Abstract: The invention provides a method of preparing a blast hole which method comprises the steps of: drilling a blast hole; placing explosives in the blast hole; filling the blast hole with a stemming material comprising a cement composition and water wherein the weight ratio of water to solids content of the stemming material is at least about 1:1.

Abstract: A method of stabilising a blasthole prior to detonation which comprises the step of coating the inner wall of the blasthole with a stabilising composition. In one embodiment, the invention comprises coating the blast hole by means of a movable spraying application. The invention further relates to the use of a silicate-containing resin but is also suitable for use with a thermoset resin system. The method can be used to apply the stabilising composition to both dry and wet blastholes.

Abstract: The invention provides an injection bolt for use in securing a rock mass having: a shaft for insertion into a hole in the rock mass which shaft has a profile and forms a profiled internal bore which bore has an inlet suitable for connection to an anchoring material pump and an outlet for injecting anchoring material into the hole in the rock mass; and a static mixer for mixing multiple components of the anchoring material; wherein the internal bore comprises the static mixer which is fixed in place by the profile; and a method for its production.

Abstract: The invention provides a system comprising two components to be mixed together to form a settable cementitious composition wherein a first component comprises: (a) Portland cement; (b) calcium sulphate; and (c) water in a weight ratio of water to Portland cement and calcium sulphate solids of from 0.5:1 to 5:1; and a second component comprises: (d) a water soluble silicate; and (e) water, in a weight ratio of water to silicate solids of from 1.5:1 to 25:1; which cementitious composition has a higher early strength than known compositions.

Abstract: A roof bolt comprises a shaft for insertion in a hole drilled in a mine roof and a head whereby the bolt may be rotated, the head being offset with respect to the longitudinal axis of the shaft so that when the bolt is rotated by means of its head the shaft is caused to describe a circle of greater diameter than its own diameter, and where the offset is at least 0.08 inch and not more than 0.25 inch. Preferably the offset is from 0.10 to 0.16 inch. The invention includes a method for the production of roof bolts which comprise a shaft for insertion in a hole drilled in a mine roof and a head whereby the bolt may be rotated, the method being characterised by being controlled so that at least 90% of the bolts produced have their head central axis offset with respect to the longitudinal axis of the shaft by an amount of at least about 0.08 inch and not more than about 0.25 inch.

Abstract: A settable fluid cementitious composition which is fluid for sufficient time to be suitable for use in a flexible container to provide support in a mine said composition comprises (i) Portland cement in an amount from at least about 8% preferably 10%, (ii) a water soluble silicate in an amount from at least about 2% and (iii) water in an amount to provide a water to solids weight ratio of at lest about 1.2:1 preferably at least abou5 1.5:1 and where the % are by weight based on the combined weights of (i), (ii) and (iii). The viscosity immediately after mixing the components together is sufficiently low that additional water can be incorporated. The composition may include (iv) a pozzolan in an amount from 2 to 35% by weight based on the combined weight of (i), (ii), (iii) and (iv).

Abstract: The invention comprises a roof bolt and nut in screw threaded engagement, said bolt comprising a shaft for insertion in a hole drilled in a mine roof and a threaded portion engaged by the nut whereby the bolt may be rotated. The nut is offset with respect to the longitudinal axis of the shaft of the bolt so that when the bolt is rotated by means of the nut, the bolt is caused to describe a circle of greater diameter than its own diameter, the amount of said offset being from about 0.015 to about 0.50 inches. Preferably the offset is from about 0.02 to about 0.25 inches. The nut may be releasably locked in screw threaded engagement with the bolt so that the bolt can be rotated by means of the nut and above a selected torque the nut will break out.

Abstract: A roof bolt comprises a shaft for insertion in a hole drilled in a mine roof and a head whereby the bolt may be rotated, the head being offset with respect to the longitudinal axis of the shaft so that when the bolt is rotated by means of its head the shaft is caused to describe a circle of greater diameter than its own diameter, and where the offset is at least 08 inch and not more than 0.25 inch. Preferably the offset is from 0.10 to 0.16 inch. The invention includes a method for the production of roof bolts which comprise a shaft for insertion in a hole drilled in a mine roof and a head whereby the bolt may be rotated, the method being characterised by being controlled so that at least 90% of the bolts produced have their head central axis offset with respect to the longitudinal axis of the shaft by an amount of at least about 0.08 inch and not more than about 0.25 inch.

Abstract: A method for providing a protective coating in a mine comprising spraying onto the rock surfaces of the mine a hot melt adhesive in an amount to form a coating at least 1 mm, preferably at least 2 mm in thickness and allowing the coating to solidify. The hot melt adhesive preferably has a melting point on the range from 70 to 250 degrees Centigrade and may include a filler such as an inert material in finely divided form such as ground limestone, mica, sand and silica, the filler comprising between 1 and 40% by weight of the combined weight of adhesive and filler.

Abstract: A settable composition which can be applied by spraying to form a coating on a surface such as the walls of a mine comprises (i) a cementitious composition comprising the following components: (a) from 25 to 95% of calcium aluminate, (b) from 0 to 10% of lien and (c) from 0 to 50% of calcium sulphate, and where the sum of (b) and (c) is at least 5% the % being by weight based on the combined weight of (a), (b) and (c) and where the proportions of the components are such that the composition on hydration is capable of absorbing at least its own weight of water and (ii) an aqueous emulsion of an organic polymer, the amount of (ii) in relation to (i) being such as to provide a weight ratio of polymer, expressed as solids, to combined weight of (a), (b) and (c) of from 0.5:1 to 10:1, preferably 1:1 to 2.5:1 or (iii) a dispersible organic polymer and where the amount of dispersible polymer is such as to give a weight ratio of polymer to combined weight of (a), (b) and (c) o from 0.5:1 to 10:1, preferably 1:1 to 2.

Abstract: A method is provided for the manufacture of elastic, fire resistant, organo-mineral systems based on water-glass in which, to the water-glass, compounds, having terminal amino groups are added, in which at least one free hydrogen atom on at least one amino group and at least one alkylene group interrupted by one oxygen and/or sulphur atom are present as well as the products and the two component systems which can be obtained therewith. The later can be applied in mining for filling and/or agglutination of anchors.