Magnetite Mines : Positive Interim Metallurgical Test Results

	ASX ANNOUNCEMENT
	21 JULY 2022
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	RAZORBACK IRON ORE PROJECT: POSITIVE INTERIM METALLURGICAL
	TEST RESULTS
		 Metallurgical testwork at lab/pilot scale generates high-grade concentrates from
use	selected stage 1 flowsheet
 Potential to produce Direct Reduction (DR) grade concentrates with flow sheet
optimisation
		 Comminution testwork shows ore body requires low-to-medium crushing and
		grinding energy
		 Vertical Roller Mill (VRM) testwork indicates potential for an alternative method for
		low energy, fine grinding of ores. Potential for VRMs to feature as a low OPEX
		alternative in early stage grinding
		 Magnetite Mines to proceed immediately with comprehensive metallurgical test
		program to assess suitability of Razorback ores for premium Direct Reduced Iron
personal	concentrates and further VRM bulk testing and analysis

Magnetite Mines Limited ("MGT" or "the Company") is pleased to announce positive interim metallurgical results confirming the Company's ability to produce high-gradeconcentrates with low gangue mineralogy (silica and alumina). The testwork to date has also identified the opportunity for premium Direct Reduced Iron (DR) concentrates from the Razorback Project ("the Project") ores. To date, analysis incorporating the full flow sheet has produced concentrates exceeding the design specification of 67.5% iron and 4.5% Silica + Alumina, with one bulk sample producing 69.7% iron with 2.6% Silica + Alumina. This represents a very high-qualityconcentrate product with a low waste component which attracts premium pricing and significant demand from steelmakers for use in d carbonising steel mills.

The testwork program designed and managed by global magnetite experts Hatch, is currently in progress and has been designed to verify and establish metallurgical performance of the process flow sheet and plant design. Subject to further analytical updates, the work program is a significant addition Forto the existing metallurgical knowledge base and incorporates leading edge analytical techniques to fully

characterise and technically derisk the ore deposit for every stage of the process flow sheet.

Definitive Feasibility Results

Processing Flow Sheet

The Definitive Feasibility Study (DFS) metallurgical testwork program aims to test, in detail, all steps of the Hatch designed processing flow sheet. This is being undertaken through the validation and analysis of bulk samples retrieved from all relevant geological domains, for laboratory testwork at bench to pilot plant scale. The general layout and configuration of the flow sheet follows that of the 2021 Pre-Feasibility Study1 and consists of crushing followed by dry HPGR and air classification processing for primary grinding. There is a rougher magnetic separation stage followed by ball milling and a rougher flotation circuit for a cleaning stage. A final silica rich flotation concentrate is subject to fine grinding before

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cleaner magnetic separation, the magnetics reporting to final concentrate. The flow sheet is conventional by modern standards and makes use of proven technologies currently installed in iron ore processing plants.

The basis of design for the processing plant is to receive 15.5Mtpa ore feed to produce 2.5 to 3Mtpa high grade concentrates. This 15.5Mtpa processing line (or train) represents a single stage of the mining production and has been designed as a replicable processing line, to be duplicated with mining expansion onlyopportunities2. The flow sheet aims to produce high grade concentrates at mass recoveries estimated at 16%, in line with the Mineral Resource estimate3 and with mine optimisation and scheduling completed to date1. Flexibility of run-of-mine (ROM) ore feed grade is considered in the design allowing the plant to

maintain consistent concentrate output within operational limits.

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Forigure 1. Schematic Razorback Iron Ore Project flow sheet

DFS Testwork and Results

The objective of the metallurgical and processing flow sheet testwork is to achieve the cleanest concentrate possible at the coarsest grind size to reduce both capital and operating costs. Designed and managed by Hatch, the testwork has predominantly occurred at Bureau Veritas Laboratories in Adelaide with significant portions of the work undertaken in the Netherlands using vendor equipment.

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The DFS metallurgical testwork program represents a significant increase in the scale of metallurgical testwork completed to date. It has included pilot plant scale testwork, focused on high-pressure grinding rolls (HPGR) and air classification equipment.

Sample selection and ore body representivity has been at the core of the testwork program with a dramatic increase in the number of spatially distributed samples targeting early year ore mineralisation typically associated with greater degrees of weathering and ore body complexity.

Testwork has consisted of the following work programs:

only	 HPGR and Air Classification testwork - HPGRs follow primary and secondary crushing circuits
and grind ores to an intermediate grind for rougher magnetic separation. The testwork program
	has been designed by Hatch and Weir Minerals to assist in the sizing and design of HPGR and air
	separator circuit to a P80 of 140 microns. Three +1000kg samples were submitted from the
use	Razorback and Iron Peak deposits. Samples were subject to feed preparation, moisture, particle
size distribution (PSD), wear rates (abrasion) and Bond mill work index (BBWi) testwork.
HPGR testwork included varied pressure/energy inputs, moisture content, PSD, closed circuit
	testing with screens and flake testing. Closed circuit, locked cycle testing with air classification
	was undertaken at Weir in the Netherlands, the products of which will be used for bulk flow sheet
	simulation testwork, pending delivery.
personal	Results: The results of the HPGR testwork are ongoing with early results suggesting grinding
targets will be achieved and within the operating capacity of the equipment.
Figure 2. Stage1 HPGR results summary
For	 Comminution Testwork - To ensure the comminution (crushing and grinding) circuits are sized
correctly the comminution program was designed to understand the variability of the ore. A total
	of 33 (30-40kg) samples were selected from Razorback (23) and Iron peak (10). Testwork
	consisted of Bond Abrasion index (ABi), Bond Ball Mill work Index (BBWi), Unconfined
	Compressive Strength (UCS) and Sag Mill Comminution (SMC) testwork.
	Results: Comminution results to date indicating that the magnetite ores require low power usage
	for crushing and grinding with Bond Ball Work Indices (BBWi of closing size 75µm) 4.1 to
	11.3kWh/t for an average of 7.7 kWh/t, requiring low to medium crushing and grinding energy
	demand. It is noted that samples from the Iron Peak Deposit performed slightly better with an
	average BBWi of 6.8kWh/t to Razorback's 8.7kWh/t.

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Abrasion index testwork indicated that the Project ores have low to medium abrasivity with an average of 0.105, with Iron Peak samples (0.05) appearing less abrasive than the Razorback Deposit (0.12).

Unconfined compressive strength (UCS) testwork for 32 analyses indicates a range of 6-80MPa for an average UCS of ~27Mpa which is considered low and well within the design specifications of the crusher circuit. Overall, the Razorback and Iron peak material presents relatively low UCS values and should not cause any problems with power requirements in the crusher circuit.

A total of 32 samples were also subject to SMC testwork. The results indicate single digit drop weight index for the majority of samples ranging from 2.6 to 10.1 kWh/m3. The derived crusher work index results (Mic) shows a similar single digit index ranging from 2.9 to 9.3 kWh/t, indicating low power requirements for primary crushing.

• Magnetic Separation Testwork - Owing to the magnetic nature of magnetite ores, magnetic separation is commonly used to separate magnetite rich particles from gangue. Low intensity magnetic separation or LIMS consists of large magnetised rotating drums on which liberated magnetite adheres and is separated from gangue minerals. Several stages of magnetic separation exist within the flowsheet. Early-stage rougher magnetic separation follows primary grinding in the flowsheet and preliminary magnetic separation testwork was undertaken to refine the operating parameters for this equipment.
  Results: Testwork was conducted on a large 50kg sample at the rougher stage (140 microns) and showed a 30-40% mass recovery to magnetics. This is a favourable rejection of siliceous gangue. Results support the selection of the primary grind size, and importantly reduce the downstream plant capacity requirement. Secondary magnetic separation testwork was undertaken on samples rod milled to a target P80 of 52 microns for 3-stage LIMS.
• Flotation Testwork - Flotation circuits were added to the PFS1 flowsheet to separate out complex composite particles (not fully liberated). The testwork was completed at Bureau Veritas laboratories in Adelaide in two stages and included reverse silica flotation testwork to investigate feed density, reagent recipe, pH, agitation and flotation duration. Vendor testwork was undertaken as part of the program. Flotation represents the penultimate concentration stage in the flowsheet, to be followed by a fine grind and magnetic separation stage to produce the final concentrate. An iterative testwork suite, the program was designed to determine the optimal reagent recipe for use in variable flotation testwork.
  Results: Flotation was investigated and the secondary magnetics concentrate would be the feed to the flotation program. Initial sighter testwork was completed on a typical reagent recipe derived from previous magnetite flotation programs and the three samples from the magnetic separation program was used as a starting point. Following several iterations of reagent recipe together with vendor testwork resulted in an optimal flotation recipe to maximise iron recovery. The results indicate that at this stage, using an optimised reagent recipe, a very high grade concentrate is produced. An average grade of 67.9% Fe with 4.4% Silica + Alumina was produced from three samples for this stage of processing.

• Variable Flotation Testwork - To fully understand the deposit's response to the ideal reagent regime identified in the flotation investigation, a total of 34 samples were collected across the Razorback and Iron Peak deposits. This testwork primarily focussed on rougher flotation optimisation testwork and reverse silica flotation, completed under optimised conditions for

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samples spatially located throughout the deposit. This testwork is ongoing with results not fully received for the analysis to date.

Summary and Next Steps

The results to date represent a preliminary confirmation of the processing flow sheet. The testwork program continues and is subject to updates as results follow. A number of logistical difficulties in completing the work program have been encountered largely due to COVID and staffing related issues at laboratories. The Company has made efforts to mitigate testwork delays by expediting transport and

lo	g-term planning of sample preparation and communication with all stakeholders. Testwork continues
as follows, with results to follow in the coming months.
only	 Variable flotation to test spatial variations in ore body variability and optimisation of reagent
use	recipe.
 Filtration, thickening and tailings product characterisation, to characterise tailings products for
use in tailings dam wall construction.
 Bulk flowsheet simulation, pending the delivery of bulk HPGR and air classification products from
the Netherlands, bulk flowsheet analysis will take place to simulate and confirm the entirety of the
processing flow sheet for 3 bulk (+1000kg) samples.
Vertical Roller Mills (VRMs)
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VRMs are a grinding technology used to grind materials into a fine powder. An emerging technology

within the mining industry, VRMs are commonly installed in the cement and other industries requiring fi e grinding. Renowned for their low operational and power costs, low wear rates and smaller footprints, VRMs are being tested for their suitability in mining applications with some success in coal processing.

The Company is testing the amenability of VRMs with respect to Razorback ores as an optimisation study running in tandem with the current DFS as a likely future alternative to HPGRs and Air classification ystems. The testwork results as given below suggest significant operational expenditure upside with low power utilisation and low wear rates.

R sults: VRM testwork has been completed with equipment manufacturer Loesche GmbH and Bureau V ritas laboratories using a Loesche VRM pilot unit which is currently located in Adelaide. A 1700kg sample from the Razorback deposit was submitted and crushed to an initial -10mmfeed before being rocessed through the VRM pilot mill to generate three samples of differing sizes to allow for equipment sizing data. A total of 450kg of the ground material was blended to produce a particle size distribution P80 52μm. This sample was then passed through 3 stage rougher LIMS to produce a magnetics product

Forfor indicative flotation testwork.

The preliminary (sighter) sample submitted for this analysis, which is being overseen by Loesche GmbH and Bureau Veritas (BV), has indicated that a fine primary grind size target was achieved at very favourable throughput and energy requirements and well within equipment specifications. Results from Loesche GmbH indicate that from the 1.7t sample submitted, product particle sizes of 36, 59 and 77 microns were targeted and achieved with no issues encountered. Throughputs were very high with specific grinding energy consumption very low ranging from 4.6kWh/t to 5.7 kWh/t. Wear rates were described as very low with grinding elements at industrial scale estimated to have a very long life.

Further testwork to test the lateral continuity of the Project deposits is planned for July/August with an additional 4.6 tonnes of fresh core material recently delivered to the laboratory for further testing.

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