Taseko's operations team have over the past nine months commissioned the 24-hole test wellfield, with injection, recovery and monitoring wells, and ramped up a solvent extraction-electrowinning plant to design capacity. The company said the project complied with all environmental guidelines during the process.

CEO Russell Hallbauer said the operation had achieved steady state and work was underway to optimise the production process.

"Sweep efficiencies in the wellfield continue to outperform our expectations. Our technical team is using physical and operating control mechanisms to adjust solution chemistry and flow rates and is successfully increasing copper concentration in solution," he said.

The main recovery well is producing copper in solution at an annualised rate of about 600,000 pounds per year, and the company expects output to continually improve as the well matures.

"We are gaining valuable operating experience that will be used to reduce the ramp-up period for commercial wellfield operations," Hallbauer said.

The company is also working closely with the US Environmental Protection Agency and the Arizona Department of Environmental Quality to advance commercial operating permits, which it expects to receive in the summer of 2020.

The Florence deposit hosts 2.4 billion pounds of copper in 340 million tons of probable reserves. At full tilt, Florence is expected to produce an average of 55Mlb/y of copper cathode for six years and then 85Mlb/y for 14 years.