A New Angle In Shaft Sinking

Sinking an inclined ventilation shaft at the Never Sweat mine of The Anaconda Co. has required a unique underground hoisting arrangement because the shaft changes direction from vertical to 71.5º. Access to the project is made through the High Ore shaft to the 2800-ft level, then by crosscut to the bottom of the vertical Never Sweat shaft. The 71.5º incline shaft starts at this point, which makes an unusual operation as the 60-cu ft sinking skip coming up the incline changes into a vertical position above the 2800-ft level before going into the dump scrolls. This requires both rollers and guide shoes on the skip. Coming up the incline to the collar of the shaft the loaded skip enters into a guard before reaching the vertical section. The tendency of the surface- mounted Never Sweat hoist is to lift the front wheels of the skip off the track, so the guard keeps the skip on the rails during the transition.