Copper is increasingly important as we try to electrify & transition away from fossil fuels. EV’s, solar panels, batteries and transmission lines use lots of copper so we’re going to need more of it to mitigate climate change.
That growing demand is driving up copper prices and whetting the appetite for mining companies eager to meet the increasing demand for Cu and to benefit from the rising price per kilo in copper-rich Arizona.
The latest effort is a mine called Florence Copper. It’s a new mine that uses acid injection into the ground to get the copper rather than the open pit mine you might be most familiar with. They expect to produce approximately 38,500 metric tons of copper annually.
Florence Copper opens new mining operation in Arizona
At today’s copper price of $14 per kilo, that’s $570M worth of copper per year. Copper is likely to keep going up because of global electrification efforts (although that will also depend on how many new mines are developed globally).
Note: There are some weird things going on right now in the global copper market because of tariffs: Tariff threat built a US copper mountain, but the effects are fading.
Instead of excavating rock like in typical open pit mining Florence Copper uses in-situ copper recovery. They inject sulfuric acid solution underground into copper-bearing rocks. The acid reacts with copper oxide, dissolving the copper into an aqueous copper sulfate solution. Then they pump that to the surface for processing.
CuO + H₂SO₄ → CuSO₄(aq) + H₂O
The copper solution is processed using solvent extraction and electrowinning (electricity) to make the copper metal. The remaining solution is reinjected to dissolve more copper.
The company says they take out more acid solution than they inject and that makes a ‘cone of depression’ in the groundwater which keeps the acid from spreading underground in the groundwater (according to geologists and hydrologists).
But… injecting acid underground obviously raises an environmental health question: How (and who) makes sure the acid doesn’t contaminate groundwater?
Who Decides Whether Acid Injection Is Allowed?
Until recently, the EPA regulated these kinds of acid injection wells. Last October EPA transferred that regulatory authority to ADEQ. EPA approved Arizona’s regulatory program Az long as ADEQ follows the memorandum of agreement defining responsibilities.
Now it’s ADEQ who issues permits, conducts inspections and enforces injection requirements. EPA keeps federal oversight authority.
EPA originally approved Florence Copper’s commercial injection permit in 2023 (they began production in February of this year). ADEQ assumed responsibility and reissued the permit in January 2026.
What Arizona Laws Govern These Decisions?
ADEQ staff and (now confirmed) Director Karen Peters make the decisions about how they regulate this via state statutes & their administrative rules:
- A.R.S. § 49-257.01: Establishes Arizona’s underground injection permitting program and prohibits injection that endangers underground drinking-water sources.
- Arizona Administrative Code, Title 18, Chapter 9, Article 6: Sets technical requirements for injection wells, permits, monitoring and enforcement.
- A.R.S. § 49-241: Aquifer Protection Permit requirements for covered facilities and discharges.
- Arizona Administrative Code, Title 18, Chapter 9, Articles 1 and 2: Fleshes out aquifer protection permit (APP) requirements, including groundwater monitoring and permit conditions.
Who Makes Sure the Company Complies?
ADEQ is supposed to review compliance information and conduct inspections and can use enforcement authority when violations occur. They continue throughout operations and post-closure monitoring.
The company oversees following their permit requirements. ADEQ is responsible for enforcing them. The Governor is ultimately responsible for the actions of the ADEQ Director… and EPA is responsible for making sure ADEQ is doing a good job.
How effective the regulations are at protecting groundwater of course depends on how good a job ADEQ does. That depends on having enough qualified staff and good, ethical, and uncaptured agency leadership.
It also depends on whether the governor allows the agency to do their job or micromanages it, directing them to pull back on compliance and enforcement work as has happened in the past. And that – of course – directly relates to who ends up winning the Governor’s race this year.
Editorial Note: The real effectiveness of this regulatory system rests on whether ADEQ has the resources, expertise, staffing and leadership to make sure the company follows them during operations and after it closes.
As we saw during the Ducey Administration, Governors can intentionally starve agencies for needed operating revenue and place arbitrary ‘head count’ caps on them to make them intentionally weak and ineffective – a passive way of kowtowing to industry.
That’s why it’s important for people to vote for elected officials, including governors, who care about how well their agencies work.
