Oxide ore, at Amantaytau Centralny has been defined as that containing less than 0.2% sulphide minerals. These surface deposits are represented by an oxide cap where most of the sulphide minerals have been oxidised to iron oxide, hydroxides, sulphates and arsenates.? The oxidised zones of the Amantaytau Centralny and Uzunbulak deposits extend to depths up to 80m and represent a significant gold and silver resource, relatively easy to mine by open pit and amenable to heap leaching.? Approximately 85% of the gold is free associated with iron oxide and hydroxide, sulphate and arsenate, rarely with quartz.
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?Extensive drilling has been undertaken on all deposits within the AGF licence area since their discovery during Soviet Exploration.? Soviet drilling techniques used were Rotary Air Blast (RAB) and core drilling.? In addition to this extensive surface trenching, shallow shafts (deep trial pits) and the development of underground workings to allow face sampling of mineralised zones at different levels in the deposits have been completed on some deposits within the licence area. As part of the development programme to bring projects forward, AGF undertakes Reverse Circulation (RC) and core drilling as part of confirmatory and infill drilling.?
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Mining commenced in February 2004 from open pits on Amantaytau Centralny oxide ores followed by the Asaukak deposit in late 2006. Gold is recovered in a Carbon-In-Pulp (CIP) processing plant. Silver is also produced from a heap leach pad and Merril Crow recovery circuit at the Vysokovoltnoye deposit. Oxide reserves at the Centralny pit will be exhausted at the end of 2007 and Asaukak is nearing depletion. The future will focus on the deeper sulphides, the Vysokovoltnoye heap leach silver deposits and on heap leach pads to mine low grade oxide ores from numerous satellite deposits.? Overall 23 oxide deposits are included in the Mineral Resources or Ore Reserves for the year ended June 2007 as well as 7 exploration targets. Ongoing exploration will focus on upgrading these resources to reserves and converting exploration targets into resources.