The volume exported in the week ended June 21 climbed to 2.04 million tonnes from 1.66Mt in the preceding period, according to Newcastle Port Corp.

More than 50 vessels were waiting outside the harbour, up from 48 a week earlier. The queue reached 60 in December, the longest since July 2007.

Coal ships waited to load for an average of 14.67 days, up from 12.30 days, according to the port’s website. That compares with 2.26 days for general-cargo vessels.

Rio Tinto, Xstrata, and BHP Billiton are among mining companies that ship the fuel from the harbour.

A spokesman for NCIG said its original development consent was for a coal export terminal with capacity up to 66Mtpa.

“Stage one of this terminal, of 30 million tonnes per annum, began shipments at the end of March this year and was officially opened in May,” he said.

“NCIG has completed a feasibility study on options for adding to its capacity and has sought finance. The board has yet to determine when the expansion will happen, and what form it will take.

“NCIG will ramp up its exports to reach full capacity in 2011. When that will be achieved is subject to a number of variable factors.”