动流碴冒落的清理与支护１地质状况张家口金矿位于冀西北山区、宣化盆地最北边，属高寒山区。矿区高度在１２３５～１４５６ｍ之间。矿体埋藏深浅不一，风化十分严重，岩体节理发育，断层多，顶板冒落频繁。历年由于顶板冒落造成的伤亡事故占总伤亡事故的５７．１％。因此... Clean-up and support of cofferdam 1 Geological conditions Zhangjiakou Gold Mine is located in the northwestern mountainous area of ​​Hebei Province and the northernmost of Xuanhua Basin. It is an alpine mountainous area. Mining height between 1235 ~ 1456m. Buried ore body varies in depth, weathering is very serious, rock joint development, fault and roof fall frequently. Over the years due to the roof casualties caused by casualties accounted for 57.1% of the total casualties. therefore...