The failure background of an isolated rock wall in soft fractured rock mass of a mine shaft bottom is introduced.

介绍了某煤矿井底车场软弱破碎岩体孤立岩墙失稳破坏工程背景。

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And the Fuzzy-follower is applied in shaft bottom coal conveyor of a medium-sized coal mine and gives good results. Thus, it solves the problem of power balance of double-motor driving system.

该模糊跟随器在某中型煤矿的井下原煤运输系统中进行了实际应用，效果良好，较好地解决了双电机拖动系统的功率平衡问题。

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They worked with hand trowels, a plywood form for lining the shaft with concrete, inch by inch, and a sturdy hand-built crank for lowering a man to the bottom and sending up buckets of sand.

他们的作业工具是：挖土用的手工泥铲、浇筑混凝土井壁用的胶合板模板、还有手工制作摇杆。 摇杆将一个人送到井底，那个人就在井底一点点挖土然后再通过摇杆把沙子一桶桶送到地面。

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Rehabilitation work on the Silver Shaft began in the first quarter of this year and is now completed to around the 5, 700-foot level, which is around 400 feet from the shaft bottom, the company said.

FORBES: Update:Hecla Plans To Reopen Lucky Friday Mine In 1Q; Loss Reported In 3Q

The entrance hall reaches up through floors of reading rooms, it is crossed over by high walkways and is penetrated from top to bottom by a glazed shaft.

ECONOMIST: New room for readers