Our Story
In 2006, the Homestake Gold Mine transitioned into a dedicated underground research facility where scientists probe the depths of space to learn more about our place in the universe.
The Sanford Underground Research Facility (SURF) is America’s underground science laboratory—the deepest in the United States at 4,850 feet, and among the deepest in the world. Managed by the South Dakota Science and Technology Authority through a cooperative agreement with the Department of Energy Office of Science, SURF operates with a clear mission: To advance world class science and inspire learning across generations.
Our roots run deep and wide, starting in the Black Hills of South Dakota and stretching around the world. Hundreds of scientists from dozens of countries work together in a variety of disciplines, trying to understand the mysteries of the universe and our planet.
Early Physics Research
Solar Neutrino Experiment
SURF’s history began with Raymond Davis Jr.’s Brookhaven Solar Neutrino Experiment, a pioneering experiment built in the mid-1960s deep underground at the Homestake Gold Mine in Lead, South Dakota. A chemist from Brookhaven National Laboratory, Davis designed his experiment based on a theoretical model developed by theorist John Bahcall. The 100,000-gallon tank built on the 4850 Level was filled with perchloroethylene (chlorine), a dry-cleaning fluid, as a way to count and capture neutrinos from the sun—a method first suggested in the 1950s by Italian physicist Bruno Pontecorvo.
The same year Davis received the Nobel Prize, the Homestake Mine closed. Scientists around the world, including John Bahcall, began a concerted effort to create a deep underground research laboratory in the United States.
The depth and stable rock made Homestake a top selection. The National Science Foundation (NSF) also considered the facility a possible future sight for underground physics research. Barrick Gold Corporation kept the pumps running while discussions about the mine’s future as a research facility were underway. However, due to soaring costs the company shut down the pumps just one year later.
Built on partnerships
In 2004, then-Governor Mike Rounds and the State Legislature formed the South Dakota Science and Technology Authority to study the feasibility of turning the mine into a research laboratory. Two years later, T. Denny Sanford, for whom the facility is named, pledged $70 million, breathing new life into the project. Barrick Gold Corporation, which owned the Homestake property, made a land donation and the State of South Dakota committed more than $40 million. These developments culminated in the creation of the Deep Underground Science and Engineering Laboratory—now the Sanford Underground Research Facility (SURF)—in 2007.
After an extensive dewatering process, the 4850 Level of SURF was dedicated in 2009. Dignitaries from around the country, including Gov. Rounds and Sanford attended the event. The underground dedication took place in an area now designated as Governor’s Corner.
Change in direction
In December 2010, the National Science Board decided not to fund further design of DUSEL. However, in 2011 the Department of Energy (DOE), through the Lawrence Berkeley National Laboratory, agreed to support science operations. Today, federal funding is managed through a cooperative agreement with the DOE Office of Science, with additional funding through the SDSTA.
The first two major physics experiments located on the 4850 Level were the Large Underground Xenon (LUX) experiment and the Majorana Demonstrator Project. Majorana was housed in a new transition cavern. LUX was housed in the renovated Davis Cavern, where Ray Davis ran his Nobel Prize-winning solar neutrino experiment for nearly three decades.
Dark Matter Experiments
In October 2013, after an initial run of 80 days, LUX was determined to be the most sensitive dark matter detector in the world. Further analysis confirmed that result in 2016, the same year the experiment was decommissioned.
The second-generation dark matter detector, LUX-ZEPLIN (LZ) began operating in 2021 and became the world's most sensitive dark matter detector with the announcement of first results on July 7, 2022.
Read More
Majorana Demonstrator
From 2015 through 2021, the Majorana Demonstrator collected data as the collaboration searched for a rare type of radioactive decay called neutrinoless double-beta decay. The final results, published in early 2023, proved that the techniques used by the collaboration could be deployed on a much larger scale to search for the rare, never-before-seen decay that could help explain the existence of matter in our Universe.
Now, the collaboration is joining another germanium experiment to create a larger experiment, the Large Enriched Ge Experiment for Neutrinoless ββ Decay (LEGEND). LEGEND will ultimately use one ton of enriched germanium to conduct the search, increasing the potential to find this elusive decay.
CASPAR
In 2015, CASPAR, the Compact Accelerator System for Performing Astrophysical Research, was installed on the 4850 Level. The experiment could help scientists better understand the processes that create elements heavier than iron in collapsing stars. The experiment collaboration is continuing to examine data collected over a three-year period.
CASPAR continues to examine data
LBNF/DUNE
Excavation for the Long-Baseline Neutrino Facility and Deep Underground Neutrino Experiment (LBNF/DUNE) began in 2019 and was completed in 2024. More than 800,000 tons of rock were removed, conveyed to the surface, and transported to the Open Cut. Learn more about LBNF/DUNE.
More than physics
Biology
From the beginning, SURF’s extreme underground environment has attracted scientists from around the world to search for and study microbial lifeforms. Could such organisms help us find better medicines, develop biofuels, sequester carbon? Some research done at SURF helped inform the search for life on Mars. More about biology at SURF.
Geology
Researchers from several national labs are using the rock at SURF to determine how hot fluids flow through rock fractures over time. The research taking place deep underground could revolutionize clean energy generation and unlock affordable clean energy for over 65 million American homes. More about geothermal energy.
Engineering
SURF supports some commercial research and develop efforts, including Caterpillar’s Minestar™ tracking technology. Additionally, the underground spaces make excellent training grounds for civil and mining engineering, as well mine rescue operations. More about CAT Minestar™.
Homestake History
Until its closure in 2001, Homestake was the largest and deepest gold mine in North America, employing thousands, and producing approximately 41 million ounces of gold and 9 million ounces of silver in its 125-year lifetime.
To learn more about the history of the Homestake Mine, visit the Black Hills Mining Museum, the Homestake Adams Research and Cultural Center (HARCC) and the Sanford Lab Homestake Visitor Center.
The Unique History of the Black Hills
SURF is indelibly linked to the history of the Homestake Mine, which operated from 1876 until 2001. While gold mining created wealth and jobs in the Black Hills for over a century, SURF has shifted the focus of the mine from profit to scientific discovery. We also recognize the culture significance of the land and work includes outreach and relationship building with South Dakota’s nine Tribes.
Čhaŋgléška Wakȟáŋ
Čhaŋgléška Wakȟáŋ, the ethnobotanical garden at the Sanford Underground Research Facility (SURF), highlights the connections between past and present and embodies the promise of a new, more equitable chapter of this story.