The Southdown deposit occupies the core of a gently east plunging, overturned tight isoclinal syncline with a steeply south dipping axial surface. The deposit is offset by moderately northeast dipping dextral reverse faults and subsidiary steeply south-east dipping sinistral faults. Currently the resource extends for 11 kilometres of the 12 kilometre strike length of the deposit, with variable depths ranging from a surface outcrop in the west, to 480 metres below surface in the east.

The Southdown Project is an advanced project with over 1.2 billion tonnes of high quality mineral resources, including ore reserves of 388Mt.

A Definitive Feasibility Study (DFS) was completed by the project owners in 2012 for 10mtpa concentrate production. An optimised project development option has been progressed to prefeasibility by our JV partners since the completion of the DFS. This would involve a smaller 5mtpa operation within the constraints of existing approvals, mineral resources and ore reserves; and is anticipated to deliver reductions in capital spend from ~A$2.9B down to ~A$1.4B. This alternative case extends the life of mine from 14 years to 28 years for the western zone, and more than 50 years for the total resource (see Project Details below). The 10mtpa DFS completed in 2012 remains the base case for the JV.

The mine will be an open pit, with modern large scale open pit mining methods employed. Mining will be a conventional hydraulic face shovel and diesel dump truck operation. The shovel size will be 650 tonnes with trucks sized to match (220 tonne payload).

Detailed mine design and schedules for the DFS have been constrained to the ore reserve west of the South Coast Highway. To achieve 10 million tonnes per annum of concentrate production a material movement in the mine averaging 110 million tonnes per annum is required.

Crushing and grinding facilities includes: primary crushing, AG milling in closed circuit with two-stage screening, Ball milling in closed circuit with cyclones and Fine grinding using IsaMills.

The process includes crushing, grinding, classification and magnetic separation. The concentrate is further upgraded using hydro separation to remove fine silica, and flotation to remove sulphur impurities. Transporting the Concentrate Slurry 110 km to the Port.

Final magnetite concentrate will be thickened and transported through a 110 km pipeline to the Port of Albany, where it will be filtered and stored for loading onto cape size ships. A second pipeline will return the filtered water back to the mine site so it can be used again in the process. Both pipelines will be buried.

The process flow sheet includes:
- Primary crushing
- Coarse ore stockpile
- AG milling in closed circuit with two-stage screening
- Rougher magnetic separation
- Ball milling in closed circuit with cyclones
- Intermediate magnetic separation
- Fine grinding using IsaMills™
- Hydro-separation
- Cleaner magnetic separation
- Flotation