Overall coal production for the period reached 7.09 million tonnes up from 7.08Mt in the corresponding period.
Metallurgical coal sales for its Curragh mine in Queensland reached 2.98Mt, dropping 5.6% from the corresponding period.
Metallurgical coal production for the mine was also down, falling 1.1% to reach 3.09Mt.
Wesfarmers said mining costs for Curragh were higher due to final flood recovery costs and non-recurring costs associated with the ramp-up of overburden removal and the run of mine stock build ahead of the $A286 mine expansion.
Sales for its Bengalla mine were down 16% on the corresponding period last year and production volumes were down 8.6% compared to the same time last year.
While revenue increased by $130 million to $1.09 billion, it was largely offset by a $38 million increase in royalties, including $55 million in one-off mining costs at Curragh.
Despite the drop in coal sales, Wesfarmers managing director Richard Goyder had a positive outlook for 2012.
“We anticipate increased export coal sales volumes, following the completion of the current expansions,” he said.
Goyder said the expansion of both its Curragh and Bengalla mines continued during the last half of 2011, with completion for the work anticipated by the end of March 2012.
The expansion of the Curragh mine will ramp up metallurgical coal production to 8.5Mt per annum.