* Two smaller unions agree to return to work
* Biggest transport union under pressure to follow
* Fuel, consumer good, cash deliveries disrupted
By Agnieszka Flak and Wendell Roelf
JOHANNESBURG, Oct 9 (Reuters) - Some of South Africa's striking truckers have agreed to return to work on Wednesday, easing pressure on Africa's biggest economy where two weeks of labour unrest in the transport sector have hit supplies of fuel, cash and consumer goods.
But disputes in the mining sector escalated after Gold One fired the majority of its 1,900 workers at its Ezulwini operation, paralysed since last week by a wildcat strike. Atlatsa Resources said it had also fired 2,161 miners for an illegal strike.
Since August, almost 100,000 workers across South Africa, including 75,000 in the mining sector, have downed tools in often illegal and violent strikes that may hit economic growth this year and undermine investor confidence in the minerals hub.
Two transport unions with 5,500 members agreed to abandon the truckers' strike, but the biggest labour group, the South African Transport and Allied Workers Union (SATAWU) which represents about 28,000 workers, pressed on with the boycott.
Another 9,500-strong transport union denied reports its members would also suspend strike action, saying negotiations were continuing.
An employers' association had earlier said three transport unions had suspended the strike because "employers have now offered double digits (a pay rise) for the year". It said it was still in talks with all groups to hammer out a final deal.
The rand currency, which fell to 3-1/2 year lows against the dollar on Monday on worsening investor sentiment about labour strife, firmed on news the transport unions would end their walk-out.
SATAWU is demanding annual wage increases of 12 percent for two years - more than double the inflation rate, while employers have offered a total 18 percent pay rise over that period.
"We are willing to compromise on our demands, but only as long as the employers do the same," said Vincent Masoga, a spokesman for SATAWU.
An employers' body said last week that the freight industry was losing around 1.2 billion rand ($135 million) in turnover each week. If the protests expand to rail and ports, exports of coal and other minerals would also be hit.
Affected companies include logistics groups Imperial Holding , Super Group, Grindrod, Barloworld and Bidvest.
President Jacob Zuma's ruling African National Congress has been criticised for letting the strikes spread. Moody's ratings agency downgraded government bonds a notch last month, saying ineffectual governance posed a long-term economic risk.
Large parts of the mining sector, responsible for about 6 percent of gross domestic product, have been brought to a standstill in the last two months by wildcat strikes by more than 15 percent of its workforce.
Platinum miner Lonmin reached a deal in September to end a wildcat strike for a yearly wage increase as high as 22 percent for some miners.
Within hours of the deal, workers at nearby platinum mines called for similar raises. In the days that followed, wildcat strikes hit sectors including gold, iron and car manufacturing.
The Chamber of Mines said it met unions on Tuesday "in an attempt to bring normalcy and stability" to the gold sector and that unions would address their members on Wednesday on proposals to correct anomalies in working conditions.
Last week, mining giant Anglo American Platinum fired 12,000 of its workers who went on an illegal strike, raising the stakes in the labour disputes. Analysts are warning of further job losses and the closure of marginal shafts.
Almost 50 people have been killed in the current labour strife - 34 of them shot dead by police on Aug. 16 at Lonmin's Marikana mine in the deadliest security incident since the end of apartheid in 1994.
"The ongoing violence that has led to the senseless and untimely death of workers will further discourage direct investment in the industry," Bheki Sibiya, chief executive of the Chamber of Mines, said in a statement.
Kumba Iron Ore said it could not honour its contractual obligations to deliver ore to ArcelorMittal's South African unit due to an illegal protest at its giant Sishen mine.
On Monday, a local government workers' union said it also planned a protest in the next few days, the first sign of labour unrest spreading into the public sector.