Pima County, the U.S. Environmental Protection Agency, the U.S. Army Corps of Engineers and the Arizona Department of Game and Fish have all raised serious concerns that could jeopardize a critical state water quality protection certification that is needed before the Rosemont Copper Company can begin construction of its proposed open-pit copper mine near Tucson.
The four agencies were responding to a draft Arizona Department of Environmental Quality (ADEQ) proposal certifying that Rosemont’s operations would not violate the Clean Water Act. ADEQ is required to provide that certification of Rosemont’s Section 404 Clean Water Act permit application before the Army Corps can approve the 404 permit and construction can begin on the mine.
Several of the agencies said additional studies and analyses would have to be conducted prior to ADEQ’s certification, which could cause significant delays in issuance of both the state’s certification and the Corps’ 404 permit.
ADEQ’s draft certification and supporting documentation acknowledges that the mile-wide, half-mile deep open pit, along with the mine tailings and waste rock that will bury more than 3,000 acres of Coronado National Forest, will reduce stream flows by 17 percent into Davidson Canyon and Cienega Creek.
ADEQ concludes, however, that if Rosemont adheres to conditions in the yet to be issued 404 permit as well as conditions in the certification, the mine “should not cause or contribute to exceedances of surface water quality standards nor cause water quality degradation in the downstream receiving waters including Davidson Canyon and Cienega Creek.”
Both EPA and Pima County have challenged that conclusion and are urging ADEQ not to certify Rosemont’s 404 permit application because of the mine’s likely impact on those two waterways, which are classified as Outstanding Arizona Waters (OAW) and are protected under state law from any degradation of water quality or quantity.
The Army Corps is also raising questions about the adequacy of ADEQ’s draft certification of Rosemont’s 404 permit application, while the Arizona Game & Fish Department is seeking 16 specific changes to the state’s draft certification.
Vancouver, B.C.-based Augusta Resource Corporation is seeking state and federal permits for its Rosemont subsidiary to construct the mine in the Santa Rita Mountains on the Coronado National Forest southeast of Tucson.
Augusta is facing a hostile takeover bid from Toronto-based Hudbay Mineral Resources. Augusta will hold its annual meeting on May 2 in Vancouver and shareholders will be asked whether to extend a shareholders’ rights poison pill plan designed to block Hudbay’s offer that expires on May 5.
Augusta has repeatedly told its shareholders to reject the Hudbay offer because Rosemont will have all necessary permits by June 30 including the Section 404 permit and that construction on the mine will begin in the second half of this year.
Lying amidst the Sonoran Desert and grasslands, Davidson Canyon Wash and Cienega Creek have been the centerpiece of the controversy over the copper mine, the Arizona Daily Star reported in an April 26 story.
“While neither carries nearly as much water as they used to due to a decade of drought,” the Star reported, “both still have rich stands of cottonwoods, willows and mesquites. The state classifies three miles of Davidson and 28 miles of Cienega as outstanding waters that can’t legally be degraded.”
The Star reported there are three major issues related to the mine’s potential impact on the waterways.
“One issue is whether the mine could pollute them by discharging chemicals or other waste materials into tributary Barrel Canyon. A second is whether the mine will make pollution more likely by cutting off water flows into the creeks, reducing their potential for dilution. A third is whether the mine’s activities will send too much sediment downstream, potentially smothering fish,” the Star reported.
Pima County Administrator Chuck Huckelberry criticized ADEQ’s draft certification in an April 7 letter for relying on “faulty information” in the Coronado National Forest’s (CNF) Final Environmental Impact Statement (FEIS) and “unsubstantiated opinions in documents provided by Rosemont Copper Company.”
“I urge ADEQ to deny the…certification for the Rosemont Copper project,” Huckelberry stated.
EPA Region IX, which has consistently warned that the mine would have unacceptable impacts on fragile desert water resources, joined the county in recommending that the state deny Rosemont’s application for the certification.
“EPA believes the draft…certification and supporting information provide an insufficient basis from which to conclude existing water quality will be maintained,” Jane Diamond, director of EPA’s Region IX water quality division, wrote in an April 7 letter to ADEQ. EPA concluded, “after a careful review” of ADEQ’s proposal, that it would not “prevent water quality degradation in Davidson Wash and Cienega Creek,” and that “the risk of water quality degradation remains high.”
EPA’s opposition triggered a federal regulation that required the Army Corps to request additional information from ADEQ concerning special conditions in the draft certification related to the mine’s impact on surface water in Davidson Canyon and Cienega Creek.
The Corps noted that the FEIS concludes there could be as much as a 40 percent reduction in stormwater flow to portions of Davidson Canyon during the 20- to 25-year life of the mine — far higher than ADEQ’s predicted 17 percent decline.
The Corps stated that it is “unclear” as to how much mitigation the state’s draft certification would require Rosemont to do to compensate for the loss in stormwater flows.
The Corps was also critical of ADEQ’s proposal to allow Rosemont to wait up to 180 days after the Corps issues a Section 404 permit before submitting a mitigation plan since the Corps is required to base its 404 permit decision, in part, on the mitigation plan.
“The Corps believes it would be more prudent to require the submittal of the plan prior to issuance of a Section 404 permit,” the Corps’ April 7 letter warned.
EPA joined the Army Corps in criticizing the state for taking a passive approach to protecting Davidson Canyon Wash and Cienega Creek.
“In general, the draft certification relies on lagging indicators (post-discharge monitoring) to trigger corrective actions, rather than a preventative approach to ensure the protection of water quality in” Davidson Canyon and Cienega Creek, Diamond’s letter states.
EPA’s opposition to the state’s issuance of the certification continues the agency’s longstanding opposition to the proposed Rosemont project. EPA recommended in November that the Army Corps deny Rosemont’s 404 permit application. EPA has veto authority over Army Corps 404 permits.
Arizona Game & Fish Department raised 16 concerns about the mine’s potential impact on Davidson Canyon and Cienega Creek and the current lack of detailed water quality analyses of the waterways.
Among other things, the department’s April 4 letter recommends that ADEQ require Rosemont to “collect baseline water quality data for the OAW reaches of Davidson Canyon and Cienega Creek,” conduct a “review of all predicted mine hazardous substance and pollutants,” and “demonstrate how stormwater runoff [from the mine] will not degrade the existing water quality of the downstream OAW’s and their designated Aquatic and Wildlife uses before a 401 Water Quality Certification is issued.”
The AGFD also said the mine’s proposed “dry stack” tailings storage system “has the potential to impact down-gradient groundwater quality” for 500 years.