Overview
Stage | Preliminary Economic Assessment |
Mine Type | Underground |
Commodities |
|
Mining Method |
- Longhole open stoping
- Longitudinal retreat
- Cemented backfill
|
Mine Life | 11 years (as of Jan 1, 2021) |
The PEA is based on a conventional truck-shovel open pit mining operation within two pits that transition to underground mining in year 6.
The Goldboro Project has potential for further Mineral Resource expansion, particularly towards the west along strike and at depth. A future study will consider upgrading and expanding potentially mineable underground Mineral Resources as part of the longer-term mine development plan. |
Source:
p. 5,17
The Goldboro Project is 100% - owned by Signal Gold Inc.
The Goldboro Project is registered to the Signal Gold subsidiary Goldboro Gold Mines Inc. (previously Orex Exploration Inc.).
Contractors
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Deposit Type
- Vein / narrow vein
- Orogenic
- Metamorphic hosted
Summary:
The Deposit is a turbidite-hosted orogenic gold deposit hosted within a sequence of alternating argillites and greywacke metamorphosed to greenschist facies. The metasedimentary units on the Property are folded into the tight, gently east-plunging Upper Seal Harbour Anticline and gold mineralization has typically been deposited at various positions and times during the fold formation process. Veins, which form during deformation, occur in three major geometries commonly referred to as reefs: saddle reefs, leg reefs, and spur reefs. The Deposit contains all three types of reefs outlined above but is also characterized by mineralization within the argillite forming the Belts. Because the Deposit contains saddle, leg, and spur reefs, and often has gold mineralization within the argillite hosting the veins, it has the potential to contain significantly more gold resources than deposits of a similar style that contain gold only within the quartz veins (reefs) themselves. The trace of the Upper Seal Harbour Anticline transects the Property and is found near the Dolliver Mountain prospect 2 km to the west of the Deposit, demonstrating that the structure which hosts gold continues for several kilometres.
At the Deposit, the Goldenville Formation consists of alternating greywacke and argillite beds with an approximate true thickness of 950 m. The base of the stratigraphic sequence intersected in the BR Gold System consists of roughly 325 m of alternating greywacke and argil ........

Mining Methods
- Longhole open stoping
- Longitudinal retreat
- Cemented backfill
Summary:
The PEA is based on a conventional truck-shovel open pit mining operation within two pits that transition to underground mining in year 6.
The mining method was selected based on economic and geotechnical parameters, ensuring it was suitable for the mineralization geometry. Longitudinal retreat longhole open stoping (LHOS) with cemented paste backfill was ultimately selected due to its relatively low cost, ability to accommodate narrow vein mineralization, and ability to mine close to the open pits without causing excessive instability. Stope dimensions were designed as 15 m in length (along strike), 20 m in height (level spacing), an average true thickness of 2.6 m (hanging wall to footwall) and an average dip of 70.6 degrees.
Stopes are accessed via overcut and undercut stope access development drifts, with associated drilling and blasting activities performed from the overcut and mucking from the undercut. Stope sequencing is based on a longitudinal retreat, progressing from the outward extents of the level, and retreating inward to the level access and ramp. The underground has been sequenced in a bottom-up manner, assuming all stopes on a level are excavated laterally before progressing vertically; however, the option to use a combination of lateral and vertical (half pyramid) sequencing is also viable.
External dilution was considered for the hanging wall and footwall of stopes. Due to the overall high rock mass quality of the deposit, e ........

Flow Sheet:
ROM mineralized material is transported from the mine to the process plant by haul trucks. The ROM bin is fitted with a static grizzly to keep large oversize rocks from blocking the primary crusher. A vibrating grizzly feeder ahead of the of the primary jaw crusher is used to screen out the finer material and feed the jaw crusher. The primary crusher product combines with the grizzly feeder undersize and is conveyed to a secondary screen. Screen oversize is fed to a secondary cone crusher and the secondary crushed product is combined with the secondary screen undersize. The tertiary crusher operates in closed circuit with a tertiary screen. The undersize from the tertiary screen is conveyed to the mill feed stockpile with 80% of the design particle size distribution passing an aperture of 8.2 mm.
Crushing circuit product is conveyed to a covered mill feed stockpile. The stockpile is designed to have a live capacity of 12 hours or 2,000 tonnes.
Mill feed from the stockpile is reclaimed by two belt feeders. The feeders transfer the mill feed onto the ball mill feed conveyor which discharge the ore directly into the ball mill. Process water is added to the conveyor discharge to create a slurry in the ball mill. The mill feed chute also receives oversized material from the gravity scalping screen and the underflow from the hydrocyclone cluster. The mill is operated in closed circuit where the product is discharged into a common pumpbox with independent pumps for both the hydrocyclone cluster and the gravity circuit and includes a trommel for scat removal. Material that is too coarse will be classified by the hydrocylone and will report back to the ball mill for further size reduction.
The cyclone cluster is configured to achieve a target design cyclone overflow product sizing of 80% passing of 100 µm. Leach testing showed that this product size is sufficient to achieve design recoveries. The cyclone cluster will have pneumatically actuated valves that allow automated feed pressure control as well as manually actuated isolation valves.
Slurry from the cyclone cluster underflow launders flow directly back to the ball mill while the cyclone overflow slurry from the cyclone cluster gravity flows to a trash screen.
Flow Sheet:
Summary:

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Projected Production:
Commodity | Units | LOM |
Gold
|
M oz
| 0 |
Operational Metrics:
Metrics | |
Daily ore mining rate
| ......  |
Waste tonnes, LOM
| ......  |
Ore tonnes mined, LOM
| ......  |
Tonnes processed, LOM
| ......  |
* According to 2021 study.
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Reserves at February 7, 2021:
Underground Mineral Resource is reported at a cut-off grade of 2.60 g/ Au.
Category | OreType | Tonnage | Commodity | Grade | Contained Metal |
Measured
|
In-Situ (UG)
|
1.384 Mt
|
Gold
|
7.36 g/t
|
327.7 koz
|
Indicated
|
In-Situ (UG)
|
2.772 Mt
|
Gold
|
5.93 g/t
|
528.6 koz
|
Measured & Indicated
|
In-Situ (UG)
|
4.156 Mt
|
Gold
|
6.41 g/t
|
856.2 koz
|
Inferred
|
In-Situ (UG)
|
3.726 Mt
|
Gold
|
5.92 g/t
|
709.1 koz
|
Commodity Production Costs:
| Commodity | Units | Average |
Assumed price
|
Gold
|
USD
|
......
|
* According to 2021 study / presentation.
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Operating Costs:
| Units | 2021 |
UG mining costs ($/t mined)
|
CAD
| 92.5 * |
UG mining costs ($/t milled)
|
CAD
| ......  |
* According to 2021 study.
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2021 Study Costs and Valuation Metrics :
Metrics | Units | LOM Total |
UG OpEx
|
$M CAD
|
......
|
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Source:

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Corporate Filings & Presentations:
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