THE IMPORTANCE OF ZINC IN COMBATING CLIMATE CHANGE AND HOW U.S. RESOURCES COULD CONTRIBUTE

Zinc (Zn) is primarily used for galvanization and is essential to prevent corrosion of wind turbines used for energy generation; therefore, Zn is an indispensable component of the low-carbon energy transition. To meet a mitigation scenario where average global temperature increase is limited to 2°C by 2100, which is less ambitious than the Paris Agreement, total Zn demand will need to increase ~80% by 2050. The current five-year average of annual apparent consumption of refined Zn in the U.S. is 887,000 metric tons. If Zn mining in the U.S. is to meet the future demands of the 2°C scenario, annual apparent consumption will need to increase to 1,597,000 metric tons by 2050.

The USGS Mineral Deposit Database (USMIN) project creates geospatial databases that are authoritative sources of the most important mines, mineral deposits, and mineral districts in the U.S. USMIN has focused on critical minerals since 2017. Zinc was added to the 2022 Final list of critical minerals due to increasing supply risk as determined by quantitative assessment. Accordingly, USMIN has started compilation of data on Zn deposits, including attributes such as resources, production, and grade.

USMIN has gathered data for 30 Zn deposits in the U.S. that have contained resources plus production values that exceed the five-year average of annual apparent consumption. Only 17 of these deposits have reported resources and when combined, they amount to 45.4 Mt Zn. The five deposits with the highest grades (>6.5% Zn) have combined resources of 19.5 Mt. At the current rate of consumption, U.S. resources could theoretically supply more than 50 years of Zn.

If annual production from U.S. Zn mines were to increase linearly to meet the future requirements of the 2°C scenario, the cumulative amount of Zn mined by the year 2050 would increase from 24.8 Mt (current production rate) to 34.7 Mt. The U.S. has sufficient resources to meet this demand when including deposits of all grades. However, only three of the five highest-grade deposits are currently being mined and it is estimated that the energy consumption for Zn mining doubles if ore grades decrease from 6.5 to 0.24 wt.%. Should the highest-grade deposits be mined first to realize the greatest margin between the energy expended for mining against the subsequent energy produced from wind generation?