Name: Windarra mine.

Location: The Windarra mine is located in the north eastern goldfields, 260 km north-east of Kalgoorlie, in Australia.

Controlling Company: Poseidon Nickel.

Brief History: In 1969, Poseidon discovered nickel at Mt Windarra and began the construction and development of an underground mining operation and processing plant. Western Mining Corporation (WMC) bought the project and completed the development, with the first production of nickel concentrate in 1974. A total resource of 8.5-million tons of ore at 2.02% nickel for 172 000 t of contained nickel metal was defined by WMC at the mine. The mine was advanced to a depth of 550 m below surface. However, mining ceased in 1990 as a result of historically low nickel prices. By that time WMC had mined five-million tons of ore at an average grade of 1.59% nickel, producing 80 000 t of nickel metal. By 1995 the processing plant was demolished and completely removed. The site was rehabilitated and the remnant headframe and remaining structures were turned into a tourist trail.

In 2005, Niagara Mining negotiated with WMC to acquire the project and by 2007 the infrastructure refurbishment was well under way, exploration drilling had begun and the company was renamed Poseidon Nickel in honour of the original discoverers.

Drilling completed at Windarra has demonstrated the continuity of the orebody to at least 900 m vertical depth.

The company started refurbishment of the underground mine in 2011.

Brief Description: The Mt Windarra orebody consists of eight distinct, steeply dipping shoots – A, A Hanging Wall, B, C, D, E, F and G Shoot. These shoots vary from 2 m to 20 m in thickness; have a strike length of between 50 m and 350 m and a down dip extent greater than 900 m. The mine has a mine life of between a seven and ten years and scope for considerable expansion.

Mining Method: Sublevel caving.

Products: Nickel.

Major Infrastructure and Equipment: The underground mine at Windarra includes an underground crushing station at a depth of about 450 m, with a horizontal shaft for hauling ore to the surface. Ore is crushed underground in a crushing station at the 450 m level.

Infrastructure facilities required to sustain, service and maintain the Windarra project operations include a water supply (borefield and pipeline), power supply (local diesel power station), ancillary buildings and facilities, an accommodation village and communications to the plant and village.

Geology/Mineralisation: The Windarra region forms part of the Mt Margaret goldfield. Mafic and ultramafics, metavolcanics and intrusives form important components of the Windarra greenstone belt. A major granitoid pluton has intruded the stratigraphy and has locally stoped out the main banded iron formation (BIF). Mafic-ultramafic and BIF xenoliths, thought to be stratigraphically equivalent to the Windarra sequence, occur within the granites in the region.

Bedrock consists of granite or granite gneiss, enclosed by north to northwest trending belts of metavolcanics, metasediments and intrusive rocks. Mafic dykes with an east-west strike are abundant in the region and crosscut the greenstone, granite and granite gneisses. Regional trends are predominantly north-west and the main BIF horizon traces the regional Mt Margaret Anticline to South Windarra where the trend is more east-west.

Economic nickel mineralisation in the Mt Windarra area is hosted at the base of the Windarra Ultramafics, a 100-m- to 300-m-thick sequence of ultramafic (komatiite) lava flows, overlain by basalts. The Windarra ultramafics host four significant nickel deposits – two previously mined nickel deposits, the Mt Windarra underground mine and the South Windarra openpit and underground mine. The third discovery is at Woodline Well, which has a small near-surface oxide deposit that may contain a deeper sulphide extension. The latest and most significant discovery made by Poseidon Nickel was at Cerberus.

Nickel mineralisation at Mt Windarra is restricted to the sulphide zones at the base of the olivine cumulate ultramafic sequence. Massive sulphides form the dominant ore type and the nonmassive sulphide mineralisation can be subdivided into three different textural types: matrix (25% to 40% sulphide), blebby (20% to 30% sulphide) and disseminated (between 5% to 25% sulphide).

Reserves: The Mt Windarra mining plan includes an implied ore reserve of 3.446-million ore tons at an average grade of 1.79% nickel.

Resources: As at October 30, 2012, total indicated and inferred resources were 3.951-million tons, with a grading of 1.73% nickel.

Prospects: Poseidon Nickel announced in 2012 that it had identified a new potentially mineable ore zone at the Windarra project. The potential orebody is north of the area currently included in the mine plan and started about 50 m from the surface, below the main oxidised zone. Poseidon believes that it has intersected the mineral- isation to a depth of 240 m, with historic drilling indicating that it may continue deeper.

Contact Person: MD and CEO David Singleton.

Contact Details:
Poseidon Nickel, tel +61 8 9382 8799, fax +61 8 9382 4760, email admin@poseidon-nickel.com.au, and website www.poseidon-nickel.com.au

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