JOHANNESBURG — A strike by tens of thousands of South African gold miners severely affected production in the struggling industry on Wednesday. There were no reports of violence and two mining companies reached a settlement with their workers.

The strike started Tuesday evening. The National Union of Mineworkers, which says it represents more than 80,000 miners in the gold sector, initially said it was demanding wage increases of up to 60 percent, about 10 times the offer that was made by gold mining companies.

The Chamber of Mines, which represents industry employers, said gold producers Pan African Resources and Village Main Reef had reached agreement with union leaders at two mines for wage increases of up to 8 percent.

"That the producers and the unions can find one another in the interests of preserving these operations indicates our mutual desire to achieve an affordable and sustainable settlement," Elize Strydom, the chamber's chief negotiator, said in a statement.

Lesiba Seshoka, spokesman for the National Union of Mineworkers, said the two settlements would not have an impact on protests at other mines.

"We just said we would be willing to ease our demands, but it must be a double-digit increase that is worth the workers' while," the South African Press Association quoted Seshoka as saying.

Another gold-mining operation, Harmony, said the strike had heavily affected most of its operations but that it continued to engage with unions to reach a settlement.

"We are encouraged by the responsible and peaceful conduct of employees engaged in the strike, and urge all parties to uphold the law and all agreements," said Graham Briggs, Harmony's chief executive officer.

President Jacob Zuma has urged both sides to reach agreements. South Africa's mining industry has been hit by rising costs, diminishing production and labor unrest in recent years.

Some 46 people were killed during a six-week period of labor unrest over wages at Lonmin's platinum mine last year in Marikana, northwest of Johannesburg. In one incident, police fired into striking miners near the Marikana mine on Aug. 16, killing 34 people and prompting an official inquiry that is still underway.