Slab heavier than many jumbo jets has been breaking absent from canyon wall
Crews drill bolts in sandstone over machine shop and power facilitiesA massive piece of rock is at risk of crashing down from a canyon wall to the base of an Arizona dam,prompting the government to send in a crew of rappellers to keep the slab in region. The 500000-pound slab – weighing more than many jumbo jets – began to crash absent from the canyon wall last week in what the US Bureau of Reclamation attributes to erosion that is typical for that type of rock. The area below the slab includes a passageway to a boat ramp, a machine shop and water and power facilities for the Glen Canyon Dam in Page, or near the Arizona-Utah border. Continue reading...
Source: theguardian.com