Colombia's government froze coal shipments by US mining giant Drummond on Wednesday, saying it has not complied with local environmental regulations.
New regulations that took effect January 1 require companies operating in the country to use coal freight methods with a low environmental impact.
But authorities said Drummond has continued to use open barges which in January 2013 were partly to blame for a major coal spill on the Carribbean coast.
"We have decided to end (Drummond's) coal shipments" until new regulations are followed, Environment Minister Luz Helena Sarmiento told reporters.
"If Drummond keeps violating the law, we will be compelled to take action... and that will worsen the situation."
Three weeks ago, the US company was fined $3.5 million for the January 2013 environmental disaster in Santa Marta in which 500-1,800 tonnes of coal were dumped into the sea.
Drummond has operated in Colombia since 1998.