The company said the concession contained estimated reserves of 6 million tonnes of high-quality thermal coal.
Borneo chairman and chief executive officer Nils Ollquist said the acquisition was a major boost for the company.
“Our ongoing efforts in the region continue to give us the opportunity to secure very attractive properties with high quality coal, thus enabling us to continue to expand the company's portfolio and increase shareholder value,” he said.
Borneo, via wholly owned subsidiary Interich International, is focused on exploring and developing coal properties in Indonesia’s East Kalimantan region.
In addition to the US, its locations include Hong Kong and Indonesia.