South Africa mining union NUM vows to fight job cuts at Lonmin

* Prospect of a resurgence of labour disputes

* NUM says has not been officially consulted by Lonmin (LSE: LMI.L - news)

* 30 pct of South African platinum sector losing money -Citi (Adds mine minister, analyst comment)

By Zandi Shabalala and Silvia Antonioli

JOHANNESBURG/LONDON, May 8 (Reuters) - South Africa's National Union of Mineworkers (NUM) said on Friday it would fight platinum producer Lonmin's plan to cut 3,500 jobs, raising the prospect of a resurgence of the labour unrest that has plagued the sector.

Lonmin, the world's third-largest producer of the precious metal, said on Thursday it needed to make the layoffs in response to depressed prices and it was holding talks with employees and unions at its South African mines.

But the NUM, which represents roughly 10 percent of Lonmin's workers, said it was shocked by the announcement and had not yet been officially consulted.

"We are going to fight against any job losses ... The platinum sector had cut 35,000 jobs since 2012 and it is time to join forces to end this bloodbath," it added.

AMCU, by far the largest mining union with about 85 percent of Lonmin's workers among its members, was unavailable for comment.

South Africa's economy relies heavily on natural resources but has been hit by recurrent and at times violent strikes.

A bruising five-month walkout across the sector -- South Africa's longest and costliest -- cut Lonmin's production and dragged it into the red last financial year, but failed to lift prices for the white metal.

In 2012, the London-listed firm was also at the centre of labour unrest and violence that left dozens dead.

"My gut feeling is that there's got to be some risk of industrial action at Lonmin. And if that's the case, it could be a trigger for another wave of industrial disputes in the country because this is only the first step in a necessary industry restructuring," said Bernstein analyst Paul Gait.

Some analysts said cash-strapped miners might be reluctant to walk out again after five months of unpaid industrial action in 2014.

The parlous state of the South African platinum industry, with many companies at risk of going out of business, might also act as a deterrent, they added.

Citi analysts said 30 percent of the South African platinum industry is losing money at current prices.

"The minister's wish is that no jobs should be shed. We already have too many unemployed people ... However reality dictates otherwise because of economic conditions prevailing," said a spokesman for South Africa's mining minister Ngoako Ramatlhodi.

Lonmin said on Thursday said it hoped to achieve the reductions voluntarily, with forced job cuts a last resort.

A source close to the company added that the company did not have immediate plans to shut down shafts.

Gideon Du Plessis, from the smaller Solidarity union, which represents mine managers, said it had been involved in discussions with Lonmin and was hoping to find an alternative to forced job losses, including early retirements.

"We are concerned because a lot of our members are fed up. It may lead to an exodus of skilled labour because of the ongoing uncertainty," Du Plessis said.

"The South African mining industry is an uncomfortable working environment, there is a negative sentiment." (Additional reporting by Jan Harvey; Editing by Mark Potter and Andrew Heavens)