The crown pillar of stope is permanent loss and not recoverable, while sill pillar and barrier pillar shall be recovered after the ore drawing work is completed.
采场的顶柱作为永久矿柱损失，采场底柱、间柱等采场大量放矿完毕后，一次性进行回收。
2
The key parameters of the oil shale resource appraisement consist of ore-bed recoverable thickness(H), orebody effective area(S), orebody weight(D) and orebody resource types, etc.