Thermal coal prices at Australia's Newcastle port, a benchmark for Asia, fell for the first time 12 weeks, dropping 3.5 percent from a record.

The weekly index for power-station coal prices at the New South Wales port declined $6.79 to $188 a metric ton in the week ended July 11, according to the globalCOAL NEWC Index. The index last week rose to a record $194.79 a ton.

Thermal coal prices from the port have more than doubled this year on increased demand from Asian electricity producers and railroad and port bottlenecks in Australia and South Africa curb supplies. Mining companies including Xstrata Plc, the world's largest exporter, won a 125 percent increase in annual contract prices in the year that started April 1 to $125 a ton.

The weekly globalCOAL index is up 41 percent since the start of May. The monthly index gained 18 percent to $163.68 a ton in June, from $138.31 the previous month.

Xstrata, BHP Billiton Ltd. and Rio Tinto Group are among mining companies that ship coal through Newcastle.

Climate-change activists delayed the loading of coal on to ships at Newcastle's Kooragang terminal between 6:00 a.m. and 8:30 a.m. today after five protesters chained themselves to a conveyor, Graham Davidson, general manager of Port Waratah Coal Services Pty, operator of the two coal terminals, said by phone. The actions are part of a six-day camp protesting against the use of the fuel.

Three trains scheduled to deliver about 20,000 tons of coal were delayed yesterday when protesters broke through fences and secured themselves to wagons at the port's Carrington terminal, Port Waratah Coal Services Pty, said in an earlier statement.

Demonstrators Arrested

Thirty seven demonstrators were arrested, the Sydney Morning Herald reported. As many as 1,000 demonstrators took part in the protests, with mounted police required to hold many back from the rail line, the newspaper said.

Newcastle shipped 84.8 million metric tons of coal last year, up 6.3 percent from a year earlier, and export capacity is set to rise to 140 million tons a year after 2010. Coal exports are Australia's biggest contribution to climate change, according to the camp's Web site.

Protesters will take further action at coal sites in the Hunter Valley and Newcastle today.