Research and Test on Overall Mining Method with Combined Wall Support of Rockbolting and Line Pillars

1. Brief Introduction to the Achievements
Sidaogou Sub-mine of Liaoning Wulong Gold Mine previously used a mining method of shallow drillhole shrinkage, as most of the deposits in this mining area being dipping or flat dipping and moderate thick, plus highly developed joints and fractures in the hangingwall, poor techno-economical indices were resulted. Its main technical indices were: stope output being 40 tons/day, delution below 50%, mining loss greater than 30%. Through test and research, the mechanical model of stope roof under pressure and supported by rock bolts was simplified into a beam wedged at both ends as the first case. The parameters designed according to this model has been proven to be reliable by the test, and more materials and engineering have been saved compared with the parameters resuggested by analog method and calculated by empiric formular recommended by the design handbook. Adopting the roof support technique recommended by this achievement, necessary safety conditions can be created for the mining of orebodies of dipping or flat dipping with broken roof and moderate or less thickness, when using high efficiency overall wall mining method.

2. Main Techno-economical Indices
The main techno-economical indices obtained from the test are: stope output being 64.59 ton/day, delution ratio 2.96%, and mining loss 5.78%. Roof support technology adopted in the test allows the exposed area of the stope to be lager than 300 m2 (150~200 m2 by original shrinkage). During the two year period of test application in Sidaogou Sub-mine of Wulong Gold Mine, more than 80% of the output of this mine was by this method, producing an annual economic profit of more than 3,320,400 yuan.

3. Application Prospects
This achievement solved the mining problem troubled the mines for many years, where the deposit is dipping or flat dipping with broken hangingwall and moderate or less thickness. Through test and the practical application in about three years, it is shown that the achievements in roof support, design and calculation of the supporting system are realiable. Comparing with other prevailing methods, it can save materials and engineering. This achievement can be widely applied in mining for dipping or falt dipping orebodies with moderate or less thickness.