Study on the classification of surrounding rock and the technology of support by rockbolt and shotcrete in Xikuangshan antimony mine

The deposit of the Xikuangshan antimony ore field lies in the silicified limestone and is output in a gently inclined way,layer by layer.Its hanging side is not solid and the ore body is firmed with the heading side.The ore body is firstly processed by applying the open-stope method and subsequently the two-step processing method is adopted for filling and handling the mined-out area.In the past,the laneway was usually supported with dressed stones or concrete and an ore canopy guard of 0.8~1.2m thickness was reserved in the stope roof.In order to save the laneway support expense,to accelerate the support speed and to increase the rate of mining recovery under the stope,the surrounding rocks have been classified into five levels according to the different rock structures/characters of the surrounding rocks of the deposit,the sizes/geometrical morphologies of the excavation bodies,as well as the excavation methods.The suitable bolt-shotcrete support types and design parameters shall be selected for different levels of surrounding rocks.The production practice shows that the application of the bolt-shotcrete support laneway,compared with that of the dressed-stone support laneway,will save 40% of expenditures and improve the advance rate;the replacement of the ore canopy guard with the bolt-shotcrete support under the stope will increase the rate of mining recovery by 5%.And better safety technologies and economic effects have been obtained at the same time.