AU4273100A - A method of lining a borehole - Google Patents

Description

S&F Ref: 490129D1

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

r i r r o si c r Name and Address of Applicants: Sanleo Holdings Pty Ltd 1st Floor, 155 Brisbane Street Dubbo NSW 2830 Australia Soothjet Pty Ltd Ist Floor, 155 Brisbane Street Dubbo NSW 2830 Australia Actual Inventor(s): Address for Service: Invention Title: The following statement is a full performing it known to me/us:- Geoffrey Robbins Spruson Ferguson St Martins Tower 31 Market Street Sydney NSW 2000 A Method of Lining a Borehole description of this invention, including the best method of IP Austraja Documents rec-ivorm n- 2 8 JUN 2000 Batch No: 5845c A Method of Lining a Borehole Technical Field This invention relates to a method of lining a borehole, in particular to a method of lining at least a portion of a borehole to receive explosives.

Background Art Currently, in the mining industry, a borehole is drilled and explosives are placed in the borehole. The boreholes are usually drilled below the water table and there is a tendency for the boreholes to fill with water and accordingly water-proof explosives are used. The disadvantage of using water-proof explosives is that they are very expensive.

~There is a need for a borehole lining which can be used to line a borehole, which lining will not stick to itself and will allow an explosive placed in the lined borehole to travel substantially unrestrictedly the entire length of the lining. There is another need for a borehole lining which reduces the need for a water-proof explosive. There is another need F[or a method of lining at least a portion of a borehole with a borehole lining and placing an explosive in the lined borehole. There is a further need for a method of lining a borehole with a borehole lining in which slippage of the borehole lining in the borehole is substantially prevented.

Objects of Invention It is an object of this invention to provide a method for lining at least a portion of a t: borehole with a borehole lining and supporting the borehole lining with a supporting means.

Summary of the Invention Throughout this specification, unless the context clearly indicates otherwise, the words "comprise", "comprises", "comprising", or other variations thereof, shall be understood as meaning that the stated integer is included and does not exclude other integers firom being present even though those other integers are not explicitly stated.

According to a first aspect of the invention there is provided a method of lining a borehole comprising the steps of: 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.

[I:\DayLi\LI BH]00395.doc:IJG In one form, the method of lining a borehole according to the first aspect of the invention may further comprise the steps of, maintaining an excess length of borehole lining proximate the mouth of the borehole; supporting the borehole lining proximate the mouth of the borehole with a means to support the borehole lining.

Optionally, in this form of the first aspect of the invention the means to support a borehole lining is a first borehole plug and the method of lining a borehole may further comprise 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 Sthe borehole; charging the borehole lining with a required amount of explosive; inflating the borehole lining before or after step and i inflating a first inflatable borehole plug after inflation of the borehole lining, wherein the inflated first borehole plug proximate the mouth of the borehole substantially seals the borehole.

According to a second aspect of the invention there is provided a method of lining a borehole comprising the steps of: 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, the method of lining a borehole according to the second aspect of the invention may further comprise 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.

According to a third aspect of the invention there is provided a method of lining a borehole with a borehole lining comprising the steps of: inserting an inflatable borehole lining in a borehole to a predetermined depth; charging the borehole lining with a required amount of explosive; [R:\I,lI BH]003 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.

In the method of lining a borehole according to the third aspect 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.

In the methods 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 plug assembly and the borehole plug may be inflated prior to inserting the borehole lining in the °borehole.

The method of lining a borehole in accordance with this invention 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 fiomn 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.

In the methods of the invention, the borehole lining may comprise a substantially S°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 is silu to travel substantially unrestrictedly to the closed end.

The borehole lining for use in the methods of the invention 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 may be disposed over at least a portion of the borehole lining and may comprise an outer sleeve.

The outer sleeve may be disposed over a portion of the borehole lining selected from the group consisting of at least the closed end; the closed end and at least a portion of the borehole lining proximate the closed end; at least a portion of the borehole lining proximate the closed end; the closed end and substantially the borehole lining; so as to substantially [R:\LIBH]00395.doc:LJG protect the outer surface of the borehole lining from damage as the borehole lining is lowered down a borehole.

The borehole lining for use in the methods of the invention may further comprise means proximate the closed end of the lining for facilitating the lining of a borehole with the borehole lining. The means may be means for supporting a weight and may be selected From the group consisting of a fixed pouch disposed proximate to the closed end, a removable pouch disposed proximate to the closed end, and means to which a weight may be attached proximate to the closed end. The pouch for containing a weight may be attached to the borehole lining or the outer protective sleeve. The means proximate to the closed end for facilitating the lining of a borehole with the borehole lining is profiled.

shaped or tapered to facilitate lowering of the bore lining down a borehole.

According to a further embodiment of this invention there is provided a method of lining a borehole with a borehole lining which methods comprises: taking a borehole lining comprising a liquid impermeable sleeve and an outer sleeve, the liquid impermeable sleeve or the outer sleeve having a pouch; :i placing a weight in the pouch to facilitate the lining of a borehole with the borehole lining; lining the borehole with the borehole lining to the required depth in the borehole whilst maintaining an excess length of the lining proximate the mouth of the borehole; supporting the borehole lining proximate the mouth of the borehole with the means to o **support.

In one form, supporting the borehole lining proximate the mouth of the borehole may include: inserting the means to support the open end into the open end of the liquid impermeable sleeve until the means to support is located proximate the mouth of the borehole to support the borehole lining and to maintain open the open end to facilitate insertion of explosive into the liquid impermeable sleeve; and passing the excess length through the means to support and folding the excess length inside out thus folding the length back onto itself, to support the open end proximate the mnouth of the borehole.

According to another embodiment of the invention there is provided a method of lining a borehole which method comprises: taking a borehole lining or a combination borehole lining with outer sleeve, the borehole lining having an open end and a closed end; placing a weight in the closed end sufficient to facilitate the lining of the borehole with the lining or the combination to the required depth in the borehole; [R:\UB -1]00395.doc: LJG lining the borehole with the lining or the combination to the required depth in the borehole whilst maintaining an excess length of the lining proximate the mouth of the borehole; and supporting the lining or the combination proximate the mouth of the borehole with the means to support.

In one form, supporting the lining or the combination proximate the mouth of the bolrehole may include: inserting the means to support into the open end of the liquid impermeable sleeve until the means to support is located proximate the mouth of the borehole to support the lining or the combination and to maintain open the end to facilitate insertion of explosive into the liquid impermeable sleeve; and folding the excess length of lining over the means to support and into the sleeve to support the open end proximate the mouth of the borehole.

~According to another embodiment of this invention there is provided a method of lining a borehole which method comprises: taking the borehole lining, or a combination borehole lining with outer sleeve; forming a pouch and adhering said pouch to the liquid impermeable sleeve proximate the closed end of the sleeve to receive a weight; ~placing a weight in the pouch to facilitate lowering of the lining into the borehole; lowering the lining into the borehole so as to substantially line the borehole whilst maintaining an excess length of the lining proximate the mouth of the borehole; inserting the means to support the open end into the open end of the liquid impermeable sleeve until the means to support is located proximate the mouth of the borehole to support the lining and to maintain open the open end to facilitate insertion of explosive into the lining; and folding the excess length over the means to support and into the sleeve to support the open end proximate the mouth of the borehole.

According to a further embodiment of this invention there is provided a method of lining a borehole which method comprises: taking a borehole lining having a pouch, or a combination of borehole lining and outer sleeve having a pouch; placing a weight in the pouch to facilitate lowering of the lining into the borehole; lowering the lining into the borehole so as to substantially line the borehole whilst maintaining an excess length of the lining proximate the mouth of the borehole; [R:\LIBH00395.doc:LJG 1( 6 inserting the means to support the open end into the open end of the sleeve until the means to support is located proximate the mouth of the borehole to support the lining and to maintain open the open end to facilitate insertion of explosive into the lining; and folding the excess length over the means to support and into the sleeve to support the open end proximate the mouth of the borehole.

According to a further embodiment of this invention there is provided a method for lining a borehole comprising the steps of: lining the borehole with a borehole lining; inserting into the borehole at least one expanded spacer element so as to permit explosive to be placed in the borehole adjacent the spacer element; and inserting the explosive, optionally with fillers, in the borehole adjacent the expanded spacer element, the overall density of the expanded spacer element being less than the density of the explosive, whereby the density of that part of the borehole comprising the spacer element and the explosive adjacent the spacer element is less than what the density of that part of the of the borehole would be if it were charged only with the explosive.

According to a further embodiment of the invention, there is provided a method of lining a borehole, comprising the steps of: inserting a borehole plug capable of supporting a borehole lining, into the borehole; lining the borehole with a borehole lining; oooo inserting into the borehole at least one spacer element; expanding the at least one spacer element in the borehole until the at least one spacer element is substantially fully expanded; locating the fully expanded spacer element in the borehole so as to permit the explosive to be placed in the borehole adjacent the spacer element; and inserting the explosive, optionally with fillers, in the borehole adjacent the expanded spacer element, the overall density of the expanded spacer element being less than the density of the explosive, whereby the density of that part of the borehole comprising the spacer element and the explosive adjacent the spacer element is less than what the density of that part of the borehole would be if it were charged only with the explosive.

According to further embodiments, a borehole plug may be inserted proximate the mouth of a lined borehole to support the borehole lining and seal the borehole.

[R:\LIIBH]00395.doc:LJG Detailed Description of the Invention Borehole Lining 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 non sticking inner surfaces thereby allowing explosive material inserted into the open end of the sleeve is 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.

o oiOne 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 tan then be filled with explosive via the hose.

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 S".o 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 the borehole lining.

For example, the liquid impermeable sleeve may be a waterproof polyethylene lining and [R:\LIB -1100395.doc:LJG 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 15-30gm, more typically about 20jim, and a, typical thickness of the means to substantially protect is 100tm-300 1m, more typically about 1501am. 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 250-50 0 mi, typically about 300jim thick waterproof polyethylene lining to form the closed end and 2 to 3 metres of the sleeve adjacent to the closed end, 150-250pm thick waterproof polyethylene lining for the next 2 to 3 metres and the remainder 100-1 50itm thick waterproof polyethylene lining.

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 o: 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 9°9. 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 S9 sleeve mnay 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 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 [R:\LI BH]00395.doc:LJG 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 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 o 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 Sthe borehole lining may be profiled, shaped or tapered to facilitate lowering of the bore lining down a borehole.

In the methods 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 is 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 imer surfaces thereby allowing explosive material inserted into the open end of the sleeve is siu to travel substantially [R:\LI BH]00395.doc:LJG 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.

S:i 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 a borehole with the borehole lining to a particular depth in a borehole, more 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 of the one or more weights is typically in the range of 1-50kg, more typically 2-20kg, even more typically S 12kg, advantageously 3-10kg, more advantageously 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 circular-shape 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.

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 U-shaped 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 rR:\LIBH]00395.doc:LJG 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 "'U"-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 sulficiently 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 [our pouches) capable of holding one or more weights disposed proximate the closed end of the outer sleeve. Generally the pouch is located 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 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 1even 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 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 2%-10%, [R:\LIII-1]00395.doc:LJG 10%-15%, 15%-20%, 20%-25%, 25%-30, 30%-35%, 35%-40%, 40%-45%, 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%,25%, 26%, 27%, 28%, 29%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 100% of the borehole lining extending from the closed end toward the open end.

Typically the length of the protective outer sleeve is in the range 0.5-30, 0.5-25, 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, 3-5, 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, 9.5, 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.

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 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 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 reinforcement may be in the form of strong adhesive tape to the closed end of the sleeve.

[R:\LIBH]00395.doc:LJG 13 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 is 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 500im thick, typically 50-300pm thick, or 50-150pm thick, or 150-300am thick, or 150- 500am thick, or 300-500utm 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

-CI

0 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 Clo 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-C, 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(ethyleneterephthalate). 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 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 is a doublelayer 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 [R:\LIBH-I]0395.doc:LJG 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 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, .lohn Wiley Sons 1982, the contents of which are incorporated herein by cross reference.

As mentioned above the liquid impermeable sleeve may also have an anti-static 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 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 [R:\LIBH]00395.doc:LJG edition, John Wiley Sons 1982, the contents of which are incorporated herein by cross reference.

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 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.

Typically the required depth assumed by the liquid impermeable sleeve is the borehole is in the range of 10%-100%, typically 25%-100%, more typically 50%-100%, even more typically 75%-100% and yet even more typically 90%-100% of the depth of the 09: 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 0•0 -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 O too much water from over flowing the borehole. Usually the open end of liquid 04 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 rolled in this fashion, the pouch is readily accessible by the user on site without having to unr1-oll 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.

Advantageously, in one form of the borehole lining the liquid impermeable sleeve is composed of high tensile strength lightweight plastic so that it can carry 1 to 1.5 tons of explosive without the plastic being very heavy. Use of a substantially liquid impermeable borehole lining provides the advantage that non water-proof explosives may be used which are relatively cheaper than water-proof explosives. The use of a borehole lining having a sleeve which has an anti-blocking compound provides the additional advantage of stopping the plastic from sticking to itself and this also stops the explosive from clumping due to kinks in the sleeve when the explosive travels down the entire length of the sleeve.

Pyritic rock can oxidise and burn. Boreholes in such strata are only loaded if the hole temperature is less than 50'C. In cases where the borehole is above ambient and less than [R:\LIBH]00395.doc:LJG a lining is used. The lining material is generally chosen so that it does not lose its overall strength characteristics at such temperatures. Advantages of the use of a lining having an outer sleeve is that the outer sleeve keeps the explosive away from the 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.

In one preferred form of the borehole lining, 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 "'!forlm 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 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 o *sleeve (see page being V-shaped in this form of the lining, includes a pre-constructed Vshaped 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 is order to protect the liquid impermeable sleeve when said sleeve is lowered down a borehole. Typically, in this form :e of the lining the V-shape, pre-construed cutting pouch of the outer sleeve is formed by firstly folding the sealed end once to form a triangular shaped end followed by two other folds mnade 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 lining 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 metres, more typically 3-8 metres and even more typically 6 metres in length. The V-shaped cutting pouch allows the lining to be 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 [R:\l.IBH]00395 .doc:LJG customer requirements. Typical lengths are in the range of 20 metres to 60 metres in increasing increments of 5 metres. Typical diameters used are those to suit 1 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.

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 too 0Longitudinal TD 100.4 Ultimate Elongation MD 380 STear Resistance (gF) MDI 168 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 Antistatic. Anti-block prevents the film sticking to itself. Anti-static helps dissipate electrical charges.

Surface Resistivity (ohm/sq) 1 .0 x Static Decay (11% Relative Humidity) 1.08 sees Relative Humidity) 0.52 sees Diesel Resistance: Good, typical of polyethylene 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).

[R:\LIBH]0039 Means to Support the Borehole Lining The support means may be of any shape. In one form, the 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 oi*• 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 to a borehole flush with ground surface and encasing said borehole while the minimum longitudinal diameter at the opposite end of said device provides a ring for the open end of the water impermeable S 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. The means to support the open end of the borehole lining may maintain open the open end of the lining to facilitate insertion of explosive into the lining and to support the open end proximate the mouth of a borehole.

Alternatively, the means to support the borehole lining may comprise a borehole plug, typically an inflatable borehole plug assembly such as is described in AU 93295/98.

Other examples of borehole plugs suitable for use as support means are described in US 5,273,110, US 5,035,286, US 4,913,233, ZA 92/9979, US 5,000,261, US 4,919,203, US 4,846,278, US 5,497,829, US 5,273,110, US5,035,286, US 5,000,261, US 4,919,203, US 4,913,233, AU656051, US 5,346,005, AU 579 395 and AU 595 887, the contents of which are incorporated herein by cross reference.

One form of the support means may comprise an inflatable borehole plug comprising 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 [R:\LIBH]i 00395.doc:LJG 19 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 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. 93295/98 the whole contents of which are incorporated herein by cross-reference.

Alternatively, the borehole plug assembly may be a combination comprising an S"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 firom 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 is 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 sleeve, causing the inflatable borehole plug to be retained particularly securely against the sides of the borehole o*o.

(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 1 70 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.

[R:\LIBH00395.doc:LJG Typically, the inflatable container of a borehole plug is dimensioned for dropping or lowering down a borehole and is adapted for containing an inflatable substance or pressurised gas after it is released from the pressurised vessel.

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 lining 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 plug at the base of a borehole as described oabove, 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 o• inserted into the upper region of the borehole after insertion and inflation of the borehole lining, and when the borehole plug assembly is inflated, it can serve as a means to support oo- the borehole lining at the top of the borehole.

Spacer Element SlThe 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 o o.

*"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 methods 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 such that when the spacer element is located in the borehole lined with said borehole lining, the element can [R:\LIBH]00395.doc:LJG 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 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 i spacer body being coupled with said first and second ends.

~The spacer element may be expandable from a substantially lay flat configuration to :°o.an elongate annular shaped spacer element, wherein the unexpanded spacer element is in the fbrm 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 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 actuated so as to allow mixing [R:\LIBH]00395. doc:LG 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 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 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 S -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 oooo 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 expand said element may be a conduit. Typically means to close the conduit such as a cap, stopper or tie are used to close the conduit after the element has been filled with 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 [R:\LIBH]00395.doc:LJG 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 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 \wvith 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 cross-sectional diameter of the borehole so as to permit explosive to be placed in the borehole alongside oo•.

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 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 45m, typically LiUp to 40m, typically up to 35m, typically up to 30m, typically up to 251n, typically up to typically up to 15m, typically up to I Om.

[R:\LiBH]00395.doc:LJG 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 15% 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%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 52%, 54%, 56%, 58%, 60%, 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 between the end and the wall or body.

Typically, the spacer element may be solid, foam, other cellular products, liquid, semi-solid, semi-liquid or enclosed gas which is formed into a suitable shape so as to o* occupy a certain volume of space in a borehole. Typical examples include a 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 S" 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.

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, 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, [R:\LLBH]00395.doc:LJG 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 *4 "and water impervious inner enclosure capable of containing a gas or 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, 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 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 i 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.

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 I B1-1]003 95 .doc: LJG 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 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 I to 5) spacer elements in the borehole. Typically, the spacer 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 surface of the body of the spacer element to enable at least two spacer elements to be 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 imnner 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 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 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 [R:\LIB1-00395.doc:LG 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 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 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 polyolefin (C2-C 10 olefin), S*copolymers of different polyolefins, terpolymers of different polyolefins and blends of polyolefins. Examples of such polymers include polyethylene, polyethylene polymer with

C

3 to CIO 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.

[R:\LIBH]00395.doc:LJG As described above, the spacer element is typically substantially gas 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 petroleum waxes, natural waxes such as carnauba or spermaceti, waxy amides such as 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(l-butene), poly(vinyl acetate), poly(vinyl alcohol), 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.

o The spacer element according to the description above, may further comprise Santistatic 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 sulfbnates 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, 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", Radian Corporation, Noyes Data [R:\LI BH 00395.doc:LJG 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.

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 tipper 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 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 0 "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. Thile 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 firom filling up with dirt and rain water. Usually, the lid will be made of any material such as cardboard, plastic, corrugated cardboard, wood, metal or ceramic.

Advantageously, in the methods 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 water-proof explosives.

Anti-stat is combined with the combination using the following procedure: [R:\LIBH]00395.doc:LJG 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; after loading unclamp lining from stand, moving lining to one side of the hole and stem.

Brief Description of Drawings The invention is now described in more detail with reference to the following drawings in which: Figure 1 is a perspective view of a borehole lining for use in the methods of the invention; Figure 2 is a perspective view of a support means for use in the methods of the invention; Figure 3 is a perspective view of a rolled up borehole lining for use in the methods of the invention, with a dowel passed through the rolled up lining; Figure 4A is a perspective side view of a borehole lining for use in the methods of the invention, in a dry borehole; Figure 4B is a perspective side view of a borehole and a support means, for use in the methods of the invention; Figure 4C 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 4D 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 5 is perspective view of a borehole lining for use in the methods of this invention.

[R:\LI BH]00395.doc:LJG Figure 6 is a perspective view of a borehole lining having an outer sleeve, use in the methods of this invention.

Figure 7 is a perspective view of a rolled up borehole lining combination as illustrated in Figure 6, with a dowel passed through the rolled up lining.

Figure 8 is a perspective view of the combination as illustrated in Figure 6, when located in situ in a dry borehole.

Figure 9 is a perspective view of a lining as illustrated in Figure 6, combined with a means to support said lining, when located in situ in a borehole.

Figure 10OA is a cross sectional view of a borehole lining as illustrated in Figure 6, located in situ in a borehole.

Figure 10B is a cross sectional view of the combination as illustrated in Figure 9, when located in situ in a borehole.

:o *Figure 10 OC 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 °o ~Figure 10D 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.

S Figure 10 OE 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 11 is a perspective view of a further embodiment of a borehole lining for use in the methods of this invention.

o*o Figure 12 is a perspective view of another embodiment of a borehole lining for use in the methods of this invention.

Figure 13 is a perspective view of yet another embodiment of a borehole lining for use ill the methods of this invention.

Figure 14A 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 14B 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.

Figure 14C 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.

[R:\LII3H00395.doc:LJG Best Mode for Carrying Out The Invention Referring to Figure 1, 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. A triangular shaped end 17 is lol-med 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.

A\s illustrated for the other side of sleeve 1, cuff 4 is adhered to sleeve 1 with two pieces of i i sealing tape 5, 5a. The lower portion 6, 6a of cuff 4 is formed by bringing together two o horizontally opposing corners of cuff 4 to formn 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. Cuff 4 is adhered to sleeve 1 by sealing tape. As stated above, sealing tape is placed so as to completely seal one side of cuff 4 to sleeve I and on the other side of sleeve 1, cuff 4 is adhered by two pieces of sealing tape 5, Sa. 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 cuff 4 by sealing tape 7. End 17 thus forms a pouch 16. Sleeve I may also be calibrated with markers 8, 8a and 8b.

Referring to Figure 2, 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 I.I by 0.4 metres.

[R:\LIBH]00395 .doc:L.JG 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 I (as illustrated in Figure A user places stones, 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 borehole because the user generally knows the length of the borehole and plastic sleeve I 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 I 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 dowel 12 from rod 11 and then removes rod 11 from plastic sleeve I. The rod 11 and dowel 12 may be discarded after use. If the borehole is to be left unattended for some time, the excess S -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. 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 4A 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 15 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 firom 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 explosive which is placed in plastic sleeve 1 will become wet, thereby inactivating the explosive.

[R:\LI BH]00395.doc:LJG 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 if a 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 4B 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. 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 I acts as a clamp and allows open end 3 to remain open. Figure 4C 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 lelft unattended, a lid 18 (as illustrated in Figure 4D) 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 I 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 illing up with dirt and rain water. Borehole 13 may be left unattended in this manner until IR:\LIBH]00395.doc:LJG required. -lowever 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 1 3 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 5, 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 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 \vater impermeable and its inner surfaces are substantially non sticking thereby allowing explosive material inserted into the open 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 S'calibrations 107, 107a and 107b on one side.

Referring to Figure 6 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 115a. Outer sleeve 109 covers a portion of sleeve 101 and is adhered to sleeve 101 proximate sealed end 102 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 corners 110 and I 1 Oa of outer sleeve 109 which can be either heat sealed or sewn together.

Corners 110 and 1 I Oa, 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 I 16a.

Referring to Figure 7 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 11 7. 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 [R:\LIBH]00395 .doc:LJG 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 duration of descent of sleeve 101 in same manner as which is described with reference to Figure 3.

Illustrated in Figure 8 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 of borehole 119.

Borehole lining 108 is illustrated in Figure 9 as being completely unrolled into borehole 119 and supported in place proximate open end 121 of borehole 119 by 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 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 fiom 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.

In accordance with a further embodiment of this invention a weight is 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 FigLure 9. Referring to Figure O10B 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.

[R:\LI BH]00395.doc:LJG With reference to Figure 10C, another embodiment provides that borehole lining 108 is lowered into borehole 119 and substantially lines said borehole 119 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 cquantity 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 co-reagent 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 oeeoo **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 IOD o° replacing support means 123 and being one which can be tied using cables or other like strong materials used for tying nots.

Figure O10E 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 of borehole 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.

.i 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 of borehole 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 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 1 30 even after release of nozzle 131 by the user, until the contents of [R:\LIBH100395.doc:LJG container 130 have been substantially discharged and plug 127 is substantially 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 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 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 rI-educing the amount of heat which would otherwise be released firom 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.

Borehole plug 130 in addition to being dimensional for dropping or lowering into ooooe: borehole 119 should be gas-tight. Preferred borehole plugs are multi-layered plastic bags o.o, 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 o:i weeks. Low gas permeability is achieved in borehole plug 127 by use of a polyester inner layer or netallised 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 11, 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 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 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 had been inserted into the borehole.

Scuff resistant outer sleeve 205 is attached to sleeve 201 by adhesive tape at locations 206 and 207, and is typically 6 metres in length. A slot 208 is formed in triangular shaped end 209 of sleeve 205 into which material rocks, dirt, sand etc.) can be inserted [R:\LIB-1100395. doc:LG to provide weight in sleeve 205 and thereby facilitate lining a borehole with the borehole lining 200. Triangular end 209 is located below end 202.

In use borehole lining 200 is pre-rolled about a hollow rod or tube (not shown but see Figure 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 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 3.

Referring to Figure 12, 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 ofa 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 metres were lined up 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 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 ofa 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 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 [R:\L1H100395.doc:LG 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 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 13, 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 live 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 .i 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 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 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 but see Figure To line a borehole with lining 400 a user attaches a weight to 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 tube and whilst holding the dowel, the user stands at the borehole opening and lets sleeve 401 unroll into borehole until [R:\LIBH]00395.doc:LJG 41 end 402 reaches the bottom of the borehole. As plastic sleeve 401 unrolls in this fashion, thle user can control the speed and duration of descent of sleeve 401 in same manner as that described with reference to Figure 3.

Figure 14A 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 m~eans 508. The upper region 5 10 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 14B 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 wvith a borehole plug 504. The borehole lining 506 is supported at thle upper region of the borehole 500 by the borehole plug 504, which prevents slippage of the borehole lining 506 in the borehole 500.

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 13. The borehole lining is charged wvith the required amount of explosive and inflated by inflation means (as described above, fbor example, with reference to IbE). A borehole plug 504 is positioned proximate the open end 5 14 of the borehole 500 and inflated with inflation means. When inflated, the borehole pl= 504 secures the open end 512 of the 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, the borehole lining 506 is supported by the borehole plug 504 at the top of the borehole 500.

In the embodiment shown in Figure 14C an inflated borehole lining 506 which contains a spacer element 518 and explosive inserted therein, is supported in a 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 pre-determined depth, typically the bottom 516 of the borehole 500, then inflated using inflation means. A borehole lining 506 is then inserted (in the manner described above with reference to Figure 1 and lowered to a depth in the borehole 500 by an operator such that the bottom closed I 1:\DayLib\LI B H]00395.doc: LJG 42 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 10E). 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 inflated borehole plugs 502 and 504, respectively.

S. m oIndustrial Applicability The methods of the invention can be readily utilised in the mining industry and the building industry to line a borehole to make that borehole water-proof.

[I:\DayLib\LIB H]00395.doc: LJG

Claims (24)

1. 2. A method of lining a borehole comprising the steps of: 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.
2. 3. A method according to claim 2, further comprising charging said borehole lining with a required amount of explosive and sealing said inflated borehole lining with sealing means to substantially prevent said borehole lining from deflating.
3. 4. A method according to claim 3 wherein said sealing means is located proximate said open end of said borehole lining. A method according to any one of claims 1 to 4, wherein said means to support a borehole lining is a borehole plug..
4. 6. A method according to claim 5 wherein said borehole plug is an inflatable borehole plug assembly and the borehole plug is inflated prior to inserting the borehole lining in the borehole.
5. 7. The method of lining a borehole according to claim 1, further comprising: maintaining an excess length of borehole lining proximate the mouth of the borehole; and supporting the borehole lining proximate the mouth of the borehole with said means to support said borehole lining.
6. 8. The method of lining a borehole according to claim 7, wherein said means to support is a first inflatable borehole plug, the method further comprising: inserting a second inflatable borehole plug in said borehole prior to lining the borehole with the borehole lining; [R:\LIBH]00395.doc:LJG 44 inflating the second inflatable borehole plug before the lining is inserted in the borehole; charging said borehole lining with a required amount of explosive; inflating said borehole lining before or after step and inflating said first inflatable borehole plug after inflation of the borehole lining, wherein said inflated first borehole plug proximate the mouth of the borehole substantially seals said borehole.
7. 9. A method of lining a borehole with a borehole lining comprising the steps of: 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; S(d) sealing said inflated borehole lining with sealing means to substantially prevent deflation of said borehole lining; i" positioning a means to support said borehole lining proximate the mouth of the borehole; and supporting said borehole lining with said means to support. 1 0. The method of lining a borehole of claim 9, wherein said means to support is an inflatable borehole plug assembly; the method further comprising: inflating said borehole plug sufficiently to substantially seal the mouth of the borehole. S 1 A method according to any one of claims 1 to 10 further comprising inserting a spacer element in said borehole lining so as to permit explosive to be placed in said borehole adjacent said spacer element, said spacer element having an overall density less .*than the density of said explosive in said borehole.
8. 12. A method according to claim 11 wherein said spacer element is expandable from a substantially lay flat configuration.
9. 13. A mnethod according to claim 12 wherein said spacer element further includes means obr expanding said element with an expanding material less dense than the density of said explosive.
10. 14. A method according to claim 13 wherein said means for expanding comprises means for providing an inflating substance, said means for providing being located within said spacer element. A method according to any one of claims 1-14 wherein said borehole lining comprises a substantially liquid impermeable sleeve adapted to substantially line a borehole, \wvhich sleeve has an open end, a closed end, an outer surface and non sticking inner surfaces [R:\LI H]00395.doc:LJG thereby allowing explosive material inserted into the open end of the sleeve is situ to travel substantially unrestrictedly to the closed end.
11. 16. A method according to claim 15 wherein the sleeve further comprises means proximate to the closed end for facilitating the lining of a borehole with the borehole lining.
12. 17. A method according to claim 16 wherein the means proximate to the closed end for acilitating the lining of a borehole with the borehole lining is means proximate to the closed end for supporting a weight to facilitate lining a borehole with the borehole lining.
13. 18. A method according to claim 17 wherein the means proximate to 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 to the closed end, a removable pouch disposed proximate to the closed end, and means to which a weight may be attached proximate to the closed end.
14. 19. A method according to any one of claims 16-18 wherein the means proximate to the closed end for facilitating the lining of a borehole with the borehole lining is profiled. shaped or tapered to facilitate lowering of the bore lining down a borehole. -20. A method according to claim 15 wherein the borehole lining further comprises 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 the borehole lining.
15. 21. A method according to claim 20 wherein the means to substantially protect at least a o part ofthe outer surface from damage is an outer sleeve.
16. 22. A method according to claim 21 wherein the outer sleeve is disposed over at least the S closed end so as to substantially protect the closed end from damage as the borehole lining is lowered down a borehole.
17. 23. A method according to claim 21 wherein the outer sleeve is 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 at and proximate the closed end from damage as the borehole lining is lowered down a borehole.
18. 24. A method according to claim 21 wherein the outer sleeve is disposed over at least a portion of the borehole lining proximate the closed end so as to substantially protect the outer surface proximate the closed end from damage as the borehole lining is lowered down a borehole. A method according to claim 21 wherein the outer sleeve is disposed over the closed end and substantially over the borehole lining so as to substantially protect the outer surface firom damage as the borehole lining is lowered down a borehole. [R :\LIBH]00395.doc:LJG
19. 26. A method according to claim 20 wherein the means to substantially protect at least a part of the outer surface from damage is disposed over the borehole lining at least proximate the closed end and further comprises means proximate to the closed end for facilitating the lining of a borehole with the borehole lining.
20. 27. A method according to claim 26 wherein the means proximate to the closed end for facilitating the lining of a borehole with the borehole lining comprises means proximate to the closed end for supporting a weight to facilitate lining a borehole with the borehole lining.
21. 28. A method according to claim 27 wherein the means proximate to 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 to the closed end, a removable pouch disposed proximate to the closed end, and means to which a weight may be attached proximate to the closed end.
22. 29. A method according to claim 26 wherein the means proximate to the closed end for facilitating the lining of a borehole with the borehole lining comprises means proximate to, but disposed below, the closed end for supporting a weight to facilitate lining a borehole with the borehole lining. A method according to claim 26, 28 or 29 wherein the means proximate to the closed end for facilitating the lining of a borehole with the borehole lining is profiled, shaped or tapered to facilitate lowering of the bore lining down a borehole.
23. 31. A method according to any one of claims 15-18, 20-29 further comprising means to support the open end to maintain open the open end to facilitate insertion of explosive into the lining and to support the open end proximate the mouth of a borehole.
24. 32. A borehole which has been lined by the method of any one of claims 1-31. Dated 28 June, 2000 Sanleo Holdings Pty Ltd Soothjet Pty Ltd Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON [R:\lIJBH]00395.doc:LG