* Gold Fields sacks 8,500 illegal strikers
* Harmony tells miners to report for work Thursday
* Harmony says strike cost it 13,000 ounces in lost production
* AngloGold Ashanti ultimatum ends Wednesday
By Olivia Kumwenda and Sherilee Lakmidas
JOHANNESBURG, Oct 23 South Africa's Gold Fields sacked 8,500 wildcat strikers on Tuesday after they ignored an ultimatum to return to work or face dismissal, ratcheting up pressure to end weeks of labour unrest.
South Africa is struggling to resolve violent unrest that has poisoned industrial relations, marred its image overseas and is spreading beyond the mining industry.
The world's fourth-largest bullion producer - one of several companies to throw down an ultimatum to striking miners - issued dismissal notices to the strikers at its KDC East mine near Johannesburg, a company spokesman said. The workers will have 24 hours to appeal.
"We have now reached a stage where we can't hold off anymore. Our hands were forced and we have now done it," spokesman Sven Lunsche said.
"We are monitoring the situation very closely and have police on standby but it has been very quiet."
Gold Fields last week resolved a strike at nearby KDC West by using a similar hardball tactic. Rival bullion producer Harmony Gold has also given wildcat strikers an ultimatum.
In issuing its threat to 5,400 workers at its Kusasalethu mine to report for duty by Thursday morning or face the sack, Harmony said the strike had already cost it 13,000 ounces in lost production.
An ultimatum issued on Monday by AngloGold Ashanti, the world's No.3 gold producer, expires on Wednesday. The company was seeing positive signs that workers will return to work by the deadline, spokesman Stewart Bailey said.
The bulk of workers at two mines, Kopanang and Great Noligwa, had returned to work and those mines were back in operation, he said, adding the company could have half of its striking workforce of 24,000 back at work on Wednesday.
Workers at Toyota Motor Corp's parts supplier are also expected to return to work on Wednesday after the company and the union reached a agreement.
The strike at Toyota Boshoku, which makes seats and door panels, forced Asia's top automaker to shut its South African car factory since Wednesday last week.
Workers at a Goodyear Tire factory in the Eastern Cape became the latest to stop work on Tuesday, going on a legal strike to protest against a change in company policy toward allowances for breaks, a union said.
About 100,000 workers have downed tools for better pay since August in a wave of strikes that has sparked two credit downgrades and raised questions about the relatively slow response of President Jacob Zuma's government.
In the worst of the unrest, police shot dead striking platinum miners at Lonmin's Marikana mine, the bloodiest security incident since the end of apartheid in 1994.
At a government-appointed commission into the "Marikana massacre" in the platinum-belt city of Rustenburg, 120 km (70 miles) northwest of Johannesburg, relatives of several victims broke down as video footage of the Aug. 16 shooting was played.
Anglo American Platinum (Amplats), the world's largest platinum producer, was the first to take a stand against wildcat strikes, sacking 12,000 workers at its Rustenburg operations earlier this month.
Its Rustenburg mines have been shut since Sept. 12.
Last week it said it would delay the dismissal process at its Union and Amandelbult operations, where it employs 20,500 people. It also said it was open to discussing the reinstatement of the sacked workers with unions.
The strikes spread to other mining industries after starting in the platinum mines.