* Tribal elders, text messages used in campaign
* Strike the most costly in South Africa's mines
* Four killed in platinum mine violence
By Ed Stoddard
MTHATHA, South Africa, May 13 (Reuters) - When the world's top three platinum firms opted to tackle South Africa's worst mining strike by sidestepping the militant AMCU union, they faced a huge logistical challenge: how to contact 70,000 men spread across the country and cowed by violence.
With many workers sitting out the four-month strike at home in rural areas such as the Eastern Cape, the answer was a two-pronged approach combining ancient and modern - a reflection of the split personality of Africa's most developed economy.
Besides SMS and email bursts and local language radio slots, the companies - Anglo American Platinum (Amplats), Impala Platinum (Implats) and Lonmin - called on tribal elders to help sell their pay offers to strikers.
"The miners want to go back to work but they are afraid of being killed," said Xolile Ndevu, general secretary of the Congress of Traditional Leaders of South Africa and one of the intermediaries asked to negotiate after talks deadlocked.
The response by the Association of Mineworkers and Construction Union (AMCU), which is accused of enforcing its will by violence and crushing dissent by taking decisions via a show of hands at meetings, was uncompromising and disdainful.
AMCU snubbed a meeting with Ndevu and management in March in the platinum belt town of Rustenburg, 120 km (70 miles) northwest of Johannesburg, and then humiliated the respected elder at a soccer stadium rally attended by only 100 people.
"Some of them were AMCU members and they sang and disrupted us and booed us. And those are the people who are supposed to respect us," Ndevu told Reuters, a pained expression etched on his face.
Most of the workforce at the strike-hit mines are AMCU members. Others are members of the National Union of Mineworkers (NUM) - the traditional mining sector union - or Solidarity, which represents white-collar workers. AMCU ousted NUM on the platinum belt in a bloody turf war in 2012.
'YES' OR 'NO'
However, the modern approach has borne more fruit for the companies, which say a majority of miners have expressed a desire to return to work.
Foremost have been mass mobile phone messages in English and languages such as Xhosa and Sotho - South Africa has eleven official languages and many miners speak little to no English - outlining the wage offers and asking for a 'yes' or 'no' reply.
"I want to go back to work but I have security concerns," one AMCU member at Lonmin told Reuters in a mine recruiting office in Mthatha, a provincial capital 700 km south of Johannesburg.
He showed Reuters Lonmin's April 30 phone message and said he had replied 'yes' about his wish to return to work but did not want to give his name because of fears he would be assaulted or worse if AMCU's leaders found out.
Four miners were killed in and around the Rustenburg platinum mines at the weekend and the three companies reported 20 incidents of intimidation over the previous two days. Police have made no arrests.
AMCU's leaders deny the intimidation accusations and say most of their members have rejected the wage offer.
However, Amplats chief executive Chris Griffith said on Tuesday the firms had polled miners using "interactive voice message" technology in a variety of languages and reached a definitive answer.
"It's pretty much like a call centre that calls you and you can choose Options 1, 2 or 3," he told Johannesburg's Talk Radio 702.
"We put out very simple messages: Do you want to come back to work? Do you want to accept the offer on the table? And the majority of employees in Lonmin, Implats and Amplats are saying to us 'We want to come back to work,'" he said.
Amplats said many of its workers had already returned to Rustenburg, where police have deployed in force to try to prevent a bloody showdown with AMCU die-hards, and bus vouchers were being given to those still in the Eastern Cape.
Not everybody is taking up the offer.
"I must wait for AMCU to call me back," said 29-year-old Implats employee Malibongwe Nodangala, standing outside an informal bar in his village.
Another Eastern Cape Implats worker, who declined to be named, was defiant. "It is not finished yet," he told Reuters.
Those who choose to hold out are going to be under huge pressure from families that have now gone four months with zero pay remitted from husbands, fathers and brothers in the mines, often their only source of income.
For 39-year-old Nosandile Mnqotho, who has seven children aged between two and 21, that means having to use meagre government grants to support her husband, who came home from Implats in March but returned to Rustenburg last month.
"I send 400 rand ($38.50) a month to my husband," she said.
The companies are offering wage increases of up to 10 percent which they say would raise the overall minimum pay package, including cash allowances for expenses such as housing, to 12,500 rand a month by July 2017.
AMCU had initially demanded an immediate increase to 12,500 rand in the basic wage, excluding allowances, but softened that in March to staggered increases that would amount to 12,500 rand within three or four years - still a third more than the offer from the companies.
The strike is the longest and costliest ever to have hit South Africa's mines and has halted 40 percent of normal global platinum production, although the platinum price has remained relatively static as the companies have run down reserves. ($1 = 10.3782 South African Rand) (Additional reporting by Olivia Kumwenda-Mtambo; Editing by Ed Cropley and Anna Willard)