Water Quality Control Commission Unanimously Upholds Proposed Mine’s Groundwater Discharge Permit Issued Under the Copper Rule

On August 13–14, 2019, in what many view as bellwether cases, the New Mexico Environment Department’s (NMED) Water Quality Control Commission (WQCC) decided two administrative appeal challenges to the first-ever groundwater discharge permit (DP) issued by NMED to a proposed new copper mine under the WQCC’s 2013 Copper Rule, N.M. Code R. § 20.6.7. The WQCC’s Copper Rule and the New Mexico Supreme Court’s unanimous affirmance of the rule against a facial challenge were reported on previously in Vol. XXX, No. 4 (2013), Vol. XXXII, No. 2 (2015), and Vol. XXXV, No. 3 (2018) of this Newsletter. The proposed mine—the Copper Flat Mine (Copper Flat) in Sierra County, New Mexico, near Truth or Consequences—would be an open pit mine with associated facilities such as a mill, waste rock stockpiles, and a tailings impoundment. The appellants challenged the DP on six grounds, including that NMED should have denied the permit as creating a “hazard to public health [or] undue risk to property” under the Copper Rule, N.M. Code R. §, and that NMED improperly concluded that the pit water body at the end of mining would be eligible for the “private waters” exemption from the application of surface water standards under New Mexico’s Water Quality Act (WQA), N.M. Stat. Ann. § 74-6-2(H). On August 14, after hearing more than five hours of attorneys’ arguments and responses to questioning, and following three hours of deliberations, the WQCC unanimously passed a motion to uphold Copper Flat’s DP without change.

The WQCC adopted the Copper Rule at the direction of the New Mexico Legislature in 2009 amendments to the WQA. Prior to 2009, the WQA prohibited the WQCC from “specifying the methods” of protecting against groundwater pollution in the state’s DP regulations. See id. § 74-6-4(D) (2008). In 2009, however, the legislature partially reversed that paradigm by requiring the WQCC to adopt supplementary copper industry-specific regulations “specifying the measures” copper mining operations must employ to protect groundwater at typical copper mining facilities. See id. § 74-6-4(K). Following more than a year of stakeholder working group meetings the WQCC adopted the Copper Rule, which the supreme court subsequently described as containing “an abundance of provisions that afford significant groundwater protections at copper mine facilities designed to prevent pollution.” Gila Res. Info. Project v. WQCC, 2018-NMSC-025, ¶ 61, 417 P.3d 369.

In issuing the DP for Copper Flat, NMED relied heavily on findings and conclusions of the hearing officer who presided over the evidentiary public hearing before the agency. Specifically, the hearing officer concluded that New Mexico Copper Corporation had shown full compliance with the requirements of the Copper Rule. Moreover, although the hearing officer left it to the NMED Secretary to decide whether permit issuance would create a “hazard to public health or undue risk to property,” the NMED Secretary found it would not, and the WQCC through its unanimous decision affirmed.

The WQCC also unanimously affirmed NMED’s determination—made in the course of issuing the DP—that the future pit water body would be eligible for the definitional exemption from the WQA for “private waters that do not combine with other surface or subsurface water.” N.M. Stat. Ann. § 74-6-2(H). The bases for NMED’s determination included findings that after mining the pit water body would be confined to private lands, that the pit would be a hydrologic sink preventing outward migration into surface or groundwater, and that determining the pit water body to be exempt was consistent with the Copper Rule’s employment of hydrologic containment principles and the inapplicability of standards within what the Copper Rule defines as the “area of open pit hydrologic containment.” N.M. Code R. §

The petitioners comprised two neighboring ranches, an environmental advocacy group, and an irrigation district dependent upon water from the Caballo Reservoir and stretches of the Rio Grande approximately 12 miles from the proposed mine site. In addition to the issues already discussed, the petitioners argued for reversal or the imposition of additional permit conditions based on assertions that (1) the hydraulic conductivity of certain andesite bedrock features underlying some of the proposed waste rock piles was inadequately characterized, (2) the monitoring wells were insufficient in terms of the number and spacing of the wells, and (3) the financial assurance initially proposed by the mine to NMED (one of three agencies requiring financial assurance) was inadequate. The WQCC’s unanimous decision upholding Copper Flat’s DP, however, reflects that the WQCC was more persuaded by evidence and arguments presented by the permit applicant and NMED, which were aligned in defending the DP in the administrative appeal taken by the petitioners on the record under N.M. Stat. Ann. § 74-6-5(Q).

Editor’s Note: The reporter represented Copper Flat in the proceedings described in this report.

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