Where: the reserves of the block section, t;-the flat area of the block, ㎡;-average thickness of coal seam, m;-average bulk density of blocks, TM;2.2.3 Calculation Parameters1) average coal thickness of block sectionThe arithmetic average value of drilling holes in the divided block segments or in adjacent block segments is adopted. As the average coal thickness of the block, when contacting with non-recoverable areas, the minimum recoverable thickness shall be appropriately increased to participate in the average calculation.