Cliffs sold its stake in the mine along with its ownership of the affiliated wash plant to its joint venture partners, QCoal Sonoma and JS Sonoma.

While QCoal gained 90% interest in the wash plant, JS Sonoma acquired the remaining 10%.

The mine has current estimated reserves of 107 million tons and produces both metallurgical and thermal coal, projected to generate 4 million tons of coal annually.

Prior to the transaction Cliffs owned 45% share in the project, with QCoal holding 45% and JFE Shoji and China Steel holding a 5% share each.

Cliffs had earlier acquired an economic interest in the Sonoma Coal Project to diversify into seaborne coking and thermal coal, strategic with its plans to expand its presence in the Australian mining sector and the steelmaking materials industry.