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US 4,377,353 AGranted
Method of selective underground mining and stabilization of rock cavities
AssigneeGränges AB
InventorsGustav Hoberstorfer, Torsten Noren
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AssigneeGränges AB
InventorsGustav Hoberstorfer, Torsten Noren
Estimating the term…
The invention relates to a method of underground mining mineral or preparation of rock cavities, in which method resulting hollow spaces can be refilled entirely or partially with temporarily stabilizing ice. The hollow space resulting from the mining is prepared in a first step for ice filling in that the geothermal heat content in the walls of the hollow space partially is removed, so that the walls assume a temperature below 0.degree. C. In a second step water is supplied, possibly together with a reinforcing additive, in layers and intermittently to the hollow space while the supplied water together with the possibly added reinforcing agent is being cooled and frozen. In a third step the frozen ice body is maintained by removing the constantly inflowing geothermal energy during a time period deemed necessary for achieving the object. The cooling preferably is effected by artificially cooled air. The first step and the third step, however, can be abolished when the climatic conditions are such, that the rock about the hollow space is frozen to below the freezing point. The cooling air flows in a closed system which is entirely separated from the ventilation air.
A method of underground mining of mineral-bearing rock or of preparation of rock cavities, in which hollow spaces resulting from the mining or preparation of rock cavities at least partially can be refilled at least temporarily with stabilizing ice, and in which the resulting hollow space is prepared for ice filling by treating walls of the hollow space with respect to the geothermic heat content of the surrounding rock, and in which water is supplied to the hollow space while being cooled and frozen by air, and in which the ice body formed is maintained, the improvement comprising preparing the resulting hollow space in a first step for a predetermined time for ice filling by removing a portion of the geothermic heat content in the walls of the hollow space such that the walls assume a temperature below 0.degree. C., and in a second step supplying the water intermittently to form layers in the hollow space, cooling and freezing the supplied water, in a third step removing the constantly inflowing geothermic energy for a predetermined period for maintaining the frozen ice body, said cooling and freezing in all three steps being carried out with artifically cooled air which flows within a closed system entirely separated from normal ventilation air.
A method of underground mining of mineral-bearing rock or of preparation of rock cavities, in which hollow spaces resulting from the mining or preparation of rock cavities at least partially are refilled with ice which due to a cold climate automatically permanently stabilizes in a natural way, and in which water is supplied to the hollow space while being cooled and frozen by air, and in which the ice body formed is maintained, the improvement comprising preparing the resulting hollow space in a first step for ice filling by cooling, in a second step supplying the water intermittently to form layers in the hollow space, cooling and freezing the supplied layers of water individually to form an ice body, in a third step maintaining the frozen ice body, said cooling and freezing in the first and third steps being accomplished primarily by using the permafrost of the cold climate and in the second step primarily by naturally cooled air of the cold climate, the naturally cooled air flowing within a closed system entirely separated from normal ventilation air.
Dependencies are inferred from the claim text.