Swan defends MRRT as long-term gainer Treasurer Wayne Swan has defended Labor's revenue-challenged mining tax, arguing it will generate more money from the big resources companies over the long-term. The mining industry on Wednesday launched an advertising campaign arguing the sector had paid its "fair share" of taxes in response to growing concerns the government may change key elements of the minerals resource rent tax (MRRT). The federal coalition, which would scrap the MRRT in government, said changes would create industry uncertainty and breach the deal Prime Minister Julia Gillard reached in 2010 with three major mining companies - BHP Billiton, Rio Tinto and Xstrata Coal. Opposition Leader Tony Abbott used parliament on Wednesday to ridicule Labor over the poor performance of the tax, which raised only $126 million in its first six months and won't reach its $2 billion full year forecast. Mr Swan told parliament the 30 per cent tax on coal and iron ore super-profits needed time to work, citing the experience of the petroleum resource rent tax which began 25 years ago and had raised $28 billion to date. He said the six-month MRRT revenue "doesn't mean that a MRRT is not important, not just for now, but for our children and our grandchildren." It gives all Australians a stake in our future prosperity. Resources Minister Martin Ferguson said the MRRT hadn't stopped job creation in the mining industry, and then described it as "the type of tax the resources sector wanted - a profits-based tax." This prompted ridicule from the opposition benches and Mr Abbott later threw the line back at Labor, saying the sector supported the MRRT because "it was a tax they never had to pay." "The great negotiator (Ms Gillard) was comprehensively ... outwitted by the mining bosses," he said. The government is in talks with the states about the way the MRRT interacts with royalties. State royalties are able to be deducted from MRRT liabilities. But Queensland Premier Campbell Newman said he would not be dictated to on any changes to royalties. "That's a constitutional thing," he told ABC Radio. NSW Treasurer Mike Baird said he was prepared to talk about changes. "But I'm not going to a position where the states either forcibly cap a tax, which means you've got no flexibility going forward, or we give up our right to tax," he told ABC radio. Minerals Council chief Mitch Hooke said the industry did not want the tax changed. The deal would be compromised. All bets would be off," Mr Hooke said. Mr Ferguson told parliament Labor had "no intention of walking away" from its agreement with the miners, including a commitment to consult about its design and operation. Miners had had a "gutful of willy-nilly increases" in state royalties, Mr Ferguson said, adding the rises had led to some closures of mines, particularly in Queensland and NSW. Meanwhile, Ms Gillard - who achieved a rare moment of bipartisanship on Wednesday with the introduction to parliament of an Act of Recognition of indigenous people - drew on US President Barack Obama's State of the Union address to talk up "Labor values." She said there were many similarities "including governing for the many, not the few, including making sure the doors of opportunity are open to every child." Mr Abbott said Mr Obama had also pledged: "Our government shouldn't make promises we cannot keep."