Mined out of an ancient salt formation more than 2000 feet (610 metres) below ground, WIPP is the USA's only repository for the disposal of transuranic, or TRU, waste. Clothing, tools, rags, residues, debris, soil and other items contaminated with small amounts of plutonium and other man-made radioactive elements from the US military programme in sealed drums are placed in "rooms" within each panel.
A panel consists of seven rooms, each measuring 300 feet long by 33 feet wide by 14 feet high. It takes about two years to cut and outfit a panel, requiring the mining of around 120,000 tons of salt rock. A continuous miner cuts into the salt rock with a rotating drum, and can generate 10 tonnes of salt per minute which is either trucked for use elsewhere in the underground facility or hoisted to a salt tailings pile on the surface.
The natural movement of the salt rock that will eventually permanently encapsulate the waste also causes mined openings to close, so mining at WIPP is timed so that a panel is only ready when it is needed for waste emplacement. Waste is currently being emplaced in Panel 8, where the first room - Room 7 - has already been filled.
The creation of new panels allows safe and compliant emplacement of waste to continue, supporting environmental cleanup and national security missions, the DOE said.
Panel 11 is connected to WIPP's new air intake shaft, constructed as part of a major investment project to increase airflow, and to the rest of the underground facility by around half a mile (just under a kilometre) of new pathways.
