Ross steel team had a banner April

Steel replacement in the Ross Shaft has progressed from the top of the shaft to well below 560 feet, according to Underground Access Director Will McElroy. Crews replaced steel in 102 feet of the shaft last month alone. ?We had a great month in April,? said McElroy, who is directing the project.

When all the steel is replaced in the 5,000-foot shaft?by September 2017?the Ross will meet engineering requirements for extracting rock and lowering equipment and materiel down the shaft in support of large experiments such as the Long-Baseline Neutrino Experiment and the Dual Ion Accelerators for Nuclear Astrophysics experiment. (See the story below.).The old steel in the shaft was constructed in 6-foot frames called ?sets.? The new steel is built in 18-foot sets In April crews installed six new sets.

Every 10 sets, or 180 feet, the crews are installing ?saddles? to hold bearing beams. (See the photo.) The saddles include a horizontal beam and two diagonal braces,installed side by side.

Saddles are attached to the walls of the shaft by steel bolts that penetrate the rock up to 11 feet. Each 1-inch diameter bolt has a tensile strength of 150 Ksi (kilo-pounds per square inch). How strong is that? ?It?s enough to hold up the world,? McElroy says. Because the rock walls of the Ross Shaft are uneven, customized saddle configurations were designed. Where necessary, the crews also ?gad? or trim rock to guarantee a snug fit, engineered to within fractions of inches. ?They definitely aren?t just winging it,? McElroy said.

The result will be a 21st century shaft built to support science for decades.