... soft marl, clay, unconsolidated sandstorm, salt, etc. Recommended Bit type: GHJ437, Drilling weight: 0.35~0.90 KN/mm, Rotary ... as shale, clay, sadstne, soft limestone, etc. Recommended Bit type: GHJ517, Drilling weight:0.35~1.05 KN/mm, Rotary ... .minisite.productShow(); oProductShow.init( { 'aImgSrc': aBigImageSrc } ); } )(); GHJ series tri-cone rock bits with metal-sealing system for oil well drilling