Question: The Belle Ayr mine is a coal mine located 18 miles southeast of Gillette, Wyoming currently owned and operated by Alpha Natural Resources, a large American producer of metallurgical coal for the industrial production of steel and iron and low-sulfur thermal coal to fuel steam boilers for the production of what type of power?
Sentence (from "Alpha Natural Resources"): Alpha Natural Resources doesn't produce all of the coal it sells; much of the coal sold by Alpha Natural Resources is purchased from independent mining operations and then resold in the worldwide market.
Relevant evidence: No