SYDNEY (Dow Jones)--Australia's main lobby group for smaller and mid-sized miners will restart advertising against the country's proposed mining tax changes, the group said Monday. The adverts will raise the tension over mining issues in the run-up to Australia's general election next month. A previous advertising campaign by the Minerals Council of Australia, the country's peak mining body, contributed to the embattled political atmosphere which preceded the overthrow of former prime minister Kevin Rudd last month. Current prime minister Julia Gillard called the Aug. 21 poll after taking the top job when Rudd lost the support of Labor parliamentarians. The Association of Mining & Exploration Companies has raised objections to the deal hashed out between the government and the country's three biggest mine operators after Rudd left office. AMEC argues that the deal, which replaced a previous proposal launched by Rudd in May, was weighted in the interests of the big three miners, BHP Billiton Ltd. (BHP.AU), Rio Tinto Ltd. (RIO.AU), and Xstrata Plc (XTA.LN). The deal has been backed by the Minerals Council of Australia but objections have been raised by AMEC and several smaller miners. Fortescue Metals Group Ltd. (FMG.AU) Chief Executive Andrew Forrest, in a press conference with AMEC, last week said the revised proposals were a "retrograde tax" that was "specifically suited" to the purposes of the big three companies. During the press conference, AMEC Chief Executive Simon Bennison said that campaign adverts by the group would be ready to start as soon as last weekend. -By David Fickling, Dow Jones Newswires; +61 2 8272 4689; [email protected] (END) Dow Jones Newswires July 26, 2010 00:11 ET (04:11 GMT)