Application Study On Pre-Weakening Hard Top-coal In Fully Mechanized Caving Of No.1 Honghui Coal Mines

The key problem of the fully mechanized top-coal caving in hard thick coal seams is that the top-coal cannot be broken and fell down fully, and the top-coal pre-weakening technique is an available method to solve it. With the site test mainly, the hard top-coal pre-weakening technology of the fully mechanized top-coal caving face in No.1 Honghui coal mines is studied in this paper.By researched and compared, it is found that the rational way of the pre-weakening laneway in No.1 Honghui mines is two-laneways. Based upon the test and observation in the mine, the pre-weakening acting mechanism and the rule of the pre-blasting and the injecting water are explained, and by analyzed, it is get out that the row holes can be well utilized the mining pressure, the rational way to set the holes and the rational main technique parameters of pre-weakening are worked out for Honghui mines. These offer the technique basis for practice application.The testing proves that it is available to ensure the working faces safety and increase the top-coal recovery that forcing blast top-coal and roof when the faces early working. The forcing blast method of the end top-coal is available, safety and reliable, it has a markedly effect to increase the recovery of the hard coal face.With the site practice, the hard top-coal pre-weakening effect of the fully mechanized top-coal caving is improved and enhanced more, and the good economical and technical benefit has obtained in the testing in No.1 Honghui mines.