Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
  • G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
  • G01V1/02—Generating seismic energy
  • G01V1/104—Generating seismic energy using explosive charges
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B33/00—Sealing or packing boreholes or wells
  • E21B33/10—Sealing or packing boreholes or wells in the borehole
  • E21B33/13—Methods or devices for cementing, for plugging holes, crevices or the like
  • E21B33/134—Bridging plugs
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42D—BLASTING
  • F42D1/00—Blasting methods or apparatus, e.g. loading or tamping
  • F42D1/08—Tamping methods; Methods for loading boreholes with explosives; Apparatus therefor
  • F42D1/24—Tamping methods; Methods for loading boreholes with explosives; Apparatus therefor characterised by the tamping material
  • F42D1/26—Tamping with foaming agents

Definitions

• the present invention relates to the fixing of plugs in boreholes and the placing of explosives in boreholes.
• a novel borehole plug is also part of the invention.
• decking The placing of plugs at selected depths in a borehole is generally called decking.
• Presently known decking methods are costly and inefficient.
• One example of a decking is a wooden or concrete disk having a cross section substantially corresponding with the bore-cross section and lowered by rope to the water surface. It has also been proposed to use as a decking a polyester resin which floats on the water and solidifies after about 45 minutes. More recently, it has been suggested to replace the decking with a gel explosive slurry which floats on the water layer.
• Timber or concrete deckings are not sufficiently reliable while gel explosive decking systems are costly and not easily prepared. Polyester resin is difficult to emplace without contamination of detonating cord, bore wall, and/or the resin and is slow to set. There thus remains a need for a decking system that is inexpensive, quick, convenient and which provides a reliable barrier above the water.
• the invention in one broad form comprises a borehole plug comprising two or more co-reagents which expand when mixed, said co-reagents being contained in a manner such that they do not inadvertently mix but are mixable when required, said co-reagents being further contained in an outer container, said outer container being adapted to retain the co-reagents as they are mixed and being dimensioned for dropping or lowering down a borehole.
• the invention also includes the method of placing an explosive charge in a borehole comprising the steps of expanding foaming reagents at a required position in a borehole to form a deck anchored to the borehole wall and loading explosives on the deck.
• the reagents may be mixed before or after lowering down the borehole.
• the invention has many advantages over known systems - compact package; light, easy to carry; quick in operation, say 1 minute to locate in desired position; package has shelf life of at least one year; particularly, field workers unskilled in the handling of dangerous chemicals cannot come in contact with them; completely safe in use, storage and transport; has been given full approval of all relevant Regulatory Bodies; low cost; multi versatile; requires no specialised equipment; easy to locate in borehole by floating on water line or suspending from light string.
• Figure 1 shows an example of the use of the plug in a borehole
• Figure 2 shows an example of the plug of the invention.
• a bag of suitable material to be located at a desired position in a borehole.
• the bag would contain an expandable material which is expanded to securely locate the bag at a desired position in the borehole.
• the bag is to be lowered to a position above or at the water line and the expandable material allowed to expand thereby sealing the water from an explosive charge located above the bag.
• a bag containing the expandable material could be lowered to a predetermined position on a rope or the like and the material allowed to expand so the material becomes anchored to the borehole walls so that the bag will locate an explosive charge at a position spaced from the bottom of the borehole.
• the expanding material can be any material that expands on activation. It would usually comprise at least two co-reagents which on admixture cause a nett increase in volume and set to a solid. There would generally be a change from liquid to solid state with a generation of gas forming preferably a closed-cell foam.
• the solid may be rigid or flexible. In this specification such preferred materials are called plastic foams.
• plastic foams examples include polyurethane , polystyrene, chlorinated or chlorosulfonated polyethylene, copolymers of vinylidine fluoride and hexafluoropropylene, polyamides, polytetrafluoroethylene, styrene-acrylonitrite copolymers, polyvinylchlo ide, polyisocyanurates, polyphenols, epoxy resins, silicone resins, cellulose acetate, cellular rubber, latex foam rubber, urea-formaldehyde resins, polyimides and polyolefins such as polyethylene, polypropylene and ethylene-propylene copolymers.
• the expansion mechanism preferred is polyurethane foam.
• Polyurethane is the generic name for a wide range of products formed from the reaction of an isocyanate and a polyol.
• Toluene diisocyanate (T.D.I.) , (predominantly used in flexible foams) .
• M.D.I. Polymeric methylene diisocyanate
• the preferred isocyanate in the system is M.D.I, as it is a less hazardous material.
• M.D.I is classified as a 6.1 (B) Hazardous Material, which must be taken into account in the design concept of the invention.
• polyetherols There are two basic polyol groups: polyetherols and polyesterols. Both of these groups are commercially available in Australia in an extensive subrange of products,
• the properties of the finished polyurethane product are varied by choice of polyol.
• the preferred polyol in the system is a polyetherol, one part of which reacts with 2 parts of M.D.I, to form the rigid polyurethane end product. Foaming
• the material composition of the containers should be compatable with the chemical components.
• the construction and sealing of the containers should be such that when filled they satisfy the requirements of the relevant Regulatory Bodies regarding- transport, storage and use.
• the preferred container is a blow moulded low density polyethylene jar with a screw on lid. This container meets all of the above requirements and is also important to the operation of the invention.
• the co-reagents can be released from the containers by application of pressure. For example, from the heel of one's foot. This means that the co-reagents can be released easily, even through several layers of encapsulating outer bags.
• the construction and materials used for the containers is such that even on rupturing no sharp edges or points result which may puncture the encapsulating bags.
• the bag provides a dual role, initially that of safety in containing co-reagents leaking from their containers and secondly as the reaction vessel for the chemicals.
• the bag is preferably: transparent in order that it can be seen that all of the co-reagents are emptied from their individual containers and that sufficient mixing of the co-reagents has been achieved. flexible enough to enable quick easy mixing of the co-reagents by hand, yet robust enough to withstand puncture during rupturing of the containers and the subsequent mixing. ? be a material compatible with the co-reagents, be strong enough to contain the reagents during reaction until at least the bag is completely filled with foam. tolerate the heat produced in the reaction without rupturing. must be made of a material capable of being competantly sealed. the walls and seals of the bag must be free from leaks.
• the dimensions of the bag are such as to encourage the foam to expand laterally to the "Borehole” wall prior to vertical expansion up the "Borehole”.
• the relative volume of the bag to the chemical foam is such as to impede free expansion and thus produce a strong, rigid, high density polyurethane plug in firm contact with the "Borehole” wall.
• the preferred inner bag is made from low density polyethylene clear "Lay Flat” tubing, approximate wall thickness 0.004 inch. The dimensions of the tubing and the length of the bags is designed to suit the "Borehole” in which it will be used.
• the bags are heat sealed around the chemical containers.
• the bag also has a dual role; one of safety providing additional insurance against leakage of co-reagents and secondly as a support to the inner bag during the reaction.
• the bag is preferably: transparent in order that previously stated operation of the inner bag can be seen. flexible enough to enable easy mixing of the reagents, yet sufficiently robust to withstand rough handling e.g. application of pressure to containers with the heel of the foot. be strong enough to support the total weight and able to tolerate the heat generated from the inner bag without leakage. be capable of being sealed. walls and seals of the bag must be free from leaks. the dimensions of the outer bag are such as to allow full expansion of the inner bag.
• the preferred outer bag is made from low density polyethylene clear "Lay Flat” tubing approximate wall thickness 0.006 inch.
• the dimensions of the bag again relate to the diameter of the "Borehole" in which it is to be used.
• the outer bag is folded and wrapped neatly around the form of the two containers further increasing the ability of the total unit to withstand rough handling in transport and storage.
• the device of the invention In use the device of the invention is taken to a borehole and the inner containers broken and the co-reagents mixed. It is then dropped down the borehole to rest on top of any water therein or it is lowered down to a required level where it expands and anchors to the borehole wall to form a deck on which explosives are loaded.

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• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Geology (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Physics & Mathematics (AREA)
• Mining & Mineral Resources (AREA)
• Environmental & Geological Engineering (AREA)
• Remote Sensing (AREA)
• Fluid Mechanics (AREA)
• General Engineering & Computer Science (AREA)
• Geochemistry & Mineralogy (AREA)
• Acoustics & Sound (AREA)
• General Physics & Mathematics (AREA)
• Geophysics (AREA)
• Containers And Packaging Bodies Having A Special Means To Remove Contents (AREA)
• Treatment Of Steel In Its Molten State (AREA)
• Closures For Containers (AREA)
• Filling Or Discharging Of Gas Storage Vessels (AREA)

Applications Claiming Priority (8)

Publications (1)

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• 1985
  • 1985-07-11 ES ES545093A patent/ES8800739A1/es not_active Expired
  • 1985-07-12 EP EP19850903186 patent/EP0187782A1/en not_active Withdrawn
  • 1985-07-12 BR BR8506823A patent/BR8506823A/pt not_active IP Right Cessation
  • 1985-07-12 WO PCT/AU1985/000151 patent/WO1986000660A1/en not_active Application Discontinuation
• 1986
  • 1986-03-10 FI FI860989A patent/FI860989A/fi not_active Application Discontinuation

Non-Patent Citations (1)

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