Based on the state of Qitaihe mine area, approaches the set rules and calculation methods of water_proof pillar at different conditions.
根据七台河矿区具体情况，对各种条件下的防水煤岩柱的留设原则及计算方法进行论述。
3
The expo organizing city Jixi enjoys great geographical advantage in linking three main coal mining cities — Qitaihe, Hegang, Shuangyashan, and Russia.