Categories

Overview

Mine TypeOpen Pit & Underground
StagePreliminary Economic Assessment
Commodities
  • Gold
Mining Method
  • Truck & Shovel / Loader
  • Blast Hole Stoping
Backfill type ... Lock
Mine Life... Lock
SnapshotThe Brookbank claim group is a part of the Greenstone Gold Mine Property and hosts the Brookbank, Cherbourg and Fox Ear deposits and the Irwin prospect.

In 2022, Greenstone Gold Mines requested BBA to perform a desktop-level study for the Brookbank deposit, based on ore being mined at Brookbank and transported by truck to the Greenstone processing plant.

The Brookbank Deposit, the on-strike Foxear and Cherbourg targets, and an underexplored ~40 km of prospective strike length present excellent potential for discovery and resource growth.

Owners

SourceSource
CompanyInterestOwnership
Equinox Gold  Corp. 100 % Indirect
Greenstone Gold Mines (GGM) owns 100% of the lease that covers the Brookbank deposit with the remaining portion of the project tenements (Cherbourg and Fox Ear deposits and the Irwin prospect) being subject to two Joint Venture (“JV”) agreements with Metalore Resources Limited (“Metalore”). The first JV is a GGM 74% / Metalore 26% split with the second a GGM 79% / Metalore 21% split.

Greenstone Gold Mines was a 60/40 joint venture company between Equinox Gold and Orion Mine Finance Group. On May 13, 2024, Equinox Gold announced the completion of the acquisition of the remaining 40% of Greenstone Gold Mine GP Inc. from certain funds managed by Orion Mine Finance Management LP, giving Equinox Gold 100% ownership of the Greenstone Mine.

Deposit type

  • Hydrothermal
  • Breccia pipe / Stockwork
  • Vein / narrow vein

Summary:

The 6.5 kilometre long Brookbank shear zone hosts the Brookbank, Cherbourg, and Foxear deposits. The deposits occur along lithological contacts between mafic volcanics and metasediments. Other areas of gold mineralization are present in one or more of the localized deformation bands within the hanging wall mafic volcanics, which are generally parallel to the Brookbank main zone within the Brookbank shear zone structure.

The zones of mineralization at Brookbank, Cherbourg, and Foxear occur within one of several bands of intense deformation and hydrothermal alteration at or near the contact between domains of mafic flows and polymictic conglomerate. Hydrothermal alteration in the vicinity of the mineralization consists of silicification, carbonatization, sericitization, chloritization, hematization and sulphidization. This alteration is commonly marginal to quartz-carbonate veins, fractures, and stockworks and may exceed 50 metres in width locally.

Mineralogical studies indicate that the precious metal mineralization consists of goldsilver particles with an approximate gold to silver ratio of 80:20. The gold occurs primarily as late fracture-controlled mineralization. The mineralization forms elongate lenticular particles associated with grain boundaries and possibly crystallographic planes. The gold generally consists of fine grained free gold particles, although there is very little visible gold even in areas of plus 30 g/t Au assays. Gold values are highest in the quartz–carbonate veinlets/stringers.

Sulphide mineralization (pyrite and minor chalcopyrite) is also present within the sheared host and quartz veinlets.

Economic concentrations of gold in the Geraldton area are typical of Archean epigenetic hydrothermal gold deposits normally considered to be mesothermal lode gold deposits. The gold mineralization is primarily located in areas of high strain and deformation with brittle structures providing a pathway and also hosting mineralization as veins or replacement zones with associated alteration. There are also low grade zones that locally have less obvious structural control, less veining, and less intense hydrothermal alteration on a hand specimen scale, but these clearly have strong deposit scale structural controls.

The mineralization on the Brookbank Project occurs within quartz-carbonate veinlets/stringers, fractures and/or stockworks associated with hydrothermal alteration. The latter is generally located within bands of intense deformation at the contacts between domains of mafic flows and polymictic conglomerate.

Reserves

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Mining Methods

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Comminution

Crushers and Mills

Milling equipment has not been reported.

Processing

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Production

CommodityUnitsLOM
Gold oz 485,800
All production numbers are expressed as metal in ore.

Operational metrics

Metrics
Daily ore mining rate  ....  Subscribe
Stripping / waste ratio  ....  Subscribe
Ore tonnes mined, LOM  ....  Subscribe
* According to 2022 study.

Production Costs

CommodityUnitsAverage
Assumed price Gold USD  ....  Subscribe
* According to 2022 study / presentation.

Project Costs

MetricsUnitsLOM Total
Pre-Production capital costs $M USD  ......  Subscribe
Sustaining CapEx $M USD  ......  Subscribe
After-tax IRR, %  ......  Subscribe
After-tax payback period, years  ......  Subscribe

Required Heavy Mobile Equipment

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Personnel

Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Dec 21, 2024

Aerial view:

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