MARIKANA, South Africa More than 3,000 striking South African miners marched through streets near Lonmin's Marikana mine on Wednesday, the largest protest at the hot spot since police shot dead 34 of their colleagues last month.
Police armed with tear gas and assault rifles deployed armoured vehicles and helicopters to keep an eye on the stick-waving protesters.
It was the strongest show of police force since the immediate aftermath of the August 16 shooting, the bloodiest security incident since the end of apartheid in 1994.
One man at the front of the column waved a placard reading "We want 12,500 or nothing else", a reference to the group's demand for a hike in base pay to 12,500 rand (942 pounds) a month, more than double their current salary.
The marchers retreated after a two-hour standoff at an entrance of Lonmin's nearby Karee mine and talks between a delegation of protesters and management. There was no violence.
The strike for the pay rise by rock drill operators and other miners is now in its fourth week and is threatening to cripple London-headquartered Lonmin. Only 4.2 percent of its shift workers reported for duty on Wednesday.
"We want all the shafts closed. We have lost loved ones and spilt blood," said a miner who asked to be called by his first name Xolani.
The unrest may also hurt President Jacob Zuma before a December vote for re-election as the leader of the African National Congress (ANC), the party that dominates politics.
Jan Thiroun, a Lonmin manager at Karee who met some of the marchers, said the strike was setting a dangerous precedent with ramifications for a sector that makes up 6 percent of output in Africa's biggest economy.
"It's like putting a gun at someone's head," he said. "From here on, if you do something like this, you might as well close all South Africa's mines."
Marikana accounts for the vast majority of the platinum output of Lonmin, which itself accounts for 12 percent of global supply of the precious metal used in jewellery and vehicle catalytic converters.
The strike has raised worries that the labour unrest which has hit the platinum belt this year could spread to the gold sector. South Africa is home to 80 percent of known platinum reserves and is the world's fourth-largest gold producer.
The Marikana unrest stemmed from a year-long turf war in the platinum sector between the dominant National Union of Mineworkers (NUM) and the small but militant Association of Mineworkers and Construction Union (AMCU).
Impala Platinum, the world's No. 2 producer, was hit by a six-week strike in January and February that cost it 2.4 billion rand ($286 million) in lost revenue and output. It said on Wednesday it had received another wage demand from AMCU.
NUM, an ally of the ANC, which has run South Africa in the 18 years since white-minority rule ended, suspects the labour unrest is being fuelled to undermine its influence.
"We can see that there is an attempt to spread it," General Secretary Frans Baleni said this week. "Gold is vulnerable."
Both Marikana and Karee, 100 km (60 miles) northwest of Johannesburg, have been closed since thousands of rock drillers went on a wildcat strike and protest nearly four weeks ago that led to the August 16 police crackdown.
Talks between Lonmin management, unions and the government to ease tensions and get the striking miners back resumed in the nearby city of Rustenburg.
Representatives from AMCU and other workers who had boycotted previous sessions attended the session, raising hopes for a "peace accord" to set the stage for wage negotiations.
World platinum prices have risen more than 10 percent since the August 16 shooting, while Lonmin's Johannesburg- and London-listed shares have lost nearly 20 percent.
The march pushed Lonmin's shares down 5 percent on Wednesday to 9-year lows. Shares of the company briefly touched 70.50 rand, their lowest since 2003.
($1 = 8.3921 South African rand)
(Writing by Ed Cropley and Jon Herskovitz; editing by Anna Willard)