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Mine Safety and Health Administration MSHA's Accident Prevention Program
Miner's Tip

Pressurized Fittings

Safety Something YOU can live with!
Mine Type: All Mines
Category: Maintenance


A coal miner in Kentucky was injured when he attempted to bleed the pressure from a conveyor grease jack. The grease jack had the OEM relief type fitting broken and a standard grease fitting had been substituted. In his own words:

Drawing 

depicting 

man removing grease fitting "I was using a 1/4" ratchet and socket when the grease fitting blew out of the jack as I began to loosen it up. The fitting shot out like a gun, went through the ratchet and hit my left thumb and cut it while knocking the end joint of my thumb out of place. The handle of the ratchet also hit me on the cheek just below my eye and made a cut. I also ended up with an eye full of grease. It could have been much worse because I had been cleaning out around the fitting with a nail so I could get the socket on it. My head had been right straight out in front of it in order to see what I was doing."

Always use the proper valves or fittings to relieve the grease pressure on a grease take-up before doing any maintenance. Use of a nail or wire to push in the ball on a standard grease fitting to relieve the pressure is very dangerous and can result in another type of injury. The grease can be pressurized to more than 10,000 P.S.I. If you push the ball in, the grease can shoot out in a thin stream and inject itself into your skin. Grease is extremely poisonous when injected into tissue and could require amputation.

Reissued: 04/30/2002
Tag # AP2002-M016


MSHA extends a thank you and a tip of the hardhat to
Caleb Caudill of Whitesburg, KY,
a winner of a limited edition sticker and patch.

If you have a tip you would like to pass on, you can e-mail it to zzMSHA-MinersTips@dol.gov. If your tip is selected, you will receive credit in this space.