Arch Coal (NASDAQOTH:ACIIQ) is warning that its Q4 results will be affected by negative developments in its operations. The company said this is due to reduced production and shipment levels. Specifically, the former saw a quarter-over-quarter drop of 40% at its Mountain Laurel facility in Appalachia, resulting from what the company described as "challenging geologic conditions in the current longwall panel." 

For the latter, a decline of over 15% on a quarter-over-quarter basis was recorded in Arch Coal's Powder River Basin mines. The company attributed this to difficulties with its rail service.

As a result, the company said its full-year 2013 metallurgical coal sales volumes came in a bit below the lower end of its expectations.

Arch Coal is scheduled to release its Q4 earnings before market open on Feb. 4. Analysts are projecting a per-share loss of $0.33 on revenues of $816 million. Those figures for Q4 2012 were a loss of $0.42 per share and $968 million, respectively.