The Southwest United States and Northwest Mexico, with similar geology and climate in the copper- and gold-rich region spanning from Utah to Baja California in Mexico, share many challenges in minerals exploration and waste remediation. Researchers working on mining sustainability north and south of the border, however, do not often share findings and technological advances.
That should soon change with the opening of the Center for Mexican Studies, a joint program based on the UA campus of the University of Arizona and National Autonomous University of Mexico, or UNAM, Latin America’s largest university.
The UA hosted a panel on environmentally sustainable mining on September 28 as part of educational and cultural events celebrating the center’s opening. More than 40 people -- including mining and chemical engineers, geologists and environmental scientists from both universities, UA students and scientists from the Arizona Geological Survey and U.S. Geological Survey -- attended the event in the Environment & Natural Resources Phase 2 building, or ENR2, the University’s newest and greenest building.
“Both the U.S. and Mexico are getting a lot more serious about mining in more environmentally sustainable and socially responsible ways,” said Raina Maier, director of the UA Center for Environmentally Sustainable Mining. “The UA-UNAM collaboration will foster more intelligent and science-based decision making on where to mine and what cleanup processes to use.”
Mary Poulton, UA Distinguished Professor of mining engineering, geosciences, law and public health and director of the Lowell Institute for Mineral Resources, stressed the complexity of minerals extraction and environmentally and social responsible mining practices in the region and the need for cross-disciplinary studies and solutions.
“How do we use less water, less energy, more benign chemicals and leave a smaller footprint?” she asked. “A lot of that will be determined at the interface between science and technology -- especially engineering,” she said.
UA professor of environmental engineering James Field discussed his research using microorganisms from sewage sludge to safely and effectively extract valuable elements from mine waste byproducts.
The world produces 18 million tons of copper each year, with an estimated 3 billion tons of copper mine tailings, noted Field, director of the UA Dean Carter Binational Center for Environmental Health Sciences and a key researcher with the UA Superfund Research Project.
“Some compounds in those tailings are toxic, and we need to stabilize or get rid of them,” he said. “But some include extremely valuable elements like tellurium, which are critical in making solar panels and many other products.”
By safely extracting tellurium from mine tailings, this bio-refinery technology could convert a hazardous byproduct into a valuable commodity for mining companies and the communities dependent upon them, he said.
Presenters from the National Autonomous University of Mexico included Elena Centeno, professor and director of the Institute of Geology, and UNAM geology faculty Martin Valencia and Rafael del Río. They discussed the region’s complex geology, which can make it difficult to find and extract minerals, reduction of mine tailing dust and contaminated wastewater transported into nearby communities, the need for a comprehensive database on climate patterns that affect release of hazardous mine waste, and market volatility in the mining industry.
One of the best ways for the mining industry, research organizations and local communities to weather the boom-and-bust cycles of metal commodities pricing is to have a balanced financial portfolio that includes federal, state and private support, said Poulton, who also predicted significant changes in the makeup of mining companies.
“There is a huge generational shift underway in mining. People of my generation -- 60 and older -- are leaving, and people in their 20s, who are often more open to new technologies and have a broader perspective on the need for environmentally and socially responsible practices and policies, are coming in.”
Top picture: UA professor of chemical and environmental engineering Jim Field presents research on biochemical processes to extract valuable tellurium from copper mine waste.