Dog rope wrapped and ready for shaft

Before technicians can lower two ?dog ropes? down the Yates Shaft, they have to transfer the ropes from shipping reels to the temporary winch in the Yates yard. That?s what?s happening in the photo at right. 

The ropes, made of strands of steel wire, are an inch and a half thick. Each one is nearly 5,200 feet long and weighs 28,000 pounds.

The forklift has positioned the cable so it winds correctly on the winch. (The reel is out of the frame.) ?You see how nice and tight it looks,? Project Engineer Mike Johnson says. ?If the rope isn?t tight on the drum, once you get part of the way down the shaft the weight of the rope will push it through the other layers on the winch. It will snap and pop and snarl ? it?s not a good thing.? Facilities Technician Jeff Essink fabricated a brake for the reel (not pictured) that helps keep the tension tight.

During installation, each rope will run over a temporary sheave, or wheel, on the floor of the Yates Shaft headframe, and down the shaft. Once lowered into place, ropes will be temporarily clamped at the top of the shaft. Then the slack top section of each rope, between the temporary clamp and the winch, will be cut to fit and hoisted to the top of the 100-foot rope-dog tower, now under construction in the Yates Shaft headframe building.

Once secured from the top of the tower, the two dog ropes will run down the north and south sides of the Yates Shaft service-cage compartment. If the main hoist rope should go slack, automatic clamps called ?dogs? will clamp the ropes, stopping the cage in the shaft. 

Next month, when this safety system is operational, the Yates Shaft will become the main access route to the Davis Campus at the 4850 Level.