeve is multi-layered. Plastic materials from which suitable multi-layer bags may be fabricated include rubber or other elastomerics, nylonlsurlyn coextrusions, polythylene, polypropylene or polythylene/nylonlpolythylene coextrusions which 20 have suitable strength and suitably low gas permeability. Low linear low density polyththylenes are preferable to other types of polythylene. Where nylon is included in the material of the containers, it should be of extrusion grade. Generally the liquid impermeable sleeve of this form of the invention is a double-layer nylon coextrusion bag, coated with linear low density polyethylene. Low liquid permeability can also be achieved by the use of a polyester inner layer or metallised plastic film. Typically the polymer of the liquid impermeable sleeve includes one ore more antistatic agents to prevent, reduce or minimise sparking from the polymer. The liquid impermeable sleeve is generally water impermeable. Generally, the liquid impermeable sleeve is impermeable to diesel oil which is the normal fuel used for commercial explosives.

As mentioned above the liquid impermeable sleeve also has an anti-blocking agent or adherent applied to the inner surface of the plastic or incorporated into the plastic to prevent the sleeve from sticking to itself. Examples of anti-blocking agents are silicones; waxes for example hydrocarbon waxes, such as petroleum waxes, natural waxes such as carnauba or spermaceti, waxy amides such as ethylene [I:\DayLb\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM bis(stearamide), oleamide or erucamide; stearates for example zinc stearate, lead stearate, calcium stearate, magnesium stearate, barium stearate, cadmium stearate, aluminium stearate, lithium stearate; cellulose derivatives for example cellulose acetate, cellulose acetate butyrate or methyl cellulose; natural products such as flour, confectioners sugar, rice flour, sodium alginate, potassium alginate, or calcium alginate; inorganic adherents such as talc, mica, fumed silica, kaolin or attapulgite.

The plastic itself may be an anti-blocking plastic such as polyolefin, polyethylene, polypropylene, poly(l-butene), poly(vinyl acetate), poly(vinyl alcohol), poly(ethylene terephthalate), fluorocarbon polymers. Further examples of adherents are described in "Encyclopedia of Chemical Technology", Kirk Othmer, 3rd edition, Volume 1, John Wiley Sons 1982, the contents of which are incorporated herein by cross reference.

As mentioned above the liquid impermeable sleeve may also have an antistatic compound applied to the outside surface or incorporated into the plastic to prevent sparks being generated when the sleeve is inserted into a borehole. Examples of anti-static compounds are amines such as ethoxylated amines or ethoxylated fatty amines; quaternary ammonium compounds; anionic surface active agents such as sulfonates or phosphates; or miscellaneous antistats such as glycol esters, sulfated waxes, fatty amides, polyhydric alcohol derivatives or inorganics. Further examples of antistatic compounds are described in "Chemical Additives for the Plastics Industry 20 Properties, Applications, Toxicologies", Radian Corporation, Table A-2, Noyes Data Corporation 1987 and "Encyclopedia of Chemical Technology", Kirk Othmer, 3rd edition, Volume 3, John Wiley Sons 1982, the contents of which are incorporated herein by cross reference.

,The liquid impermeable sleeve typically being a plastic sleeve may also have additives applied to a surface or incorporated into the plastic. Examples of the types of additives which may be included are antioxidants, blowing agents, colorants, coupling agents, fillers, reinforcers, flame retardants, heat stabilisers, lubricants, preservatives, or stabilisers. Specific examples of plastics additives are described in "Chemical Additives for the Plastics Industry Properties, Applications, Toxicologies", Radian Corporation, Noyes Data Corporation 1987 and "Encyclopedia of Chemical Technology", Kirk Othmer, 3rd edition, John Wiley Sons 1982, the contents of which are incorporated herein by cross reference.

Typically the required depth assumed by the liquid impermeable sleeve in the borehole is in the range of 10%-100%, typically 25%-100%, more typically [I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM 100%, even more typically 75%-100% and yet even more typically 90%-100% of the depth of the borehole. Advantageously the full length of the borehole is lined by the sleeve. Generally the sleeve is made to suit any borehole length and the side of the sleeve usually has calibrated markings. The calibrated markings are advantageous because boreholes are usually drilled to a certain depth and the sleeve may be unrolled into a dry borehole until the calibrated marking corresponds to the known depth of the dry borehole and usually the length of sleeve unrolled into the borehole is longer than the borehole. If the sleeve is unrolled into a borehole containing water, the sleeve is unrolled as far as possible to avoid too much water from over flowing the borehole.

Usually the open end of liquid impermeable sleeve is affixed to a rod to provide a compact package. In this case the sleeve is rolled around the rod with the closed end being located on the outer surface of the rolled sleeve. With the sleeve rolled in this fashion, the formation of and adherence of a pouch to the liquid impermeable sleeve, on site, is facilitated. Alternatively, with the borehole lining of the invention rolled in this fashion, the pouch is readily accessible by the user on site without having to unroll the sleeve. A weight such as stones, soil, sand or any other weight is then placed in the pouch. The pouch also acts as a scuff barrier to maintain the integrity of the sleeve.

Typically, the borehole lining has a liquid impermeable sleeve which is composed of high tensile strength light-weight plastic so that it can carry 1 to 1.5 tons ""of explosive without the plastic being very heavy. Usually, the borehole lining has a sleeve which includes an anti-blocking compound to stop the plastic from sticking to itself and this also stops explosive from clumping due to kinks in the sleeve when the eeeeee explosive travels down the entire length of the sleeve.

In the processes of the invention, where the borehole is above ambient and less than 50'C after oxygen has been removed or reduced in the borehole and immedaitely before it is desired to charge explosive into the borehole, a lining is typically used.

The lining material is generally chosen so that it does not lose its overall strength characteristics at such temperatures. Advantages of the lining of the invention having an outer sleeve is that the outer sleeve keeps the explosive away from hot rock and stops the explosive running off into fissures and thereby concentrating in fissures as well as providing strength to the liquid impermeable sleeve and protecting it from abrasion and breakages.

[I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM In one preferred form the liquid impermeable sleeve is a plastic layflat extrusion designed to open in the borehole forming a continuous tubular lining which acts as a barrier protecting ANFO from water damage, hot rock or loss of explosive into cavities. Typically the leading end of the liquid impermeable sleeve is heat sealed and then folded into a V-shape (or any of the hereinbefore mentioned shapes (see page Formation of the V shape is achieved by firstly folding the sealed end once to form a triangular shaped end portion, one of the apexes of the triangle at this point being located at the centre of the sealed end followed by two other folds made by folding each of the other apexes of the triangle located on either side of the sleeve across to approximately the central longitudinal axis of the sleeve. The V-shape is then taped to hold it in position. An outer sleeve which is dimensioned to be slightly larger than the liquid impermeable sleeve it is intended to cover and having a similarly shaped end to the liquid impermeable sleeve (see page being V-shaped in this form of the lining, includes a pre-constructed V-shaped cutting pouch incorporated into the V-shaped end, being on the outside surface of the outer sleeve and capable of holding one or more weights disposed proximate the closed end of said sleeve, is placed over the liquid impermeable sleeve in order to protect the liquid *...impermeable sleeve when said sleeve is lowered down a borehole. Typically, in this form of the invention the V-shape, pre-construed cutting pouch of the outer sleeve is 20 formed by firstly folding the sealed end once to form a triangular shaped end followed two other folds made by folding each of the other apexes of the triangle located on either side of the sleeve across to approximately the central longitudinal axis of the sleeve. One can see that in this form of the invention both the liquid impermeable sleeve and the outer sleeve are folded exactly the same way. The V shape end of the outer sleeve forms a pouch which is held together by sewing or welding the two **folded portions together.

Typically the outer sleeve is 1-20 meters, more typically 3-8 meters and even more typically 6 meters in length. The V-shaped cutting pouch allows the lining to be °o...weighted for correct location of the lining at the bottom of dewatered vertical or angled blastholes. The open end of the borehole lining is secured proximate the open end of the borehole by a simple light weight frame which holds the layflat extrusion open for easy loading with bulk ANFO. The lining is rolled onto a cardboard or plastic core in lengths according to customer requirements. Typical lengths are in the range of 20 metres to 60 metres in increasing increments of 5 metres. Typical [I:\DayLib\LBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM diameters used are those to suit 150mm, 230mm, 270mm, 311mm and 350mm. The preferred plastic used for the liquid impermeable sleeve is a combination of polyethylene resins coextruded to produce a film impermeable to water, resistant to diesel oil and with much greater tensile strength, tear and puncture resistance than that of commercially available low density polyethylene layflats.

Anti-stat is combined with the combination using the following procedure: pass a suitable rod PVC wooden dowel) through cardboard/plastic core; place sufficient drill cuttings into the "cuttings" pouch; hold ends of rod in either hand and allow the lining to unroll at a controlled rate down the borehole until it rests on the bottom of the hole. Control speed by using legs or chest as a brake; remove rod and cardboard core from end of the lining; prime boreholes at normal height; pass open end of lining through the centre of the stand. Fold at least 200mm of layflat over the outside of the stand or through the inside of the stand and clamp firmly to prevent the lining being dragged down the borehole during loading; load with ANFO; "settling" of the lining, for example, by 100mm, may occur; 20 after loading unclamp lining from stand, moving lining to one side of the hole and stem.

In one particularly preferred form the liquid impermeable sleeve is colour coded according to hole diameter and has printing or other printed matter a line) or other indication running down the central longitudinal axis or substantially parallel to the central longitudinal axis of the liquid impermeable sleeve. Typically a combination of plastics is used to form a coextruded liquid impermeable sleeve which has the desired overall strength characteristics required for use as a borehole lining with the following characteristics: Ultimate Tensile Strength (N/25 mm) Circumferential 1 MD 69.2 Longitudinal TD 100.4 Ultimate Elongation MD 380 Tear Resistance (gF) MDI 168 [I:\DayLib\LBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM Puncture Resistance Maximum Force to Break 76.9 Energy to Break (Nm) 2.9 Static Electricity Two additives are typically present in the extrusion, Anti-block and Anti-static.

Anti-block prevents the film sticking to itself. Anti-static helps dissipate electrical charges.

Surface Resistivity (ohm/sq) 1 .0 x 1011 Static Decay (11% Relative Humidity) 1.08 secs (15 Relative Humidity) 0.52 sees Diesel Resistance Good typical of polythylene based materials.

UV Resistance Pigmentation increases the UV resistance of plastics. Typically the liquid impermeable sleeve is coloured to indicate size of borehole in which it is to be used.

Usually the liquid impermeable sleeve should be kept in a box until required for use.

Embrittlement of the plastic will occur after extended periods of exposure (months).

Support means A support means for a borehole lining may be of any shape. In one form, the 20 support means is a cone shaped support means (generally a hollow cone shape). In this form, the support means is of such size as to dip into the sleeve yet jam into the top of the borehole. Typically this support means is made from cardboard; corrugated cardboard; plastic, for example a flower pot with the closed end removed; wood; metal or ceramics. Typically the support means is made of cardboard or plastic. The cardboard may be wax impregnated by a hot wax dipping process. In another form the support means is a cone or ring or other suitable shape with a means to support the cone or ring (which may be circular, rectangular, square, elliptical or other suitable shape) which could be legs two, three, four or five legs). In yet another form the support means is an annularly splayed device. Said device is fundamentally the same and similar in shape to the previously mentioned hollow cone support means but is in the reversed position to that of said previously mentioned support means, when in use as a means of support for the borehole lining of the present invention when said lining is disposed within a borehole. In this arrangement the maximum longitudinal diameter of the annularly splayed support means device is positioned over the opening [I:\DayLib\LBXX\Dackup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM to a blast hole flush with ground surface and encasing said blast hole while the minimum longitudinal diameter at the opposite end of said device provides a ring for the open end of the water impermeable sleeve to be inserted through, in an upward direction and folded over. Clamping said sleeve to said means of support by attaching a lid to the support means, seals the open end of borehole and the open end of borehole lining so as to keep both from filling up with dirt and rainwater.

Alternatively, the means to support the borehole lining may comprise a borehole plug, as described in detail herein above.

A borehole plug may be inserted at the base of the borehole or partway down a borehole, prior to insertion of a borehole lining in the borehole, to support the lining at the base of the borehole, and/or a borehole plug may be inserted into the top of the borehole, after insertion of a borehole lining, to support the lining at the top of the borehole. A borehole plug may be lowered to the base of the borehole, positioned at a predetermined depth and secured, for example, by tethering means extended from the top of the borehole and attached to the borehole plug, and subsequently inflated. The borehole plug can then support the borehole lining at the base of the borehole and prevent slippage of the liner in the borehole. Further, the borehole plug can be used to ensure the lining is most suitably positioned at a predetermined depth in the borehole to match the underground conditions around the borehole. Insertion of a borehole 20 plug at the base of a borehole as described above, is particularly useful when the borehole has water included therein, as it can be used_as a means to protect the borehole lining from the water. A borehole plug may also be inserted into the upper region of the borehole after insertion and inflation of the borehole liner, and when the borehole plug assembly is inflated, it can serve as a means to support the borehole liner at the top of the borehole.

In one form of the invention, a borehole may have a borehole lining inserted ooo therein and the borehole lining may be subsequently substantially inflated by an inflating substance. Explosive may be inserted in the borehole lining at a time selected from the group consisting of before, after or during inflation of the borehole lining. The inflating substance may comprise, a combination of a co-reagent and a further co-reagent disposed within said lining, wherein for example, one co-reagent is a solvent (preferably water) and a further co-reagent is a solid mixture of citric acid (or other similar acid) and sodium bicarbonate (or other similar bicarbonate or carbonate) and said inflatable substance is completely sealed within said lining by [I :\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Speci fi cation ]Oxygenrem4.doc:J FM tying the end of said lining. The inflatable bag of a borehole plug assembly can then be inserted in the borehole and inflated to provide a means of support to the borehole lining.

Spacer Element The energy or pressure pulse generated by an explosive upon detonation is proportional to its density. The inclusion of a spacer element as described below in a borehole effectively lowers the density of a bulk explosive in a drill hole. The inventor has found that the explosion efficiency of an explosive can be improved to more closely match ground conditions around the borehole by providing appropriate air spaces, or spaces of density lower than the density of the explosive charge, above and/or below, and/or adjacent to the explosive charge, so as to reduce the overall density of the explosive in the borehole. The air spaces transmit shock waves to assist in breaking up rock, ore, coal body or any other in ground structure, during the explosion process.

A spacer element for insertion into a borehole in the processes of this invention may have an expanded configuration or an expandable configuration.

In one form the spacer element may have an expandable configuration, wherein the shape of the spacer element when substantially fully expanded is S 20 such that when the spacer element is located in the borehole lined with said borehole S:i- lining, the element can be positioned within the borehole so as to permit explosive, :optionally with fillers, to be placed in the borehole adjacent the spacer element; and the spacer element is expandable with an expanding material less dense than the density of an explosive to be placed in the borehole adjacent the spacer element, optionally with fillers, whereby said overall density of said expanded spacer element is less than the density of said explosive and whereby the density of that part of the borehole lined with a borehole lining that comprises the expanded spacer element and the explosive adjacent the spacer element is less than what the density of :o said part of said borehole would be if it were charged only with the explosive.

The spacer element may comprise a spacer body having a first end and a second end. The spacer body may be linked to said first and second ends in a manner selected from the group consisting of the spacer body being integral with said first and second ends and the spacer body being coupled with said first and second ends.

[I:\DayLib\LIBXX\Backup\My Documents\Docs\My Doc uments\Spec i fication ]Oxygenrem4.doc:JFM The spacer element may be expandable from a substantially lay flat configuration to an elongate annular shaped spacer element, wherein the unexpanded spacer element is in the form of a substantially lay flat configuration.

The spacer element may comprise a material selected from the group consisting of plastics, polyethylenes, and high quality coextruded polymeric materials and wherein said material is substantially impervious to gas.

The spacer element may further include means for expanding said element with an expanding material less dense than the density of an explosive to be placed in the borehole adjacent the spacer element, optionally with fillers, from a substantially lay flat configuration to an expanded spacer element.

The means for expanding may comprise means for providing an inflating substance, the means for providing being located within said spacer element. The means for expanding may comprise means for providing an inflating substance located within the spacer element and is capable of being actuated by a user. The means for providing may be selected from the group consisting of at least one aerosol canister including an inflating substance, at least one aerosol canister including an inflating substance and having delay means for delaying the release of the inflating substance on actuation of the canister so as to permit the unexpanded element to be located in a borehole after actuation of the canister, at least one aerosol canister 20 including an inflating substance and having slowing means for slowing the release of the inflating substance on actuation of the canister so as to permit the unexpanded element to be located in a borehole after actuation of the canister, co-reagent separation means having co-reacting reagents separated from one another which on mixing release an inflating substance said containment means capable of being

A

actuated so as to allow mixing of said co-reagents and co-reagent separation means having co-reacting reagents separated from one another which on mixing release an inflating substance said separation means capable of being actuated so as to allow mixing of said co-reagents said separation having delay means for delaying mixing of said co-reagents after being actuated so as to permit the unexpanded element to be S" 30 located in a borehole after actuation of the separation means.

The means for expanding may comprise means for providing an inflating substance, the means for providing being located within the spacer element and further comprising delay means for delaying the inflation of the spacer element on actuation of the means for expanding, the delay means being operatively associated [I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specitication]Oxygenrem4.doc:JFM with said spacer element. The delay means is an outer material located about said spacer element which material fails once a certain pressure is reached inside said spacer element.

The means for expanding may comprise means for providing an inflating substance said means for providing being located within said spacer element and further comprising slowing means for slowing the inflation of the spacer element on actuation of the means for expanding said slowing means being operatively associated with said spacer element. The slowing means may be an outer material located about said spacer element which material slows the expansion of said element.

The spacer element may include means through which expanding material less dense than the density of an explosive to be placed in the borehole adjacent the spacer element, optionally with fillers, can be passed so as to expand said element from a substantially lay flat configuration to an expanded spacer element. The means through which expanding material less dense than the density of an explosive to be placed in the borehole adjacent the spacer element, optionally with fillers, can be passed so as to expand said element may be a valve (in particular a one way valve such that it only lets the expanding material into the element but not out). The means through which expanding material less dense than the density of an explosive to be placed in the borehole adjacent the spacer element, optionally with fillers, can be passed so as to 20 expand said element may be a conduit. Typically means to close the conduit such as a tee..: *cap, stopper or tie are used to close the conduit after the element has been filled with o the expanding material.

The shape of said spacer element when substantially fully expanded may be that of an elongate substantially cylindrical member, such that the cross-sectional diameter of the expanded spacer element when inserted in a borehole lined with a borehole lining is less than the cross-sectional diameter of the borehole so as to permit explosive to be placed in the borehole alongside and adjacent the spacer element.

In another form, a spacer element may be a substantially fully expanded spacer element capable of insertion in a borehole lined with a borehole lining, wherein S 30 the shape of the substantially fully expanded spacer element is such that when the spacer element is located in the borehole lined with said borehole lining, the element can be positioned within the borehole so as to permit explosive, optionally with fillers, to be placed in the borehole adjacent the spacer element; and [I:\DayLib\LBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM the spacer element is expanded with an expanding material less dense than the density of an explosive to be placed in the borehole adjacent the spacer element, optionally with fillers, whereby said overall density of said expanded spacer element is less than the density of said explosive, whereby the density of that part of the borehole that comprises the expanded spacer element and the explosive adjacent the spacer element is less than what the density of said part of said borehole would be if it were charged only with the explosive.

The expanded spacer element may comprise a spacer body having a first end and a second end. The spacer body may be linked to said first and second ends in a manner selected from the group consisting of the spacer body being integral with said first and second ends and the spacer body being coupled with said first and second ends.

The expanded spacer element may comprise a material selected from the group consisting of plastics, polyethylenes, and high quality coextruded polymeric materials and wherein said material is said spacer element is substantially impervious to gas.

The shape of said spacer element when substantially fully expanded may be that of an elongate substantially cylindrical member, such that the cross-sectional diameter of the expanded spacer element when inserted in a borehole is less than the 0000 cross-sectional diameter of the borehole so as to permit explosive to be placed in the borehole alongside and adjacent the spacer element.

In another form, the spacer element may be any element capable of insertion in a borehole lined with a borehole lining, whereby on insertion of the element in the borehole, the volume of the borehole capable of being filled with an explosive is reduced. Generally, the spacer element is filled with a material whose density is substantially lower than the density of the explosive a gas vapour or other low density material).

~Typically the length of the spacer element varies depending on the length of the borehole. The length of the spacer element is substantially the same as the length 30 of the borehole or shorter than the length of the borehole, depending on the particular requirements. Typically, the length of the spacer element is up to 70m, typically up to typically up to 60m, typically up to 55m, typically up to 50m, typically up to typically up to 40m, typically up to 35m, typically up to 30m, typically up to typically up to 20m, typically up to 15m, typically up to [I:\DayLib\L1BXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM Typically, the length of the spacer element is from 1% -100% of the entire length of the borehole, still typically still typically 10%-90%, still typically 85%, still typically 20%-80%, still typically 25%-75%, still typically 30%-70%, still typically 35%-65%, still typically 40%- 60%, still typically 45%-55%. More typically, the length is 10%, 11%, 12 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 52%, 54%, 56%, 58%, 63%, 65%, 68%, 70%, 75%, 80%, 85%, 90%, 95% or 100% of the length of the borehole.

Typically, the spacer element comprises a spacer body having a first end and a second end, capable of insertion in a borehole. The spacer body having first and second ends may further comprise a first end and second end coupled together or integral with, a surrounding wall. Typically, the spacer element may be an annular element comprising an annular spacer body having first and second ends. The first or second ends of the annular spacer body may be integral with the annular body or one or both ends may be coupled with the annular spacer body. Coupling an end with the wall or spacer body may be achieved by gluing, taping, sewing, heat welding, adhesive welding, for example. Generally, the coupling results in a gas tight seal

S*

20 between the end and the wall or body.

0 ~Typically, the spacer element may be solid, foam, other cellular products, S:ao: liquid, semi-solid, semi-liquid or enclosed gas which is formed into a suitable shape so as to occupy a certain volume of space in a borehole. Typical examples include a fee@*: solid column or bag containing a free flowing powder such as sawdust. Still typically, the spacer element is inflatable and made of a flexible material. Still more typically, the spacer element is made of a flexible material such that the spacer element is substantially flat before inflation and is inflated after insertion in a borehole to particular shapes as required, suitable for occupying a substantial portion of the volume of space in the borehole.

a 30 Typically, the spacer element is a balloon shaped member, cylinder shaped member, toroidal shaped member, U shaped member, C shaped member, S shaped member, W shaped member, L shaped member, T shaped member, F shaped member, V shaped member, Z shaped member, J shaped member, X shaped member, A shaped member, B shaped member, D shaped member, E shaped member, G shaped member, [I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM H shaped member, I shaped member, K shaped member, M shaped member, N shaped member, P shaped member, Q shaped member, R shaped member, Y shaped member, frusto-conical shaped member, ellipsoidal shaped member, cube shaped member, cone shaped member, spherical shaped member, rectangular prism shaped member, tetrahedron, decahedron, dodecahedron, dome shaped member, hexahedron, heptahedron, icosahedron, nonahedron, octahedron, ring shaped member, sinusoidal shaped member, arch shaped member, arcuate shaped member, corrugated solid member, parabolic shaped member, oblong shaped member, or any suitable configuration which allows occupation of volume in a borehole.

Still typically, the spacer element may be a solid member of any suitable shape with an aperture therein to allow insertion of an explosive. Still more typically, the spacer element is a balloon shaped member or an ellipsoidal shaped member which is easily insertable and movable within the borehole. Still more typically, the spacer element is capable of being aligned along the longitudinal axis or wall of the borehole so as to allow a substantially even reduction in the volume of an explosive in the borehole. Still more typically, at least one spacer element is capable of being aligned across the width of the borehole to occupy the volume of the borehole.

Typically, the spacer element comprises a protective outer sleeve and a flexible gas and water impervious inner enclosure capable of containing a gas or 20 vapour, such as a gaseous hydrocarbon, air, carbon dioxide, nitrogen etc. The protective outer sleeve and inner enclosure are both typically made of a material that does not rupture upon inflation. Typically, the inner enclosure is in the form of a bag, ooooi and still typically, the inner enclosure is in the form of a balloon. Still typically, the inner enclosure is in the form of an annular body having first and second ends that are 25 integral with or coupled with a spacer body, wherein typically a first end is closed and the second end is open and the second open end is capable of being closed by sealing means. Typically, the protective outer sleeve is in the form of a bag; still typically, the protective outer sleeve partially encases the annular body of the inner enclosure.

Still typically the protective outer sleeve encases one sealed end and substantially partially encloses the body of the inner enclosure. Still typically, the protective outer sleeve encases substantially all of the inner enclosure comprising a spacer body and two ends, and still typically, the dimensions of the protective outer sleeve are just oversize of the dimensions of the inner enclosure.

[I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM Still typically, the spacer element is formed from a flexible but tough material, such as a plastic, into a plastic or plastic multi-layered bag and similar bags.

The bag may be a polyethylene/nylon polyethylene multi-layered bag. These bags can be typically inflated to about 20-26 psi which will inflate the bag sufficiently to be inserted into the borehole and provide the required shape to be positioned along the length and/or width of the borehole to allow a substantially even reduction of volume of explosive in the borehole. Typically, the bag does not need to be formed from a transparent material and therefore a broad selection of bag materials can be used. The bags may be clear to enable an operator to see, for example, co-reagent canisters and so ensure they are adequately mixed prior to lowering the bag into the borehole. In such arrangements, the selection of bag materials is severely limited to those that are substantially clear or transparent.

The spacer element typically also comprises a protective outer plastic sleeve, which is generally an elongated, flexible sleeve, which encloses an inner plastic gas impervious enclosure capable of containing a gas. Typically, a gas impervious film is coated on either the inner portion, outer portion or whole of the spacer element.

Alternatively, the spacer element is integrally made of a gas impervious material.

Typically, at least one spacer element is inserted in the borehole lined with a borehole lining, whereby, on insertion, the volume of space in the borehole capable of 20 being filled with an explosive, is reduced. However, it is not essential that a spacer :element be used. Typically there are 1, 2, 3, 4 or more (e.g 1 to 500, 1 to 250, 1 to 100, 1 to 50, 1 to 10, 1 to 5) spacer elements in the borehole. Typically, the spacer .:.oo element includes a means of facilitating coupling of one element to another spacer element, for example, eyelets, velcro, wire, rope etc., said means being located at the 25 surface of the body of the spacer element to enable at least two spacer elements to be S optionally co-joined. The number of spacer elements inserted in the borehole is dependent upon the size (length and/or diameter) of the borehole, the desired intensity of the explosion and the explosive used. Typically, the explosive is ANFO.

Typically, the inflation means comprises a flexible conduit that is attachable to the spacer element to allow inflation thereof. In the embodiment of the at least one spacer element having an inner bag and a protective outer bag or sleeve, the flexible conduit is attached either releasably or rigidly to the inner bag to allow inflation thereof. The flexible conduit can be of any suitable type and typically comprises a plastic or rubber hose. Typically, the hose is rigidly fixed to an inlet of the spacer [I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM element such that it cannot be separated from the bag during normal use. Typically, the inflation means may also_comprise the use of one or more aerosol cans typically located within the spacer element so as to release, for example, a gaseous hydrocarbon. Typically, the number of aerosol cans used is one per 15m of length of the spacer element. However, typically 1-10, typically 1-5, typically 1-3, more typically, 1, 2, 3, 4 or 5 numbers of aerosol cans are used. Typically the inflation means may also comprise the use of co-reacting reagents, typically located within the spacer element such that when the reagents react, a gas is released. Typically, one coreagent is a solvent (for example, water) and a further co-reagent is a solid mixture of an acid, for example citric acid or other similar acid, and a carbonate, for example sodium bicarbonate, ammonium carbonate, calcium carbonate, or other similar carbonate.

Typically, the spacer element may be weighted by suitable means such as stones or sand or soil or any other like material. The weights may be placed in a protective outer sleeve of the spacer element, but are generally added to a pouch. The pouch may be formed by adhering or including integrally as part of the same material as that forming an outer sleeve, a pouch on the outside and proximal to the closed end of the sleeve. In this case, the closed end of the pouch may be sealed in a variety of shapes, typically a rectangular or triangular shape. Alternatively, prior to sealing the 20 closed end of the outer protective sleeve of the spacer element, the pouch may be formed by folding the sleeve back onto itself and then heat sealing this end to form the desired shaped end and pouch which, as already mentioned may be in a triangular shape. The sealed, closed end may be reinforced to withstand any downward pressure as a result of the explosive travelling down the sleeve after the spacer element has 25 been lowered down the borehole. For example, the reinforcement may be in the form of strong adhesive tape applied to the closed end of the protective outer sleeve encasing the pouch.

The spacer element comprising a plastic enclosure is typically formed from a high tensile strength plastic, and is lightweight, durable, and not destroyed by the explosion. Usually, the plastic enclosure is a thin polymer material 2 to 10mm thick, 2 to 6mm thick, 100m-1000m, 100m-750m, 100m-500m, 100m-250m, 100m-200m, 100m-150m thick. Typically, 100m, 125m, 150m, 175m, 200m, 250m, 300m, 350m, 400m, 450m, 500m, 600m, 700m, 800m, 900m, 1000m thick. Polymers such as [I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM polyolefin (C 2

-C

10 olefin), copolymers of different polyolefins, terpolymers of different polyolefins and blends of polyolefins. Examples of such polymers include polyethylene, polyethylene polymer with C 3 to C 10 alkenes, polyethylene/butadiene, polyethylene/vinyl acetate, different types of polyethylene including high density polyethylene (HDPE), low density polyethylene (LDPE), linear-low density polyethylene (LLDPE) and mixtures and blends of different types of polyethylene with each other and other copolymers, polypropylene, copolymers of polypropylene and blends with polyethylene and blends with polyethylene and polyethylene copolymers, propylene/butadiene, polyethylene polypropylene block copolymers and ethylene propylene C 4

-C

6 diene terpolymers. Other suitable polymers include polyurethane blends, poly(vinylchloride), polyvinylchloride blends (see flexible polyblends listed in Table 1 page 461-463 of "Encyclopedia of Chemical Technology", Kirk Othmer, 3rd edition, Volume 18, John Wiley Sons 1982, incorporated herein by cross reference), and poly(ethyleneterephthalate) are examples of suitable polymers. The major materials for the sleeve are coextrusions, usually layers of polyethylene types over a nylon core (trapped nylon). Combinations of grades of polyethylene could also be effective depending on the strength required.

As described above, the spacer element is typically substantially gas e* impermeable or impervious. Generally, the plastic enclosure is also impermeable to water and diesel oil which is the normal fuel for commercial explosives.

The plastic enclosure component of the spacer element typically also has an antiblocking agent or abherent applied to the inner surface of the plastic or incorporated into the plastic to prevent the sleeve from sticking to itself. Examples of antiblocking agents are silicones, waxes, for example hydrocarbon waxes such as 25 petroleum waxes, natural waxes such as camauba or spermaceti, waxy amides such as

V

ethylene bis(stearamide), oleamide or erucamide; stearates for example zinc stearate, lead stearate, calcium stearate, magnesium stearate, barium stearate, cadmium stearate, aluminium stearate, lithium stearate; cellulose derivatives for example cellulose acetate, cellulose acetate butyrate or methyl cellulose; natural products such as flour, confectioners sugar, rice flour, sodium alginate, potassium alginate, or calcium alginate; inorganic abherents such as talc, mica, fumed silica, kaolin or attapulgite. The plastic itself may be an antiblocking plastic such as polyolefin, polyethylene, polypropylene, poly(1-butene), poly(vinyl acetate), poly(vinyl alcohol), [I:\DayLib\LIBXX\Backup\My Documents\DocsAMy Documents\Specification]Oxygenrem4.doc:JFM poly(ethylene terephthalate), fluorocarbon polymers. Further examples of abherents are described in "Encyclopedia of Chemical Technology", Kirk Othmer, 3rd edition, Volume 1, John Wiley Sons 1982, the contents of which are incorporated herein by cross reference.

The spacer element according to the description above, may further comprise antistatic compounds applied to the outside surface or incorporated into the plastic to prevent sparks being generated when the spacer element is inserted into a borehole.

Examples of antistatic compounds are amines such as ethoxylated amines or ethoxylated fatty amines; quaternary ammonium compounds; anionic surface active agents such as sulfonates or phosphates; or miscellaneous antistatic such as glycol esters, sulfated waxes, fatty amides, polyhydric alcohol derivatives or inorganics.

Further examples of antistatic compounds are described in "Chemical Additives for the Plastics Industry Properties, Applications, Toxicologies", Radian Corporation, Table A-2, Noyes Data Corporation 1987 and "Encyclopedia of Chemical Technology", Kirk Othmer, 3rd edition, Volume 3, John Wiley Sons 1982, the contents of which are incorporated herein by cross reference.

The spacer element according to the description above may also comprise additives applied to a surface or incorporated into the plastic. Examples of the types .of additives which may be included are antioxidants, blowing agents, colorants, 20 coupling agents, fillers, reinforcers, flame retardants, heat stabilizers, lubricants, preservatives, or stabilizers. Specific examples of plastics additives are described in "Chemical Additives for the Plastics Industry Properties, Applications, Toxicologies", S"Radian Corporation, Noyes Data Corporation 1987 and "Encyclopedia of Chemical Technology", Kirk Othmer, 3rd edition, John Wiley Sons 1982, the contents of 25 which are incorporated herein by cross reference.

When used, a flexible conduit may be rigidly attached to the spacer element.

Alternatively, the inlet of the spacer element may by releasably attached to the flexible conduit. The flexibility of the spacer element in the form of a bag, and the way it is positioned in the borehole, may result in the inlet of the spacer element not being positioned in an upper portion of the borehole.

The end of the flexible conduit not attached to the spacer element is typically attached to a canister containing pressurized gas. Such a canister can be in the form of a known type of aerosol can which can dispense a pressurized gas such as a hydrocarbon, carbon dioxide, nitrogen, etc. It is possible that the conduit may be [I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM attached to the aerosol can in a non-removable fashion such that the entire assembly can be bought and used as a kit.

The borehole may be lined by one person with a borehole lining which comprises a substantially liquid impermeable sleeve. Typically a person stands at the open end of the borehole and places a dowel through the rod to which the sleeve is affixed. The person holds onto the dowel and lets the sleeve, which is typically weighted, unroll into the borehole. The person unrolling the sleeve can also control the speed at which the sleeve unrolls to the bottom of the dry borehole or to a position that is as far as possible in a borehole containing water. When the sleeve reaches the bottom of a dry borehole, as indicated by the markings on the side of the sleeve, or as far as possible in a borehole containing water, a support means is placed into the open end of the sleeve and is pushed down into the sleeve until the support means abuts the open end of the borehole. The excess length of sleeve is then folded over the support means and into the sleeve and this acts as a clamp as well as maintaining the open end of the sleeve open. The sleeve is then ready to receive the explosive which can travel the entire length of the sleeve substantially unrestrictedly. Typically, the explosive is ANFO or other desirable explosive material. Additionally a lid may be placed over the borehole lining to prevent the borehole lining from filling up with dirt and rain water. Usually, the lid will be made of any material such as cardboard, plastic, :i 20 corrugated cardboard, wood, metal or ceramic.

:Advantageously, in the processes of the invention, the borehole lining is lowered in the borehole in less than 1 minute and the support means is inserted in the lining and abuts the borehole opening in less than 2 minutes. Thus a borehole is lined before there is considerable water in the borehole, thus avoiding the use of waterproof explosives.

Brief Description of Drawings Figure 1 is a schematic diagram of a borehole having an oxygen absorber or o scavenger and a borehole plug.

.i Figure 2 is a schematic diagram of a borehole having two borehole plugs and an oxygen absorber or scavenger.

Figure 3 is a schematic diagram of a borehole into which a conduit for providing a non oxygen containing gas is inserted and having a borehole plug through which or around which is a conduit one end of which has a one-way valve to prevent air from entering the borehole.

[I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM Figure 4 is a schematic diagram of a borehole having a carbon dioxide liberating solution at the bottom of the borehole and a borehole plug through which or around which is a conduit one end of which has a one-way valve to prevent air from entering the borehole.

Figure 5 is a schematic diagram of a borehole having an electrolyte solution in the bottom of the borehole in which is a heater element connected to an electrical power supply located outside the borehole, the borehole having a borehole plug through which or around which is a conduit one end of which has a one-way valve to prevent air from entering the borehole.

Figure 6 is a perspective view of a borehole lining for use in the processes of the invention; Figure 7 is a perspective view of a support means for use in the processes of the invention; Figure 8 is a perspective view of a rolled up borehole lining for use in the processes of the invention, with a dowel passed through the rolled up lining; Figure 9A is a perspective side view of a borehole lining for use in the processes of the invention, in a dry borehole; Figure 9B is a perspective side view of a borehole and a support means, for use in the processes of the invention; 20 Figure 9C is a perspective side view of a borehole lining in a dry borehole and a support means, with the borehole lining folded over the support means and into the lining; and •Figure 9D is a cross-sectional view of a borehole lining in a dry borehole and a support means, with the borehole lining folded over the support means and into the lining.

~Figure 10 is perspective view of a borehole lining for use in the processes of this invention.

Figure 11 is a perspective view of a borehole lining having an outer sleeve, use in the processes of this invention.

Figure 12 is a perspective view of a rolled up borehole lining combination as illustrated in Figure 11, with a dowel passed through the rolled up lining.

Figure 13 is a perspective view of the combination as illustrated in Figure 11, when located in situ in a dry borehole.

[I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM Figure 14 is a perspective view of a lining as illustrated in Figure 11, combined with a means to support said lining, when located in situ in a borehole.

Figure 15A is a cross sectional view of a borehole lining as illustrated in Figure 11, located in situ in a borehole.

Figure 15B is a cross sectional view of the combination as illustrated in Figure 14, when located in situ in a borehole.

Figure 15C is a cross sectional view of said combination additionally combined with an inflating substance, whilst said further combination is located in situ in a borehole.

Figure 15D is a cross sectional view of said combination additionally combined with said inflating substance and illustrates the sealing of said additional combination, whilst said additional combination is located in situ in said borehole.

Figure 15E is a cross sectional view of a further additional combination combining said additional combination with a means to support said additional combination, while said additional combination is located in situ in a borehole.

Figure 16 is a perspective view of a further embodiment of a borehole lining for use in the processes of this invention.

Figure 17 is a perspective view of another embodiment of a borehole lining for oo use in the processes of this invention.

i S 20 Figure 18 is a perspective view of yet another embodiment of a borehole .lining for use in the processes of this invention.

Figure 19A is a cross sectional view of a borehole having a borehole plug supporting a borehole lining at the base of the borehole, located therein.

Figure 19B is a cross sectional view of a further embodiment of this invention where a borehole lining in a borehole is supported by a borehole plug positioned at the top of the borehole.

S.Figure 19C is a cross sectional view of a borehole lining with a spacer element contained therein, supported at the top and bottom ends respectively by two borehole plugs, located in situ in a borehole.

S 30 Best Mode And Other Modes For Carrying Out The Invention Figure 1 depicts a borehole 100 having an oxygen absorber or an oxygen scavenger 101 comprising iron particles at the bottom of the borehole 100 and having a borehole plug 102 located near the top of borehole 100 to substantially prevent air from entering the borehole. To remove oxygen from or reduce oxygen in borehole [I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM 100 a sufficient amount of oxygen absorber or oxygen scavenger 101 is dropped into borehole 100 to substantially absorb or scavenge substantially all of the oxygen in borehole 100 in an amount which is sufficient to remove substantially all of the oxygen from borehole 100 or to remove enough oxygen from borehole 100 to maintain the temperature in borehole 100 at a desired level or below a particular temperature below say about 70'C and more typically less than about The borehole plug 102 is lowered in an uninflated or partially inflated state into borehole 100 to the location depicted in Figure 1 where it is inflated so as to plug borehole 100 to substantially prevent air from entering borehole 100. When desired borehole plug 102 can be deflated so as to provide access to borehole 100. The closed borehole 100 may be allowed to stand for an appropriate time 1 day 6 weeks or longer as required) to allow it to cool down prior to providing access. A borehole lining (not shown) can then be used to line borehole 100 the liner inflated and sealed and borehole 100 can be closed thereafter. When required borehole 100 can be opened up again and an explosive placed in the liner in borehole 100 and detonated as required or alternatively explosive may be placed in the liner in borehole 100 at the time the borehole 100 is being lined with the liner and detonated as required.

Alternatively, a borehole liner (not shown) can be used to line borehole 100 after oxygen absorber or oxygen scavenger 101 has been dropped into borehole 100 20 and before borehole plug 102 has been lowered in an uninflated or partially inflated state into borehole 100 to the location depicted in Figure 1. At this time an explosive may also be placed in the liner in borehole 100 and detonated as required or alternatively explosive may be placed in the liner in borehole 100 at a later time and detonated as required. Thereafter borehole plug 102 is lowered in an uninflated or partially inflated state into borehole 100 to the location depicted in Figure 1 where it is inflated so as to plug borehole 100 to substantially prevent air from entering borehole 100 and to support the liner. When desired borehole plug 102 can be S" deflated so as to provide access to the lined borehole 100. If explosive has not been placed in the liner in borehole 100 prior to access of borehole 100 it can be dropped down the liner and detonated as required.

Figure 2 depicts a borehole 200 having an oxygen absorber or an oxygen scavenger 201 disposed on top of borehole plug 203. The borehole plug 203 is located near to the bottom of the borehole 200. The borehole 200 has a borehole plug [I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM 202 located near the top of borehole 200 to substantially prevent air from entering borehole 200. The borehole plug 203 is lowered in an uninflated or partially inflated state into borehole 200 to the location depicted in Figure 2 where it is inflated so as to form a platform near the bottom of borehole 200. The use of borehole plug 203 is particularly advantageous where the bottom of borehole 200 is filled with water. To remove oxygen from or reduce oxygen in borehole 200 a sufficient amount of oxygen absorber or oxygen scavenger 201 is dropped into borehole 200 onto borehole plug 203 in an amount which is sufficient to remove substantially all of the oxygen from borehole 200 or to remove enough oxygen from borehole 200 to maintain the temperature in borehole 200 at a desired level or below a particular temperature (e.g.

below say about 70'C and more typically less than about 55°C). The borehole plug 202 is then lowered in an uninflated or partially inflated state into borehole 200 to the location depicted in Figure 2 where it is inflated so as to plug borehole 200 to substantially prevent air from re-entering borehole 200. When desired, borehole plug 202 can be deflated to provide access to borehole 200. The closed borehole 200 may be allowed to stand for an appropriate time 1 day 6 weeks or longer as required) to allow it to cool down prior to providing access. A borehole lining (not shown) can then be used to line borehole 200 the liner inflated and sealed and borehole 200 can be closed thereafter. When required borehole 200 can be opened up 20 again and an explosive placed in the liner in borehole 200 and detonated as required.

Figure 3 depicts a borehole 300 having a borehole plug 301 located near the top of borehole 300 to substantially prevent air from entering borehole 300. Conduit 302 extends from non oxygen containing gas supply or vapour supply 303 through 25 borehole plug 301 to near the bottom of borehole 300 as depicted. Conduit 304 extends through borehole plug 301 and has one way valve 305 to substantially prevent air from entering borehole 300 via conduit 304. In use, borehole plug 301 is located in an uninflated or a partially inflated state into the top of borehole 300 as depicted in Figure 3 where it is inflated so as to plug borehole 300 to substantially prevent air from entering borehole 300. A non oxygen containing gas such as carbon dioxide or nitrogen, for example, or non oxygen containing vapour such as steam, is released from supply 303 and a sufficient amount of such gas or such vapour is allowed to flush borehole 300 such that borehole 300 has substantially no oxygen or a [I:\DayLib\L[BXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM substantially reduced oxygen level as compared to the oxygen level in borehole 300 prior to flushing so as to remove enough oxygen from borehole 300 to maintain the temperature in borehole 300 at a desired level or below a particular temperature (e.g.

below say about 70'C and more typically less than about During flushing gas or vapour passes through conduit 304 to the atmosphere via one way valve 305 and plug 301. An oxygen sensor may be placed in conduit 304 to monitor the oxygen level of the gas passing through conduit 304. Once oxygen reaches the desired level the flushing may be stopped. The flushed borehole 300 may be allowed to stand for an appropriate time 1 day 6 weeks or longer as required) to allow it to cool down prior to providing access. A borehole lining (not shown) can then be used to line borehole 300 the liner inflated and sealed and borehole 300 can be closed thereafter.

When required borehole 300 can be opened up again and an explosive placed in the liner in borehole 300 and detonated as required.

Figure 4 depicts a borehole 400 having a borehole plug 401 through which conduit 402 passes. Conduit 402 includes one way valve 403 to substantially prevent air from entering borehole 400 conduit 402. In use, an aqueous acid containing solution and an aqueous alkali bicarbonate containing solution are added sequentially into borehole 400 to form a carbon dioxide liberating solution 404 at the bottom of borehole 400 as depicted. The borehole plug 401 is lowered in an uninflated or 20 partially inflated state into borehole 400 to the location depicted in Figure 4 where it is inflated so as to plug borehole 400 to substantially prevent air from entering borehole 400. As carbon dioxide is liberated by solution 404 it flushes oxygen from *,**"borehole 400 via conduit 402 and one way valve 403 whereby essentially no oxygen remains in borehole 400 or a reduced amount of oxygen remains in borehole 400 so as 25 to maintain the temperature in borehole 400 at a desired level or below a particular temperature below say about 70'C and more typically less than about Borehole plug 401 is deflated when required to provide access to borehole 400. The flushed borehole 400 may be allowed to stand for an appropriate time 1 day 6 weeks or longer as required) to allow it to cool down prior to providing access. A borehole lining (not shown) can then be used to line borehole 400 the liner inflated and sealed and borehole 400 can be closed thereafter. When required borehole 400 can be opened up again and an explosive placed in the liner in borehole 400 and detonated as required.

[I :\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM Referring to Figure 5 borehole 500 includes an aqueous solution 501 to which a salt such as sodium chloride is added, if required, to make the aqueous solution 501 ionically conducting. The heater element 502 which is immersed in solution 501 is connected to electric power supply 503 via conducting cables 504 and 505. Cables 504 and 505 typically pass around the outer surface of borehole plug 506. Conduit 507 passes through or around borehole plug 506. Conduit 507 includes one way valve 508 to substantially prevent air from re-entering borehole 500. In operation, if necessary, water is added to borehole 500 in a sufficient amount such that it can be boiled to provide steam in an amount sufficient to flush borehole 500 so as to remove or reduce oxygen from borehole 500. Water may be naturally present in borehole 500 and it will depend on the amount of such naturally occurring water as to whether any additional water is required to the added. Sodium chloride is added to the water if required for the reason already described above. Borehole plug 506 is lowered in an uninflated or partially inflated state into borehole 500 to the location depicted in figure 5 where it is inflated so as to plug borehole 500 to substantially prevent air from entering borehole 500. Electrical energy is supplied to heater element 502 to boil solution 501 so as to create steam in borehole 500. The steam flushes oxygen from borehole 500 via conduit 507 and one way valve 508 so as to remove oxygen or reduce oxygen in borehole 500 so as to remove enough oxygen from borehole 500 to 20 maintain the temperature in borehole 500 at a desired level or below a particular temperature below say about 70'C and more typically less than about When desired, borehole plug 506 can be deflated so as to provide access to borehole O* "500. The flushed borehole 400 may be allowed to stand for an appropriate time 1 day 6 weeks or longer as required) to allow it to cool down prior to providing 25 access. A borehole lining (not shown) can then be used to line borehole 500 the liner inflated and sealed and borehole 500 can be closed thereafter. When required borehole 500 can be opened up again and an explosive placed in the liner in borehole 500 and detonated as required.

Referring to Figure 6, a borehole lining comprises plastic sleeve 1 which is substantially longer than a borehole (which is not illustrated) and has a closed end 2 and an open end 3. Plastic sleeve 1 is generally substantially water impermeable.

Plastic sleeve 1 is also generally impermeable to diesel oil. The closed end 2 is generally heat sealed in a variety of shapes, typically a rectangular or triangular shape.

[I:\DayLib\LBXX\Backup\My Documerts\Docs\My Documents\Specification]Oxygenrem4.doc:JFM A triangular shaped end 17 is formed by adhering a 0.1 to 1 metre long rectangular plastic cuff 4 proximate closed end 2. Generally cuff 4 is 0.5 meter long and is typically adhered to plastic sleeve 1 with sealing tape. Cuff 4 is usually the same material as that forming plastic sleeve 1. On one side of sleeve 1 (not illustrated), sealing tape is placed so as to completely seal cuff 4 onto sleeve 1. As illustrated for the other side of sleeve 1, cuff 4 is adhered to sleeve 1 with two pieces of sealing tape 5a. The lower portion 6, 6a of cuff 4 is formed by bringing together two horizontally opposing corners of cuff 4 to form a triangular shaped end 17. The lower portion 6, 6a of cuff 4 is then sealed, preferably by heat sealing. The triangular shaped end 17 is adhered to cuff 4 with sealing tape 7 approximately midway on cuff 4. A pouch 16 is thus formed between cuff 4 and plastic sleeve 1. Sleeve 1 is illustrated (not to scale) as having calibrations 8, 8a and 8b on one side.

An alternative means of forming a pouch 16 may be used. Prior to heat sealing closed end 2 in a variety of shapes, typically a rectangular or triangular shape, more typically a triangular shape. Triangular shaped end 17 is formed by folding a portion of sleeve 1 inside out so that it forms a cuff 4 around the outside circumference of sleeve 1. The dimensions of cuff 4 may vary depending on the depth of the borehole Cuff 4 is usually the same material as that forming plastic sleeve 1. Cuff4 is adhered to sleeve 1 by sealing tape. As stated above, sealing tape 20 is placed so as to completely seal one side of cuff 4 to sleeve 1 and on the other side of sleeve 1, cuff 4 is adhered by two pieces of sealing tape 5, 5a. The lower portion 6, 6a of cuff 4 is formed from two opposing corners of cuff 4 which are brought together •to form a triangular shaped end 17 and heat sealed. The triangular shaped end 17 is adhered to cuff4 by sealing tape 7. End 17 thus forms a pouch 16. Sleeve 1 may also 25 be calibrated with markers 8, 8a and 8b.

Referring to Figure 7, a support means is illustrated as a piece of cardboard which has been folded into a cone 9 and fixed in place by two pieces of sealing tape 10, 10a. The dimensions of cone 9 will vary depending on the size of the borehole opening. Generally the dimensions of cone 9 are 1 to 1.5 metres by 0.3 to 0.5 metres.

Typically the dimensions are 1.1 by 0.4 metres.

To line a borehole with plastic sleeve 1, a user must determine the length of the borehole and select a plastic sleeve 1 length which is longer than the length of the borehole. Plastic sleeve 1 is typically rolled about a rod 11 with end 17 being on the surface of rolled plastic sleeve 1 (as illustrated in Figure A user places stones, [I :\DayLib\LIBXX\Backup\My Documents\Docs\My Documen ts\Spec i fication ]Oxygenrem4.doc:JFM sand or soil or other weights suitable to weigh plastic sleeve 1 in pouch 16 which is conveniently located on the surface of rolled plastic sleeve 1. Pouch 16 is located proximate closed end 2. The user places a dowel 12 through rod 11 and whilst holding dowel 12, the user stands at the borehole opening and lets sleeve 1 unroll into the borehole until the closed end of plastic sleeve 1 reaches the bottom of a dry borehole. As plastic sleeve 1 unrolls in this fashion, the user can control the speed at which plastic sleeve 1 unrolls to the bottom of the dry borehole. The weighted pouch 16 facilitates the unrolling of sleeve 1 into the borehole so as to line the borehole.

The user generally knows when plastic sleeve 1 reaches the bottom of a dry borehole because the user generally knows the length of the borehole and plastic sleeve 1 has calibrated markings to enable a user to determine when the closed end has reached the bottom of the dry borehole. If the borehole contains water, the user unrolls plastic sleeve 1 as described above. However, the user knows when plastic sleeve 1 has reached the water line in the borehole because the displaced water from the borehole overflows from the borehole opening. Furthermore, it is preferable to unroll an excess length of sleeve 1 into the borehole, whether the borehole is dry or contains water.

When plastic sleeve 1 has been unrolled in the dry borehole, the user removes o o "o dowel 12 from rod 11 and then removes rod 11 from plastic sleeve 1. The rod 11 and dowel 12 may be discarded after use. If the borehole is to be left unattended for some time, the excess length of plastic sleeve 1 at open end 3 may be placed to one side of the borehole opening so that open end 3 is folded to one side of the borehole opening.

i A weight such as sand, soil or stones or other like weights may be placed on the surface of the folded over excess length of plastic sleeve 1 at open end 3 to prevent plastic sleeve 1 from either falling down the borehole or prevent the borehole from filling up with dirt and rain water. Alternatively a lid may be placed over the borehole opening to prevent the borehole from filling up with dirt and rain water.

Figure 9A shows plastic sleeve 1 after it has been unrolled by a user into a dry borehole 13. Figure 4A also shows an excess length of plastic sleeve 1 at bottom of the dry borehole 13 as well as an excess length at borehole opening 14. If the borehole contains water, the same procedure as described above is used to remove rod 11 and dowel 12 from plastic sleeve 1. Similarly, open end 3 may be weighted as described above to prevent plastic sleeve 1 from falling down the borehole containing water. However the user should avoid having water enter open end 3, otherwise, any [I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM explosive which is placed in plastic sleeve 1 will become wet, thereby inactivating the explosive.

After plastic sleeve 1 has been unrolled into the borehole 13, a cone 9 to support open end 3 is selected which has a cross section along its principal longitudinal axis whose diameter corresponds approximately to the diameter of borehole opening 14. Cone 9 is a piece of cardboard which has been folded into a cone shape. If weights have been placed at the surface of the folded over open end 3 to prevent plastic sleeve 1 from falling into the borehole 13 or to prevent borehole 13 from filling up with dirt and rain water, then the weights are removed prior to inserting cone 9. Alternatively ifa lid has been placed over borehole opening 14, then the lid is removed. The user holds open end 3 open whilst placing cone 9 into open end 3 of sleeve 1. The user pushes cone 9 down into sleeve 1 until cone 9 abuts borehole opening 14. Figure 9B shows cone 9 abutting borehole opening 14 after it has been placed into plastic sleeve 1. In this position,.cone 9 is jammed at borehole opening 14 thereby jamming plastic sleeve 1 at borehole opening 14. This procedure is followed whether borehole 13 is a dry borehole or a borehole containing water. If borehole 13 is to be left unattended for some time, a lid may be placed over borehole opening 14 to prevent borehole 13 from filling up with dirt and rain water.

~If a lid has been placed over borehole opening 14, then the lid is removed.

20 The user takes the excess length of plastic sleeve 1 and folds it over cone 9 and into plastic sleeve 1. The folding over of the excess length of plastic sleeve 1 acts as a clamp and allows open end 3 to remain open. Figure 9C shows plastic sleeve 1 after the excess length has been folded over cone 9 and into plastic sleeve 1. This ::procedure is followed whether borehole 13 is a dry borehole or a borehole containing water. An explosive, such as ANFO or other desirable explosive material, may then be placed into sleeve 1. The explosive will travel substantially unrestrictedly down the entire length of sleeve 1 to closed end 2 without stopping. The reason for the substantially unrestricted travel is that the inner surfaces of sleeve 1 are non sticking that is they do not stick to themselves. Since inner surfaces of plastic sleeve 1 do not stick to themselves, it also does not clump and thus on insertion of the explosive into sleeve 1 in situ the explosive travel substantially unrestrictedly the entire length of sleeve 1 to the closed end of sleeve 1. The explosive may then be detonated or alternatively, the explosive may be left for some time at closed end 2 of plastic sleeve 1. If the explosive is left unattended, a lid 18 (as illustrated in Figure 9D) may be [I:\DayLib\LIBXX\Backup\My Documents\Docs\ly Documents\Specification]Oxygenrem4.doc:JFM placed over borehole opening 14 to prevent borehole 13 from filling up with dirt and rain water. However, if borehole 13 contains water, the explosive should not be left in plastic sleeve 1 for an excessive length of time otherwise the explosive may become wet and thereby become inactivated.

Alternatively, once plastic sleeve 1 has been folded over cone 9 and into plastic sleeve 1, a lid 18 may be placed over borehole opening 14 to prevent borehole 13 from filling up with dirt and rain water. Borehole 13 may be left unattended in this manner until required. However if borehole 13 has a tendency to rapidly fill up with water, borehole 13 should not be left unattended for a considerable length of time.

When borehole 13 is required, lid 18 is removed and an explosive, such as ANFO or other desirable explosive material, is placed into plastic sleeve 1. The explosive may then be detonated or alternatively, the explosive may be left for some time at closed end 2 of plastic sleeve 1. If the explosive is left unattended, a lid 18 may be placed over borehole opening 14 to prevent borehole 13 from filling up with dirt and rain water. However if borehole 13 contains water, the explosive should not be left in plastic sleeve 1 for an excessive length of time otherwise the explosive may become wet and thereby become inactivated.

Referring to Figure 10, a borehole lining of a length suitable for lining a borehole in which it is intended to be used comprises plastic sleeve 101 which is S 20 typically five to ten percent or more typically eight percent longer than said borehole (which is not illustrated) and has a closed end 102 and an open end 103. Plastic sleeve 101 is generally substantially water impermeable and its inner surfaces are substantially non sticking thereby allowing explosive material inserted into the open S end of sleeve 101 in situ to travel substantially unrestrictedly to the closed end of sleeve 101. Plastic sleeve 101 is also generally impermeable to diesel oil. The closed end 102 is generally heat sealed in a rectangular shape. A triangular shaped end 106 is formed by folding together two horizontally opposing corners 104 and 104a of sleeve 101 proximate closed end 102 and adhering them together with sealing tape 105 and 105a. Sleeve 101 is illustrated (not to scale) as having calibrations 107, 107a and 107b on one side.

Referring to Figure 11 borehole lining 108 comprises liquid impermeable and scuff resistant outer sleeve 109, and plastic sleeve 101, where outer sleeve 109 is typically 6 metres in length indicated at 114, 114a, 115, and 1l15a. Outer sleeve 109 covers a portion of sleeve 101 and is adhered to sleeve 101 proximate sealed end 102 [I:\DayLib\LIBXX\Backup\My Documents\Docs My Documents\Specification]Oxygenrem4.doc:JFM of sleeve 101 with adhesive tape at 113 and 113a. A pouch 112 is formed on the exterior of outer sleeve 109 proximate triangular end 106 of sleeve 101, by bringing together two horizontally opposing comers 110 and 110 Oa of outer sleeve 109 which can be either heat sealed or sewn together. Corners 110 and 110a, when sealed together, form said pouch 112 and a triangular end 111 to outer sleeve 109. Inner sleeve 101 can be of varying length indicated at 116 and 116a.

Referring to Figure 12 borehole lining 108 is rolled about hollow rod or tube 117 so as to leave end 111 accessible once borehole lining 108 is fully rolled on tube 117. To line a borehole with borehole lining 108 a user places one or more rocks, stones, sand or soil or a mixture of two or more thereof or any other weights suitable to weight plastic sleeve 101 into pouch 112 (and thereby facilitates lining a borehole with borehole lining 108) which is conveniently situated on the outer surface of outer sleeve 109 when borehole lining 108 is fully rolled on tube 117 and provides ready access to the user. The user places dowel 118 through tube 117 and whilst holding dowel 118, the user stands at the borehole opening and lets sleeve 101 unroll into borehole until the closed end of plastic sleeve 101 reaches bottom of said borehole.

As plastic sleeve 101 unrolls in this fashion, the user can control the speed and 0 duration of descent of sleeve 101 in same manner as which is described with reference 00*.

to Figure 3.

20 Illustrated in Figure 13 is a dry borehole 119 lined with the borehole lining 108 illustrated in Figure 6, where 120 is the bottom of said borehole 119, 121 is the open end of said borehole 119 and 122 and 122a are indicators of the variable depth ofborehole 119.

Borehole lining 108 is illustrated in Figure 14 as being completely unrolled into borehole 119 and supported in place proximate open end 121 of borehole 119 by *1 support means 123. Open end 103 of borehole lining 108 is secured at the top of the borehole by a simple light weight stand 124 (which may have two, three, four or five legs) and ring (or cone) 125 (which may be circular, rectangular, square, elliptical or other suitable shape) supported by said stand 124, together combining to provide support means 123 intended to support borehole lining 108 and holds the layflat extrusion open for easy loading into sleeve 101 bulk ANFO. Open end 103 of sleeve 101 can be affixed to support means 123 in a manner such that the user holds excess length of sleeve 101 at open end 103 open while inserting said length through the underside of ring 125 then folding said length over, back down and around ring 125 :\DayLib\LIBXX\Backup\My Documents\DocsMy Documents\Specification]Oxygenrem4.doc:JFM so as to enable excess length to fold back upon itself (101). The folding over of the excess length acts as a clamp and allows sleeve 101 to remain substantially open along the entire length of borehole 119. Furthermore, to prevent plastic sleeve 101 from falling into borehole 119 and to prevent plastic sleeve 101 from filling up with dirt and rainwater a lid 126 is snapped onto ring 125 of support means 123. Said lid 126 is marginally larger than said ring 125 so as to clamp onto support means 123 by fixing to ring 125 thereby enabling borehole lining 108 to be left in situ in borehole 119 unattended. Support means 123 lid 124 is typically fabricated from plastic, metal or ceramic.

A weight may be placed into pouch 112 of outer sleeve 109 of borehole lining 108 to facilitate lowering of said lining into borehole 119 so as to substantially line said borehole 119 whilst maintaining an excess length of inner sleeve 101 proximate open end 121 of said borehole 119 illustrated here in Figure 14. Referring to Figure the user then secures open end 103 of plastic sleeve 101 to support means 123 as described hereinbefore, providing borehole lining 108 with a support means and the ability to maintain open end 103 of plastic sleeve 101 to facilitate insertion of explosive into said sleeve.

With reference to Figure 15C, another embodiment provides that borehole ."lining 108 is lowered into borehole 119 and substantially lines said borehole 119 20 whilst maintaining an excess length of inner sleeve 101 proximate open end 121 of borehole 119 whereby open end 103 is secured to support means 123. An inflating substance 127 of a quantity that will substantially inflate sleeve 101 while sleeve 101 is disposed within borehole 119, is preferably comprised of a co-reagent and a further co-reagent in which a combination of said inflating substance comprising one coreagent being a solvent (preferably water) and a further co-reagent being a solid mixture of citric acid (or other similar acid) and sodium bicarbonate (or other similar ***bicarbonate) is disposed proximate closed end 102 of sleeve 101. The combination of both co-reagents liberates a gas (preferably C0 2 which in turn effectively expels all oxygen present in sleeve 101, and at the same time inflates sleeve 101 and thus lining 108 so as to form a tubular borehole lining capable of supporting itself while disposed inside a borehole. Sleeve 101 is then sealed proximate open end 103 of sleeve 101 with a form of valve 128, illustrated in Figure 15D replacing support means 123 and being one which can be tied using cables or other like strong materials used for tying nots.

[I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM Figure 15E refers to inflated borehole lining borehole lining 108 and a means to cover open end 121 of borehole 119, said means being borehole plug 129. Plug 129 is positioned uninflated in the entrance to open end 121 ofborehole 119 and then inflated to secure open end 103 of borehole lining 108 against inner surface of borehole 119 wall proximate borehole opening 121. In this embodiment a combination of borehole plug 129 and the disposal of inflatable substance 127 within plastic sleeve 101, is used to support borehole lining borehole lining 108 and seal the entrance to borehole 119.

In this arrangement inflatable plug 129, which is to be used as a means of support for borehole lining 108 when said lining is lining borehole 119 and is also a method of sealing borehole opening 121 whilst borehole 119 is lined by said lining, is inserted into open end 121 ofborehole 119 so as to secure plastic sleeve 101 end 103 against inside surface of borehole 119 when said plug 129 is substantially inflated by the preferred inflatable substance or pressurised gas. Typically the source of inflatable substance or pressurised gas which can inflate plug 129 is aerosol container 130 containing same. Aerosol container 130 typically has pressure releasing means.

The pressure releasing means is typically nozzle 131 coupled to plug 129 via conduit 132 with conduit 132 incorporating a valve 133 which is preferably a one way valve to be sure the inflatable substance does not travel back along conduit 132 toward 9@*00@ 20 aerosol container 130. Typically nozzle 131 is activated by being depressed by a user.

Typically once activated by a user nozzle 131 continues to discharge contents of container 130 even after release of nozzle 131 by the user, until the contents of o,!container 130 have been substantially discharged and plug 127 is substantially o* inflated. Inflatable substance or pressurised gas being the contents of aerosol container 130, intended to be used for the inflation of borehole plug 127 is described in Australian patent application no. 93295/98 the whole content of which is *400 0 incorporated herein by cross reference. The use of inflatable plug 129 once inflated in open end 121 of borehole 119 prevents or substantially reduces or reduces ingress of o air into borehole 119. Thus the amount of oxygen which comes into contact with pyritic rock in borehole 119 is reduced and consequently the amount of oxidisation of pyritic rock in borehole 119 is reduced thereby reducing the amount of heat which would otherwise be released from the reaction of oxygen in the air which would otherwise come into contact with pyritic rock in borehole 119 in the event that inflatable plug 129 was not included in borehole 119.

[I:\DayLib\LBXX\Bakup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM Borehole plug 130 in addition to being dimensional for dropping or lowering into borehole 119 should be gas-tight. Preferred borehole plugs are multi-layered plastic bags which have suitable strength and suitably low gas permeability. It is preferred that the bags be able to withstand 20 to 25 psi internal pressure and to maintain that pressure for up to 4 weeks. Low gas permeability is achieved in borehole plug 127 by use of a polyester inner layer or metallised plastic film.

Examples of suitable inflatable borehole plugs are described in Australian patent Nos.

579395 and 595887 and Australian patent application no. 93295/98 the whole contents of which are incorporated herein by cross reference.

Referring to Figure 16, a borehole lining 200 of a length suitable for lining a borehole in which it is intended to be used comprises plastic sleeve 201 which is typically five to ten percent or more typically eight percent longer than said borehole (which is not illustrated) and has a closed end 202 and an open end 203. Plastic sleeve 201 is generally substantially water impermeable and its inner surfaces are substantially non sticking thereby allowing explosive material inserted into the open end 203 of sleeve 201 in situ to travel substantially unrestrictedly to the closed end 202 of sleeve 201. Plastic sleeve 201 is also generally impermeable to diesel oil. The closed end 202 is generally heat sealed. Sleeve 201 is illustrated (not to scale) as o Se. having calibrations 204, 204a and 204b on one side. When a particular calibration point is aligned with the mouth of a borehole into which lining 200 has been inserted e ee it is indicative that the length indicated on the calibration is in the borehole. Thus if a calibration mark of 40 metres were lined up with the mouth of a borehole into which it had been inserted then this would be indicative that 40 metres of borehole lining

S

oe.o had been inserted into the borehole.

0000 Scuff resistant outer sleeve 205 is attached to sleeve 201 by adhesive tape at o locations 206 and 207, and is typically 6 metres in length. A slot 208 is formed in

SOS.

S0oo,° triangular shaped end 209 of sleeve 205 into which material rocks, dirt, sand 0setc.) can be inserted to provide weight in sleeve 205 and thereby facilitate lining a 0* 0" 0 0borehole with the borehole lining 200. Triangular end 209 is located below end 202.

0 In use borehole lining 200 is pre-rolled about a hollow rod or tube (not shown but see Figure 12). To line a borehole with lining 200 a user places one or more rocks, stones, sand or soil or a mixture of two or more thereof or any other weights suitable to weight plastic sleeve 201 into pouch 208 (and thereby facilitates lining a borehole with lining 200) which is conveniently situated on the outer surface of outer [I:\DayLib\LBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM sleeve 205 when lining 200 is fully rolled on the tube and provides ready access to the user. The user places a dowel through the tube and whilst holding the dowel, the user stands at the borehole opening and lets sleeve 201 unroll into borehole until the closed end 209 of sleeve 201 reaches the bottom of the borehole. As plastic sleeve 201 unrolls in this fashion, the user can control the speed and duration of descent of sleeve 201 in same manner as which is described with reference to Figure 8.

Referring to Figure 17, a borehole lining 300 of a length suitable for lining a borehole in which it is intended to be used comprises plastic sleeve 301 which is typically five to ten percent or more typically eight percent longer than said borehole (which is not illustrated) and has a closed end 302 and an open end 303. Plastic sleeve 301 is generally substantially water impermeable and its inner surfaces are substantially non sticking thereby allowing explosive material inserted into the open end 303 of sleeve 301 in situ to travel substantially unrestrictedly to the closed end 302 of sleeve 301. Plastic sleeve 301 is also generally impermeable to diesel oil. The closed end 302 is generally heat sealed. One half of a zip 304 extends across end 302.

Sleeve 301 is illustrated (not to scale) as having calibrations 305, 305a and 305b on one side. When a particular calibration point is aligned with the mouth of a borehole into which lining 300 has been inserted it is indicative that the length indicated on the calibration is in the borehole. Thus if a calibration mark of 30 metres were lined up S. 20 with the mouth of a borehole into which it had been inserted then this would be !indicative that 30 metres of borehole lining had been inserted into the borehole.

A layer of scuff resistant material hyperlon) is coated on the outside of S"outer sleeve 301 up to line 306 and is typically 6 metres in length from closed end 302. A separate triangular shaped pouch 307 has one half of a zip 308 which mates with zip 302. Slot 309 is formed in triangular shaped pouch 307 into which material rocks, dirt, sand etc.) can be inserted to provide weight in pouch 307 which when _attached to sleeve 301 facilitates lining a borehole with the borehole lining 300.

In use borehole lining 300 is pre-rolled about a hollow rod or tube (not shown but see Figure 12). To line a borehole with lining 300 a user attaches pouch 307 to sleeve 301 via zips 302 and 308. The user then places one or more rocks, stones, sand or soil or a mixture of two or more thereof or any other weights suitable to weight plastic sleeve 301 into pouch 307 (and thereby facilitates lining a borehole with lining 300). One half of zip 302 is conveniently situated on the outer surface of sleeve 301 when sleeve 301 is fully rolled on the tube and provides ready access to the user to [I:\DayLib\LIBXX\Backup\My Documents\Docs\My Doc uments\Speci fication]Oxygenrm4.doc:J FM enable the user to easily attach pouch 307 to sleeve 301. The user places a dowel through the tube and whilst holding the dowel, the user stands at the borehole opening and lets sleeve 301 unroll into borehole until pouch 307 reaches the bottom of the borehole. As plastic sleeve 301 unrolls in this fashion, the user can control the speed and duration of descent of sleeve 301 in same manner as is described with reference to Figure 3.

Referring to Figure 18, a borehole lining 400 of a length suitable for lining a borehole in which it is intended to be used comprises plastic sleeve 401 which is typically five to ten percent or more typically eight percent longer than said borehole (which is not illustrated) and has a closed end 402 and an open end 403. Plastic sleeve 401 is generally substantially water impermeable and includes an anti blocking agent such that its inner surfaces are substantially non sticking thereby allowing explosive material inserted into the open end 403 of sleeve 401 in situ to travel substantially unrestrictedly to the closed end 402 of sleeve 401. Plastic sleeve 401 is also generally impermeable to diesel oil. The closed end 402 is generally heat sealed to form a triangular shape. Sleeve 401 is illustrated (not to scale) as having calibrations 405, 405a and 405b on one side. When a particular calibration point is aligned with the mouth of a borehole into which lining 400 has been inserted it is indicative that the length indicated on the calibration is in the borehole. Thus if a 20 calibration mark of 60 metres were lined up with the mouth of a borehole into which it had been inserted then this would be indicative that 60 metres of borehole lining °had been inserted into the borehole.

A layer of scuff resistant material hyperlon) is coated on the outside of outer sleeve 401 up to line 406 and is typically 6 8 metres in length from closed end ooee° 25 402. Eyelets 407, 408 and 409 are located at various locations on end 402 as illustrated. String or wire can be inserted into eyelets 407, 408 and 409 to attach a •weight to end 402 which when attached to sleeve 401 facilitates lining a borehole with the borehole lining 400.

In use borehole lining 400 is pre-rolled about a hollow rod or tube (not shown 30 but see Figure 12). To line a borehole with lining 400 a user attaches a weight to end end 402 via eyelets 407, 408 and 409 (the weight may be in a pouch or a rope basket, for example) which are conveniently situated on the outer surface of sleeve 401 when sleeve 401 is fully rolled on the tube and provides ready access to the user to enable the user to easily attach a weight to sleeve 401. The user places a dowel through the [I :\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM tube and whilst holding the dowel, the user stands at the borehole opening and lets sleeve 401 unroll into borehole until end 402 reaches the bottom of the borehole. As plastic sleeve 401 unrolls in this fashion, the user can control the speed and duration of descent of sleeve 401 in same manner as that described with reference to Figure 8.

Figure 19A depicts a borehole 500 in which an inflated borehole lining 506 is supported at the bottom of the borehole 500 by an inflated borehole plug 502. In use, a borehole plug 502 is positioned at a suitable depth in a borehole 500, typically the bottom of the borehole 500, and inflated. A borehole lining 506 of suitable length is then lowered into the borehole 500 in the manner described above, to a suitable depth such that the bottom closed end of the borehole lining 506 is in contact with the inflated borehole plug 502. The borehole lining 506 is then charged with the required amount of explosive, inflated, and the open end 512 of the lining 506 sealed with sealing means 508. The upper region 510 of the borehole 500 is then filled with soil or other suitable fillers prior to detonation of the explosive. In this arrangement the borehole plug 502 supports the borehole lining 506 in the borehole 500 and prevents slippage of the lining 506 in the borehole 500.

The embodiment depicted in Figure 19B shows a borehole lining 506 inserted in a borehole 500 such that the borehole lining 506 is supported at the top of the borehole 514 with a borehole plug 504. The borehole lining 506 is supported at the upper region of the borehole 500 by the borehole plug 504, which prevents slippage of the borehole lining 506 in the borehole 500.

:i In use, a borehole lining 506 is lowered into a borehole 500 to a predetermined depth in the manner described above with reference to Figure 18. The borehole lining is charged with the required amount of explosive and inflated by inflation means (as o described above, for example, with reference to Figure 15E). A borehole plug 504 is positioned proximate the open end 514 of the borehole 500 and inflated with inflation means. When inflated, the borehole plug 504 secures the open end 512 of the S borehole lining 506 against the inner surface of the borehole 500 wall proximate the borehole opening 514, effectively sealing the borehole lining. In this embodiment, 30 the borehole lining 506 is supported by the borehole plug 504 at the top of the borehole 500.

In the embodiment shown in Figure 19C an inflated borehole lining 506 which contains a spacer element 518 and explosive inserted therein, is supported in a [I:\DayLib\LBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM borehole 500 at the bottom 516 and top 514 of the borehole 500 by borehole plugs 502 and 504, respectively.

In use, a borehole plug 502 is positioned in the borehole 500 at a predetermined depth, typically the bottom of the borehole 516, then inflated using inflation means. A borehole lining 506 is then inserted (in the manner described above with reference to Figure 18) and lowered to a depth in the borehole 500 by an operator such that the bottom closed end of the borehole lining 506 is in contact with the inflated borehole plug 502. In this manner the borehole lining 506 is supported at the bottom 516 of the borehole 500 by the borehole plug 502. An expanded or expandable spacer element 518 is inserted in the borehole lining 506 and, if required, the spacer element 518 is filled with suitable filler material such that it is in a fully expanded configuration within the borehole lining 506 in the borehole 500. Explosive and other filler materials as appropriate are then be inserted into the borehole lining 506, which is then inflated by inflation means (in the manner described above with reference to Figure 15E). A second borehole plug 504 positioned proximate the open upper end 514 of the borehole 500 is inflated such that when inflated, the borehole plug 504 effectively seals the open end 512 of the borehole lining 506 by pressing the lining fast against the inside surface of the borehole 500 wall. In this arrangement the borehole lining 506 is supported at the top 514 and bottom 516 of the borehole 500 by 20 inflated borehole plugs 502 and 504, respectively.

.i [I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM

Claims (11)

1. A process of lining a borehole, said process comprising: placing oxygen removing means or oxygen reducing means in the borehole to remove oxygen from or reduce oxygen in the borehole; lining at least part of the borehole with a borehole lining; and closing the borehole to substantially prevent air from entering the borehole.

2. A process of lining a borehole, said process comprising: removing oxygen from or reducing oxygen in the borehole; lining at least part of the borehole with a borehole lining; and closing the borehole to substantially prevent air from re-entering the borehole.

3. A process of lining a borehole, said process comprising: placing oxygen removing means or oxygen reducing means in the borehole to remove oxygen from or reduce oxygen in the borehole; lining at least part of the borehole with a borehole lining; locating support means in the borehole to support the borehole lining; and closing the borehole to substantially prevent air from entering the borehole.

4. A process of lining a borehole, said process comprising: removing oxygen from or reducing oxygen in the borehole; lining at least part of the borehole with a borehole lining; 20 locating support means in the borehole to support the borehole lining; and closing the borehole to substantially prevent air from re-entering the borehole.

5. A process of lining a borehole, said process comprising: removing oxygen from or reducing oxygen in the borehole; •eo.oi positioning means to support a borehole lining in the borehole at a predetermined depth; and, before or after step lining the borehole with a borehole lining, such that the means to support the borehole lining supports the borehole lining in the borehole. S6. The process of claim 5 further comprising the steps of: maintaining an excess length of borehole lining proximate or above the mouth of the borehole; and supporting the borehole lining proximate or above the mouth of the borehole with a means to support the borehole lining. [I:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM

7. The process of claim 6 wherein the means to support a borehole lining is a first borehole plug and the lining of the borehole further comprises the steps of inserting a second inflatable borehole plug in a borehole prior to lining the borehole with the borehole lining; inflating the second inflatable borehole plug before the lining is inserted in the borehole; charging the borehole lining with a required amount of explosive; inflating the borehole lining before or after step and inflating a first inflatable borehole plug after inflation of the borehole lining, wherein the inflated first borehole plug is located proximate the mouth of the borehole and substantially seals the borehole.

8. A process of lining a borehole, said process comprising: removing oxygen from or reducing oxygen in the borehole; positioning means to support a borehole lining in the borehole at a predetermined depth; inserting an inflatable borehole lining, having a closed end and an open end, in the borehole such that the closed end of the borehole lining is in contact with said means to support; and inflating the borehole lining with inflating means; wherein the means 20 to support the borehole lining supports the borehole lining in the borehole. .ooo: S9. The process of claim 8 further comprising the step of charging the borehole lining with a required amount of explosive and sealing the inflated borehole lining with sealing means to substantially prevent the borehole lining from deflating.

10. A process of lining a borehole, said process comprising: removing oxygen from or reducing oxygen in the borehole; inserting an inflatable borehole lining in a borehole to a predetermined depth; charging the borehole lining with a required amount of explosive; 30 inflating the borehole lining with inflation means; sealing the inflated borehole lining with sealing means to substantially prevent deflation of the borehole lining; positioning a means to support the borehole lining proximate the mouth of the borehole; and [I:\DayLib\LIB XX\Backup\My Documents\Docs\My Documents\Specifi cation]Oxygenrem4. doc:JFM supporting the borehole lining with the means to support.

11. The process of claim 10 wherein the means to support is a borehole plug and the process further comprises the step of: inflating the borehole plug sufficiently to substantially seal the mouth of the borehole.

12. A process of lining a borehole, said process comprising: inserting an inflatable borehole lining in a borehole to a predetermined depth; charging the borehole lining with a required amount of explosive; inflating the borehole lining with inflation means; sealing the inflated borehole lining with sealing means to substantially prevent deflation of the borehole lining; positioning a means to support the borehole lining proximate the mouth of the borehole; and supporting the borehole lining with the means to support.

13. The process of claim 12 wherein the means to support is a borehole plug and the process further comprises the step of: inflating the borehole plug sufficiently to substantially seal the mouth of the borehole. Dated 28 June, 2001 Mintech Pty Ltd Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON [l:\DayLib\LIBXX\Backup\My Documents\Docs\My Documents\Specification]Oxygenrem4.doc:JFM