NEW YORK ( TheStreet) -- The Australian floods have made a bad situation worse for many steelmakers around the world. Posco ( PKX), the big Korean steel concern, was the latest to cement the notion Thursday when it reported quarterly results that missed expectations. Its top executive also told investors that the rising cost of crucial steel raw materials -- coking coal especially -- will be hard to pass on to customers, Reuters reported Thursday. Coking, or metallurgical coal, is used to smelt iron ore in blast furnaces. Australia's Queensland state, hardest hit by the monsoon rains and resulting floods, produces more coking coal than anywhere else in the world. The floods have forced the closure of mining in the state, driving coal prices to record highs. The New York-listed shares of Posco were declining 3% midday Thursday, changing hands at $108.30. Other steel names were mixed. Europe-based ArcelorMittal ( MT), the world's largest steel producer, which has substantial operations in the U.S., saw its American depositary receipts slip 0.4% to $36.36 Thursday. Spurred by the global raw-materials price inflation, steelmakers and mining companies in recent months have been shopping the planet for iron ore and coking-coal mines. ArcelorMittal has been among the busiest. The steel giant is engaged in a bidding war for a mine under development in the far north of Canada, on Baffin Island near the Arctic Circle. And earlier this week, Cliffs Natural Resources ( CLF), a major supplier of iron ore and coal to steel producers in the U.S., agreed to spend $5 billion on a Canadian company with a newly built iron ore mine in northern Quebec. The mine supplies Asian steelmakers primarily. The deal was a move by Cliffs to tap fast-growing Asian markets, where commodity prices have risen the most. Elsewhere, among U.S. steelmakers, shares of Nucor ( NUE), which uses scrap metal to make steel and is thus not dependent on coking coal or iron ore, were gaining 1% to $45.17. U.S. Steel ( X), which controls much of its own feedstock sources, was rising 0.6% to $56.95. AK Steel ( AKS), which does not, was declining by two pennies to $15.21. -- Written by Scott Eden in New York >To contact the writer of this article, click here: Scott Eden. >To follow the writer on Twitter, go to http://twitter.com/ScottEden. >To submit a news tip, send an email to: firstname.lastname@example.org.