Overview
| Stage | Feasibility |
| Mine Type | Open Pit |
| Commodities |
|
| Mining Method |
|
| Mine Life | 10.2 years (as of Jan 1, 2020) |
Borborema is considered a technically low risk operation in terms of resource definition, mining operation and metallurgical processing and is fully permitted in terms of have all environmental, mining and installation licences required to commence operations. |
Source:
p. 1
Borborema is 100% owned by Big River through its wholly owned subsidiary Cascar Mineração Ltda (Cascar).
On September 21, 2022, Aura Minerals Inc. closed the previously announced acquisition of Big River Gold Limite). Moving forward, the Borborema Gold Project, located in Brazil, being Big River’s sole asset, will be held pursuant to a joint venture among Aura and Dundee Resources Limited (a wholly owned subsidiary of Dundee Corporation) with Aura holding an 80% interest and Dundee holding the remaining 20% interest.
Contractors
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Summary:
The project area is situated in the Borborema Province within the domain of the Seridó Fold Belt in north-eastern Brazil. It is situated in the top of the Seridó Group stratigraphy (the Seridó Formation) within a sequence of banded arkosic metapelitic schists, subjected to upperamphibolite facies regional metamorphism. Gold mineralisation is located within a NNE trending structure which forms part of the northern segment of the Santa Mônica dextral shear zone. The shear zone displays a penetrative NNEtrending fabric, dipping east at around 35 degrees. In the project area the principal mineralised shear zone, termed the Morro Pelado shearis around 30m thick.
The modelled mineralised zone has dimensions of 3,250m (surface trace striking 035) of varying thickness between 30m and 60m, and ranging between 150m and 500m RL (AMSL).
For the statistics and subsequent grade estimation descriptions, the mineralised zone has been arbitrarily subdivided into the Southern (Zone 1), Central (Zone 2) and Northern (Zone 3) domains based on the 20,050mN and 21,300mN northings.
Summary:
The mine will be an open pit with contractor operated equipment including excavators with 3.5 m 3 buckets and 45 t trucks. The access roads will be 15 m wide with 10% maximum inclination, meeting safety standards and specifications of the mining fleet. The operational slopes will have 5 m benches in ore and 10 m benches in waste, with a total height of 20 m.
It is anticipated that only 70% of mined material will require blasting.
Material storage:
• The ROM (Run of Mine) ore >0.7 g/t Au will be transported by trucks and discharged directly into the ROM receiving hopper at an average feed rate of 330 tph. Oversize will be removed and broken by hydraulic hammer. Three days crusher feed of 18,000 tonnes will be stockpiled for wheel loader recovery and production continuity.
• Medium Grade Ore (0.5g/t Au to 0.7g/t Au) in the first 4 years, will be transported to the allocated NW1 Stockpile close to the plant. From years 5 to 10, this material will be reclaimed to feed the plant.
• Marginal ore with less than 0.5 g/t Au, will be stockpiled in the NW Waste stockpile which will be reserved specifically for low grade or mineralised waste.
• The waste rock will be transported to the NE Waste stockpile where it will be co-disposed with the filtered tailings generated in the Filtration Plant.
The Stage 1 open pit designed by GE21 Consultorio Mineral for the DFS. The portion of the reserves that will be mined in the 10.2 year L ........
Source:
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Flow Sheet:
Summary:
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Projected Production:
| Commodity | Units | Avg. Annual | LOM |
|
Gold
|
oz
| 71,500 | 729,374 |
All production numbers are expressed as metal in doré.
Operational Metrics:
| Metrics | |
|
Stripping / waste ratio
| ...... |
|
Waste tonnes, LOM
| ...... |
|
Ore tonnes mined, LOM
| ...... |
|
Total tonnes mined, LOM
| ...... |
|
Tonnes processed, LOM
| ...... |
|
Annual processing capacity
| ...... |
|
Annual ore mining rate
| ...... |
* According to 2020 study.
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Reserves at March 6, 2018:
Ore Reserve estimate for the Borborema Gold Projec reported at a 0.4g/t Au cut-off for oxide and 0.5 g/t Au cut-off for fresh material.
Mineral Resource reported above 0.5 g/t Au cut-off.
| Category | OreType | Tonnage | Commodity | Grade | Contained Metal |
|
Proven
|
Sulphide
|
7.26 Mt
|
Gold
|
1.25 g/t
|
292 koz
|
|
Proven
|
Oxide
|
0.65 Mt
|
Gold
|
0.8 g/t
|
17 koz
|
|
Probable
|
Sulphide
|
32.82 Mt
|
Gold
|
1.2 g/t
|
1,260 koz
|
|
Probable
|
Oxide
|
1.68 Mt
|
Gold
|
0.7 g/t
|
38 koz
|
|
Proven & Probable
|
Total
|
42.41 Mt
|
Gold
|
1.18 g/t
|
1,610 koz
|
|
Measured
|
|
8.2 Mt
|
Gold
|
1.22 g/t
|
320 koz
|
|
Indicated
|
|
42.8 Mt
|
Gold
|
1.12 g/t
|
1,547 koz
|
|
Measured & Indicated
|
|
51 Mt
|
Gold
|
1.14 g/t
|
1,867 koz
|
|
Inferred
|
|
17.6 Mt
|
Gold
|
1 g/t
|
566 koz
|
|
Total Resource
|
|
68.6 Mt
|
Gold
|
1.1 g/t
|
2,430 koz
|
Corporate Filings & Presentations:
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