Before the recent advent of open-pit mining, Cripple Creek-Victor was the home to several hard-rock underground mines. As these mines were deepened water seepage became a major problem and therefore several drainage tunnels were constructed. The Roosevelt Tunnel was the first of these major projects and was completed in the early 1900s. It lowered the water table around some of the mines nearly 1500 feet. The Carlton Tunnel was the last of the group and was completed in 1941 and drained water perhaps 3000 feet below the elevation of the Vindicator Mine. As I understand the situation, World War II put a big blunt in the mining operations and the Carlton became inoperative shortly after it opened.
A fascinating couple of statements appeared in the 1985 edition of the journal Economic Geology (Thompson and others): “Very near the short drift on the new vein was the terminus of the Carlton drainage tunnel. This tunnel was driven just before WWII to enhance the drainage of the deeper workings in the Victor area. At the entrance to the tunnel were two simple, swinging metal doors with a gap of a few inches beneath their lower edges and a small amount of water running under them. Looking down the tunnel, it was so straight that it was possible to see the portal, a star-like pinpoint of light over 6 miles away.”