Australian mining magnate Nathan Tinkler has pulled out of a Aus$5.3 billion (US$5.5 billion) takeover bid for Whitehaven Coal, the company said Friday. Whitehaven said it had granted the Tinkler Group access to due diligence so it could further develop an indicative and non-binding proposal for a Tinkler Group-led bid vehicle to take Whitehaven private for Aus$5.20 cash per share. \"The due diligence period expired yesterday and Whitehaven has now been advised by the Tinkler Group that a formal binding proposal of Aus$5.20 cash per share will not be forthcoming,\" it said in a statement. Whitehaven, which has several operating coal mines in New South Wales state and exploration assets there and in Queensland, said it would always assess firm proposals which were in the best interests of shareholders. Australia\'s mining industry has been rattled this week by Resources Minister Martin Ferguson\'s remarks that the mining boom is over and BHP Billiton reporting a profit slump and delaying its Olympic Dam expansion. Ferguson said he was referring to the fact that commodity prices had peaked, and there remained a strong pipeline of investment in the sector. Shares in Whitehaven, in which Tinkler holds a 22 percent stake, closed down some 13 percent Friday at Aus$3.03.