Quarterly updates from the likes of Yancoal (ASX:YAL) and Whitehaven (ASX:WHC) have already given a big hint about the likely slide in June 30 earnings for the coal mining sector, but the interim results from US and Australian miner, Coronado (ASX:CRN), confirmed that the reporting season for this sector won't be pleasant.

Earnings for the half fell 62% on an EBITDA basis to $US135.4 million because of the impact of weak pricing for its coking coal product and production problems—which seem to have been reined in during the June quarter.

Coronado said on Tuesday that revenue for the half was $US1.34 billion, down from $US1.49 billion a year earlier. Net income fell 92% to $US16.2 million despite a 2.2% rise in sales volumes to 7.8 million tonnes for the half.

The average realized price per tonne sold dropped 13% to $US199 a tonne, while Coronado said its mining costs were up 10.8% to $US107.7 a tonne, mostly due to rises in first-quarter costs from the wet weather.

On the face of those figures, a tough half-year is evident, but the company took steps in the June quarter to improve costs and returns from its major asset, the Curragh export coking coal mine in Queensland.

The company noted that completion of improvements at Curragh led to higher production, higher sales, lower costs, and improved margins in the second quarter, with improved results "expected to continue for the remainder of the year."

Coronado said "dramatic cost and productivity gains" at Curragh will set "new benchmarks for future performance."

In a brief comment Tuesday afternoon, Moody's Ratings said that while the weak EBITDA result was "credit negative" for Coronado, the second-quarter improvement was a positive.

"While the result reflects a moderation in met coal prices compared to those in 2023, the first-quarter results saw elevated costs due to weather-related disruptions, further impacting its financial performance. However, Coronado's second-quarter production costs have significantly reduced due to cost initiatives at its Curragh mine. We expect ongoing operational optimization to continue to support its margins in the second half of 2024.

"The company maintains good liquidity buffers with $414 million of available liquidity and reported net debt of $4.7 million," Moody's added.