Restoring efficiency to harvested cane transport in New South Wales : SRDC Final report

Abstract

The New South Wales sugar industry has transported mechanically harvested burned cane to its three mills using a multilift bulk bin system since 1974. The transport has been both efficient and cost effective, until the introduction of Whole-of-Crop (WoC) harvesting in 2007. In 2005 the NSW Sugar Milling Co-operative Ltd (NSWSMCo-op), committed the NSW Sugar Industry to cogeneration of electricity at its three mills, using bagasse and cane trash as fuel. The whole crop would be harvested and transported to the mill to have its sugar extracted and the remaining carbohydrate burned as fuel. All sectors of the industry began to modify equipment to harvest, transport and mill, whole-of-crop prior to the project commencement in 2007. Critical to the economic viability of the co-generation project is the efficient transport of the low density WoC material. NSWSM Co-op economists calculated the economical bulk haulage tonnage at 23.5 net tonnes per trip, and constructed new, low weight aluminium multilift bins with a capacity of 90m3, the maximum dimensions allowed on NSW roads, to assist in achieving this weight. Harvester operators faced a daunting challenge of loading 23.5 tonnes of low and varying bulk density WoC material, into the bins. At the beginning of the 2007 harvesting season no operator in NSW using standard harvesting techniques, was able to consistently achieve this target, increasing the number of trips needed to carry WoC to the mill, significantly lowering transport efficiencies and increasing the cost of fuel for the co-generation plant. This reduction in the average net weight of material in each bin, has been estimated to increase transport costs by $1,300,200 on a one million tonne crop delivered to Broadwater mill. The project sought to increase the bulk density of harvested WoC material in the multilift bins, to achieve a payload of 23.5 tonnes net, thereby restoring the transport efficiencies required for the viability of the co-generation project. The project investigated existing research, knowledge and technologies used to compact organic fibrous wastes with similar physical properties to WoC. Researchers conducted similar trials on WoC material and collected data that favoured compaction over compression as the most practical and effective method of increasing the bulk density of this material in the existing bulk transport bins.