Frozen baclfill mix formulations and process for use thereof in underground mining applications

Abstract

Formulations are provided for producing structural members or back fill for mine stopes in environments having sub zero temperatures such as permafrost. The formulations having constituents including crushed rock (rockfill), powdered tailings, ice and water in specific ratios with attention to the prescribed gradations of the rockfill and tailings. The tailings, a readily available and very finely divided material, fill the naturally existing voids in the rockfill. The gradation of the rockfill and the bulk density of the rockfill establish the rockfill/tailings ratio, which has been determined to lie between 1 and 3 or from 50/50 to about 75/25 for optimum strength. The ice in the mix design arises from the pre-existing moisture content in the rock and tailings typically 2% to 5% for the rockfill, 8% to 25% for the tailings. The change of state of liquid water to ice on the particle surfaces is the binding mechanism of the system and is enhanced by vigorous mixing.

Dependencies are inferred from the claim text.