Arch bid $1.35 per ton for the 1,977 acre tract, which contains an estimated 222 million tons of minable coal reserves in Campbell County, US state of Wyoming.

The South Hilight tract contains some of the highest quality coal in the southern PRB, with an average heat content of more than 9,000 British Thermal Unit (Btu) per pound and an ultra-low sulfur dioxide content of less than 0.55 pounds per million Btus.

Arch chairman and CEO Steven F. Leer said the South Hilight reserves are exceptionally well positioned to serve both the growing export market and expanding domestic demand for ultra-low-sulfur coal because of their very high quality.

"Black Thunder is already producing the highest-Btu coal in the southern PRB, and the addition of the South Hilight reserves should extend that quality advantage still further over time" added Leer.

The U.S. Bureau of Land Management (BLM) has determined that Arch’s bid meets the agency’s fair market standards.

The $300m bid amount will be paid in five installments of $60m each, with the first installment paid immediately.

Furthermore, Arch will begin pursuing the necessary permits for South Hilight right away, with the goal of integrating the new lease into the existing mine plan at Black Thunder.