Mining Intelligence and News
Canada

Brookbank Project

Click for more information

Categories

Summary

Mine TypeOpen Pit & Underground
Study CompletedPreliminary 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
On May 13, 2024, Equinox Gold acquired the remaining 40% interest in Greenstone resulting in the Company owning 100% of Greenstone. The Mine is operated by Greenstone Gold Mines (GGM).

Deposit type

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

Summary:

The Brookbank property is underlain by metavolcanic and metasedimentary rocks that trend predominantly east–west and dip steeply to vertically to the south. Metavolcanic rocks consist of massive and pillowed, locally amygdaloidal, flows of basaltic composition along with related tuffaceous rocks. Pillowed flows exhibit tops to the north.

The Brookbank property is transected by an east–west trending zone of extensive heterogeneous brittle and ductile deformation and hydrothermal alteration, which is referred to as the “Brookbank shear zone”. The deformation can be traced for a minimum of 10 km along strike through Irwin Township and remains open in either direction.

Brookbank Property Mineralization
The 6.5 km-long Brookbank shear zone hosts the Brookbank deposit and numerous other targets including Cherbourg and Foxear. 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 conglomerates. Hydrothermal alteration accompanying the mineralization consists of silicification, carbonatization, sericitization, chloritization, hematization, and sulphidation. This alteration is commonly marginal to the mineralized quartz-carbonate veins, fractures, and stockworks, and may exceed 50 m wide locally.

Mineralogical studies indicate that the precious metal mineralization consists of gold-silver particles with an approximate gold-to-silver ratio of 80:20. The gold occurs primarily as late fracture-controlled mineralization. The mineralization forms elongated 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 rock and quartz veinlets.

Reserves

Lock

- subscription is required.

Mining Methods

Lock

- subscription is required.

Required Heavy Mobile Equipment

Lock

- subscription is required.

Comminution

Crushers and Mills

Milling equipment has not been reported.

Processing

Lock

- subscription is required.

Commodity Production

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

Operational metrics

Metrics
Daily ore mining rate  ....  Subscribe
Stripping 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

Personnel

Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Jun 30, 2024
....................... Subscription required ....................... Subscription required Subscription required Mar 31, 2025

Workforce

Aerial view:

Lock

- subscription is required.