Australia's Fortescue Metals put multi-billion dollar iron ore projects expected to employ thousands of people on hold on Wednesday, blaming uncertainty caused by a major new tax on mining companies. The proposed 40 percent levy on miners' 'super profits' has incensed the key export industry and also prompted Anglo-Australian giant Rio Tinto to review all capital projects in the country. 'Fortescue Metals Group wishes to advise that two of the companys three expansion projects have been placed on hold due to the financial impact of the federal governments proposed Resource Super Profits Tax (RSPT),' a company statement said. 'The uncertainty in the financial markets caused by the proposed tax and the cash impost that RSPT payments will place on future business revenues has necessitated an urgent review of the economics surrounding the development of Fortescues major projects.' Fortescue said development of its flagship Solomon Hub in Western Australia, which will cost nine billion US dollars in proposed investment and employ about 21,000 people, was 'on hold until the finance impact of the RSPT can be fully determined'. The company said it was also shelving plans for a Western Hub estimated at six billion dollars and employing 11,500 people in operations and construction. 'Similar to the development of Solomon, the impact of the RSPT will be felt through the erosion of cash flows that are required to finance major project development.' 