The National Union of Mineworkers (NUM) said on Thursday it was ready to sign a three-year wage offer from state power firm Eskom provided the utility agrees not to discipline staff who went on strike illegally.
Investors want to see a resolution to the standoff between workers and Eskom as any further strikes could lead to widespread power cuts that have hobbled Africa's most developed economy in the past.
Eskom and its three main unions reached the outline deal a week ago, agreeing on salary increases of 7.5% this year and 7% next year and in 2020, plus other benefits.
As part of the deal, the two largest unions with workers at Eskom, NUM and the National Union of Metalworkers of South Africa, wanted members who participated in an illegal strike to not face disciplinary action, a condition Eskom rejected.
The utility on Wednesday sought arbitration relating to the disciplinary dispute, threatening to delay implementation of a wage deal to avoid further power cuts.
"As the NUM, we are ready to sign the deal anytime," said NUM president Joseph Montisetse in a statement.
"On the issue of taking disciplinary action against our members, we are saying the matter could be resolved outside the bargaining unit. We are ready to meet Eskom outside the bargaining unit."
The cash-strapped utility is desperate to push ahead with a turnaround plan that is a centrepiece of President Cyril Ramaphosa's efforts to reform the economy.