The 2550 mm milling tandem at Proserpine sugar mill

In 1990, the Proserpine Co-Operative Sugar Milling Association Ltd put in place a plan for the progressive development of the Proserpine Sugar Mill. The objective was for the factory to process cane at the rate of 750 tonnes per hour at average fibre levels and appropriate efficiency levels. The existing milling tandem was beyond its realistic sustainable capacity at 510 tonnes per hour. Planning to remove this bottleneck began in .1995. A number of options were considered, with and without the existing milling tandem. These options were: (a) cane diffusion; (b) bagasse diffusion; (c) conventionally driven milling tandem; and (d) hydraulically driven milling tandem. By the time tenders were called in December 1995, only options (c) and (d) remained. The contract for design, manufacture, installation and commissioning of the new milling equipment was awarded in March 1996. The option chosen was a new milling tandem behind the existing No.1 mill, to consist of three 2550 mm mills, conventionally driven by steam turbines through reduction gearing. Associated items of equipment, such as intermediate carriers, platforms and walkways and a bagasse conveyor, were also included in the contract. The milling house, foundations and major piping systems were provided by Proserpine Sugar Mill, some under a separate contract and some by its own workforce. The new equipment began operation on 4 June 1997, the start of the 1997 crushing season. This paper outlines the approach to planning, installation, commissioning and operation of the largest, single, milling tandem in Australia.