Coal petrological and coal facies characteristics of the No. 2 seam from Huangling mine, Shanxi Province, China

Twenty-two coal samples and six parting samples of two sections of seam 2 from Huangling mine in Shanxi Province were collected and then were analyzed by using optical microscopy. The coal petrological characteristics indicate that vitrinite, with an average content of 77%, is the dominant maceral. The average content of inertinite is only 19%. Liptinite shows only in trace contents. All GWI, VI, GI, TPI values and a ternary diagram of indicator macerals indicate that the main coal facies were formed in moist forest moors, which are the main moor types of the No. 2 coal seam. The evolution of the moors can be divided into 5 stages: I, II, III, IV and V, which evolved from moist forest-moor to open moor, and then became moist forest-moor again.