Ammunition and explosives – Blasting – Terrain clearance
Reexamination Certificate
1999-01-08
2001-11-20
Nelson, Peter A. (Department: 3641)
Ammunition and explosives
Blasting
Terrain clearance
C102S312000, C102S313000, C102S315000, C166S299000
Reexamination Certificate
active
06318272
ABSTRACT:
THIS INVENTION relates to breaking or splitting of rock or the like. The invention relates more specifically to a method of breaking or splitting of rock or the like, and also to a rock breaking charge suitable for use in breaking or splitting of rock or the like.
The Applicant expects the invention to be of particular importance in mining, but it will also be applicable in other fields like civil construction, and the like.
In the specification, reference will be made to drilling of holes in rocks to be broken. Such holes can be drilled at virtually any orientation or attitude. However, for purposes of this specification, the term “bottom of the hole” or similar wording must be interpreted to indicate a blind end of the hole.
Further, in the specification, reference is made to a rock breaking charge. For purposes of this invention, “rock breaking charge” is to be limited to a charge which includes a non-detonating substance, for example (and preferably) a propellant.
Furthermore, in the specification, reference will be made to a tamping medium which, optionally, may be in the form of a “flowable substance”. “Flowable substance” or similar wording must be interpreted to include a liquid and also a substance which can be urged to flow under pressure including a colloid, gel, or the like.
Further, in the specification, reference is made to a rock breaking charge. For purposes of this invention, “rock breaking charge” is to be limited to a charge which includes a non-detonating substance, for example (and preferably) a propellant.
In accordance with a first aspect of this invention, there is provided a method of breaking or splitting of rock or the like, the method including providing a drilling machine having drilling means to dill a hole in rock or the like along an operating axis, charging means for charging a charge into a hole, and indexing means for selectively withdrawing the drilling means from the operating axis and indexing the charging means with the operating axis;
drilling a hole in rock by means of the drilling means along an operating axis;
withdrawing the drilling means and indexing the charging means with the operating axis;
charging a rock breaking charge by means of the charging means along the operating axis into the hole; and
actuating the rock breaking charge from a remote position.
The method may include removing the drilling machine from the vicinity of the rock prior to actuating the rock breaking charge.
Charging the rock breaking charge may be by pushing it along the hole. Instead, charging the rock breaking charge may be by launching it at speed into the hole to cause the momentum of the charge to displace it down the hole.
The charge may be a composite charge comprising a plurality of components, the charge being contained in a casing. The charge may include a pressure generating substance toward a leading end of the casing and a tamping medium trailing the pressure generating substance, the tamping medium being in the form of settable, flowable substance.
Advantageously, the method may include displacing air from the bottom of the hole around the pressure generating substance. Said displacing air may be by displacing the tamping medium into spaces at the bottom of the hole around the pressure generating substance. Displacing the tamping medium may be by means of a plunger urged into the hole from behind the tamping medium.
In one method, the tamping medium may be in the form of a two component epoxy resin, the method then including forcing the components into contact in a mixing chamber provided for that purpose in the casing and thence into said spaces.
Instead, the method may include mixing the components by rotating the plunger while it is urged into the hole.
Preferably, actuating the charge may be electrically, the charge including conductors anchored in the charge and being extensible out of the hole to the remote location.
Instead, actuating the charge may be by means of a chemical time delay device.
In accordance with a second aspect of this invention, there is provided a rock breaking charge including
a pressure generating substance;
actuating means for actuating the pressure generating substance;
a tamping medium;
a casing containing the pressure generating substance and the actuation means toward one end thereof, and the tamping medium spaced from said one end.
The casing may be elongate and of generally round cross section, and suitable for insertion into a hole drilled in a rock to be broken, said one end being a leading end.
Advantageously, the pressure generating substance may be contained in a cartridge and the actuation means may be in the form of an electrically actuable fuse head, the tamping medium being in the form of a settable, flowable substance.
In some embodiments, the casing may be a composite casing, the cartridge providing a portion of the casing.
The rock breaking charge may include passage means for conducting the tamping medium prior to setting into spaces surrounding the cartridge when received in a hole in a rock in use.
The tamping medium may be in the form of a two component epoxy resin. Then, the rock breaking charge may include a mixing chamber in communication with the passage means and the two-component epoxy resin, the components of the epoxy being arranged to be urged into the mixing chamber to be mixed and thence into the passage means and into the spaces. Instead, the rock breaking charge may include rotatable agitation means for mixing the components of the epoxy resin.
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Denel (Proprietary) Limited
Ladas & Parry
Nelson Peter A.
LandOfFree
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