"We will further investigate tax planning alternatives to minimise this additional deferred tax," Sibanye's statement said.
Sibanye-Stillwater Mining News
South Africa intends to play its role as part of the global effort to reduce global greenhouse emissions.
AMCU has been on strike since mid-November over a wage dispute - after losses at some of its mines last year.
Sibanye-Stillwater said it had entered into talks with stakeholders on restructuring its gold operations following financial losses at the Beatrix 1 and Driefontein 2,6,7,8 shafts during 2018.
Gold producers in Africa's most industrialised economy, have seen profits squeezed by rising costs, labour unrest and declining grades.
The new strike would begin on Jan. 22 and involve around 12,500 of its members.
Since the union downed tools at Sibanye's gold operations in mid-November, four employees have been killed during strike-related violence.
The company's gold output in 2018 will be lower than forecast as almost half of the employees stopped working since mid-November in a wage strike.
AMCU's strike is a protected strike and the AMCU members' constitutional right to strike remains protected.
The all-share deal is likely to lead to more than 10,000 layoffs.
The union's Sibanye-Stillwater members remain on strike, disputing the miner's argument the action is now illegal.
Potentially putting an end to a strike that has seen almost half of its employees down tools since mid-November.
The South African miner is kicking off this week its Far West gold recoveries project in Gauteng with the pumping of reclaimed tailings into the carbon-in-leach circuit, just four months into construction of the first phase.
Lonmin also said on Thursday it expects Sibanye's deal to close early next year, but cautioned that some uncertainty still exists over its completion.
Operations at Driefontein, Kloof and Beatrix mines were halted late on Wednesday.
South Africa's Sibanye has proposed to buy Lonmin for about 285 million pounds ($365 million) to create the world's No. 2 platinum producer.
Deal would create the world’s No.2 platinum producer.
Sibanye-Stillwater currently employs over 32,000 people at its South Africa gold operations.
If approved, merger would create the world’s No.2 platinum producer as Lonmin is the world’s third-largest while Sibanye-Stillwater is the fourth.
The company shares the same core management team as Regulus Resources and is focused on projects in Argentina.
Shares in Sibanye-Stillwater hit a monthly low on Thursday, down 13.28 percent.
The project, located in the San Juan province, is about 10km from the border with Chile, the world’s No. 1 copper producer.
Under the deal, Lonmin will repay most of the loan by delivering platinum and palladium over a three year period to a subsidiary of Jiangxi Copper, China’s largest copper producer.
Sibanye and Lonmin said in a joint statement they remained fully committed to the deal, which is expected to close by the end of the year.
The transaction would create the world’s No.2 platinum producer as Lonmin is the world’s third-largest while Sibanye-Stillwater is the fourth.