Florence Copper officials could break ground on a $24 million “in-situ” copper mining facility by December, after an administrative appeals board last week turned down objections to the project from the Town of Florence and another opponent.

The ruling by the Environmental Protection Agency’s EPA Environmental Appeals Board rejected challenges that the in-situ form of mining – which injects acidic water into copper ore deep underground, to draw it out and refine it – could pose a threat to the area’s drinking water.

An attorney for the town said in an email that Florence officials were disappointed with the ruling, which they fear leaves the water supply at risk of pollution, “a condition that is not acceptable to the town.” She said the town is reviewing legal options moving forward.

But officials with the mining company welcomed the decision, which capped a six-year permitting process for the project.

“Clearly it is our view, and the view of the agencies that there is no danger,” said Brian Battison, vice president for corporate affairs at Taseko Mining Ltd., which owns Florence Copper. “These agencies are charged with protecting drinking water, that is their priority.”

The mining company said the Florence project could eventually create as many as 800 jobs for the state. After a two-year pilot period, the project is expected to produce about 85 million pounds of copper a year over most of its planned 25-year life, adding $3.4 billion to the state’s economy, according to a 2013 study by Arizona State University.

Stacy Gramazio, a spokeswoman for Florence Copper, said the company “has continued to do extensive outreach, including local presentations and site visits,” to show community members that the project is safe and environmentally responsible.

Gramazio called the permitting process for the Florence project “one of the longest in Arizona’s history,” and said the amount of environmental vetting that went into it ensured the safety of the program.

But Jess Knudson, assistant town manager for Florence, said the town’s appeals were “all about protecting the resident’s water resources.” The project was also challenged by John L. Anderson, who worried that the in-situ process would contaminate area drinking water.

A four-judge EPA panel rejected both appeals last Friday, writing that it “appreciates Mr. Anderson’s concerns about potential impacts to drinking water sources, but holds that Mr. Anderson’s Petition does not satisfy threshold procedural requirements necessary to support Board review.”

Anderson did not immediately return requests for comment.

Town officials had challenged an “aquifer exemption” for the project that was issued by referencing a permit issued in 1997 as part of a previous project. The town said that because of changes since 1997, EPA administrators “should have rescinded or revoked the 1997 aquifer exemption and prepared a new aquifer exemption specifically tailored to the small scope of Florence Copper’s Production Test Facility.”

But Battison said experts from state and local agencies had thoroughly reviewed the safety and environmental impact of the systems, and decided they were safe.

The EPA panel said it “is not the proper forum to resolve the Town’s aquifer exemption-related arguments because aquifer exemption decisions are discrete final agency actions … that must be challenged in the appropriate federal circuit court of appeals.”

“The Board therefore denies review of the Town’s Petition,” the opinion said.

Barbara U. Rodriguez-Pashkowski, an environmental attorney representing the town, said she was disappointed in the “board’s denial to review an issue of such important public policy.”

“It is also clear that EPA did not dispute the fact that circumstances have so substantially changed since the 1997 issuance of the Aquifer Exemption,” Rodriguez-Pashkowski said in an emailed statement.

“Yet EPA made no effort to revise the AE to take into consideration those changed circumstances; thereby, leaving the Florence citizen’s groundwater at risk of being polluted; a condition that is not acceptable to the Town,” she wrote.