Mining giant Rio Tinto has celebrated a 'major milestone' for its iron ore project in Pilbara with rail and ports reaching a run rate of 290m tonnes per annum (Mt/a), two months ahead of schedule.Rio's Pilbara operations represent Australia's largest integrated mining project, with a network of 15 iron ore mines, three port facilities and a 1,500km rail network.Early completion of the first phase of expansion is said to have added "significant value" to the project.The completion of the infrastructure component to the expansion in September 2013 came in four months ahead of schedule and $400m under budget."This is a significant milestone which adds real value for our business and our shareholders by moving more iron ore through the Pilbara at low cost," Andrew Harding, Chief Executive of Rio's Iron Ore division."It builds on an impressive track record of delivery, achieved through our culture of driving performance and the quality of our people."Harding said the company is now focused on the next phase of expansion to a targeted 360Mt/a.Despite the good news, the stock was down 0.5% at 3,324.5p by 15:37.BC