a method for concentrating coal tailings and for dewatering coal products employing a copolymer of diallyldimethlylammonium halide and a vinyl alkoxysilane , preferably a copolymer of diallyldimethylammonium chloride and vinyltrimethoxysilane as a coagulant . the method for concentrating coal tailings comprises steps of : feeding the coal tailings to a thickener ; treating the coal tailings with the coagulant , discharging substantially concentrated tailing ; and withdrawing substantially clarified liquid from the thickener . a method for dewatering coal products containing water comprising the steps of : feeding the clean coal containing water to a twin belt filter press ; treating said coal with an effective amount of a copolymer coagulant of diallyldimethylammonium halide and vinyl alkoxysilane , preferably diallyldimethylammonium chloride and vinyl trimethoxysilane is also disclosed . the method encompasses removing water from the coal product through the addition of the subject polymer coagulant ; removing the dewatered clean coal product from the filter ; and withdrawing the recycled water through the filter .