Underground Borer

(large-diameter), a machine designed for drilling well holes up to 390 mm in diameter upward along a coal seam and for drilling out drill holes 500-850 mm in diameter downward in steep, inclined, or gently sloping seam beds. The first large-diameter underground borers in the USSR were manufactured by the Kemerovo Factory in the Kuzbas (1936) and Gorlovka Factory in the Donbas (1938). An underground borer consists of a rotary boring machine, a boring-tool stand, bracing supports, and coal-removal and dust-collecting devices. Lightduty underground borers—the so-called underground boring machines—are used for drilling inclined and horizontal drill holes.