Shanxi Lu'an Environmental Energy Development (SHA:601699) sold 4.2 million tons of commercial coal in May, jumping 2.5% from 4.1 million tons a year earlier, according to a Shanghai bourse filing on Saturday.
The coal miner's shares fell 3% at the close of Monday's trade.
The company's coal output slipped 1% year on year to 4.6 million tons.