Research On Key Technology And Application Of Large Diameter Deep Hole Mining

The large-diameter deep-hole mining method is known for its high production capacity and is widely used in mining.In production practice,most of the blasting schemes and parameters depend on the selection of experience,which is inconsistent with the actual conditions of the mine,resulting in problems such as hidden safety hazards,low productivity,and increased production costs.This paper relies on the current status of large-diameter deep-hole mining production in a large-scale iron mine.Based on reading relevant literature,it comprehensively uses theoretical analysis and field test methods to study large-diameter deep-hole mining undercutting,erosion prevention,roof breaking,and side The technology of collapsing mine has been applied in the field and achieved good results.The main research results of this article are as follows:（1）Based on Livingston’s blasting crater theory,a field test of a blasting crater with a diameter of 100 mm was carried out.The results showed that the optimal crater depth of the 2.1kg charge best depth was 1.26 m,the critical depth was 2.07 m,and the rock deformation energy coefficient was 1.62m/kg^1/3.On this basis,combining the theoretical calculation and empirical formula calculation method to determine the blasting parameters of the cut hole of the patio;the charging structure of the double-layered spherical charge pack and the blasting sequence of the cut hole are proposed.（2）On the basis of analyzing the mechanism of blasting and punching,establish a physical and mechanical model of the plugging material,analyze the force and movement of the plugging material in the blast hole,and derive the formula for calculating the length of the plugging of the upper and lower ends of the large-diameter deep hole.Combined with the blasting mechanism of the water seal,the blast hole blasting recoil technology of the combined water seal blocking structure was formulated.（3）Apply the plastic limit method,the first strength theory method,and the thin elastic deformation theory to calculate the safe thickness of stope roof blasting and determine the minimum safety thickness of roof blasting is 6.2m.The stope broken roof lasting scheme is proposed around the minimum safety thickness of the top,the charge structure and the sequence of initiation.（4）According to the test results of the blasting crater,the study determined that the parameter of the hole network in the side-collapse area is 2.8×3m,and the method and plan of the lateral blasting in the stope.By comparing and analyzing the advantages and disadvantages of the five types of ore initiation sequence,three schemes of ore inversion sequence are selected.The parameter of the side hole mesh is 2.2×3m.The smooth blasting and air space charge technology are used to effectively control the blasting boundary and vibration.（5）On-site industrial tests show that the optimized plan blasting ore bulk rate is reduced by 2.2%compared with the original plan,and the unit consumption of the blasting of the cavity expansion blasting and lateral ore collapse is reduced by 0.38kg/t and 0.08kg/t,respectively.The material cost is saved by 0.52 yuan.