"We are signing the agreement tomorrow. That means the strike has come to an end officially," Amcu leader Joseph Mathunjwa said at a mass rally.
Miners will go back to work on Wednesday.
Mathunjwa asked thousands of striking miners whether they wanted to sign a wage deal with the three leading producers on Monday, eliciting thunderous applause.
"Yes! Yes," the miners roared.
"The strike is officially over," Mathunjwa then shouted back, to unrestrained jubilation.
The spot price of platinum fell 1%, the rand firmed slightly against the dollar and the London-listed shares of number three producer Lonmin [JSE:LON] rose nearly 5%.
The Johannesburg stock market, where the other two producers Impala Platinum [JSE:IMP] and Anglo Platinum [JSE:AMS] are listed, had closed by the time Mathunjwa finished his speech, but their shares closed up 1.1% and 1.6% respectively.
Earlier, Mathunjwa praised miners at the Royal Bafokeng Sports Palace in Phokeng, near Rustenburg in the North West, for not giving up during the protracted strike.
"Platinum will never be the same again... What other unions could not do in more than 20 years, you could do in five months."
Mathunjwa presented to loud applause a revised wage deal to miners at the rally.
Thousands of miners were given a programme that included "back to work arrangements".
Mathunjwa read out the details of the deal for different salary bands at Lonmin, Implats and Amplats, which included a R1 000 per month salary increase for lower earners.
The deal would be back-dated to last July at Implats and Amplats but the back pay would end on January 22, when the strike started. This meant miners would not be paid for the months they were on strike.
At Lonmin the deal would be back-dated to last October until January 22.
"In 2012, we asked for R12 500 and people died... and left us with a challenge [to keep fighting]," he told miners at the Royal Bafokeng Sports Palace in Phokeng, near Rustenburg in the North West.
Before reading out the deal, Mathunjwa asked all miners in the stadium to stand and have a moment of silence for "fallen comrades".
He said the strike was one of the most peaceful strikes in South Africa.
Mathunjwa boasted about organising a strike that lasted five months, and mocked rival union National Union of Mineworkers (NUM) for a three-day long strike in the gold sector.
In a series of mass meetings in early June, members of Amcu accepted wage offers "in principle", while introducing new demands that producers said were unaffordable.
The strike has hit 40% of global production of the precious metal used for emissions capping catalytic converters in automobiles.
The stoppage dragged the economy into contraction in the first quarter and has so far cost the companies almost R24bn in lost revenue, according to an online tally run by the three firms.
- Sapa, Reuters