M Mining director Matt Latimore said achieving first coal so quickly since announcing the acquisition in April was the result of teamwork from partners, suppliers, managers and workforce.
"Since commencing operations in August with an innovative mine restart plan, this has been an important early production milestone for us," he said.
"In the nine weeks since completion of the sale of Millennium Mine, M Mining has established a strong operating team and issued $464 million in contracts for auger, auger support, open cut and underground."
Latimore said Millenium was a low capital, fast-to-market asset, producing high quality coal.
"First coal came the day after a new historic high of US$380/tonne for Australian hard coking coal," he said.
"The next key milestone for M Mining is open cut mining at Millennium by November of this year.
"Our work is underwriting the future growth of this operation, economic activity and local employment opportunities."