Underground Mining, Copper Mining Australia, Copper Mine

Birla Nifty

Copper Production Operations

Aditya Birla Minerals’ principal asset is the Birla Nifty copper mine in WA, located in the Great Sandy Desert Region of the East Pilbara in Western Australia, approximately 1,250 km north of Perth and 350 km east of Port Hedland.

The Nifty Sulphide Operation is one of the largest underground copper mines to be commissioned worldwide in this decade. The project was also delivered at one of the globally most competitive capital cost per tonne of annual copper production over a 25 year horizon.

The West Australian copper mine exploits oxide, transitional and chalcocite mineral resources. The Nifty operation comprises of an historical open pit oxide mine with associated SX–EW processing operations, and an underground sulphide mine with an associated concentrator. Site infrastructure (powerhouse, camp, airfield, tailings storage facility) supports both the oxide and sulphide operations. A concentrate storage facility is located at Port Hedland where the concentrate is shipped to overseas customers.

Copper is recovered via SX-EW processing methods, the oxide circuit capable of producing approximately 25 ktpa of copper cathode. The Nifty Sulphide deposit mines chalcopyrite ore treated by standard flotation for production of copper concentrate.

The Western Australian copper mine has a capacity of 2.3 mtpa and the concentrator plant has a capacity of 2.5 mtpa. Concentrate produced is trucked to Port Hedland for shipping to Hindalco Copper’s Dahej smelting and refining facility in India.

The Nifty Sulphide Operations has an expected remainder life of approximately nine years, based on last published reserves. However, based on further drilling completed during 2009 it is expected that mine life will extend beyond nine years.

Mining

Underground mining is performed by Birla Nifty, using modern diesel or electro-hydraulic equipment of large capacity. Underground mining is currently carried out using open stoping methods and backfill. This is a bulk mining method where stopes (25m wide, 25 to 50m long and 40 to 60m high) are drilled and blasted, and copper ore is loaded and hauled into to an underground crusher and conveying system. The conveying system transports the copper ore to the surface for processing by conventional flotation techniques (an example is shown in the figure above).

The ore is drilled with electro-hydraulic rigs prior to blasting. Broken ore is loaded using load-haul-dump machines into 50 t capacity trucks for transport to the underground crusher, where it is conveyed to the mill, surface ROM pad or stockpile.

The underground mining method at Nifty is considered a low cost method as opposed to other underground selective mining methods due to the inherent economies of scale and the use of conveyors to transport ore to the surface as opposed to trucking. The backfilling of mining voids allows for high recovery of resources and savings in lifting tailings dams. The equipment used in underground mining is supplied by various manufacturers like Caterpillar and Sandvik etc.

Processing

The processing plant at Nifty consists of a sulphide flotation circuit which produces a saleable concentrate. It also includes a leach and SX-EW circuit, which produces saleable copper cathode sheets.

Processing of the sulphide copper ore extracted from underground is by conventional comminution, grinding and flotation, to produce a concentrate that is then filtered and sold as concentrate.

The open pit oxide and transition ore, including some chalcocite (sulphide) ore is obtained by heap leaching, solvent extraction and electrowinning (SX-EW) to produce cathode copper to LME A Grade quality specifications.

Copper Production

The Nifty copper operation is a fly in–fly out operation with access provided via a sealed airstrip on site, serviced regularly by flights from Perth. The mine is also accessed by bitumen road from Port Hedland to the Woodie Woodie mine, only the final 45 km or road is unsealed. Copper in concentrate is trucked to Porthedland (distance from Nifty approximately 420 KM) and then shipped to Hindalco Copper’s Dahej copper smelting and refining facility in India.

The mine facilities are well supported by modern and efficient infrastructure and services, with significant upgrades and extensions made to village facilities, workshops, power reticulation and offices constructed under the Nifty Sulphide Operation development.

The main power source is a 21 mW GE dual fuel gas/diesel turbine, with back-up of 5.4 mW solar centaur turbines and 3.5 mW Caterpillar diesel generators. A 46 km spur gas pipeline, owned and operated by Gas Transmissions of Australia Pty Ltd, has been constructed from the Port Hedland to Telfer and is the pipeline to the Nifty Western Australian copper mine. Gas is sourced under contract from Apache Northwest Pty Ltd.

The Nifty copper operation uses groundwater sourced from mine dewatering. Mine water is reticulated from the largest source, the underground mine, to the Fines Dam where suspended solids are settled. Once clarified, the mine water is pumped to either the sulphide concentrator or Raw Water Dam (RWD) for distribution elsewhere on site. In addition to the mine dewatering source, groundwater derived from the East Nifty Borefield is pumped to the RWD or directly to the Reverse Osmosis (RO) plant for desalination. The supply capacity is of about 2,000 kL/hr.

Current operating experience suggests that under existing conditions, the mine produces 5,000 kL/day from the borefield and has a regulating storage of 27,100 kL.

The main water demand comes from the concentrator at a rate of 200-210 kL/hr, the Electro-Winning plant 104 kL/hr and miscellaneous consumption leaving abundant water sources and storage capacity at Nifty and vicinity to sustain operations for the next 15 years. The Nifty Sulphide operation produced approximately 49.6kt and approximately 56.5kt of copper in concentrate in the 2009 and 2010 financial year respectively.

Copper Resources and Reserves

Nifty 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 according to the JORC Code (2004). Ore reserves and resources have been reviewed by PAH.
2. Totals may not add due to rounding.
3. Recoverable copper in inventory under leach is additional to proved and probable reserves.
4. Mineral resources are inclusive of ore reserves, but exclude recoverable inventory under leach.

Background

Open pit mining operations ceased in June 2006 and heap leaching operations ceased in January 2009. Heap leach retreatment project, to recover approximately 40,000 tonnes copper from existing heap leach pads, has been postponed due to the subdued economic environment.

Oxide copper was first discovered at Nifty in 1981 by WMC Limited (“WMC”). Drilling of the oxide resource ultimately led to the discovery of the deep sulphide resource in 1983. WMC commenced an open pit, heap leach, SX-EW operation on the relatively high grade part of the oxide mineralisation in 1993. In 1998, the Nifty operation was purchased by Straits Resources Limited (“Straits Resources”), from which Aditya Birla Minerals acquired the operation and surrounding exploration tenements in March 2003. Before acquisition of Nifty Operations a detailed due diligence was undertaken by Aditya Birla Minerals.

Due diligence of Nifty operations was conducted by various experts in their respective fields:

• Technical due diligence by SRK Consulting
• Commercial due diligence was done by Cutfield Freeman & Co Ltd
• Financial due diligence was done by Ernst and Young and
• Legal due diligence by Minter Ellison
• Environmental audit by R.W. Corkery & Co Pty Ltd.

The due diligence process highlighted significant values in the Nifty underground mine. There were no material adverse findings. Subsequent to acquisition, following the completion of a positive feasibility study, underground development was commenced in January 2004 to exploit the sulphide resource via an exploration decline from the open pit. First sulphide ore was intersected in February 2005. Construction of the concentrator commenced in October 2004, with first concentrate being produced in March 2006. Other plants previously under construction include the paste fill plant, which was completed in August 2009.

Copper Opportunities

Underground mining and copper production at the Birla Nifty copper mine in WA provided opportunities for further copper exploration and development. This includes the extension of mine life via extending resource base in existing ore body and converting more resource in to reserve category and finding another ore body through exploration and evaluation.

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.