Mackay MIne Hill Double Aerial Tramway Support March 7 2010

This special anchor and tension structure was one of 36 support towers constructed in 1917. It was part of the ore-hauling aerial tramway that covered a distance of 3 ¼ miles from mines up on the mountain down to the unloading terminal at the smelter site just above the Big Lost River. Ore buckets rolled on a stationary loop of 1 ¼ inch steel cable over 16,000 feet long, supported by these wooden towers. Like the other “through” type towers, both the support and traveling cables with their hanging ore-buckets passed through this structure on it s left and right sides. However, this double tower was different from the others. Its purpose was to anchor and maintain a uniform tension on the long stationary support cables under varying loads and temperatures. Weights, consisting of large re-enforced wooden boxes loaded with rock fill were connected to support-cable ends here. These cable ends ran over sheaves with short axles that allowed the weights to move up and down and maintain the desired tension. As ore buckets rolled on the support cables entered the tower, they rolled onto a metal track-rail that supported them as they passed the structure and back onto the cable at the other end. From the White Knob Preservation Committee