U.S. exports hit a 2012 record of 126 million tons and, until recently, many observers predicted this year would be even better. But in April, met coal exports decreased 29% from March and were down 13% from the prior three-month average, according to Census Bureau statistics quoted by Bloomberg News. Thermal coal exports, meanwhile, fell 35% in April and 16% from the previous three-month average.

U.S. producers in Appalachia, where many met coal mines are located, have taken the biggest hits, as the highest grades for steelmaking properties are normally deeper underground and, hence, more expensive to extract. And while some Midwestern companies are benefitting from lower-than-usual gas prices, producers in the eastern U.S. are witnessing no relief.

Exports represent a small amount of U.S. coal production, but met coal exports have an acutely disproportionate impact on profits, providing greater income than low-sulfur thermal coal. Nearly 70% of U.S.-mined met coal, moreover, is export-dependent, leaving many U.S. producers at the mercy of global market demands—especially in Asia.

Prevailing demand, according to analysts, based partly on 2011’s sky-high coking coal prices, drove producers in the U.S., Australia toward new development—along with several U.S. mergers. Chinese growth, however, has since slowed along with an increased Australian contribution to the Asian market after massive 2011 flooding there receded. Meanwhile, the mergers also saddled businesses with higher debts.

Other overseas factors are further eroding demand. China, for instance, has been producing more of its own coking coal, while recycling more scrap metal for steel. Amid leadership changes, according to analysts, the Chinese central government is also tightening credit, complicating efforts by domestic consumers seeking coal from foreign markets.