hard mineral

When a slot is cut in middle length hole post and stall method with hard ore,it is often used to cut raise or to cut raise and entry.

坚硬矿石内中深孔房柱法切割立槽的开掘,通常使用切割天井拉槽法或切割天井与切割平巷联合拉槽法。

Estimated height of water conducted fracture zone is 16m,and height of in-situ tension fracture zone is 5m after the ore bed was mined;the estimation is based on anhydrite ore bed floor limestone hydrogeological and engineering geological conditions.

基于硬石膏矿层底板灰岩水文地质和工程地质条件计算的矿层开采后导水裂隙带的高度为16m,原位张裂隙带高度为5m。