* Platinum strike "officially over" after five months
* Thousands of miners cheer wage offers
* Deal amounts to 20 pct basic wage increase
* Strike dragged down economy, hit platinum output
* Several weeks before mines start producing again (Adds quotes, details)
By Zandi Shabalala
RUSTENBURG, South Africa, June 23 (Reuters) - South Africa's AMCU union declared a five-month platinum strike "officially over" on Monday as thousands of miners roared their approval when leader Joseph Mathunjwa asked if they wanted to end the longest work stoppage in the country's history.
"Yes! Yes!" the miners chorused as the union boss asked whether they wanted to accept the wage offers from producers.
"The strike is officially over," Mathunjwa then shouted back, to unrestrained jubilation from the tens of thousands of workers packed into Rustenburg's Royal Bafokeng Stadium, one of the venues for the 2010 soccer World Cup.
The spot price of platinum fell 1 percent, the rand firmed nearly 1 percent against the dollar to two-week highs and the London-listed shares of number three producer Lonmin (Frankfurt: LRH.F - news) rose as much as 7 percent.
The precious metal's two biggest producers, Anglo American (LSE: AAL.L - news) Platinum and Impala Platinum (Other OTC: IMPUF - news) , are listed on the Johannesburg stock market. It had closed by the time Mathunjwa finished his two-hour-long speech, but their shares closed up 1.6 percent and 1.1 percent respectively.
Mathunjwa said wage deals would be signed on Tuesday and workers would start reporting for duty the following day, ending industrial action that started on January 23 - five months ago to the day.
Industry sources said they could not confirm signings would take place on Tuesday but expected workers to return this week.
"I'm very glad the strike is over, because we made a terrible wound in the South African economy and we are happy to heal that wound. Our children are suffering because they had no food," said Lucas Makgwe, a miner at Amplats.
Mathunjwa, a Salvation Army lay preacher who casts himself as a class warrior doing battle for downtrodden black miners whose lives have changed little in the 20 years since apartheid ended, was exultant.
"Today we are creating a historic day in the mining sector," Mathunjwa, clad in a trademark AMCU green shirt, told the crowd.
"The platinum sector will never be the same. What other unions have failed to do over many years, you have achieved in five months."
Under the populist battle cry of a "living wage", AMCU had initially demanded that basic wages be more than doubled immediately to 12,500 rand ($1,200) a month. In the end, its members settled for three-year deals that amount to monthly increases of around 20 percent, or 1,000 rand a month.
The mining companies, constrained by depressed prices and soaring costs, had said the massive hikes AMCU was initially seeking would sink the industry.
Marred at times by violence, the strike hit 40 percent of global production of platinum, which is used in jewellery and for emissions-capping catalytic converters in automobiles.
The stoppage dragged Africa's most advanced economy into contraction in the first quarter and cost the companies almost 24 billion rand ($2.25 billion) in lost revenue, according to an online tally run by the three firms. (http://www.platinumwagenegotiations.co.za/)
Companies will lose revenue for several more weeks as the mines slowly grind back into life and production is restarted.
The resolution, while welcome, does not spell an end to the most turbulent bout of labour unrest since the end of white-minority rule, with the NUMSA metal workers' union threatening a strike in the auto industry from next month.
The platinum sector also faces a painful restructuring, with job cuts almost inevitable - in part because of the losses incurred during the AMCU strike. That could trigger a further wave of walkouts or violence.
($1 = 10.7127 South African Rand) (Additional reporting by Olivia Kumwenda-Mtambo and Ed Stoddard in Johannesburg; Editing by Ed Cropley, Pascal Fletcher and Catherine Evans)