The Jambreiro Project is part of a sequence of Archean to lower Proterozoic iron formations (locally known as “itabirite”) and described as the Guanhães Group in the Guanhães region. Mineralisation is hosted in a metavolcanic-sedimentary sequence of rocks including itabirites, quartz-mica schist, amphibolite and gneiss. The friable itabirite extends to a vertical depth of 120m before becoming more compact. The principal ore zone, known as the Tigre Deposit, has a strike extent of 1.8km with true widths varying between 40-80m.

There are three satellite prospects in the immediate project area within 500m of the Tigre Deposit, being: the Cruzeiro, Galo and Coelho (North and South) Deposits. The friable iron mineralisation is continuous along strike, homogenous, medium to coarse grained and composed of mainly hematite and quartz with small amounts of magnetite.

The proposed mining method for the Jambreiro Project is an open pit mine. There are minimal pre-strip requirements and site access preparations are minimal and will be carried out by a local mining contractor.

The ore will feed a conventional beneficiation plant and the waste will be stored in appropriate waste dump locations. Filtered tailings are to be filtered and blended with mine waste.

A mining dilution factor of 2% has been applied for the deposit. The ore contacts are sharp and visual and the small mining equipment will allow for selective mining.

A mining recovery factor of 98% has been utilised. Similarly to mine dilution, the configuration of the deposit and the selected mining equipment will allow good mining recoveries to be achieved.

The mine parameters were set to accommodate the selected 40t trucks and are set out below. Free digging is expected in all friable itabirite and waste and as such the mining will be performed on nominal 5 metres benches, with final bench heights of 10 metres.

The friable Ore Reserve will provide the Company with approximately 17.9Mt of high-grade product, at an average life-of-mine recovery of 41%, underpinning the initial 18-year mine life at Jambreiro. The average strip ratio for the first four years of the operation is 0.56:1, with a total life-of-mine strip ratio of only 0.68:1 based on a total material movement of 72.9Mt.

The nature of the Jambreiro ore bodies allows for low strip ratios and shorter haulage routes for the first five years, which has a positive impact on both operating and deferred capital costs. The ore and waste are predominantly free-dig from surface over the life of the current mine design, with blasting only expected for 5% of the total material movement for the project. Pit exit ramps have been designed to allow easy access to the ROM-pad area, primary crusher and the main waste storage areas while maintaining a minimum haulage distance.

Where possible, ramp development has been restricted to the footwall side of the pit to minimise the strip ratio.

The mine will be operated by a local mining contractor using 40-tonne off-road trucks that are commonly used in Brazil and readily available in the region.

The Jambreiro Project ROM ore is friable in nature and composed mostly of iron oxides (hematite with minor magnetite) and silica. The grain size distribution test on the ROM ore showed that the top size of the friable material is 44.5 mm with 80% passing at 2.4 mm, demonstrating the sand-like nature of the ore.

The ore characteristics and the desired concentrate specifications lead to the choice of jigging, spirals and Wet High Intensity Magnetic Separation (WHIMS) as the core Jambreiro beneficiation route.

The feed to the WHIMS circuits is also pre-treated in a Low Intensity Magnetic Separation (LIMS) circuit to recover (to concentrate) the small amount of magnetite in the ore.

The process plant consists of the following major elements:
• Primary Screening
• Primary Crushing and Secondary Crushing and Screening (from year 11, introduction of semi-compact ore)
• Tertiary Crushing and Screening
• Jigging
• Scavenger Ball Mill
• Spirals concentration
• Magnetic Separators (LIMS and WHIMS)
• Slimes and tailings Thickener
• Centrifuge Tailings dewatering
• Products dewatering by screens

Bench scale testwork and pilot runs consistently demonstrate metal recoveries of +90% Fe and average mass recoveries of 41%.

The interesting aspect of the proposed Jambreiro process flowsheet and plant is that the operator will be able to produce different products tailored to the domestic market. By changing the blends of the jig and magnetic separation products the operator will be able to increase iron grade and change grain size distribution specs to meet customer demands.