Overview
Stage | Permitting |
Mine Type | Open Pit |
Commodities |
|
Mining Method |
|
Processing |
- Gravity separation
- Spiral concentrator / separator
- Jig plant
- Dewatering
- Magnetic separation
|
Mine Life | 18 years (as of Jan 1, 2019) |
The Jambreiro Project’s potential economics have continued to improve since the July 2019 PFS was completed, and in May 2020, Centaurus updated the key inputs to the Jambreiro project economics, including: - Updating of the Capex for CDE Global’s latest proposal for the 1Mtpa modularised plant (including corresponding adjustment to the contingency on the capex; and - Applying up to date FX considerations for the GBP, AUD and USD against the BRL.
Consistent with the 2019 PFS, the results of the updated 1Mtpa PFS considered forecast production of 17.9Mt of high-grade low-impurity product at a rate of 1Mtpa over a period of 18 years using the same resource and reserve previously outlined.
All other inputs and parameters used in the Revision were the same as those that outlined in the July 2019 PFS Results release of 5 July 2019. There were no material changes required to the assumptions underlying the Jambreiro Ore Reserves outlined above. |
Source:
p. 6
The Jambreiro Iron Ore Project comprises three granted Mining Leases (ML’s). All of these ML’s are 100%-owned by Centaurus Brasil Mineração Ltda, a wholly-owned Brazilian subsidiary of Centaurus.
Summary:
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 Itabirite mineralisation comprises concentrations of medium - coarse grained friable, semi-compact and compact material that have undergone enrichment. The mineralisation is composed of quartz, hematite, magnetite, martite with minor goethite, limonite, amphibole (Grunerite), Mica (muscovite) and clay minerals.
Itabirite thicknesses vary from 10m to up to 100m generally dipping 45-70° to the W-SW. The combined strike length of the mapped mineralisation is around 3,000m. Itabirite has been intersected at depths of 240m with friable itabirite intersected to 80m.
With the combination of the Tigre (1,700m), Cruzeiro (1,200m), Galo (1,500m) and Coelho (900m) prospects, the Jambreiro Resource has dimensions of approximately 5,500m of total strike length. The ore body outcrops in most places with a localized thin colluvial cover in places and is open at depth with the deepest mineralisation being intersected at 240m depth. The mineralisation is between 10-100m thick with the average thickness in the main deposit (Tigre) being around 60m.
Summary:
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. 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. 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 road widths in the pit are 12m, including 6m safety berms and a 10-12% road gradient to accommodate the 40-tonne truck fleet.
Flow Sheet:
Crusher / Mill Type | Model | Size | Power | Quantity |
Ball mill
|
|
|
|
1
|
Summary:
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;
• Scavenger Ball Mill.
Processing
- Gravity separation
- Spiral concentrator / separator
- Jig plant
- Dewatering
- Magnetic separation
Flow Sheet:
Summary:
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:
• Jigging;
• Spirals concentration;
• Magnetic Separators (LIMS and WHIMS);
• Slimes and tailings Thickener;
• Centrifuge Tailings dewatering;
• Products dewatering by screens.
Recoveries & Grades:
Commodity | Parameter | Avg. LOM |
Iron Ore
|
Recovery Rate, %
| 41 |
Iron Ore
|
Head Grade, %
| 29.1 |
Iron Ore
|
Concentrate Grade, %
| 65 |
Projected Production:
Commodity | Units | Avg. Annual | LOM |
Iron Ore
|
kt
| 0 | 0 |
All production numbers are expressed as concentrate.
Operational Metrics:
Metrics | |
Stripping / waste ratio
| 0.68 * |
Waste tonnes, LOM
| 29,522 kwmt * |
Ore tonnes mined, LOM
| 43,339 kwmt * |
Total tonnes mined, LOM
| 72,861 kwmt * |
* According to 2019 study.
Reserves at December 31, 2020:
Ore Reserves and Mineral Resource estimate 20% Fe cut-off grade.
Category | Tonnage | Commodity | Grade |
Proven
|
35.4 Mt
|
Iron
|
28.5 %
|
Probable
|
13.1 Mt
|
Iron
|
27.2 %
|
Proven & Probable
|
48.5 Mt
|
Iron
|
28.1 %
|
Measured
|
44.3 Mt
|
Iron
|
29.2 %
|
Indicated
|
37.7 Mt
|
Iron
|
27.5 %
|
Inferred
|
45.1 Mt
|
Iron
|
27.3 %
|
Total Resource
|
127.1 Mt
|
Iron
|
28 %
|
Commodity Production Costs:
| Commodity | Units | Average |
Cash costs
|
Iron Ore
|
AUD
|
...... *
|
Total cash costs
|
Iron Ore
|
AUD
|
...... *
|
Assumed price
|
Iron Ore
|
USD
|
...... *
|
* According to 2020 study / presentation.
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2020 Study Costs and Valuation Metrics :
Metrics | Units | LOM Total |
Pre-Production capital costs
|
$M AUD
|
......
|
Gross revenue (LOM)
|
$M AUD
|
......
|
EBITDA (LOM)
|
$M AUD
|
......
|
Pre-tax NPV @ 8%
|
$M AUD
|
......
|
After-tax NPV @ 8%
|
$M AUD
|
......
|
After-tax IRR, %
|
|
......
|
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Proposed Heavy Mobile Equipment as of July 5, 2019:
HME Type | Size | Leased or Contractor |
Truck (haul)
|
40 t
|
|
- Subscription is required.