(Adds updates on Narrabri mine status, thermal coal outlook, details)
Oct 16 (Reuters) - Australia's Whitehaven Coal Ltd WHC.AX on Thursday said equity coal sales fell 14 percent in the September quarter, as certain mechanical issues choked output from its Narrabri mine.
Equity coal sales for the quarter came in at 4.1 million tonnes, compared to the 4.7 million tonnes clocked in the corresponding period a year ago.
The figure overtook a UBS forecast of 3.84 million tonnes.
This result follows a disappointing June quarter which saw equity coal sales decline 7.0 percent, again due to issues at Narrabri when the company had said longwall production at the mine is expected to recommence in September.
The company said production at Narrabri has returned to normal and is currently ramping up on schedule.
Whitehaven said it sold thermal coal for an average of $113 per tonne over the quarter, at a 4.0 percent discount to the Newcastle index price of $117.51 per tonne.
Newcastle coal is thermal coal exported from the port of Newcastle in New South Wales and is the price benchmark for seaborne thermal coal in the Asia-Pacific region.
"Thermal coal demand in the global power industry increased by 3.4 percent year-over-year in 2017 and is forecast to increase by a further 2.4 percent year-over-year in 2018," said Whitehaven.
Australian spot thermal coal prices have traded around six-year highs in recent months, pushed up by a summer heatwave across the northern hemisphere as well as output cuts in China, the world's biggest consumer of coal. stock, which debuted on the Australian exchange in 2007, has advanced over 24 percent so far this year on the back of intensifying demand for coal.