Alliance Resource Partners (ARLP), a U.S. coal miner, recently confirmed it has been using excess power at its facilities to mine bitcoin (BTC). Cary Marshall, the senior vice president and CFO, said the miner initially began this “as a pilot project to monetize already paid for yet underutilized electricity load.” According to a transcript of ARLP’s first-quarter earnings call, the company mined and held BTC worth $30 million at the end of the quarter. Conversely, the plant and property associated with crypto mining had a book balance of $7.3 million at the end of the quarter.