"Spring Creek clearly has its challenges," Mr Coupe told the Greymouth Star.
However, they had not given up on any asset yet or determined it could not be sold.
He could not say when Solid Energy expected to reach the end of the asset sale process, noting it had taken 12 months to get this far.
They were aware the announcement yesterday helped give more certainty, but some would remain uncertain for longer.
"We are still hopeful. The level of confidence varies from asset to asset," Mr Coupe said.
Bathurst will announce details of the Phoenix Coal Ltd purchase tomorrow.
Union E tu director of industries Ged O'Connell said the pending sales "mean income flowing through local communities".
"We're confident they (buyers) are well-established businesses and they know the industry.
"Bathurst, which is one of the parties which has acquired Stockton on the West Coast as well as Rotowaro and Maramarua in Waikato, is a competent operator which we have an established relationship with."
Birchfield was "also well-known to us".
"They're long-time West Coast operators."
Labour's State-owned Enterprises chairman David Parker, said the "sorry saga" had cost many hundreds of jobs, and damaged communities across the country.
"We wish the new owners and their workers well, but record our dismay at this debacle."
- Greymouth Star