drill holes on coal seam,soft sandstone or shale in coal mine or construction engineering,and can be used manually . QMZ2/8 Pneumatic Coal Drilling Rig can drill hole manually,or used as air leg coal drilling rig by equipped with FT100 air leg.This rig is drive by compressed air,with planetary gear speed reucing system,large torque,explosion-poof,easily operated and maintain,especially be ...