PWCS - majority owned by giants Xstrata Coal and Rio Tinto - wanted to revise the current allocation system that allows access to export facilities to all producers.
Its submission was contested by the New South Wales Government, with Ports Minister Joe Tripodi urging the ACCC to delay making a decision on how exports would be allocated until it could consider all applications.
The current system for allocations will expire on December 31.
Yesterday the ACCC officially rejected the PWCS application, a decision endorsed by Tripodi.
"The quick decision by the ACCC in refusing interim approval to this application has been useful," he said.
"This proposal could have led to mine closures and job losses in the Hunter Valley.
"I note the ACCC are still considering the NSW Government submission by Newcastle Port Corporation to extend the current system for up to 12 months to give industry the time to develop a system."