By Michael Lucibella
Photo by Rachel Harris
The Homestake Mine in Lead, South Dakota
A now-defunct gold-and-silver mine in South Dakota was set to host a next generation underground science lab, but the National Science Foundation (NSF) has backed out of the project. The Department of Energy (DOE) is working to save the biggest physics experiments, but because of budget uncertainties, it is unclear how many will ultimately be built.
The DOE and the NSF had planned to jointly build and operate the expansive underground lab in the Homestake mine in Lead, S.D. In December, following a directive from its oversight body – the National Science Board – the NSF unexpectedly pulled out of the project, citing concerns over the cost and its broad role in running the lab. This development halted the project, and the DOE had to rethink its plans for the site.
The Homestake mine is a sprawling web of underground chambers and tunnels at depths up to 8,000 feet. When the mine shut down in 2002, it was the largest and deepest one in the country. After the shut down, water flooded the lowest level. Congress stepped in, appropriating $15 million to run pumps to keep upper levels dry and viable for any future science experiments.
The original plan for the Deep Underground Science and Engineering Laboratory, known as DUSEL, featured a massive multidisciplinary lab at multiple levels in the mine. In addition to physics, the lab would have had facilities for biological, geological and structural engineering experiments. That comprehensive vision is essentially dead. The DOE is considering how to build the three largest physics experiments planned for the mine.
The biggest hurdle facing the facility, now officially known as Sanford Underground Research Facility at Homestake, is that of funding. According to a recent report by the DOE, the facility would likely cost around $2 billion.
The three experiments the DOE is considering would probe some of the most fundamental questions about the makeup of the universe. A DOE report examined multiple construction options for the proposed experiments. Possible plans range from locating the experiments as deep as 7,400 feet underground, 4,850 feet or as shallow as 800 feet, installing different experiments at different levels, or building some of them in existing labs in other parts of the world.
The report concluded that if the experiments were to be located in the South Dakota mine, bundling them on the same underground level would save money because they could share infrastructure such as electricity, utilities and mine shafts. “Locating the facility in the U.S. would help to promote U.S. leadership in these fields for the foreseeable future,” the report stated.
William Brinkman, director of DOE’s Office of Science, has said he wants to move forward with the proposed experiments. However, what final form they take remains up in the air because of budget uncertainties.
“I am optimistic about things coming together,”said Kevin Lesko, of the University of California, Berkeley, and DUSEL principal investigator. “I’m optimistic we have all the elements on hand to help the DOE decide how they want to go forward with the facility.”
Lesko added, “The science is absolutely first rate. The idea of putting things in the same place to share infrastructure and share intellectual excitement makes sense.”