(Australian floods article, and its impact on mining stocks, updated from Wednesday.)NEW YORK ( TheStreet) -- Monsoon rains and heavy flooding in Australia continue to ding big coal-mining interests Down Under. On Thursday, BHP Billiton ( BHP) followed rival Rio Tinto ( RIO) by saying that sales of coal from its mines in the hard-hit Queensland state will be hurt by the stormy weather. BHP's assets there form the largest coal-mining operation in Australia. Like Rio Tinto on Wendesday, BHP said it had declared "force majeure" on sales of coal extracted from mines in Queensland's coal fields, known as the Bowen District. By enacting a force majeure clause in a sales contract, a company can't be held responsible -- or pay penalties -- on late shipments to customers caused by acts of God or events outside its control. Anglo-American, the giant British mining company, Macarthur Coal, and Brazil's Vale ( VALE) have all declared force majeure in response to the Queensland floods. In a statement Wednesday, Rio Tinto said, "The severe monsoonal rain, on top of the significant rainfalls in November and December, has had an adverse impact on mining operations, and has cut access roads and rail networks." The company said it couldn't yet estimate the financial impact of the monsoons, nor could it say how long the force majeure declaration would last. Rio Tinto has four coal mines in the region: Hail Creek, Kestrel, Blair Athol and Clermont. The monsoon rains have ravaged Australia's Queensland state; some reports are calling the floods the worst in 150 years. The deluge has also hit key Australian ports, which could serve to disrupt the global coal trade, pushing prices higher. The Dalrymple Bay coal terminal, world's largest coal-exporting port, reported Wednesday that operations had ground to a halt because of flood-related disruptions.