Castelo de Sonhos Gold Project
The Deposit
The Castelo de Sonhos gold project is situated in Pará State, 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 Pre-Feasibility Study
- Mineralization at surface → simple open pit
- Good metallurgical properties → high gold recovery
- Connected to grid power, close to highway → good infrastructure
The Pre-Feasibility Study was conducted by GE21 Consultoria Mineral Ltda ("GE21") of Belo Horizonte, Brazil, and Piteau Associates of Sandton, South Africa, both of whom are independent of TriStar.
Details are reported in the press release dated October 5th, 2021 titled ‘TriStar Gold Announces Positive PFS with 1.4 Moz Gold Reserves and Pre-Tax 33% IRR and $400 Million NPV' and NI43-101 report dated October 4th, 2021 titled ‘Castelo de Sonhos Project Pre-Feasibility Study’ filed on Sedar.com.
Key Economic Parameters
Pre-Feasibility Study results in October 2021 indicate pre-tax IRR of 33% at a gold price of US$1550, with a low-cost base and strong leverage for higher gold prices.
The base case economics are calculated on a long-term gold price of US$1,550/oz, and a foreign exchange rate of US$1 = BRL5.0. The economics include the effect of the project royalties, including NSR royalties totaling 3.5% and Brazilian federal gross royalty of 1.5%.
Parameter |
Unit |
Pre-tax |
Post-tax |
Cash Flow |
US$ (Millions) |
635 |
524 |
IRR |
% |
33 |
28 |
NPV (5%) |
US$ (Million) |
399 |
321 |
NPV (7%) |
US$ (Million) |
332 |
263 |
Cash Cost |
US$/oz |
877 |
|
AISC |
US$/oz |
900 |
|
CAPEX |
US$ (Million) |
261 |
|
Life of Mine Production |
Moz Au |
1.3 |
|
Payback Period (Mine Life) |
Years |
2.8 |
Notes: Estimated All In Sustaining Costs per ounce of gold produced is a Non-GAAP measure that is equal to 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. Cash costs per ounce of gold produced is also a non-GAAP financial measure and is equal to on-site mining and processing costs, on-site general and administration costs, realized gains and losses on hedges due to operating costs, community and permitting costs related to current operations, third party refining and transportation costs, non-cash site remuneration costs, stripping costs, stockpile and inventory write-downs, exploration costs related to current operations and by-product credits all divided by ounces of gold cost produced.
Annual Gold Production and AISC over life-of-mine:
|
Average Annual |
Cash Cost US$/oz |
AISC |
Phase 1 (Year 1 – 6) |
146 |
821 |
854 |
Phase 2 (Year 7 – 11) |
91 |
983 |
990 |
LOM |
121 |
877 |
900 |
Mineral Resource Estimate
Region |
Classification |
Tonnage (Mt) |
Grade (g/t Au) |
Metal Content (Moz Au) |
Esperança South |
Indicated |
29.0 |
1.3 |
1.2 |
Inferred |
10.0 |
1.2 |
0.4 |
|
Esperança East |
Indicated |
5.0 |
0.8 |
0.1 |
Inferred |
12.8 |
0.7 |
0.3 |
|
Esperança Center |
Indicated |
19.1 |
0.7 |
0.4 |
Inferred |
3.3 |
0.9 |
0.1 |
|
Project Total |
Indicated |
53.1 |
1.0 |
1.8 |
Inferred |
26.0 |
0.9 |
0.7 |
Mineral resource estimate for the Castelo de Sonhos gold project (with an effective date of October 4, 2021) above a reporting cutoff grade of 0.26 g/t Au. The Qualified Person is Leonardo de Moraes Soares MAIG of GE21.
Project totals may appear not to sum correctly since all numbers have been rounded to reflect the precision of Inferred and Indicated mineral resource estimates.
The reporting cutoff corresponds to the marginal cutoff grade for an open pit with processing + G&A cost of $US 12/t, metallurgical recovery of 98% and a gold price of $US 1,550/oz. To meet the requirement of "reasonable prospect for eventual economic extraction" the mineral resources must also fall within a bounding pit shell with 55° walls. 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.
Mineral Reserve Estimate
The Mineral Reserves for Castelo de Sonhos are a subset of the Indicated Mineral Resources as described above, as none of the mineral resources were classified in the Measured Category there are no Proven Reserves. Probable Mineral Reserves are modified from Indicated Mineral Resources and are summarized in the table below. Inferred Mineral Resources are set to waste.
Region |
Classification |
Tonnage (Mt) |
Grade (g/t Au) |
Metal Content (Moz Au) |
Esperança South |
Probable |
24.2 |
1.28 |
0.99 |
Esperança East |
Probable |
3.1 |
0.82 |
0.08 |
Esperança Center |
Probable |
11.4 |
0.78 |
0.29 |
Project Total |
Probable |
38.7 |
1.1 |
1.4 |
The Mineral Reserve estimates were prepared by Guilherme Gomides Ferreira MAIG of GE21 , and have an effective date of October 4, 2021.
Mineral Reserves are reported using the 2014 CIM Definition Standards and are estimated in accordance with the 2019 CIM Best Practices Guidelines. Mineral Reserves are based on the PFS LOM plan.
Mineral Reserves are mined tonnes and grade; and includes consideration for modifying factors such as loss and dilution.
Mineral Reserves are reported at a cut-off of 0.26 g/t gold. The cut-off grade covers processing costs of $9.99/t, general and administrative ("G&A") costs of $2.00/t, a gold price of US$1,550/oz. and uses a 98% metallurgical recovery for gold.
Numbers have been rounded as required by reporting guidelines. There are no other known factors or issues that materially affect the Mineral Reserve estimate other than which is disclosed above, and normal risks faced by mining projects in the jurisdiction in terms of environmental, permitting, taxation, socio-economic, marketing, and political factors and additional risk factors as listed in the "Cautionary Note Regarding Forward-Looking Information" section below.
Details are reported in press release dated October 5th, 2021 titled ‘TriStar Gold Announces Positive PFS with 1.4 Moz Gold Reserves and Pre-Tax 33% IRR and $400 Million NPV'
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) | 1.1 g/t |
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.