The video of my 9-day, 153-mile loop hike around the Burr Trail in Grand Staircase-Escalante National Monument and Capitol Reef National Park. The windy/cold May 2016 trek through the land of slot canyons and wide-open vistas features Big Horn Canyon, Zebra Slot, Harris Wash, Choprock Canyon, Lower Muley Twist, Upper. This is a cool little slot canyon near the Zebra Slot. (Actually, by following the directions at the link, you can hike overland to the other end of Tunnel Slot – but the official trail is down the wash.) The reason for the name “tunnel” is because the top seems to close overhead in this short slot canyon.

In 1931, a construction contract was let to Six Companies, Inc., a consortium of six major western firms. Together with the government, they built almost 30 miles of railroad connecting Boulder City with all the facilities needed to build Hoover Dam (eg., cement mixing plants, quarry pit, gravel sorting plant). The Hoover Dam construction railroad system had three segments. The first, from Las Vegas to the Boulder City site, was built and operated by the Union Pacific Railroad.

Tunnel Slot Hike Games

The second segment was built by the U.S. Government. It ran from Boulder City down Hemenway Wash to Himix, the concrete mixing plant on the rim of the Black Canyon overlooking the dam. It provided concrete for the final 242 feet of the dam and the buildings on its crest. The airline distance from Boulder City to Himix was 6.7 miles. A drop of 1,100 feet in elevation however, necessitated ten miles of winding tracks to keep the grades from being too steep.

Six Companies, Inc. built and operated the third segment of the system. The tracks branched off the U.S. Government Construction Railroad at Lawler, about a mile up Hemenway Wash from the Visitor Center. It crossed Hemenway Wash and followed the base of the River Mountains and then looped eastward to the gravel plant on the flat overlooking the Colorado River. One branch went upstream 7.3 miles from the gravel plant to the gravel beds on the Arizona side.

Tunnel Slot Hike Grand Canyon

Isolation demanded the tons of concrete needed for the dam to be manufactured locally. An electric dragline with a five cubic yard capacity loaded gravel into railroad cars. Concrete was made by mixing sand and crushed rock, called aggregate, with Portland cement and water. More than four million cubic yards of aggregate were taken from the Arizona side of the river. The other branch followed the river downstream into Black Canyon, to Lomix, a concrete mixing plant situated at the base of Black Canyon. Lomix provided the concrete for the diversion-tunnel linings, the powerhouse foundation, and two-thirds of the dam. To prevent the concrete from drying during transportation the mixing plant was put as close to the river as possible. Locomotives hauled tons of gravel to a screening plant on the other side of the river 24-hours a day. A round trip took slightly more than two hours.

Tunnel Slot Hike Game

The Six Companies, Inc. Railroad was abandoned after the completion of Hoover Dam in 1935. The U.S. Government Construction Railroad section was sporadically used until 1961, when the last generator was hauled over its rails and installed at the power plant.