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US 4,786,211 AGranted
Filling cavities in mining
AssigneeBASF SE
InventorsBernd Leutner, Berthold Mueller, Wilhelm Volkenborn
Life of this patent
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Abstract
Cavities in mining are filled by introducing a mixture consisting of a slurry or sludge which evolves CO.sub.2, foams and solidifies and predominantly comprises alpha-hemihydrate, alpha-CaSO.sub.4. 0.5 H.sub.2 O, an alkali metal or alkaline earth metal carbonate and water, by a method in which the mixture is mixed with a bisulfate-containing aqueous solution or suspension of one or more metals before being introduced into the cavities to be filled.
Claims7
A process for filling empty cavities associated with the facing of mine workings which comprises the steps of:
- (a) preparing an aqueous slurry for introduction into said cavities which, in addition to water, consists essentially of alpha-hemihydrate, alpha-CaSO.sub.4.0.5H.sub.2 O and a metal salt capable of evolving CO.sub.2 when in contact with an acid with said salt being selected from the group consisting of alkaline and alkaline earth metal carbonates;
- (b) prior to being introduced into said cavities, admixing said slurry with an aqueous medium which contains a metal bisulfate foaming agent;
- (c) conveying the resulting foamable mixture into said cavities;
- and
- (d) allowing the mixture to foam and thereafter solidify to fill the cavities.
2 more elements
Dependencies are inferred from the claim text.