In-situ leach, or ISL, recovers minerals from porous orebodies by chemical leaching in wellfields, and is also known as in-situ recovery. The wellfield production patterns are now operating at Rosita, enCore said, with oxygenated water circulating through the satellite ion exchange (IX) facility and being injected back into the uranium ore body. Uranium concentrations in the production wells are "meeting expectations", and the company said it expects to make its first shipment of yellowcake "over the course of the next 45 to 60 days".
Rosita has undergone refurbishment since enCore acquired it from Westwater Resources - formerly Uranium Resources Inc (URI) in 2021.
"It is with great satisfaction that in less than 20 months' time, the enCore team completed the refurbishment and upgrading of the Rosita CPP from long-term cold standby to monitor well ring installation, wellfield pattern and infrastructure installation, and construction of a new satellite IX facility," enCore CEO Paul Goranson said. "Our team has aggressively worked through supply chain disruptions and a significant expansion of our operating workforce to meet our targeted production schedule. We are very pleased to have our first uranium production under way at enCore, and we are honoured to be both the first uranium producer in Texas in 10 years and the newest uranium producer in the United States. With these monumental achievements at hand, we continue to push for our second uranium processing plant, the Alta Mesa CPP, to commence production in early 2024."
The Rosita CPP, about 60 miles from Corpus Christi, Texas, has a capacity of 800,000 pounds U3O8 (308 tU) per year and is designed to process uranium feed from multiple satellite operations in the South Texas area.
The plant produced some 2.64 million pounds U3O8 between 1990 and 1999, when production was halted due to low uranium prices. Production restarted for a few months in 2008, but technical difficulties, coupled with a sharp decline in uranium prices, led to the decision by then-owner Uranium Resources Inc (URI) to suspend production activities that October. Several years later - in 2015 - the company was considering dismantling the Rosita plant and shipping it to Turkey for use at the Temrezli uranium deposit, but the Turkish government later revoked its exploration and mining permits for the deposit.
URI, by now renamed Westwater Resources, sold its US uranium assets including Rosita to enCore in 2021.
