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Abstract Various test results show that hard rock in high geostress tends to be broken more easily，which provides us a good opportunity to investigate non-explosive mining when unloaded. The characteristics of stored energy in hard rock metal mines under high geostress are described. Consequently，the possibility of the continuous mining methods in deep metal mines is analyzed. At present，there are two mandatory conditions to realize non-explosive mining in deep metal mines. One is the high-performance equipments，and the other one is the site-specific geographical conditions，such as well developed rock discontinuities. After unloaded in excavation，the strength of rock mass is weakened by the redistribution of high geostress，which is helpful for seepage of groundwater and thus the number of unstable blocks increases. These conditions provide the advantages for non-explosive continuous mining. In this paper，a geological survey of deep phosphate deposit in Kaiyang phosphate mine is carried out. The rock classification of deep phosphate deposit in this project is put forward according to rock mass classification system(CSIR). Non-explosive mining test for the deep phosphate deposit ore is implemented in Kaiyang phosphate mine. The results of geological survey and non-explosive mining test demonstrate the feasibility of hard rock cracking in high geostress region. The excavation damaged zone(EDZ) of roadway is tested and its scale is larger than the range of the blasting-disturbed zone. The rock mass in EDZ could be efficiently cut by a low power road header. It is easier to cut rock mass in the excavation damaged zone than full-face excavation. It shows that non-explosive mining can be employed in high geostress hard rock for its effectiveness in mining-induced fracture.
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Received: 05 November 2012
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2013, Vol. 32 
