coal drill bit - 2 views
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greatdrillbit on 15 Jul 20he production system of Mining Industry is a complex system composed of many links.In coal mine drilling, complicated geological and hydrologic conditions, thick alluvium of topsoil, many quicksand layers, large water inflow, large well diameter, deep wellbore, and often concentrated operation scale, as well as high temperature, high pressure and high formation stress in the deep well, will greatly aggravate the severity of underground complexity and the difficulty of treatment.