Castelo de Sonhos Gold Project
The Deposit
The Castelo de Sonhos gold project is situated in the Pará state of Brazil, approximately 20km from the town of Castelo de Sonhos. It is a paleoplacer gold deposit that is large, simple and in the right location.
Key Attributes
- Substantial amounts of untested growth potential
- Robust Preliminary Economic Assessment
- Mineralization at surface → simple open pit
- Good metallurgical properties → high gold recovery
- Connected to grid power, close to highway → good infrastructure
Preliminary Economic Assessment results in November 2018 indicate pre-tax IRR of 51% at a gold price of US$1250, with a low-cost base and strong leverage for higher gold prices.
Key Economic Parameters
|
Parameter |
Unit |
Pre-tax |
Post-tax |
|
Cash Flow |
US$ millions |
441 |
372 |
|
IRR |
% |
51 |
43 |
|
NPV 5% |
US$ millions |
319 |
264 |
|
NPV 10% |
US$ millions |
233 |
188 |
|
Cash Cost |
US$/oz |
660 |
|
|
AISC |
US$/oz |
687 |
|
|
Initial Capital |
US$ millions |
184 |
|
|
Life of Mine Production |
Moz gold |
1.1 |
|
|
Average Annual Production |
oz gold |
130,000 |
|
|
Payback Period (Mine Life) |
years |
1.9 (of 8.1 years) |
Details are reported in press release dated Nov 16, 2018 titled '51% IRR from PEA at TriStar Gold’s Castelo de Sonhos Project’
The PEA is preliminary in nature and includes Inferred Mineral Resources that are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as Mineral Reserves. There is no certainty that the economic results described in the PEA will be realized. Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability.
Estimated All In Sustaining Costs per ounce of gold produced is a Non-GAAP measure that is equal the total of site mining costs, site and corporate G&A costs, royalties and production taxes, realized gains/losses on hedging transactions, community and permitting costs relating to current operations, refining costs, site based non-cash remuneration, inventory write-downs, stripping costs, byproduct credits, reclamation costs, and sustaining costs related to exploration and studies, capital exploration, capitalized stripping and underground mine development, and capital expenditures, divided by the estimated total ounces of gold produced during the life of the mine.
Current Resource
The project currently has mineral resources of:
Indicated: 17.7 million tonnes at 1.2 g/t, containing 0.7 million ounces (“Moz”) of gold.
Inferred: 39.8 million tonnes at 1.0 g/t, containing 1.3 Moz of gold.
| Region | Classification | Tonnage (Mt) |
Grade (g/t Au) |
Metal Content (Moz Au) |
|---|---|---|---|---|
| Esperança South | Indicated | 11.8 | 1.4 | 0.5 |
| Inferred | 21.7 | 1.2 | 0.8 | |
| Esperança East | Indicated | - | - | - |
| Inferred | 11.8 | 0.9 | 0.4 | |
| Esperança Center | Indicated | 5.9 | 0.9 | 0.2 |
| Inferred | 6.3 | 0.7 | 0.1 | |
| Project Total | Indicated | 17.7 | 1.2 | 0.7 |
| Inferred | 39.8 | 1.0 | 1.3 |
Numbers have been rounded to reflect the imprecision of Inferred and Indicated mineral resource estimates.
The reporting cutoff of 0.3g/t gold corresponds to the marginal cutoff for an open pit with operating cost (processing + G&A) of $US 10/t, metallurgical recovery of 98% and a gold price of $US 1,200/oz. These are mineral resources and not reserves and as such do not have demonstrated economic viability.
The metal content estimates reflect gold in situ, and do not include factors such as external dilution, mining losses and process recovery losses.
TriStar is not aware of any environmental, permitting, legal, title, taxation, socio-economic, marketing or political factors that might materially affect these mineral resource estimates.
Details are reported in press release dated Sept 17, 2018 titled ‘35% Increase In Resources At Castelo De Sonhos As Preliminary Economic Assessment Begins’
Geology and Mineralization
The Castelo de Sonhos property encompasses a 15km by 12km plateau in the Tapajós region of Pará state. It has an average elevation above sea level of approximately 600m and stands around 350m above the surrounding plains.
The Castelo de Sonhos Formation is a package of sandstones and conglomerates which form a roughly circular plateau surrounded by intrusive granites of the Tapajós-Parima Province.
The gold mineralization is generally associated with the conglomerate reefs. The main alteration types are hematite and silicification, although these are not believed to be directly linked to the deposition of the gold in the conglomerates.
Analogous Deposits
| TARKWA | JACOBINA | CASTELO DE SONHOS | |
|---|---|---|---|
| Location | Ghana | Brazil | Brazil |
| Age (Ga) | 2.1 | 1.88 ─ 2.09 | 2.1 |
| Total Deposit (Moz Au) | ~30 Moz Au | ~10 Moz Au | tbd |
| Mine Type | Open Pit & Underground | Open Pit & Underground | Initially Open Pit |
| Grade | 1.2 g/t (pit) | 1.9 g/t (pit) | 1.45 g/t (PEA) |
| Underground Grade | > 6 g/t | 2.5 ─ 9.5 g/t | - |
| Thickness of Mineralized Zones | ≤ 8 m | ≤ 25m | ≤ 20m |
| Host Rock | Quartzites and pebble conglomerates | Quartzites and pebble conglomerates | Quartzites and pebble conglomerates |
Two billion years ago, a large continent lay near the South Pole, with a chain of lode gold deposits along its central mountain ridge. Gold accumulated in placer deposits down-slope, in alluvial fans, on beaches and in the near-shore marine environment. In modern times, these now include gold deposits at Tarkwa, Jacobina and Castelo de Sonhos.
