Rudd to Julia Gillard as leader of the party. After becoming Prime Minister, Gillard cancelled the Rudd government's controversial $40 million advertising campaign supporting its mining super profits tax and called on miners to withdraw their own media campaign against the tax. Gillard pledged to re-negotiate the tax proposal and a revised Minerals Resource Rent Tax was approved by the House of Representatives on 24 November 2011, with the government announcing that a 30 per cent tax would start on 1 July 2012 and would be expected to generate about $12 billion to 2013/14. The government said that it would allocate funds raised towards a company tax rate cut, infrastructure and an increase in the superannuation guarantee rate from nine to 12 per cent. The 2012–13 Budget set aside the proceeds of the new tax to fund family payments, a bonus for school-aged children and small business tax breaks. However, rather than generating revenue, in the first quarter the new tax incurred a tax credit liability for the government, as mining companies had no tax payable under the MRRT calculation, but could credit their state government royalty payments against future MRRT liabilities. The federal government must pay 10% compound interest on MRRT tax credits. In February 2013, Treasurer Swan announced that the new tax had raised $126 million during its first six months. The government had originally budgeted for the MRRT to raise $3 billion through the 2012–13 financial year. Relations with mining companies In 2012, Gillard and Treasurer Swan made a number of public criticisms of mining company bosses. Swan singled out Gina Rinehart, Andrew Forrest and Clive Palmer and accused them of using their wealth and position to try to undermine public policy. Swan and Gillard repeated such criticisms in Parliament and in various media outlets. When Gillard suggested in May 2012 that people who lived on Sydney's North Shore were not "real people", the Opposition and media commentators accused the government of pursuing "class warfare". In May, ministers in the Gillard government re-stated government approval for mining magnate Gina Rinehart to bring in 1700 skilled foreign workers to get her $9.5 billion Roy Hill iron ore mine underway in the Pilbara. The move drew criticism from some trade unionists and some Labor MPs. Union leader Paul Howes "I mean I thought we were actually attacking these guys at the moment. Whose side are we on?" Prime Minister