Presplit Blasting Technology for Hard Top Coal of Xingtai Coal Mine Second 1 Coal Seam

The mining of a sharply inclined hard thick coal seam is one of the difficult technical problems in the mining technology. In the sharply inclined hard thick coal seam, the mining pressure does not show clearly and the coal seam roof management is complex, in addition to roof accidents, low stopping rate and other factors, which makes the improvement of the mine production and the economic benefits very difficult. The Xingtai coal mine of second 1 coal seam has remarkable characteristics of hard coal, large dip angle of coal seam, high mashgas and thick seam. Thus, the main technical problems that the Xingtai Coal Mine has to face, are the improvement of hard top-coal caving characteristics. This paper, on the basis of analysis of the broken characteristics of hard top-coal, and combined with the coal seam's second 1 engineering geological conditions, suggests some major technical measures and three kinds of presplit blasting schemes of improving the second 1 coal seam hard top-coal caving characteristics. Through the field test, the problem that the second 1 coal seam hard top-coal is difficult to release is successfully solved, and the desired effect is achieved.