Hudbay Minerals plans to redirect portions of Sonoita Creek on this property north of Patagonia as part of their mitigation plan for the Rosemont Mine. Photo by Marion Vendituoli

1,580 acres of the Sonoita Creek Ranch (SCR), running along the east side of Hwy 82 five miles north of Patagonia, represents the core of Hudbay Mineral’s Mitigation and Monitoring Plan (HMMP) for the Rosemont Mine north of Sonoita.

A mitigation plan is an environmental management plan required for federal permitting of a mining project under the Clean Water Act (CWA). Its purpose is to minimize mining’s impacts on the environment and nearby communities.

The Rosemont Mine HMMP, which was approved by the Army Corps of Engineers in March, would redirect sections of Sonoita Creek by “placing channelized portions of Sonoita Creek back into the floodplain, which mitigates for 40.4 acres of waters impacted by Rosemont; re-establish 25.3 acres of riparian habitat by eliminating agricultural use of lands; and release approximately 580 acre-feet of surface water per year into the channel at Sonoita Creek to return perennial flow into the system,” according to the HMMP.

There are reservations in the community about the mitigation plan at this point, however. There has been no public input regarding the Sonoita Creek mitigation process, according to Ron Pulliam, of Patagonia, who is the founder and board member of Borderlands Restoration, an ecologist, professor, and past Science Advisor for the Secretary of Interior.
Pulliam calls the measures by Rosemont “an engineer’s approach to fixing an immediate problem without fixing the underlying cause.”

Hudbay plans to repair part of the Sonoita Creek channel with a massive earth-moving project to create a new channel. This will also entail filling in a portion of the existing Sonoita Creek channel. The company claims that the mitigation work they propose on Sonoita Creek will make the creek “ecologically superior” to the creek’s current condition. Pulliam, however, believes that the massive earth moving project to create a new channel will likely fill with sediment and overflow, causing flooding. He describes the current
condition of Sonoita Creek as significantly stable. It has been repairing itself, he pointed out, for the last 82 years since being originally channelized for irrigation purposes.

Pulliam has three main objections to the mitigation as proposed: It does not look at the whole watershed, it does not involve the community and it is in the wrong watershed. He emphasized the need to look at the entire watershed starting with outlying landscape and working into the stream bed as the last process in watershed management. In contrast
to the Corp’s claim that the mitigation will contribute significantly to the ecological sustainability of the watershed, Pulliam states there is no basic analysis and science to the mitigation proposals. Dr. Mathias Kondolf, a noted expert on wetlands and river restoration, has contributed key findings that agree with Pulliam’s analysis. Kondolf stated that the new channel “would destroy existing riparian habitat, and fill material generated from the excavation would be spoiled on existing riparian habitat, also without mitigation.”

The Environmental Protection Agency (EPA) review from October 7, 2017 concurred with Pulliam’s assessment that mitigation of the Sonoita Creek Watershed failed to address the potential damage to the watershed at the Rosemont mine site “and consequently does not offset the pervasive damage to aquatic resources in the Cienega Creek Watershed. SCR lies outside the watershed where the Rosemont Mine project will be constructed.” The Sonoita Creek Ranch is 12.5 miles south of the Rosemont site.

Hudbay responded to the ‘wrong watershed’ objection in January 2018, arguing that the EPA was incorrect in its claim that mitigation must take place in the watershed being affected by mining activities. Hudbay’s response was accurate, as the EPA rules do allow for mitigation outside of the impacted area if the mitigation benefits the nearest navigable waters, which in this case would be the Santa Cruz River.

The 2017 EPA report continued to list its objections to the mitigation plan, stating that the “preservation of Existing Wildlife Migration Corridors at SCR will not mitigate for fragmentation of critical animal migration corridors at the project impact site.” It also
stated that “There is no compelling ecological justification to reestablish Sonoita Creek at the RX Ranch Property, or at SCR. Extension of three tributary channels to the reconstructed SCR channel is unnecessary and will not provide any long-term ecological

The final permit required of the Rosemont Mine was a Section 404 permit issued by the Army Corps of Engineers in March 2019. Section 404 of the Clean Water Act regulates the discharge of dredged or fill material into waters of the United States, including wetlands. This permit was granted despite a recommendation by the Los Angeles district office
of the Army Corps of Engineers in July 2016 that the the Corps deny the Section 404 water permit to the Rosemont project. This recommendation was based on their conclusion “that
the proposed mitigation to offset the impacts of the massive mining project was ‘inadequate,’” according to a letter to the Corps from congressmen Raul Grijalva and Ann Kirkpatrick.

The Rosemont Mine will be located on Hwy. 83 between mileposts 43 and 47 on the east side of the Santa Rita Mountains. The mine will be one mile wide, 2,900 feet deep. It is estimated that Rosemont mining will blast out 660 million tons of ore, use 500 million gallons of water per day which comes to approximately 182 billion gallons of water per year. Once the mine is up to steady state running conditions, probably during the first year, the water used will be recycled up to 85%.

Rosemont has “continued to listen to concerns and has responded by offering to implement many mitigation and conservation measures,” according to a statement issued by Hudbay Minerals. Alan Hair, Hudbay’s president and CEO stated that “Rosemont is now a fully permitted, shovel-ready copper project and we look forward to developing this world-class asset.” Hudbay plans to start early work this June 2019.

As of March 27, 2019, five opponents representing 16 groups, plus three Native American tribes have filed suit to overturn the permit.