Rio Tinto eyes critical minerals potential in Montana

UK-Australian mining company Rio Tinto has partnered with the US Geological Survey (USGS) to survey critical minerals beneath the Continental Divide near Boulder, southwest Montana.

"By working together, we are sharing expertise, resources and knowledge to make the search for critical minerals more efficient," Rio Tinto's exploration director, Chris Welton, said. Data collected through this partnership will be made publicly available.

Rio Tinto will provide support to USGS airborne magnetic and radiometric surveys to be carried out next year for a better understanding of potential critical mineral resources in the area. Recent USGS studies as part of its Earth Mapping Resources Initiative (Earth MRI) have found the region's batholith — a large rock mass that forms when magma rises into the earth's crust but does not breach the surface — to have favourable conditions for critical minerals including rare earths, tellurium, tin, tungsten, copper, molybdenum and gold. Previous mining efforts have yielded significant quantities of copper, gold, lead, silver and zinc, among other metals.

The aim of the Earth MRI programme is to improve knowledge of the US' geological framework and identify areas that may have the potential to contain undiscovered critical mineral resources. It will also advance understanding of valuable mineral resources (such as copper, zinc, gold and industrial minerals), energy and groundwater resources and geological hazards.

This is the first partnership between a mining company and Earth MRI. The barriers to further development of the critical mineral potential of the US remain primarily economic and regulatory. But this initiative also reflects a growing awareness of the need to better understand and diversify supply chains for the critical materials fundamental to economic and technological advancement.

By Caroline Messecar