Taseko Mines Obtains EPA Underground Injection Control Permit for Florence Copper In Situ Recovery Project in Arizona

Posted by Paul Moore on August 15, 2022

Taseko Mines Ltd has announced that the United States Environmental Protection Agency (EPA) has issued a draft Underground Injection Control (UIC) permit for its Florence copper project which will use in situ recovery (ISR) . The EPA said the public comment period for the draft federal permit will last 45 days, ending September 29, with a virtual public hearing to be held September 15.

Stuart McDonald, President and CEO of Taseko, said, “The UIC permit is the final key permit required for the construction and operation of the Florence Copper commercial facility. Our project has been the subject of intense scrutiny by the Arizona Department of Environmental Quality and the EPA over the past eight years, and we are confident that the rigorous work performed by these two regulators will mean success in the months to come.

According to Taseko Mines, Florence Copper is expected to have the lowest energy and greenhouse gas (GHG) intensity of any copper producer in North America, and will reduce the United States’ reliance on foreign producers for a metal considered essential to the transition to a low-carbon economy. “As the United States moves toward its goal of net zero carbon emissions by 2050 – including 100% clean electricity by 2035 and 50% light electric vehicle sales by 2030 – the country will have to address its reliance on imports of critical metals. Low-impact, environmentally friendly projects like Florence Copper will help meet the growing demand for copper in the United States,” McDonald concluded.

The planned ISR facility consists of a set of injection and recovery wells that will be used to inject a weak acid solution (raffinate – 99.5% water, 0.5% acid) into the ore of copper oxide and recover the copper-loaded solution (pregnant leaching solution, or PLS) in a five-point well pattern for processing into pure copper cathode foils. The mine design is based on the use of five-point well models, with each model consisting of four extraction wells in a 100 foot grid plus a central injection well. The flow is balanced so that the extraction exceeds the injection flow and therefore the surface hydraulic slopes towards the ISR wells and the solutions are maintained in the leach zone. Shafts are lined to isolate ore zones for extraction and are sealed and tested for mechanical integrity. Well drilling will continue throughout the life of the project and will be carried out by contractors.

Since acquiring Florence Copper in November 2014, Taseko has progressed the project through the licensing, construction and operation phases of the Phase 1 Production Test Facility (PTF). , a $25 million test facility, was designed to prove the integrity of the in situ copper recovery process and provide Taseko with important technical information. The 24-well facility and SX/EW plant began operations in December 2018. Over the course of 18 months, Taseko evaluated operational data, confirmed project economics, and demonstrated its capability to produce copper cathodes high quality with strict environmental guidelines.

Bonny J. Streater