Research And Application Of Buffering Controlled Blasting In Side Slope Engineering Of Bayan Obo West Mine

Bayan Obo West Mine of Baotou Iron and Steel Co.,Ltd.has an annual output of 10 million tons of raw ore and a total of 75 million tons / A.It is a super large open-pit stope.The height of stope in mining stage is 12 M,and the slope angle of bench is 65 °.At present,with the advance of mining engineering,the pre splitting blasting technology has some limitations,which mainly shows as follows: after the pre splitting technology is adopted in the area near the surface where the lithology is weak and easily weathered,there is no good design slope shape and qualified slope half wall porosity;the area with insufficient platform width is not suitable for presplitting blasting.It is of great significance to solve the problem of slope stability and safety production.In this paper,the application of buffer controlled blasting in Bayan Obo west mine is taken as the research object.Based on the experimental study on the physical and mechanical properties of the stope rock and the structural characteristics of the ore rock structure,the blastability zoning of the ore and rock is established,and the main lithology of the side slope area is confirmed.Based on this,the bench blasting parameters are selected.Based on the principle of improving blasting quality,safety,reliability,economy and reasonableness,two perforation schemes and four buffer controlled blasting charging schemes are studied based on the blastability zoning of ore and rock,and the tendentious selection is given through comparative study;at the same time,the comprehensive evaluation model of buffer controlled blasting in stope is established through systematic research;the small-scale test typical blasting area test is used to popularize the comprehensive evaluation model The field test and practice are carried out by means of comparison test,and the test effect is evaluated to verify the buffer control blasting scheme of main blasting rock types,and the slope leaning effect under different interval conditions is obtained.Through the above research,the main conclusions are as follows:(1)through the blasting tests of 5 groups and 9 zones,the sidewall hole retention rate of the top spacing scheme(63.11% ～ 65%)is better than that of the non separation scheme(57.14% ～ 61.68%),but lower than that of the middle interval and multi-point initiation scheme The wall pore retention rate was 69.92% ～ 72.86%.(2)Under the same conditions,the half wall hole retention rate of the middle interval and multi-point initiation scheme is 11% higher than that of the top separation scheme and 20% higher than that of the non interval scheme.(3)Through the study on the physical and mechanical properties and blastability of ore and rock,it is concluded that in the explosive area with solid coefficient f = 5 ～ 10,150 mm hole diameter blasting is adopted for 12 m bench,the explosive consumption of the side work unit should be controlled within 0.5 ～ 0.67 kg / M ～ 3,and the recommended unit consumption table of representative lithology is formed.(4)In the test of blasting vibration,the particle vibration velocity decreases with the distance,and the attenuation rate of equal distance increases;at the same distance,the damping effect of the middle interval and multi-point blasting scheme is 11% better than that of the top spacing scheme under the same conditions,and the damping effect of the top spacing scheme is 16% better than that of the non spacing scheme.