In response to the problem of small layered thickness and low production capacity of the subleve caving mining with spherical charge,based on the theory of bunch-holes blasting,the bunch-holes crater retreat mining method(BCR)is developed.Bunch-holes blasting has the enhancing rock breaking effect.When using equivalent spherical charge(ESC)of a bunch-holes with 4-5 holes,the blasting layering height is 2-3 times that of a single hole.The BCR mining method uses equivalent spherical charge(ESC)crater for blasting with deep bunch-holes,and the spacing between bunch-holes is 7-8 m,and the ordinary industrial explosives are used.Each layered blasting has a height of 5-8 m.The dilution rate is 8％,the loss rate is 10％,the large block rate＜5％and the production capacity is 1 800-2 400 t/d.Compared with the single hole spherical charge blasting VCR method,the large block rate is reduced by 10％-20％,and the stope production capacity is increased by more than twice.BCR mining method is a large-scale and efficient mining method suitable for thick and large ore bodies,medium thick and steeply inclined ore bodies.
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