Keith Pitt denies previous donations to Liberal party played a role while another coalminer says it wasn’t contacted regarding 70,000-tonne shipment

The Australian government publicly pledged to buy 70,000 tonnes of thermal coal from miner Whitehaven to donate to Ukraine before finalising the cost to the taxpayer – and failed to approach at least one other major coalminer to gauge their interest.

The prime minister, Scott Morrison, on Sunday announced the federal government was buying coal from Whitehaven to donate to the Ukrainian government, with the assistance of Poland, to help provide energy security to the war-torn nation.

The announcement was welcomed by Ukraine and trumpeted by the Coalition which publicly thanked Whitehaven, a Liberal donor, for its assistance.

The government pledged to pay the entire cost of supplying and transporting the coal. The price of coal has surged to unprecedented levels due to Russia’s invasion of its neighbour.

The federal resources minister, Keith Pitt, said on Wednesday the cost of acquiring the coal and sending it to Ukraine was “still being finalised” three days after the government publicly committed to the purchase.

Guardian Australia made inquiries with several major coalminers, two of whom confirmed they had not been directly approached.

New Hope Group, an Australian-owned coalminer, said it had “not been approached by the federal government” in relation to the deal to donate thermal coal to Ukraine.

Glencore, another major coalminer, declined to comment about whether it had been approached. BHP and Yancoal did not respond to requests for comment.

Pitt said he had contacted Whitehaven management directly. Asked whether he approached other resource companies at the same time he said Whitehaven was “the first company to give a positive response to the request”.

“Given the urgency of the request I contacted Whitehaven management directly who indicated they could provide the coal for Ukraine without disrupting existing contracts despite high international demand,” Pitt said.

Estimates based on current coal prices have suggested 70,000 tonnes of thermal coal is worth at least $31m. The volume of coal would reportedly only power a medium-sized coal-fired generator for three to five days.

Ukraine, which first made the request to Australia, says it would welcome any further coal the government can provide. Ukraine’s ambassador to Australia, Volodymyr Shalkivskyi, said Ukraine had not nominated any single amount of coal when it requested help from the Australian government.

“The request was that we would appreciate any amount of assistance, any amount of coal that you would find possible and relevant to provide in this situation,” the ambassador said. “So we are grateful for what was announced and we would welcome any additional steps in the future if the Australian government finds it’s possible.”

Since the 2013-14 financial year, Whitehaven Coal has declared $140,000 in donations, all to the Liberal party. Guardian Australia is not suggesting those donations played any role in the decision to procure the coal through Whitehaven.

Pitt rubbished the notion that donations were a factor, stating: “The only motivation was to meet Ukraine’s request to supply the coal as quickly as we can to meet the urgent energy needs of the country’s people. Any suggestion otherwise is rubbish.”

Pitt said he had no contact with Whitehaven’s chair, former deputy prime minister and Nationals leader Mark Vaile, about the deal.

The minister said the resources department was speaking with other coal producers about whether they could supply more coal to Europe.

“The department has also [been] engaging with all Australian coal producers who may be able to assist meet any shortfalls among European friends,” he said. “They’ve all indicated they will help where they can.”

Idemitsu Australia, which owns the Boggabri coalmine, said it was not approached directly about potentially supplying coal to Ukraine but its chief executive, Steve Kovac, said it was working as part of an “industry response to the government’s request for assistance”.

Morrison said on Sunday when announcing the Whitehaven deal that finding thermal coal that was not already tied up in export contracts was difficult.

“When we had to put this together, Minister Pitt, who’s done a terrific job on this, was able to work with them to access those coal supplies and then to be able to work through to arrange the shipping at very short notice,” the prime minister said.

“Much of Australia’s coal exports are contracted. And so this was not a simple matter, and it was able to be resolved quite quickly.”