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The Facility
Learn more about the Sanford Underground Research Facility in Lead, South Dakota


What is SURF?

The Sanford Underground Research Facility is the deepest underground laboratory in the United States and among the deepest in the world. Nearly a mile underground, SURF hosts world-leading experiments in physics, biology, geology, and engineering. SURF holds a critical place in underground research and will house the largest-ever international neutrino experiment on U.S. soil.

Why do scientists go underground to do research?

There are many reasons—depending on the field of study. For physicists, it’s all about escaping the cosmic rays that constantly bombard the Earth’s surface. Although cosmic radiation is unlikely to harm humans, it does pose a problem for sensitive physics experiments that are looking for rare events. So, scientists go deep underground where the rock serves as a shield to block out the “noise” and create a quiet place for these sensitive searches.

Biologists go deep underground to learn more about different lifeforms that exist in extreme environments. Understanding the strange evolutionary pathways these extremophiles use to survive in seemingly desolate conditions could help researchers better understand the climate, create new antibiotics, and even harness clean energy.

SURF offers a variety of rock formations, an extensive drill core archive, rock properties (fractures, stress, etc.), and geology logs. Geologists study the movement of the earth, monitor the underground, do geothermal testing, and study mineral deposits.

What kind of experiments take place underground at SURF?

SURF hosts world-leading experiments in physics, biology, geology, and engineering. To learn more, visit our Science Impacts webpage.

What is LBNF/DUNE?

The Long-Baseline Neutrino Facility will provide the infrastructure for the Deep Underground Neutrino Experiment and will produce the world’s most powerful neutrino beam, using the PIP-II particle accelerator at Fermilab near Chicago. Researchers with DUNE will fire a beam of neutrinos from Fermilab 800 miles straight through the earth to massive detectors deep underground at SURF.

DUNE has three major science goals: find out whether neutrinos could be the reason the universe is made of matter; look for subatomic phenomena that could help realize Einstein’s dream of the unification of forces; and watch for neutrinos emerging from an exploding star, perhaps witnessing the birth of a neutron star or black hole.

To learn more, visit Fermilab's LBNF/DUNE website.   

Will the neutrino beam from Fermilab be safe?

Yes, the beam of neutrinos will be safe. Neutrinos do not emit radiation, they don’t create heat, and they don’t change the properties of the materials through which they travel. In the production of neutrinos, some radiation will be produced, but only inside a concrete vault in an underground facility on the Fermilab site. 

Where can I find out more about neutrinos and the LBNF/DUNE project?

To learn more, visit Fermilab's "For our South Dakota neighbors" webpage.


The Facility

How big is SURF?

SURF is comprised of 223 surface acres and 7700 underground acres, including about 370 miles of tunnels, shafts, and ramps. Approximately 12 miles are maintained for science. Two shafts—the Yates and the Ross—are the main access points to the Davis Campus and Ross Campus on the 4850 Level. Rock removal for the LBNF/DUNE project is done through the Ross Shaft. The facility is perfect for sensitive physics experiments that need extra shielding—and, as it turns out, the rock stability is ideal for excavating the massive caverns needed for such experiments as the LUX-ZEPLIN dark matter experiment and the DUNE experiment.

Why can’t we tour the underground laboratory?

Access to the underground is limited due to staff, safety, and infrastructure constraints. There are inherent risks to traveling underground even with SURF's strong safety record and SURF does not have the capacity to offer public tours of the underground spaces. During the summer, the Sanford Lab Homestake Visitor Center offers surface tours to the Yates Hoistroom as part of its historic tour of Lead, South Dakota.

What are the benefits of SURF to South Dakota?

South Dakota benefits from SURF activities in many ways.

  • Economic: The science activities at SURF are expected to have $2 billion dollar net impact on South Dakota and create nearly 1,200 jobs through 2029.
  • Education: SURF’s K-12 programming for students includes field trip experiences, classroom presentations and curriculum modules. In 2021-22, 20,000 K-12 students were served, while 1,000 teachers participated in professional development between 2020 and 2022.
  • Tourism: The Sanford Lab Homestake Visitor Center features exhibits about the history of Lead and world-leading science at SURF, 3-D displays, and a unique museum store. Visitors can also learn a bit about indigenous culture. The Visitor Center hosts a variety of tours, activities and events, drawing thousands of visitors to Lead every year.

What happens to the water that is pumped from underground?

Water is treated from two sources: groundwater pumped from the underground and overflow from Grizzly Gulch, a reservoir with remaining tailings from Homestake operations. The water passes through two filtration systems and one biological system that together remove suspended solids and other impurities (like iron and ammonia from the Grizzly Gulch tailings). After treatment, the water is discharged into Gold Run Creek, which joins Whitewood Creek.

Is the discharged water safe?

A South Dakota Department of Agriculture and Natural Resources permit allows the South Dakota Science and Technology Authority to discharge treated dewatering water to Gold Run Creek. The SDSTA, which manages SURF, has 14 years of 100% compliance with the limits of the permit. Additionally, SURF regularly monitors the health of these waterways, counting fish and macro invertebrate populations and testing for contaminants. 


Historic Preservation

Where can I find more information about the history of the Homestake Mine and the Homestake company?

The Sanford Lab Homestake Visitor Center features some history of mining, as well as the city of Lead. A 3-D model of the underground, featured prominently in the Visitor Center exhibit hall, shows the vast expanse of tunnels, ramps and shafts that make up the underground facility. Two books by Stephen Mitchell outline the history of Homestake and the transition from mining to scientific research. The books, Nuggets to Neutrinos and the riches of our universe are available for sale at the Visitor Center. Additionally, both the Homestake Adams Research and Cultural Center (HARCC) in Deadwood and the Black Hills Mining Museum (BHMM) in Lead are great resources for the mining history of the Black Hills.  

What does SURF do to preserve the historic buildings of the Homestake site?

To be considered historic, a building must be more than 45 years old, and be associated with significant events in history or significant historical individuals; employ significant architecture, engineering or design; provide, or likely provide, significant historical information (archaeology), which includes Native American Artifacts and human remains.

Before a historic property can be modified, demolished, or disturbed it must be evaluated by the Department of Energy and the South Dakota State Historic Preservation Office. Documentation is done before demolition.

What kind of safety measures are in place?

One of SURF’s Core Values focuses on safety and SURF maintains a rigorous training program to ensure all on-site personnel have the required training to do their jobs safely and effectively, with an eye toward protecting the environment.



What is the purpose of the conveyor belt across the highway?

The conveyor belt moves the rock that has been excavated for the LBNF/DUNE project to the Open Cut. All rock removed from underground is moved to the Open Cut, no excavated materials are sold or removed the Black Hills.

Does SURF conduct gold mining operations?

SURF does not mine. The excavation taking place at SURF is done to create space for science experiments. All of the rock removed from underground stays in the Black Hills, in accordance with SURF policy and land usage agreements.

Is there gold in the rock being excavated?

The excavation at SURF is being carried out in an area of the underground that does not contain gold ore, as determined through surveys and historical documents.


Cultural Topics

What is the ethnobotanical garden?

Guided by a working group of Indigenous stakeholders, the Cangleska Wakan (Sacred Circle) Garden will promote understanding and appreciation of the area’s Indigenous cultures and histories and serve as a physical reminder of SURF’s pledge to build meaningful relationships with tribal partners and be a leader in safe environmental practices in our region. Once completed, the garden will serve as an educational space for community members, SURF employees, students, tourists, and others to participate in: 

  • Cultural programming held by Indigenous groups and organizations;
  • STEM education including ethnobotany, science at SURF, and connections between Indigenous ways of knowing and the science being conducted at SURF;
  • Other activities and events as guided and determined appropriate by the Cangleska Wakan Working Group.

Is it accessible to the public?

Once completed, the public will have access to the garden through limited trolley stops or through educational events. Check our website for future events at the garden.