UPDATE 1-Workers begin strike at RUSAL Guinea alumina plant

* Workers demand higher salaries

* Skeleton crew keeping refinery running

(Adds details, background)

CONAKRY, April 1 (Reuters) - Workers at Russian aluminium firm RUSAL's Friguia alumina refinery in Guinea began a strike on Wednesday, a mines ministry official in the West African country said.

"Workers at Friguia went on strike today for better salaries," the official said, speaking on condition of anonymity. "We are on site, and we have convinced them to begin negotiations," he said.

"A reduced workforce is keeping a minimum service going so the refinery does not shut down completely," the official said.

Friguia employs more than 1,000 people to refine bauxite into alumina, an intermediate product which is then smelted to become aluminium MAL3.

It has capacity to produce 640,000 tonnes of alumina per year, according to the firm's website. RUSAL is expanding Friguia's capacity to around 1 million tonnes.