Are silver miners turning a corner on carbon emissions?

Latin America’s silver mining companies are making progress in efforts to decarbonize operations – but emissions per ounce of silver produced will rise due to falling grades across the industry.

Mining companies in general are seeking to lower carbon emissions from their mines, with major producers already committed to net zero by 2050, in line with Paris Agreement goals to limit global warming to below 2C this century.

Despite this push, carbon emissions among key silver miners increased in 2020, both per ounce of silver produced and per metric ton of ore processed, according to a 2022 report by trade body The Silver Institute.

On a per-ton basis, emissions hit a low of just over 17kg of carbon dioxide equivalent (CO2e) in 2019, before rising to over 18kg the following year.

Emissions hit a low of just over 12t CO2e per thousand ounces of silver produced in 2018, rising to over 17t in 2020.

But the 2020 rise may reflect temporary COVID-19 impacts, and efforts are already being taken to lower carbon emissions, institute president Brad Cooke told BNamericas.

“Both per ton and per ounce emissions were falling until 2019, and 2020 is anomalous because of COVID-19 so hardly a trend here, but emissions per ton should trend down over time as more companies increase automation to reduce power consumption and embrace alternative power sources, and emissions per ounce should slowly increase over time as we mine lower and lower grades,” he said via email.

Editor's note: The emailed interview with Mr. Cooke was conducted shortly before he died unexpectedly last week.

AUTOMATION, GREEN POWER

Automated systems such as ventilation-on-demand and pumping-on-demand are already being adopted to slash power use, and firms are seeking to tap into alternative energy sources as they come online, according to Cooke, who was also founder and executive chairman of Mexico-focused Endeavour Silver.

This drive toward alternative or renewable energy has some way to go, however.

Renewable energy accounts for 16% of power consumed by the industry compared to 58% from diesel and 21% from other non-renewable electricity, the report said.

“This is highly dependent on location,” Cooke said.

In Mexico, Fresnillo’s mines use 25% wind power, with Hecla Mining’s Canadian operations sourcing 70% hydro power.

Endeavour Silver plans to install 100% liquefied natural gas (LNG) for power generation at its Terronera primary silver project in Mexico, which has a lower greenhouse gas footprint than the fuel oil burned to generate part of the country’s electricity needs, according to Cooke.

POLITICAL FACTORS

Mexico’s energy reforms – aimed at propping up state entities such as power utility CFE and blocking or overturning private power projects – have also proven a key challenge in the push for decarbonization.

“Political factors heavily influence what energy sources are available to silver mining companies. Mexico is the largest producer of silver worldwide, and their government just changed the law to ban private alternative energy projects,” Cooke said.

Another challenge is the need for better storage required for wind and solar power, due to the variable nature of their operations.

Some silver-focused companies, such as Pan American Silver and Endeavour Silver, achieved reductions in greenhouse gas (GHG) emissions intensity last year, according to latest sustainability reports, while those at Fresnillo were broadly flat.

SMALL FIRMS

While larger mining companies are leading the shift toward net zero, silver miners – which are mainly small to medium-sized firms – are not necessarily falling behind their larger rivals.

“Small silver miners typically operate small underground mines which have significantly smaller GHG emissions per ton compared to large open pit mines,” Cooke said.

“Net zero is a very long-term goal given how power intensive the mining industry is, and how remote many mines are.

“Silver mining companies need to focus on what they can control, and make steady progress year after year on reducing GHG emissions, rather than worrying about politicians’ pie in the sky carbon reduction targets,” he added.

Mexico and Peru are the world’s first and third biggest silver producers, with Chile, Bolivia and Argentina all in the top 10, according to latest US Geological Survey data.