Abstract: The mining method of this invention is particularly suitable for the underground extraction of large mineral deposits, wherein a subsidiary road is formed perpendicularly to the work face from which the mineral deposit is to be removed. A boundary subsidiary road is formed substantially perpendicularly to the subsidiary road, a first mine tunnel is formed by removing the mineral deposit from the work face along the subsidiary road until the boundary gate road is reached. Then the material around said first mine tunnel is collapsed to fill the same along the subsidiary road and the collapsed matter is consolidated along the subsidiary road. Finally a second mine tunnel is formed along the subsidiary road. The second mine tunnel can be horizontally or vertically adjacent to the first mine tunnel.

Abstract: There is disclosed a process for the extraction of thick coal seams by means of which coal seams not extractable in one bank or slice and/or located at peripheral areas may also be extracted under improved mine safety conditions and with high productivity.According to the invention the thick coal seam is if required, divided horizontally and/or vertically into extraction blocks which are bounded and separated by stowing pillars arranged according to the direction of advance of the extraction. The cavity of the pillars is advanced at a level higher than the level of the roof of the extraction space, after which the cavity of the pillar is back-filled. Then the block is extracted by means of block caving in a manner known per se. In a preferred embodiment of the invention incombustible material that agglomerates under the effect of the static pressure of the rock is used for stowing.The utilization of the process for extraction according to the invention results in a considerable increase of intensity.

Abstract: In mining a heavy coal seam that must be excavated in several benches, the excavation of the uppermost bench is accompanied by the introduction of a cementitious slurry into the resulting stope for consolidating the waste rock present therein, preparatorily to the excavation of the next-lower bench, and proceeding in like manner with the second bench if a third one is to follow. The cementitious slurry comprises burnt or slaked lime, and/or portland cement, suspended in water in a quantity of about 10 to 60% by weight and preferably together with a small percentage of chlorides of one or more alkali or alkaline-earth metals, to which ceramic aggregates at large specific surface such as mineral ashes, slag, sand or dolomite powder may be added in a quantity of up to about 30% of the weight of the water.