Shares in Endeavour Mining fell almost 9% in London on Thursday after the West African gold miner warned that full-year production would probably land only at the lower end of its guided range, following stoppages at one of its mines.

The FTSE 100 company opened sharply lower after the update, with its London-listed shares down nearly 9% at 3,758p, according to Dow Jones Newswires. Market data shortly after the open showed the shares at 3,753p, down 369.50p or 8.95% on the day, making Endeavour the biggest faller on the FTSE 100.

Problems at the Mana mine

The warning follows problems at Endeavour's Mana gold mine in Burkina Faso. Underground mining at Mana was suspended after an access ramp leading to the depleted Wona open pit partially subsided, restricting access to the Dangouna and Aviera underground portals. The incident took place on Wednesday last week.

Endeavour had said on Monday that it remained on track to achieve its 2026 group production and all-in sustaining cost guidance. Thursday's update changed that picture, with the company now expecting to hit only the lower end of its production range as the stoppages bite.

The company said it would provide an update on the geotechnical analysis and its remediation plan alongside its third-quarter results. Mana is one of four mines Endeavour operates in Burkina Faso, alongside Hounde, with further operations at Ity and the Lafigue project in Côte d'Ivoire, Sabodala-Massawa in Senegal and the Kalana project in Mali.

Gold miners under pressure

The fall came on a weak day for gold miners more broadly. Gold held below $4,000 an ounce on Thursday, down for a third straight session, as hotter-than-expected United States inflation data and hawkish comments from Federal Reserve officials strengthened expectations of an interest rate rise in December. Fresnillo, the other big London-listed precious metals miner, fell 3.41% in early trading.

Endeavour's shares had been trading strongly into the update, with the stock up by more than 15% over the previous five sessions before Thursday's fall, reflecting the strong run in the gold price earlier in the year. The production warning is a reminder of the operational risks that come with mining in West Africa, where a single geotechnical incident can move a full-year outlook.

Investors will look to the third-quarter results for detail on how long the Mana stoppage is expected to last, what it costs in lost ounces, and whether the lower end of guidance can still be held if the remediation work runs longer than planned. For now, the market has taken the cautious view, sending the shares to their lowest level of the session within minutes of the open.