【Ferro-alloys.com】:Antofagasta Minerals will have to improve its tailings management in response to sanctions issued by Chilean environmental authority SMA.

The authority issued a ruling in late May, saying tailings ponds at Los Pelambres copper mine in Coquimbo region were deficient and the emergency protocol failed in response to a leak detected in November last year.

The SMA issued an order on May 27 that Los Pelambres must present a compliance program within 10 business days of the order (June 10) and would have 15 business days to prepare explanations.

On May 31, Antofagasta Minerals reported another leak from a copper concentrate pipeline that links to Los Vilos port. While an emergency protocol was activated immediately after a pressure drop was detected in the system, the leak extended 45m along a ditch near road D-835 in the Salamanca area, according to a press release.

In a release published on Tuesday, the miner said access to the site is still being blocked by community members, but added that talks with the local representatives and authorities were ongoing.

Mining and processing plant operations continue, while concentrates are being stockpiled at the plant. The full-year production impact will depend on the duration of the shutdown. The group’s overall copper production is not expected to be impacted. Guidance remains unchanged at 660,000-690,000t.

“Capital expenditure in bringing the pipeline back to normal operations is not expected to be material,” it said in the release.

THE TAILINGS PROBLEM

Antofagasta Minerals is facing a common problem. Copper and gold operations generate most tailings in Chile, according to geology and mining service Sernageomin's latest tailings report, from 2020.

The report identified 742 tailings dumps in the country, of which two were under construction, 104 in operation, 463 inactive and 173 abandoned. Geographically, 74% of them are in Atacama and Coquimbo regions.

The problem is becoming more urgent, since ore grades are declining, but demand is rising to fuel the energy transition and meet zero carbon targets. Lower grades also require more energy and water use, which is another problem in drought-stricken countries like Chile.

“Precision mining can reverse this trajectory by identifying high-grade ore, extracting ore with minimal waste and sorting waste from ore to reduce the quantity of waste processed,” according to a report by non-profit resource research company Amira.

Meanwhile, Earthworks, another non-profit group, said a global registry of tailings dams does not exist, but China alone has some 12,000 such dumps, so the worldwide number likely exceeds 18,000.

The group added that while the dams are generally resistant to failure, accidents happen with increasing frequency and severity. Recent failures have caused hundreds of deaths and serious environmental damage, as well as billions of dollars in lost profits and mitigation costs for miners.

Companies should therefore aim to limit environmental harm that inevitably occurs at mine sites, Earthworks said, adding that miners should also improve community outreach, define environmental protections and increase transparency. 

“As climate change brings increasingly severe and extreme weather conditions, and the transition to renewable energy increases demand for certain minerals, addressing the problems of mine tailings management is more urgent than ever,” Earthworks tailings campaign manager Jan Morrill said in a release.

“We must prioritize safety over cost,” he underlined.

• [Editor:Alakay]