China’s fourth-largest coal producer reported a preliminary first-half net loss of about 2.35 billion yuan ($US383 million) for the six months ended June 30, citing exchange-rate losses and struggling coal markets for the decline.

In a Securities and Exchange Commission filing on Monday, the producer apologized for the results being worse than it last forecast in April, while promising its forecasts will be more scientific and accurate in the future.

In April Yanzhou forecast its first-half net income would be down 75% from last year’s 4.91 billion yuan.

The results estimate was affected by changes in exchange rates that cut net income by 1.79 billion yuan more than previously estimated, according to the statement.

The continued decline of the coal price was also blamed for the lower forecast, with Yanzhou reporting that impairments on the value of some of its mines were 1.12 billion yuan more than expected and falling prices for its coal products reduced the period’s income by an additional 890 million yuan.