Ed Miliband has said the Government rejected a bid to keep Hatfield Colliery open - resulting in the immediate loss of more than 400 jobs.
The Doncaster North MP and former Labour leader told Sky News that managers of the site, one of the last deep coal mines in the country, had asked for a £12m loan extension.
He said if this had been agreed, the deal would have returned more money to the Government through tax receipts.
John Grogan, chair of the Hatfield Colliery, confirmed Mr Miliband's comments were accurate, saying the Government refused to extend an existing loan arrangement despite the company lining up contracts to sell more than half their coal.
The Government had refused to extend funding to Hatfield colliery on the grounds that a lack of orders meant it was no longer 'economically viable'.
It had been due to close in August next year, but without the extra funds it had to stop producing coal a year early.
Mr Miliband said: "The reality is this Government has pulled the rug from under it a year early, but refusing to give it anymore aid.
"I think that actually would have been economically viable for the Government, because more money would have come back in taxation and VAT and other revenues.
"There is a human cost here and it has not been factored in."
Business Minister Anna Soubry said: "We’ve been working closely with the company throughout this difficult time, doing all we can to help.
"That has included providing up to £20m to support the company’s managed closure plan.
"Hatfield's directors have however taken the decision to close the mine because it could not sell enough coal at the price needed to keep it operational."
In the same interview with Sky, Mr Miliband said he would not openly take sides in the contest to find his successor, and would give his full support to whoever is chosen.
Mr Miliband, who stood down after the disappointing general election result in May, said: "It's not my place to either commentate on decisions which the party is making or commentate on the Labour leadership election."
Asked about those candidates who have criticised his own leadership, he replied: "That's their prerogative."
He added: "I think the party needs space to have this debate - when a party has lost a general election there is a debate and people have different views.
"The right thing to do is to let the party have that debate, to chose a new leader and whoever that new leader is I will support them 100 per cent."
The Doncaster North MP also criticised Chancellor George Osborne's Budget, which was the first for a majority Conservative government since November 1996.
"I think the shine has worn off the budget in record time frankly, because 48 hours later we now know this is a budget that hits the poorest not the richest," he said.
"It is not a one nation budget, it is a regressive budget and for all the welcome rise in the minimum wage that is more than off-set by the cuts to tax credits."