... ,yt28: pneumatic breaker tools,mining tools,rock tools,rock drill,leg drill,atlas copco,drifters Air-leg Rock Drills yt27,yt24,yt28 ... and hard rock with a hardness of (f=8-18) .YT28 may also be uesed for making roof bolting holes.the drill ... is an important instrument in mining, raiway, communtication and water conesrvancy projects.Technical specifications Type ...