The Razorback Project is a large low grade, high tonne magnetite – iron ore project in the central portion of the Mawson Iron Province and is wholly owned and operated by Magnetite Mines Limited. The Project is located 250 km NE of Adelaide, South Australia and is located central to existing infrastructure.

The Project consists of two main ore bodies, the Razorback Deposit and the Ironback Hill Deposit. Together these deposits account for 3.9 Billion Tonnes of JORC 2012 Inferred to Indicated resources (see ASX Announcements on 12/11/18 & 20/11/18). Magnetite Mines began work on Razorback in late 2009 and is well underway in developing one of the largest iron ore projects in Australia. Magnetite Mines completed resource definition and a Prefeasibility Study in early 2013 and is currently optimising several of the study parameters to improve the financials of the project.

Iron mineralisation at the Razorback and Ironback Hill Deposits are hosted in the Braemar Iron Formation. The formation can be best described as a meta-sedimentary iron siltstone, not a typical Banded Iron Formation (or BIF). This ore type is inherently soft as opposed to the very hard BIF’s as common in Western Australia. The Razorback Deposit area covers an approximately 10 km continuum of Iron Prospects: Razorback West- Razorback Ridge-Interzone-Iron Peak Prospects with much strike-length not yet tested here.

The mineralisation within the Braemar Iron Formation forms a simple dipping tabular body with only minor faulting, folding and intrusives. Grades, thickness, dip, and outcropping geometry remain very consistent over kilometres of strike.

The head grade of the iron ore (before processing) ranges from 15-35% Fe, with the Razorback Project capable of producing up to ~69% Fe concentrates (after processing) (see ASX Announcement on 13/09/16).

The iron species contained within the ore is predominantly magnetite, with lesser amounts of hematite. Magnetite, as its name implies, is a naturally magnetized mineral. Given it’s magnetic properties, magnetite is easily separated via several processing options. This processing rejects gangue minerals producing a very high-grade Fe product with low silica and deleterious elements, very much sought after in steelmaking.

Updated November 2018

 

Magnetite Mines has progressively increased it’s resource from the first drill program in early 2010. The latest JORC 2012 Compliant Razorback Iron Resource completed in November 2018 stands as follows:

 

The Razorback Project will consist of a conventional large-scale open cut mining operation. Based on previous studies, due to the relative softness of the rocks mined and the long shape of the open pit, optimisation work has determined that IPCC (In Pit Crushing and Conveying) may be the appropriate mining method, which has significant operational advantages and lower OPEX.

Given the outcropping nature of the deposit, there is minimal to no overburden, therefore production can begin almost immediately. The current mine optimisation has determined the stripping ratio to be extremely low for life of mine to be 1: 0.24 at the Razorback Deposit.

Results suggested a standard magnetite flowsheet can be applied to the Razorback Project.

Crushing consists of a single stage gyratory crusher feeding a crushed product stockpile with tunnel conveyor reclaim feeding two modules each with one SAG mill and two ball mills. The ore is ground to 45µm and passed through a rougher and cleaner Low Intensity Magnetic Separator. Final product upgrading is achieved using gravity/hydro separation. The final product specification targeted, which is expected to command a premium price is shown below:

Razorback Concentrate Production Results

 Sample  Mass Rec  Rougher Rej%  Fe%  SiO2%  Al2O3%  P%  S%
 Sighter  16.2  54.3  68  4.22  0.43  0.01  trace
 Bulk  14.6  56.5  68.8  3.33  0.35  0.01  trace

(See ASX Announcement 27/06/16)

The Braemar Iron Formation mineralogy is unlike that of banded ironstones seen in the Pilbara and Mid West, Western Australia in that Braemar sedimentary rocks are not made up of fine grained chert, but rather magnetite-bearing siltstones. This has significant cost saving for Braemar in regards to having lower rock hardness and abrasion during beneficiation and mining.

Updated November 2018