LBNF long baseline neutrino facility; LBNF long baseline neutrino facility;

Long Baseline Neutrino Facility, Lead, South Dakota

Carving out space for DUNE—a ground-breaking physics experiment

LBNF Far Site is designed to house DUNE’s gigantic, state-of-the-art particle detector. Located inside the former Homestake Goldmine, the Far Site Detector is comprised of four massive cryostats (cryogenic vessels) housed inside two seven-story tall caverns stretching the length of two football fields.

As the lead designer of conventional facilities at LBNF Far Site, Arup is overseeing design of both the cryostat caverns and supporting facilities, including a control room and a central utility cavern for cryogenic and power distribution, HVAC, and IT systems. In addition, we are leading the design of the infrastructure responsible for routing the argon, power, and IT/communications systems needed to power Far Site operations down from the surface. The Arup team has also designed a range of surface-level upgrades required to facilitate the project.

Project Summary

Flagship experiment hosted by Department of Energy's Fermilab

2facilities to support the Deep Underground Neutrino Experiment

4cryostats comprise the experiment's Far Site Detector

deep underground neutrino experiment cavern deep underground neutrino experiment cavern

What is LBNF?

The Long Baseline Neutrino Facility (LBNF) will be home to the Deep Underground Neutrino Experiment (DUNE), an international flagship experiment hosted by the Department of Energy’s Fermilab that will help physicists unravel the mysteries of neutrinos, one of the universe’s tiniest and most elusive subatomic particles. 

Despite its name, LBNF is not one facility but two – LBNF Near Site and LBNF Far Site – which together furnish the infrastructure required to support DUNE. LBNF Near Site, located at Fermilab in Batavia, Illinois, will provide “the world’s most intense beam of high-energy neutrinos,” powered by the new Proton Improvement Plan-II (PIP-II) particle accelerator. This beam will be sent 800 miles through earth to LBNF Far Site, located within the Sanford Underground Research Facility (SURF) in Lead, South Dakota, where it will be intercepted by a DUNE detector located nearly a mile beneath the surface.

800,000 tons of rock: Excavation and removal at LBNF Far Site

One of Arup’s primary tasks on this project has been finding the best approach to excavating and removing the 800,000 tons of rock that must be mined to make room for the Far Site’s three massive caverns. Excavating this volume of rock nearly a mile beneath the ground, transporting it to the surface, and then transporting it to its final location is a monumental undertaking. The task is made more complicated by the limited number of shafts and tunnels (known as “drifts”) available to move material in and out of the facility, which makes the construction process much like building a ship in a bottle. The Arup team drew on insights garnered working on deep underground tunnelling for rail projects and other science and energy facilities to address the extreme site conditions at LBNF Far Site and make excavation and removal as safe and efficient as possible.

The team began by mapping, scanning, and drilling to collect detailed data on site conditions. The data was then used to create a robust and highly accurate 3D ground model capable of modelling rock movement and behavior both during and after excavation. The insights garnered from the model enabled our team to design a compatible permanent ground support system that ensures stable conditions over the design life of the facility.

In addition to designing supporting infrastructure systems, such as a rock conveyance system, Arup took every opportunity to repurpose elements of the mine’s existing infrastructure to enhance safety, save time, cut costs, and meet Fermilab’s overall project objectives. 

Arup is proud to have helped set the stage for excavation to begin at LBNF Far Site in 2021. To learn more about our work on this project, we invite you to watch Making space for a ground-breaking experiment



Our team worked with science collaboration teams from around the world to ensure we were developing a facility that would meet their needs and support their goals well into the future. ”

Yacknowitz Josh Joshua Yacknowitz Principal