Sigma Lithium plunges for second day on waste piles shutdown at key Brazil mine

Jan 16 (Reuters) - Shares in Toronto-listed Sigma Lithium SGLML.V plunge for a second day after Brazil's Labor Ministry shut down three waste piles at the firm's flagship mine in Minas Gerais state

The ministry pointed out a "grave and imminent" risk to workers and the local community to justify the move, according to documents seen by Reuters

The order added to Sigma's struggle to restart the lithium mine, Brazil's largest, even though it said the restrictions do not affect its schedule for resuming production

Bank of America last week downgraded the firm's shares, citing a lack of clarity on when production would resume

Sigma's shares dive 15% in Toronto trading, following a 12.5% drop on Thursday