By Micah Jonah
January 16, 2026
Brazil’s Labor Ministry has ordered the closure of three waste piles at Sigma Lithium’s flagship Grota do Cirilo mine in Minas Gerais state, citing a “grave and imminent” risk to workers and nearby communities.
The order comes as Sigma, Brazil’s largest lithium producer, continues efforts to resume operations at the mine, which has been inactive since October 2025. The ministry warned that a collapsed waste pile could affect local homes or spill into the Piaui River.
Sigma said the restrictions do not affect its production schedule and denied safety hazards, noting the piles contain only soil with no contaminants. The company also highlighted potential operational and economic impacts if access to the piles remains blocked.
The company has faced additional challenges, including a legal dispute with former co-CEO Calvyn Gardner over mining rights and a 15% share drop after Bank of America downgraded the stock, citing unclear production timelines.
A labor inspector previously reported a “partial rupture” of one pile near a school, prompting the ministry to reject Sigma’s appeal to lift the closure order. The company must now provide documentation proving the issues have been addressed to resume using the wastes.
