Sonoma Mine is owned by QCoal Group, which initiated development of the deposit, in partnership with:

• JFE Shoji Trade Corporation, part of the JFE Steel Goup, one of the largest steel producers in Japan
• China Steel, the largest steel producer in Taiwan
• Watami Trading, a Hong Kong based trading company

Established in September 2007, the mine's first shipment of coal product was railed in January 2008, with the first load of coal being shipped in February 2008. Sonoma Mine produces 4 million product tonne of coking and thermal coal products per year for export to countries such as Japan, Korea, Taiwan and China. It represents a 170 million tonne resource.