Coal mining companies mined underground reserves of non-renewable resources of coal industry. Since China's coal mines are mainly mined in the form of mines, it has several characteristics: 1. Production and construction cycle, coordinated development In order to extract the coal buried deep u
Core Tip: One day, a source in Qinghai Province Temple Door County Ditch gold mine gold mining team of 13 workers, as usual, took the iron shovel came in June 1997 in the ditch beside the spiny dig the bunker. Under the scorching sun, the worker Xiao Liu sweated and the other workers repeated the sa
Visual inspection First of all, the overall appearance of the PLC system can be checked and the risk factors in the system can be checked in a timely manner. For example, some parts that have entered the wear out period should be replaced at regular intervals; corresponding measures must be taken