Based upon performed analysis of mining resistance as a function of mechanical properties of the mined material, mineability index WUB was determined. With regard to the fact that the coal is a brittle, heterogeneous with inclusions, fracturing, these factors as a function of mining resistance were considered when mineability index was estimated. New mineability index WUB, regarding so far separately analyzed values of A and ψ, more precisely describes the coal in the seam. It describes the coal’s mineability, as a function of the length of rock breaking line (cutting), with regard to the real shape of the measuring cut groove. After analyzing the percentage of values of the mineability index, the new classification with three instead of eight classes, which is precise enough for proper selection of cutting mining machines (longwall tumble heading machines).