SITE EXAMPLES NEW BENDIGO GOLD PROJECT The Bendigo Goldfield has...

SITE EXAMPLES NEW BENDIGO GOLD PROJECT The Bendigo Goldfield has historically produced over 22 million ounces of gold with 82 percent of this coming from quartz reef mining carried out from surface to an average depth of 500 m and the deepest mine going to 1,400m. Between 1854 and 1954 quartz reef mining yielded about 18 million ounces of gold from 40 million tonnes of ore, the recovered grade being 0.5 oz/t (14.3g/t). No processing plant presently exists although a bulk sampling plant has been modified to trial process the 65,000 tonnes of development ore that will be produced whilst exploring the Sheepshead and Deborah lines of the reef during 2003. This trial processing will assist with further metallurgical testing. Initial test work indicates greater than 90 percent recovery using gravity, with up to 99 percent recovery by flotation of the gravity tail without the use of cyanide in the main circuit. Metallurgical testwork performed on bulk samples taken from the Bendigo Mine Development have shown that excellent gravity gold recoveries are achievable. Due to the large amount of coarse gold present, gravity concentration recoveries of up to 98 percent have been achieved. Even at low head grades (1.38g/t) recoveries of greater than 80 percent have been reported. Combined with flotation, the recovery at low head grades exceeded on average 91.4 percent and up to 99.6 percent at higher head grades (+8 g/t). These results are shown in the figure 6, below. Bendigo New Moon Metallurgical Recoveries Vs Head Grade 1.6 6 11.4 98 92 80 98 99.6 91.4 0 20 40 60 80 100 1.38 8 77 Head Grade (g/t) Recovery (%) Flotation Recovery Gravity Recovery Total Recovery Fig 6: Metallurgical Recoveries vs. Head Grade for Bendigo