Local opinion: Hudbay's dangerous plans for Copper World

Hudbay Mining & Minerals is presently undergoing the permitting process to construct a large copper mine in the Santa Rita Mountains (“Copper World”). Arizona Department of Environmental Quality (DEQ) has focused upon permitting for groundwater protection and air emissions, but they have omitted review of a critical component of this project, namely Hudbay’s plans to construct and operate a huge, onsite sulfuric acid production factory facing Sahuarita and Green Valley. As a practicing industrial ecologist, I often work with plants like these, and they are far from benign. Hudbay will bring sulfur from outside, burn this in process equipment, and according to Pima County and Hudbay, manufacture 1,100 tons of acid per day. Toxic chemicals such as sulfur trioxide and sulfur dioxide will be formed during the acid manufacturing process. Furthermore, according to their own published documents, Hudbay does not intend to use much of this sulfuric acid for their own copper production in Copper World but will market and sell the acid to others as a separate profit-making enterprise. Therefore, Hudbay are pulling a scam on the State of Arizona, intending to abuse our generous state water rules meant for mining in order to manufacture sulfuric acid for sale as a commodity chemical.

In local advertisements, Hudbay claims that they will focus upon producing “the copper we need, made in Arizona.” However, in their own Technical Report (NI 43-101 Technical Report Phase I), Hudbay states that “it was deemed preferable from an economic standpoint to simply sell the sulfuric acid produced from the leaching of the copper concentrate on the local market than to use it to leach oxides with high calcium content.” Therefore, they are choosing to boost profits from sulfuric acid sales rather than mine all available copper as they have promised. If they were truly sincere about producing copper, they would seek recovery of the metal from all sources in the Santa Ritas including the oxide copper ores.

Therefore, I encourage the State of Arizona to reject Hudbay’s mine plan unless and until the proposed sulfuric acid plant has been fully evaluated for its impact upon our environment and potential threat to public health. Eleven hundred tons of sulfuric acid per day equals nearly one billion pounds per year, and this hazardous chemical will be transported by truck on our local roads and highways. The recent nitric acid truck accident on February 14th, 2023 resulted in one death and a major environmental response in Tucson, and we should not have to bear this risk for any mining company, domestic or foreign. Diesel emissions from acid manufacture and trucking will pollute our already burdened atmosphere in Pima County and increase levels of ozone and particulates. I consult to mining companies and support sustainable and environmentally responsible mining, and Hudbay’s Copper World will be neither.