The Deep Underground Neutrino Experiment (DUNE) is currently under construction in a former gold mine in the U.S. state of South Dakota. The experiment will feature the largest underground caverns in history, with two main caverns that are seven stories tall, 100 metres long and 19.5 metres wide, and a third utility cavern that is three stories tall, 150 metres long, and 19.5 metres wide. The caverns will be located at a depth of 1,486 metres below the surface.
Who:
The U.S. Department of Energy is building the DUNE facility, which will hold massive tanks of liquid argon to detect neutrinos coming in from a beam generated at Fermilab in Illinois. The project is being led by Willhite, which is overseeing the construction of the caverns.
Why it matters:
The construction of these caverns at such a depth presents formidable engineering challenges. According to Willhite, every bit of air that is underground has to come down through one shaft and go back out of another shaft, and this requires management of air movement. The natural temperature of the surrounding rock walls is 35 degrees Celsius, so ventilation for air conditioning is key. Additionally, heavy equipment and construction materials are hard to come by at DUNE, and the rock being excavated from these large caverns must be placed back on conveyances and moved to the surface.
Another challenge is the installation of basic necessities such as bathrooms. Almost 2,200 psi of pressure is required to pump water between the surface and the construction site. Engineers have broken down the plumbing that supplies water into a series of stepped segments to reduce the pressure needed by individual pumps.
The experiment will provide insights on neutrino physics and the nature of matter itself, which is important for understanding the properties of the universe. 
