Study on triangle fan shaped pressure released initial mining technology with long first weighting interval

In order to solve a long first weighting interval, serious mine pressure behavior problems occurred during mining with medium hard rock strata, a theoreti cal study and practices combined method was applied to study the sectional pressure released roof control method of the triangle fan shaped initial mining and its techn ology with No. 41107 coal mining face in No.4-1 seam of Daheng Coal Industry as the engineering background. In combination with the site certain condition, the top a nd lower gateways were vertically layouted for the open-off cut and the coal mining face. At the initial mining period, one end of the face was fixed and at the other end was pushed forward. Each integrated basic roof of the conventional rectangle coal mining face was converted to a sectional breaking basic roof in sequences in order t 0 eliminate the mine pressure bump danger occurred from the integrated initial breaking weighting of the basic roof above the rectangle initial mining face. The results s howed that with application of the triangle fan shaped initial mining method, the pressure behavior of No.41107 coal mining face was not obvious at the initial mining pe riod. The top coal caving circulation production was increased at the triangle seam section in the open-off cut of the coal mining face. Meanwhile, the coal resources mi ning rate was increased, a safety mining was realized with long first weighting interval.