Causes analysis and prevention for shaft accidents in carbonaceous phyllite stratum in Yangshan gold mining area,Gansu Province
The main ore-bearing strata in the Yangshan gold mining area are carbonaceous phyllite,calcareous phyllite,siliceous limestone,etc.Among them,the construction difficulty is the highest in carbonaceous phyllite.Its structure is sedimentary bedding,with major minerals of illite and kaolinite,low strength,developed fractures,softening when encountering water,and with interlayer of quartz particles,susceptible to fragmentation.In the drilling construc-tion process,it is extremely easy to cause drilling accidents and the success rate of processing is very low.This paper summarizes the characteristics of shaft accidents encountered when drilling carbonaceous phyllite stratum in recent years and analyzes the causes of the accidents and difficulties of handling from 3 aspects:strata,personnel,and equip-ment.It proposes preventive measures and treatment key points:adjusting the slurry performance and enhancing the sand discharging capacity of the pump to improve the hole environment,and maintaining the equipment performance of the drilling rig,drilling rod,and connector,can effectively reduce the frequency of shaft accidents;for the borehole fail-ure,broken drilling,stuck drilling,and buried drilling,rapid handling should be taken as the principle,and the prob-lems can be bypassed by using water-cement grouting and directional drilling to significantly reduce economic losses and shorten the duration of shaft accidents.
万方数据
维普
