Floyd Gray
Research Geologist
the US Geological Survey (USGS)
View from the Top

Geology Creates Opportunity for Cooperation

Wed, 10/18/2017 - 15:18

Q: What interest does USGS have in the Mexican mining sector?

A: We have a long-term interest in the Mexican mining sector because it provides significant material input into the hemisphere’s regional commodity flow, and particularly in Sonora because it is very much a geological extension of what we work on in southern Arizona. We study the Laramide porphyry copper belt, for example, and much of the adjacent epithermal systems in Mexico as well as in the US. I participated in a mapping and isotopic age-dating program to better define the age range of geologic units potentially relevant to mineralization episodes in northern Mexico. We were working jointly with Mexican scientists from SGM, the Geological Institute at UNAM and UNISON through an entity called the University of Arizona-USGS- Mining Industry Mexico Consortium. This initiative was established in 1991 and supported by companies like Minera Kennecott and Cypress.

These efforts help us define the corresponding mineral belt on the US side, plus we can see different data and different exposures. Some of the land in the US might be privately owned or park land, meaning it could be difficult to obtain access, so it can be easier to come to Mexico to work on the same geological province. We have worked extensively over 60 years with SGM and we have carried out several joint projects defining areas of interest.

Q: What projects are you working on and what practical applications result from these ?

A: The most recent project we worked on was the mineral resources assessment of Mexico, which was a joint study with UNISON, UNAM and SGM. We had several joint exercises and we were given 36,000 analyses before they were released to the public. We obtained the digital map and carried out a three-part quantitative probabilistic assessment in Mexico, where I led the portion looking at Laramide-age mineralization processes and their contained deposits and deposit potential.

We also work with mining companies that are starting up to help with the environmental characterization. USGS was customarily called upon to review this part of the permitting process after completion but now we are trying to get involved from the beginning of the characterization process to act as advisors in developing basic scientific information needed to make workable engineering decisions and systems that minimize environmental impacts. For example, we are planning on working closely with Resolution Mining, whose project will be 7,000 feet below ground.

Q: How is this information used by mining companies?

A: As a federal entity, our assessments are available to the public. We publish a worldwide estimate of mineral resources as a tool that juniors as well as major mining companies compile internally. They potentially could base their planning and activities including prospecting, targeting, and mineral concessions acquisitions on this estimate. We have developed our own version of it to use as a public document for city planners, managers and perhaps junior exploration companies.

Q: How likely is the USGS to fund any Mexico-based research projects in the near future?

A: The USGS funds binational studies that involve developing or interpreting data from the Mexico side. We are trying to develop studies on a project that may involve the San Pedro River in Mexico to examine the spill effects caused by unexpectedly intense monsoon storms. Specifically, we are examining the contaminant reservoir and remobilization potential. This proposed study would be in cooperation with local public and private entities. I am currently examining a spill area in Arizona and comparing its mineralogical aspects with an area in Colorado and we would like to include a part of the Sonora and San Pedro Rivers to compare the effects on the soil. Such a study would be carried out in conjunction with the Mexican Civil Protection Agency.