(Adds detail, background) Oct 27 (Reuters) - Global miner Anglo...

(Adds detail, background)

Oct 27 (Reuters) - Global miner Anglo American AAL.L said on Thursday its third-quarter output was broadly in line with last year, as a drop in copper production offset a ramp up in coal operations and strong performance at its De Beers diamond unit.

In the quarter ended Sept. 30, production of rough diamonds rose 4% year-on-year to 9.6 million carats, supported by higher grades in Botswana, while copper production dipped 6% on lower grades at the group's operations in Chile.

Steel-making coal production jumped 28% to 5.5 million tonnes as the group ramped up longwall operations at its underground mines in Grosvenor and Aquila.

Demand for rough diamonds has risen this year as gold and diamonds from Russia went off-limits due to western sanctions against Russian companies, including Alrosa ALRS.MM , the world's largest producer of rough diamonds that competes with Anglo American's unit De Beers.

Anglo American's quarterly output grew 16% from the previous three months led by the robust coal and diamond operations.

The group reiterated its annual production outlook for diamonds but flagged that sales in the fourth quarter could be hit by closure of cutting and polishing factories for holidays in India.