Filling up underground cavities remaining after mining - with compsn. contg. deacidified marl, portland cement and gypsum

摘要

Compsn. contains (in wt.%) 'de-acidified' marl 50-85 (pref. 60-80), Portland cement 46-14 (37-19) and gypsum dihydrate or anhydrite 4-1 (3-1). This compsn. can take up a double amt. of water and yet solidify rapidly forming a prod. having sufficient mechanical strength. Thus the consumption of raw materials is low (450 kg. per 1 m3). The workability of the aq. mixt. is good, as the viscosity is relatively low (suitable for pumping), and the setting is not too rapid.