The extension is less than one mile from its wholly owned Rosita In-Situ Recovery uranium processing plant.
enCore installed 43 monitoring wells in total, which includes 38 perimeter and 5 overlying monitor wells. The Rosita expansion area will provide uranium for the plant.
"We are pleased to have completed the installation of the monitoring wells at the Rosita Extension PAA on budget and on schedule," chief executive Paul Goranson said.
enCore is targeting uranium production in 2023.
The plant is one of only 11 licenced and constructed uranium processing plants in the United States. In-situ recovery recovers uranium from low-grade ores, where other mining methods may be too costly or environmentally damaging.
To recover uranium using the ISR method, a lixiviant solution is injected through several wells into the uranium ore body to dissolve the uranium. The lixiviant is then collected in recovery wells, according to the U.S. Nuclear Regulatory Commission.
Uranium developers then purify, concentrate, and dry the uranium extract to produce yellowcake, which is then packed and sent to a conversion facility.
Uranium production across the board had been at a standstill following the Fukushima nuclear disaster in March 2011. However, uranium prices are increasing and demand is rising as nuclear is increasingly seen as an environmentally preferable energy source to fossil fuels.