Research On Pre-split Technology Of Deep-hole Multi-directional Cumulative Blasting In Oblique Penetrating Fault

The 1067 coal face of Linhuan coal mine encountered oblique penetrating fault,which seriously affected the operation.of the coal face.In response to the problem of1067 working face over fault,it adopts pre-split to weaken hard rock of fault,and then the coal miner cuts through the fault structure area,which reduces the loss of coal resources and,at the same time,reduces the coal face moving processes.The implementation of deep-hole multi-directional cumulative blasting in the overrun coal face fully pre-split the hard rock on the cutting track of shearer,reduced the loss of shearer pick,improved the coal shearer speed,and provided engineering practical experience for coal face to directly pass the hard rock of the fault.The following results were achieved through systematic research in the thesis:(1)A 3D reconstruction method is used to reproduce the structure of the oblique fault at the coal face.According to the conditions and equipment,reasonable track of shearer is designed.It is proposed to adopt the deep hole blasting pre-split technology to weaken the hard rock of the fault on track of shearer.(2)Numerical calculations were conducted to analyze the blasting technical parameters.Adopting 94 mm diameter borehole,75 mm diameter pillar and deep hole blasting technology,the deep hole blasting pre-split operation of NDF153 fault in Linhuan coal mine 1067 coal face was conducted,which improved the process of equipment selection and matching,charging and sealing.(3)Adopting multi-directional cumulative blasting pre-split method,together with the liquid hydrogel explosives,realized the full coupling charge in the large-diameter pillar.The directional fracturing effect of the coal mine explosive is exploited,which greatly overcomes the influence of deep three-dimensional stress clamping action,improved coal mining efficiency.The deep hole blasting pre-split technology are adopted for 1067 coal face of Linhuan coal mine,compared with the II1036 coal face over the fault in the adjacent mining area,the former had better performance,and the average daily advancement of1067 coal face reached 1.89m/day.This thesis has 47 figures,18 tables and 86 references.