The South African government hosted negotiations Friday aimed at ending a pay dispute between tens of thousands of striking platinum mineworkers and mining firms, amid reports of clashes on the picket lines. As the country's mines and labour ministers led talks seeking to limit the economic damage of the strike, police said strikers were hurling stones at cars and barricading roads. South Africa produces 80 percent of the world's platinum -- used in products from catalytic converters to computer hard disks to dental fillings, and around 134,000 people are employed in the sector. "Decent employment and decent salaries, those are our demands," strike leader Joseph Mathunjwa, president of the Association of Mineworkers and Construction Union told AFP as talks opened. We hope to achieve the demands of our members." The union is demanding a doubling of the minimum monthly wage to $1,150 and better working conditions. Companies have rejected the pay increase as untenable. But anger over the vast income disparities between poor South Africans and the country's rich -- even 20 years after the end of Apartheid -- permeate workers' emands. "They are able to pay one CEO 20 million rand ($1.8 million) in bonuses," Mathunjwa remarked. Nearly 80,000 workers affiliated with AMCU have downed tool at South Africa's top three platinum producers, Lonmin and Anglo- American Platinum and Impala Platinum. The mines are located in northwestern South Africa's restive platinum belt, the scene of waves of violence in the last two years. Fears of more job losses Police in Rustenburg, a key town in the mining zone, reported instances of violence by AMCU members, who pelted cars with stones and barricaded roads Friday. "The police have started to receive reports of roads barricading and other incidents that are in contravention of the law," said Brigadier Thulani Ngubane. "We still urge AMCU leadership to take control of their members on the ground so that the police can continue to do their work in providing safety to lives and properties." Police in armoured vehicles are patrolling hostels and settlements near the mines, with private security guards manning the gates. Firms have welcomed the talks, fearing another wave of strikes that have already pummelled their share price and cost them as much as $1.2 billion in lost revenue. "We are committed to finding a positive and sustainable resolution to this dispute, and management continues to engage at all levels to seek agreement," Lonmin CEO Ben Magara said earlier. But the walkout is still likely to bite. Implats reported attendance as low as 10 percent Thursday at facilities in the platinum belt north of Johannesburg. Meanwhile, Amplats spokeswoman Mpumi Sithole said the firm expects "production to be impacted by the strike action." Lonmin said it expects losses to be in the region of 3,100 ounces per day during the strike. And in a country where as many as one in three is unemployed, there are also fears of further job losses. Amplats, Implats and Lonmin have warned that previous strikes, rising operating costs and a sharp drop in platinum prices had resulted in the loss of around 11,000 jobs since December 2011.