The Arizona Court of Appeals, Division One holds that Arizona mines may determine whether groundwater meets pollution standards without digging a monitoring well at a statutory “point of compliance,” unless the Arizona Department of Environmental Quality (“ADEQ”) requires otherwise.

Arizona law requires mines to test whether groundwater meets pollution standards at particular “points of compliance” determined by ADEQ. While this can be accomplished by digging a “monitoring well” at this point of compliance, the applicable statute is silent on whether this method is required. In 2018, ADEQ issued a permit for a mining operation to South32 in Santa Cruz County, with several points of compliance. For one of these points of compliance, South32 agreed to determine the water quality without digging a monitoring well.

On appeal from an administrative decision upholding this agreement, the Arizona Court of Appeals affirmed. At issue was the interpretation of A.R.S. § 49-244, which directs Arizona mines to “determine” if groundwater meets quality standards at a particular point of compliance, which is defined as “the point at which compliance [for Aquifer Water Quality Standards] must be determined.” Using the everyday understanding of the word “determine,” the court found South32 must only ascertain through “investigation and calculation” whether the groundwater meets standards. In this case, ADEQ implemented its comprehensive regulatory scheme, studied South32’s designs and technology, and relied on South32 comprehensive system of oversight to ensure compliance. This satisfied A.R.S. § 49-244’s “holistic approach” for ensuring groundwater meets quality standards.

Judge Weinzweig authored the opinion, in which Judges Furuya and Morse joined.

Posted by: Gloria Farrisi