HARVEST AND FACTORY DATA TO ASSIST IN EVALUATING THE EFFECT OF EXTRANEOUS MATTER ON SUGAR PRODUCTION COSTS AND REVENUES

There has been considerable debate about the cost of extraneous matter to the Australian sugar industry in recent years. Opinions are split as to whether it is worthwhile expending effort to reduce extraneous matter; whether extraneous matter should be reduced at the harvesting stage, separated at the factory, or processed with the cane; and whether benefits can be realised from the collection or processing of extraneous matter. In addition to these issues, payment for extraneous matter or penalties for the supply of extraneous matter need to be addressed. In 1998, Mossman Mill and the Sugar Research Institute provided experimental evidence of the effect of trash on factory throughput and performance. This earlier investigation found that trash had a significant effect on bin weight, CCS, crushing rate, final bagasse moisture content and mixed juice purity. In 1999 and 2000, further experiments were conducted to provide information with which to determine the effect of extraneous matter (with a focus on trash) on sugar production costs and revenues. Harvesting experiments were conducted to determine the effect of extractor fan speed and ground speed on extraneous matter, cane loss and harvesting costs. The experiments found a strong link between extractor fan speed and cane loss, leading to the conclusion that increases in extractor fan speed are not a satisfactory option for reducing extraneous matter. Factory experiments, similar to those conducted in 1998, were conducted to determine the effect of trash on factory throughput and performance. In addition to measuring the effect of trash on the parameters that were explored in 1998, samples of mixed juice were collected and processed into liquor using small-scale processing equipment. The results confirmed the 1998 results that reduced trash levels resulted in higher bin weight, higher CCS, higher crushing rate, lower final bagasse moisture content and higher mixed juice purity. The analysis of the liquor produced also determined that reduced trash levels resulted in higher liquor purity, a further indication that lower trash levels result in more sugar production.