Minerals in coal

Coal contains variable amounts of largely incombustible mineral matter co-existing with the organic matrix (Bryers, 1996; Crouch, 1994; Gluskoter et al., 1981; Stach et al, 1982; Swaine, 1990; Valkovic, 1983; Vassilev and Vassileva, 1996; Vorres, 1986; Ward, 1986). Mineral matter is generally considered to consist of all the inorganic minerals (discrete phases), as well as all elements (apart from C, H, O, N and S) that are in, or associated with, coal. This definition includes discrete crystalline particles, amorphous mineral phases, inorganic elements chemically bound to the organic material and compounds dissolved in the pore or surface water of the coal. Minerals occur as discrete flakes, grains or aggregates in a number of modes (Bryers, 1996): microscopically disseminated inclusions within organic matter, as layers or partings, as nodules including spherical or lenticular concretions, as fissure/cleat/fracture filling material, and as megascopic rock fragments resulting from faulting or slumping.