The union's Sibanye-Stillwater members remain on strike, disputing the miner's argument the action is now illegal.
Sibanye-Stillwater Mining News
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.
Sibanye said in a statement that it would fund the tender offer from existing cash resources.
Lonmin has been the biggest casualty in South Africa's platinum mining industry.
Wage negotiations in the gold sector are at a deadlock and the South Africa's National Union of Mineworkers (NUM) has declared a dispute, a move that is one step short of a strike.
Sibanye-Stillwater is due to report half-year results on August 23.
Hundreds of South African gold mine workers were rescued and over 100 treated for smoke inhalation after an underground fire.
The Canadian streaming firm has bought all of Stillwater's gold production for the life of the mine and, initially, also 4.5% of its total palladium output.
Producers have been giving above-inflation wage hikes for years, adding to the cost burden of an industry that has been battling in the face of depressed prices, labour unrest and soaring power bills.
Streaming deal involves production from Sibanye's Stillwater and East Boulder mines, located in Montana.
Sibanye Canada and Regulus’ newly formed Argentinean subsidiary Aldebaran Resources will create a strategic partnership to unlock value at the copper-gold project, located in the San Juan province.
US law firm Bernstein Liebhard said the suit would deal with "misleading statements" made by the precious metals producer, which has had 21 fatalities on its operations so far in 2018.