... namecoal mining bits conical picks, flat bitsBrandTechgongmateriallow alloy high grade steel 42CrMo, tungsten carbide tip and reinforcement vacuum quenching ... ... bit, retainer, holder/block, sleeveusagemining, trenching used in coal mines, iron ores, aluminum ores and geotechnical engineering, as ... work efficiency, which is twice to 3 times of the common bits. Hot sale!! coal pick for coal mining