Huckelberry wants studies from Forest Service on water

A new Pima County study of water flow impacts of the proposed Rosemont Mine on the Davidson Canyon and Cienega Creek watersheds concludes that pumping and discharge impacts could persist for “thousands of years,” County Administrator Chuck Huckelberry said in an April 28 cover letter to the report.

In the same letter, Huckelberry asked the Forest Service to conduct two studies under the National Environment Policy Act, to be paid for by Rosemont owner Augusta Resources, as part of the costs associated with the development of an Environmental Impact Statement.

One study would analyze the impacts of the mine on all aspects of flooding, groundwater infiltration and streambed water recharge. A second would have the Forest Service conduct “an independent study of potential pumping and recharge effects in the Green Valley-Sahuarita area.”

Davidson Canyon, which drains the mine to the northeast, and the Cienega Creek watershed to the east are lower than the pit. Pumping and drainage disruptions created will impact them “slowly at first,” according to “Hydrogeology of the Santa Rita Rosemont Site … and Effects of the Construction of the Proposed Open Pit,” by hydrogeologist Tom Myers.

But “after 4,000 years, the lowered water table created by open pit mining would extend through much of the Davidson Canyon area … Cienega Creek ... ecosystem would be slightly more susceptible to the effects of drought and global warming,” Myers said.

A greater concern than pumping, Myers and Pima County Flood Control Director Suzanne Shields suggested, “would be disruption of surface flows to Davidson Canyon” as a result of 4,415 acres of mining development outside of the pit.

Myers provides a number of recommendations for monitoring the Cienega and Davidson and other Santa Rita mountain aquifers before and, if it becomes a reality, during the operation of a mine. He noted that it is unknown whether the springs in Davidson Canyon are water sitting on rocks or whether they are part of regional aquifers.

Coronado Deputy Supervisor Reta Laford did not respond directly to Huckelberry’s requests for two Forest Service analyses, saying, “Please remember where we are in the (NEPA) process—the beginning. Also, please help us remind the public where we are. The scoping period for public comments on the proposal runs through July 14. Given that the scoping period is still open, the scope of analysis for water resources has not yet been determined. We welcome the opportunity to review the report and will give it due consideration by the interdisciplinary team.”

Regional 3 Forest Service hydrogeologist Roger Congdon is evaluating information submitted by Augusta’s consultants and will be handling all water information on Rosemont throughout the EIS process.

Much of the information he is getting is “in the early stage” and centers around identifying sites for appropriate monitoring wells.

Congdon said Myers “had data that is a bit limited; he used four monitoring wells in the pit area and did what he could with what he had.”

He agreed with Myers that pumping the pit will lower the water table immediately around it over 2000 feet, adding, “Most of his presumptions are sound but we have a lot of uncertainties out there. We don’t know how ‘expansive’ the aquifer is. I worked on an EIS on the Battle Mountain, Nevada mine that was supposed to have a thousand years of water that was pumped out in a few years.”

“Hopefully, over time, we’ll have hard data that can better answer those questions,” added Congdon who, like La Ford, stressed, “The EIS process can take a long time and we’re still early in the process. New information keeps coming in, like this idea to run a tunnel through the Santa Ritas.”

In an April 25 e-mail responding to questions from Sonoita residents about the proposed tunnel, Augusta Resource Vice President Jamie Sturgess said, “A technical evaluation of a slurry concentrate pipeline (to the west side of the Santa Ritas) is underway. The filter process would produce a concentrate … for shipment … but at a different location to reduce truck traffic on Highway 83.

“This concept was suggested during the public review process of the (plan of operations)…. the important concept is that the slurry line transport water would be contained, recycled, and returned to the process water circuit for reuse.”

When asked about where a concentrate slurry pipeline would be located in the Santa Ritas and if the water could be reused in the concentrator at the Rosemont mine, Sturgess responded to a reporter, “The concentrate transport study is underway. If I knew the results, we would not be doing the study. The results will be made available when completed.”

Dick Kamp is Wick Communications environmental liaison. Contact him at bepdick@att.net.