(Bloomberg) -- Shares of precious metals producer SSR Mining Inc. plunged as much as 61% Tuesday after the US company halted operations at its flagship Turkish gold mine following a landslide — its second incident at the site within two years.

SSR said it suspended operations at Çöpler Mine in eastern Turkey after a “large slip” on the mine’s heap leach pad — a pond where metals are extracted from ore — Tuesday morning. Rescue teams were sent to the area and nine workers were unaccounted for, according to a statement from Turkey’s Energy & Natural Resources Ministry.

SSR’s US shares were briefly halted after the disclosure triggered a plunge in the stock. The shares were down 60% to $3.87 as of 1:19 p.m. in New York, its lowest intraday since January 2016. More than half of SSR’s market value has been wiped out, leaving the Denver-based company with a market capitalization of about $785 million.

Turkish politicians are criticizing SSR after the mishap, citing the company’s past issues at the site near the Euphrates River, about 650 miles (1,046 kilometers) east of Istanbul. The latest incident comes nearly 20 months after a spill of cyanide waste at the same site forced the company to suspend operations in June 2022.

“We had warned the government on the dangers of cyanide gold mining under the nose of the Euphrates River, but our warnings weren’t heeded,” said Meral Aksener, leader of Turkish opposition IYI Party, in a post on X.

Turkish authorities have initiated judicial and administrative investigations and the main opposition, Republican People’s Party, sent a delegation to the area to observe the situation.

Çöpler is SSR’s second-largest producing gold mine, with output of 56,768 ounces in last year’s third quarter. The facility has been operating since 2010 and is currently producing ore through two plants.

SSR cut short its Tuesday conference call with analysts to discuss 2024 guidance, with Executive Chairman Rodney Antal citing the incident.

“It’s front and center on our mind right now, and still very early, so we don’t have a lot more detail to provide,” Antal said before asking the operator to end the call.

(Updates shares. A previous version corrected mine production in seventh paragraph.)

©2024 Bloomberg L.P.