At Stockton, the mine losses have averaged $2.1 million a month this financial year as the international price of coal fell from US$120 ($161) a tonne to US$83.
The Engineering, Printing and Manufacturing Union says the latest cuts will suck $10 million out of the Buller economy in wages alone.
Mr O'Connor said the Government would have been considering the ramifications on the rail line, and Lyttelton.
"We are naive if we believe it's just the workers at Stockton the Government are concerned about."
The Coast had suffered through restructures before, but this time it had access to capital and fast broadband. "Development West Coast is going to be a key part of [its future]. If we want a bank, we have NBS [Nelson Building Society]."
Development West Coast chairman John Sturgeon, who once worked at Denniston, told Radio New Zealand yesterday: "It [Westport] is a dying town all right; there's no doubt about that, and that's a shame.
"Some of these people have been there their whole lives; it is not good."
But Buller Mayor Garry Howard disagreed with Mr Sturgeon's "dying town" comments. "I take issue with that."
He said he was trying to look forward, with a real estate announcement looming, aimed at addressing the glut of houses expected to be listed as people move away.
Union organiser Garth Elliott said it would take time for the impact of the job cuts to trickle down, and compound. About 94 collective contract members would get redundancy.
Grey District Mayor Tony Kokshoorn said Greymouth had been through the pain already, with the loss of 500 jobs at Pike River and then Spring Creek.
Solid Energy expects to finalise the restructure on May 26. The company will then undertake a process to select employees for the remaining mining jobs and in other areas where fewer people are required, with redundancies confirmed by mid-June.
- Greymouth Star