Events are taking place across South Africa to remember the 44 people killed in recent violence at the north-western Marikana platinum mine.
A hymn-filled memorial service at the Lonmin-owned mine is being attended by church leaders, politicians and thousands of mourners.
Reports of worker action at two other platinum mines have added to industry fears that the unrest is spreading.
The price of platinum has leapt to its highest since May.
A week ago, 34 miners died when police opened fire at the mine, where workers were on strike to demand higher pay.
Previously 10 people, two of them police officers, had died in violent clashes.
The mine has been closed as a result of the unrest.
Politicians, religious leaders from all denominations, and thousands of workers and members of the local community are attending a memorial service at a church near the mine to commemorate all those who have died in the violence.
Among those due to attend the service was the head of President Jacob Zuma's office, Collins Chabane.
But the BBC's Navdip Dhariwal at the service says the police - seen by many there as perpetrators of the massacre - are keeping a very low profile.
Ahead of the memorial, a traditional prayer service was scheduled to ritually cleanse the spot where the 34 strikers were shot dead by police.
Services were also expected in Johannesburg, Cape Town and Mthatha - a city in the rural Eastern Cape province. Many miners were migrant labourers from around the country and the bodies of some of the dead have already been returned to their home villages, reports the Agence France-Presse.
The deadly clashes have thrown South Africa into a frenzy of outrage and grief, say correspondents.
President Zuma has rejected criticism that his handling of the situation hurt investor confidence, adding that he is confident that South Africa is in control of the situation.
But fears expressed by analysts and industry executives that unrest could spread to other parts of the mining sector were given weight with reports of worker action at two other platinum mines.
The world's top platinum producer, Anglo American Platinum, said it had received a broad list of demands from its South African workers.
Meanwhile, some 500 workers at a shaft in the nearby Royal Bafokeng Platinum Mine downed tools demanded a pay increase and reportedly blocked fellow miners from going to work.
Mr Zuma has expressed sympathy with some of the grievances expressed by the Marikana miners, saying the mining sector can afford to increase wages and threatening companies which fail to raise miner housing standards with the cancellation of their mining licences.
Visiting the mine on Wednesday, Mr Zuma told workers he "felt their pain" and promised a thorough investigation of the shootings.
On Tuesday, British-owned Lonmin dropped its threat to fire workers if they failed to end their strike after many workers ignored the ultimatum. The company says the strike is illegal.
Religious leaders have brokered talks between the Lonmin management and workers in an attempt to break the deadlock in the dispute over pay.
No unions were involved because "they already failed us", Zolisa Bodlain, one of five workers who met managers, told the BBC.
Part of the background to this complex dispute is the rivalry between two unions - the long-established National Union of Mineworkers (NUM) and the newly-formed Association of Mineworkers and Construction Union (AMCU), which is more militant.
Police said they opened fire last week because strikers wielding machetes and clubs had refused to lay down their weapons.
The striking miners say they are currently earning between 4,000 and 5,000 rand (£305-£382: $486-$608) a month and want their salary increased to 12,500 rand.
The company says most workers are paid about 10,500 rand, if bonuses are added.