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Rigging crews at SURF are doing a series of tests on a large wooden model L-beam in anticipation of lowering the real thing down the shaft to the 4850L.
By Zach Burton and Mike Ray

Putting an L shaped block into a square shaped hole is possible with just a tiny bit of creative thinking, engineering, and manipulation.

If your L-shaped block weighs 6 US tons, is 18 feet long and 12 feet wide and the square shaped hole you’re aiming for is a mile deep, maybe consider a few test runs first.

This is what the rigging crews at the Sanford Underground Research Facility (SURF) are doing with a series of tests using a large wooden model L-beam. The testing is in anticipation of the next phase of the Long Baseline Neutrino Facility / Deep Underground Neutrino Experiment (LBNF/DUNE) project hosted by Fermilab at SURF. The wooden L-beam is a model built to the same scale as one of the huge steel components that arrived in South Dakota in January after being shipped from Spain. These steel components will be used in building the giant cryostats that will house the five-story-high neutrino detectors inside the recently completed LBNF/DUNE caverns at SURF.

LBNF/DUNE is an international collaboration, and every piece of the giant puzzle from the tiniest high-tech components to the massive steel beams that hold up the underground particle detector involve collaborators from around the world. Teams at CERN in Switzerland, Fermilab in Illinois, and SURF in South Dakota are working alongside 200 institutions from across the globe on all aspects of this project. Even the wooden test models, that will pave the way for the steel delivery and construction, include a global team of individuals.

While the wooden model weighs far less than the actual steel pieces being used for DUNE’s massive detectors, it has the identical dimensions and a similar center of gravity. This gives SURF’s rigging crews a chance to determine the best way to lower these pieces down the Ross Shaft, 4850 feet below the surface.

Jeff Barthel leads a highly skilled team of riggers at SURF who are testing the L-beam lowering strategy. In addition, a team of LBNF/DUNE engineers and technical experts are designing and building hovercraft-like air carts that will slide the beams onto the cage, or steel box, which will hold them on their trip deep underground. Members of CERN helped complete testing on the steel beams and are taking part in the test lifts for the wooden models. The crews will employ cranes and an array of rigging cables, straps, and ropes that have been designed for the unique job of transporting these components from the surface into the narrow shaft to the underground.

Barthel says because there is zero margin for error, the wooden model gives crews a better understanding of how to safely and effectively manipulate the actual steel L-beam into place for lowering.

“Of course the wood model takes up just as much space as the steel one does,” Barthel said. “So we’ve practiced moving it, loading and unloading it, hanging it, manipulating it, and changing it from horizontal to vertical. We’re doing all of the manipulations with the wooden mock-up that we will be doing with the actual beam just so that we can double check our math and better understand what we'll need for rigging and moving the real thing.”

For Barthel the old adage of, “practice makes perfect,” is fitting here. The end goal is to minimize risk while maximizing safety and efficiency. Each of the large DUNE detectors include 92 total steel L-beams. Lowering these components will keep Barthel and his crew busy for many months to come.

The wooden model L-beam inside the hoistroom
The wooden model L-beam inside the Ross Hoistroom at SURF.  Photo by Stephen Kenny.