Name and Location
Deflector gold/copper project, Australia.

Client
Doray Minerals.

Project Description
A detailed review has confirmed a high-grade, low-cost project, with robust financials and significant upside.

Mining at Deflector will initially comprise openpit mining, transitioning to an underground operation towards the end of the first year.

The Western and Central lodes at Deflector are steep mineralised structures, dipping between 80° and 90°, typically 1 m to 5 m wide and hosted within a competent basalt host. The total strike length of the orebody is about 850 m.

Openpit mining will occur in stages, initially focusing on mining the narrower Central lode pit.

Underground access will be gained through a portal established in the Central lode pit at a depth of 35 m below the surface. Mining of the wider Western lode pit and the smaller Northern pit on the Central lode will then continue to a maximum depth of 85 m, concurrent with underground mining.

Following the establishment of the portal, underground mining will be carried out using a conventional sublevel long-hole open stope mining method at 20 m sublevel intervals. Underground ore access will be gained through a 5.3 m × 5.5 m decline to mine 3.2 m × 4 m, and 4 m × 4 m ore development drives to suit lode widths.

The decline and level access development are located centrally between the Western and Central orebodies. Underground mining is currently planned to 270 m vertical metres below a 15 m crown pillar, limited only by current drilling depth.

The top-down mining method, retreating to a centrally located access crosscut, allows for stoping to start as soon as level development has been completed. Any ore remaining within a stope can then be extracted from a lower level, ensuring minimised ore loss because of mining.

Rock mass characteristics assessed by two specialist geotechnical consultants found the basalt host rock to be competent, with high strength (uniaxial compressive strength averaging 250 MPa). Full-depth rib pillars will be left at appropriate intervals in accordance with geotechnical recommendations.

Doray will build a new processing plant at Deflector, which is specifically designed to suit the metallurgy of the orebody.

The plant will comprise three-stage crushing and screening, a ball mill, a gravity circuit, an elution circuit and gold room, as well as a flotation circuit.

The fit-for-purpose plant will be built adjacent to the orebody to minimise mine haulage costs from the openpits and underground.

The plant will average 454 000 t/y, with expected average recoveries of 89.5% for gold and 93% for copper from the primary ore, which provides 82% of total ore feed for the plant.

Based on the above recoveries, the project will produce an estimated 61 000 oz/y of gold or about 74 500 oz/y on a gold-equivalent basis.

Doray will use the existing tailings storage facility (TSF), at the Gullewa mine site, with tailings to be transferred from the new Deflector plant using a purpose-built pipeline. Two further pipelines will supply raw water from an existing bore field, supplemented by a pipeline that recycles water from the existing TSF for use in the processing plant.

Site offices, a workshop and stores will be located in close proximity to the mine, along with the power station, fuel farm and underground mining contractor facilities.

The company plans to build a new accommodation village within 1 km of the mine, minimising the level of traffic on the Deflector access road and integrating medical services and administrative management of the mine site and village.

Net Present Value/Internal Rate of Return
The project has an internal rate of return of 28%, with a payback of 3.2 years.

Value
Preproduction capital is estimated at A$67.6-million.

Duration
The start of production is expected in the fourth quarter of the 2016 financial year.

Latest Developments
Doray Minerals has started plant commissioning at its Deflector operation, while openpit mining is progressing.

The first-stage commissioning of the purpose-built 480 000 t/y processing plant is on schedule, with the first parcels of waste material being fed into the crushing circuit.

Commissioning of the ball mill and flotation circuit will follow, with all processing plant areas set for completion in May 2016.

Underground mining and production at Deflector will start in June this year.

The Deflector mine was expected to deliver first gold by mid-2016. The openpit operation is expected to produce 1 972 oz of gold and the underground mine will deliver 348 592 oz of gold over a mine life of about six years.

Key Contracts and Suppliers
GR Engineering Services (processing plant).

On Budget and on Time?
Not stated.

Contact Details for Project Information
Doray Minerals, tel +61 8 9226 0600, fax +61 8 9226 0633 or email info@dorayminerals.com.au.
GR Engineering Services, tel +61 8 6272 6000, fax +61 8 6272 6001 or email gres@gres.com.au.