The company said Thursday that it received the necessary approvals to begin mining from the Sewell mid-vol seam and, sticking to its previous guidance, anticipated mining 10,000 to 12,000 tonnes per month as it begins shipments early next year.

By year-end, the producer said it was targeting 50,000-60,000tpm. It estimates adding about 100 staff during that time as well.

“The opening of our Greenbrier operations marks the beginning of a long anticipated transformation to our production profile,” Xinergy chairman and chief executive Jon Nix said.

“We are very pleased to have commenced operations at Greenbrier on schedule and are committed to continuing the optimization of our asset portfolio towards maximising value for our shareholders.”

Xinergy and South Fork announced the completion of the complex’s mineral exploration, development and production review in March and filed a National Instrument 43-101-compliant report with its consultant, Summit Engineering.

The evaluation reflected a measured and indicated mineral resource of about 32.4 million tonnes currently leased at Greenbrier.

Of those tonnes, about 25.4Mt are proven and probable mineral reserve tonnes in seven seams: Hughes Ferry, Castle, Sewell B, Sewell A, Sewell, Beckley and Fire Creek.

Total capital expenditure for the Greenbrier property is expected to range between $US25 million and $40 million, officials said earlier this year.

Xinergy's other key producing assets are Straight Creek in Bell County and Harlan County, Kentucky, and the Raven Crest complex in Boone County, West Virginia.