Police investigators have ''not ruled out'' that the Morwell mine fires could have started in the mine itself.
The revelation is contained in a ''supplementary affidavit'' produced by the head of the arson and explosives squad, Michael Roberts, dated May 28 and provided to the mine fire inquiry.
Mr Roberts revealed in the affidavit that police investigators ''have not been able to conclude that the fires'' in the mine were caused by spotting from two nearby fires on the weekend the mine fires broke out. And he added: ''Investigators have not ruled out that the fires that burned in the mine originated inside the mine.''
Mr Roberts' statement is a dramatic development, because the two local fires which burnt near the mine, known as the Driffield and Hernes Oak fires, have repeatedly been blamed as the possible cause of the coalmine fire.
The inquiry heard yesterday that angry Hazelwood mine workers blasted mine owner GDF SUEZ over its approach to fire safety just hours after the coalmine fire ignited, with one claiming it had sold $8 million of fire suppression equipment ''for scrap metal''.
CFA volunteer Doug Steley, who was sent to the mine on the first night of the fire, said mine workers at the scene told him the ability to fight fires had been reduced.
''They were particularly unhappy with the whole situation. They were not happy gentlemen,'' he said.
Asked what they were unhappy about Mr Steley said: ''The fire, the lack of fire suppression gear.
''It was pointed out that this wouldn't have happened if they had left the $8 million worth of fire suppression gear that was already set up and running in the mine.
''One of them said the company shouldn't have taken it out and sold it for scrap metal. Other people said the company had decided it was too expensive to cover the batters in clay as should have been done.
''Others mentioned how much the firefighting ability of the mine had been reduced - that they used to have full crews and full fire engines and full training to prevent things like this happening, but in an effort to save money they'd been cut down.''
Mr Steley conceded that he could not evaluate the truth of the claims made by the workers, and had not been to the mine before.
When Fairfax Media asked for a response from GDF SUEZ to Mr Steley's comments, we were directed to evidence provided a day earlier by mine worker Rob Dugan.
Mr Dugan had admitted that some water pipes had been removed from coal batters, ''due to batter stability issues … because of the water seeping out of the pipe work and the likes''.
The inquiry was told this week that the mine had a number of ex-CFA trucks to respond to fires, two huge 30,000 litre water carts and an extensive network of water pipes, although the water system could not soak all the mine at once. It also conducted an extensive slashing program across hundreds of hectares to reduce fire threats.