tsk, tsk.. well I don't know.. I think some are fascinated. Can you get 5,000 continuous feet on a jumbo, with a single steel, without every changing the steel? It was normal where you were drilling with jacklegs to use a starter steel, depending on clearance, so there was always a natural change out cycle, but I was always taught to vary my steels, as the steel could get fatigue under constant use, and steel did break.. I know it is illegal to hold the steel for a driller, but it was often done to save time on an angled face.. and it is illegal for three reasons, but the chief one is breakage.. which never happened with Ajax steel. I admit steel breaking is rare on hand held instruments and less rare on air trac and jumbo.. and wear is a more common reason to change out. freepatentsonline.com
patentstorm.us
asse.org
"After graduation from college I continued working at the Homestake mine mainly due to the excellent pay and benefits. I worked at the Ross Shaft, which was a mile deep, steel shaft, helping to maintain the shaft and I was responsible for rigging all loads that were lowered or hoisted to and from the mine during my shift. I drilled holes and installed rock bolts in the the walls of the shaft with fall exposures of several thousand feet up to a mile and no fall protection being provided. I would place two steel ladders across the shaft, one for me to walk on and the other to position a jack-leg drilling machine with the drill steel. Should the steel stick or break, it could cause you to lose your balance and fall into the hole. The jack-leg machine's water and air hoses could possibly save the machine but likely would not support the worker." |
