Dry sprayable cementitious mix - comprising cement fly ash and crushed slag, for stopping mining cavities

摘要

Mortar mixt. comprises by wt. 15-30 (20)% fly ash, 15-30 (20)% cement, 70-40 (60)% crushed slag of grain size 0-4 mm is used for stopping up underground cavities and lining mine chambers etc. It can be transported by compressed air into the desired location or can be sprayed dry onto walls together with finely sprayed make-up water. Method avoids the tendency for demixing when slurries premixed with all their setting water are transported by air pressure over long distances before setting.