Copper Results, Copper Resources

Birla Mt Gordon

The Mt Gordon operation is located in northwest Queensland, approximately 120 km north of Mt Isa. The Mt Gordon copper production was set up to produce copper in concentrate, the mine producing at an annual production rate of approximately 20 kt before it was put under care and maintenance in February 2009. Development of Esperanza South underground mine was also stopped after developing 967 meters due to significant reduction in copper prices.

The operation has ability to mine 1.2 mtpa of ore from Mammoth underground decline operation. Mining of the Esperanza open cut was completed in November 2005. The Mt Gordon Operation is currently under care and maintenance and an evaluation of its re-opening feasibility is in progress.

Mining

Mining operations are focused on the Mammoth underground mine, following the exhaustion of the Esperanza open pit in November 2005. The Esperanza South Decline was in development before the operations went into care and maintenance. The underground mine extends from surface to a depth of approximately 600 m. All underground mining is performed by a contractor, using modern diesel or electro-hydraulic equipment of large capacity.

The ore is drilled with electro-hydraulic rigs prior to blasting. Broken ore is loaded using 7 m3 load-haul-dump machines into 55 t capacity trucks for transport to the surface ROM pad or stockpile, where it is dumped in preparation for feeding into the crushing and grinding circuit.

2 Lens is mined using the sublevel cave (SLC) method in a longitudinal configuration, with some isolated areas being mined by the uphole bench method. B Lens material remaining from a collapse which occurred during ownership by another organisation, is mined using an undercut cave method. D Lens is mined by uphole benching, but will eventually be connected to 2 Lens and mined by a SLC. Excavation of the connection between 2 Lens and D Lens is in progress. 4 Lens is mined by uphole benching.

Apart from the B Lens undercut cave, all of the existing or planned mining methods are in common use. This mining method and copper resources are familiar to MGO staff and mining contractors, and have been successfully employed at MGO over recent years. Expert advice has been sought by Aditya Birla Minerals with regard to the undercut cave mining of B Lens. Detailed plans have been prepared and endorsed by Aditya Birla Minerals’ mining consultants.

Ongoing geotechnical surveillance supports the suitability of the current mining methods and geotechnical reviews of the future mining plans has confirmed the ongoing suitability of the planned methods. With uphole benching, there is an opportunity to retain waste underground as backfill rather than having to haul it to the surface waste dumps. The copper results found, show the potential copper investment opportunities for the future.

Processing

The operation is set up for concentrate copper production using a standard flotation plant. Due to currently available ore sources which are more amenable to concentrate copper production, copper cathode operations consisting of a ferric leach plant and SX-EW were suspended in January 2006. The processing plant at MGO consists of a sulphide flotation circuit which produces a saleable concentrate.

Blended ore is fed from the run of mine stockpile to the crushing and grinding circuit, which consists of a jaw crusher, crushed ore stockpile, semi-autogenous grinding (SAG) mill, screening and cycloning tower and regrind ball mill. The slurry produced by the grinding circuit enters the flotation circuit which includes rougher and scavenger cells, with the concentrate reporting to a high intensity conditioner operating in an open circuit configuration. The copper grade of the initial concentrate is then upgraded through two cleaning stages of flotation. The final flotation concentrate is dewatered in a filter press before being trucked off-site to Cloncurry . From here copper results are railed to Townsville, then shipped to Hindalco Copper’s Dahej copper smelting and refining facility in India. Copper in concentrate produced is sold to Hindalco under a LOM off–take agreement based on arm’s length terms.

The mine facilities are well supported by infrastructure and services located at the mine site and in the Mt Isa region. Entire electricity requirement of approximately 9MW is supplied by Mt Isa Mines power plant located in Mt Isa through transmission lines owned by Ergon. Mt Gordon has diesel generators with total capacity of 4MW as back up for emergency power requirement. Current infrastructure is expected to be sufficient for the life of the operation.

The Mt Gordon operation is a fly in–fly out camp with access provided via a 1.2 km airstrip on site. The mine is linked by a 120 km bitumen road to Mt Isa. Power is purchased through a 220 kV transmission line from the natural gas fired Mica Creek power station located near Mt Isa.

The Queensland copper mine has several dams, process water storage ponds and a tailings dam. Site water balance has been tested prior to copper production and exploration and is positive.

Process water is obtained from process plant recycling, tailings, Lake Waggaboonya (approximately 1,350 ML water storage), a freshwater dam and the Esperanza pit (around 2 GL available) if required). The process water storage dams holds around 60 ML. Consumption is around 5 ML per day. A 2.5 ML steel process water tank above the plant is used to store the Waggaboonya water. Potable water is delivered by tanker. Water from the dam is obtained using 2 x 44 kW pumps on a pontoon and 2 x 11 kW Mono pumps.

Copper Resources and Reserves

Mt Gordon ore reserves and mineral resources as on 31 March 2010 are shown below.

Notes

1. Ore reserves and mineral resources have been estimated as at 31 March 2010 by Aditya Birla Minerals and classified and reported according to the JORC Code (2004). Totals may not add due to rounding.
2. Ore reserves are generally based on a copper cut-off grade of 1.5%; however minor individual lower grade stopes are included in the overall reserve.
3. Mineral resources are inclusive of ore reserves.

Background

Copper oxide mineralisation was first discovered in the district at Mt Oxide in 1882, followed by the discovery of the Mammoth deposit in 1927. This was intermittently worked on a small scale until 1969. VAM Ltd, Consolidated Goldfields and Adelaide Brighton produced copper in concentrate and copper cathode from the Mammoth deposit between 1969 and 1995. Aberfoyle purchased the operation in 1995 and delineated the Esperanza deposit before being acquired by Western Metals Limited (“Western Metals”) in 1998, which commissioned the ferric leach plant that year to treat Esperanza ores. The Mammoth underground mine was reopened in late 2002.

Aditya Birla Minerals acquired the operations in November 2003 from receivers appointed for Western Metals. Aditya Birla Minerals obtained copper exploration tenements around the Mt Gordon copper mine and the Nifty copper mine in WA. Previous focuses were on copper production, though Aditya Birla Minerals plans to significantly increase the copper exploration activities at this site and persue development, extending copper investment opportunities across Australia and worldwide.

Opportunities

The copper production activities at the Birla Mt Gordon copper mine provided opportunities for further copper exploration and development. Esperanza South, will enhance production rate and hence viability of the Mt Gordon Operations and the hoisting of shaft for haulage of ore will enable Aditya Birla Minerals to reduce mining cost and improve copper production operations.

To learn more about our credible copper production, copper exploration , copper mine in WA and QLD, copper mining, underground mining or copper investment opportunities, copper operations, contact Aditya Birla Minerals.

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