Mines primarily engaged in producing anthracite, bituminous coal, brown coal and lignite; and coal crushing, pulverizing, cleaning, screening, and sizing plants, whether or not operated in conjunction with the mines served. Also included is the agglomeration of coal and lignite into briquettes and other packaged fuels at mining sites. The manufacture of briquettes and other package fuels from purchased coal or lignite is classified in group 3540 (Manufacture of miscellaneous products of petroleum and coal). The mining and preparation of peat is classified in group 2909 (Mining and quarrying not elsewhere classified).