United States

Mesquite Mine

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Overview

Mine TypeOpen Pit
StatusActive
Commodities
  • Gold
Mining Method
  • Truck & Shovel / Loader
Production Start... Lock
Mine Life... Lock
SnapshotMesquite is an open-pit, run-of-mine heap leach gold mine.

2023 plan: Pivot to less stripping and small-pit mining in 2023 to reduce costs, continue exploration and permitting for mine life extension.

Owners

SourceSource
CompanyInterestOwnership
Western Mesquite Mines Inc. (operator) 100 % Direct
Equinox Gold  Corp. 100 % Indirect
Western Mesquite Mines, Inc., Equinox’s wholly-owned subsidiary, holds a 100% interest in the property and operates the Mesquite mine.

Contractors

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Deposit type

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

Summary:

The gold mineralization at Mesquite Mine was deposited in an epithermal setting, within 500 to 1,000 ft of the surface. The majority of the economically attractive mineralization is found in the biotite gneiss and hornblende-biotite gneiss, while the mafic gneiss and intrusive rocks are generally less mineralized. Gold mineralization is found both disseminated and vein hosted within these units. The majority of the veining is controlled by faults and fault junctions, which have moderate to steep dips.

The gold mineralization dominantly occurs in two types:
- pods of mineralization limited in lateral and vertical extent at fault intersections;
- trends of mineralization along faults.

The principal types of mineralization defined at Mesquite are as follows:
• Early epidote - quartz veinlets overprinted by chlorite veinlets;
• Two-stage siliceous matrix breccia (SMBX) developed along faults planes with quartzadularia matrix ± pyrite;
• Quartz ± adularia ± pyrite ± electrum veinlets with sericite halos;
• Ankerite ± Dolomite ± pyrite veinlets;
• Bleached zones on fault planes with green sericite ± pyrite;

Gold occurs at Mesquite as both submicron disseminated and coarse gold. All documented gold occurrences are native gold, and classification has been based on silver content and grain size. A silver-free native gold is the most common type in the oxidized zone. It occurs in particles less than five microns, although clusters up to 100 µ are common in fault zones. Gold grains are subhedral to anhedral in shape, with anhedral morphology predominating. In general, the grains are characterized by irregular, ragged boundaries and equant to elongate shape. Gold within the oxide portion of the deposit is commonly associated with goethite pseudomorphs after pyrite and mica minerals. Later stage gold, less than five microns, is found along the cleavages of the micas.

A second type of gold is the silver-bearing (5% to 20%) coarse (10 µ to 600 µ) gold. Its average size is 30 µm to 50 µm and it is typically found in the unoxidized zone, and only occasionally in the oxidized zone. Grains have octahedral morphology, with cuspate to sharp boundaries. Gold specimens are usually bright yellow electrum, with minor inclusions of galena and pyrite. Silver-bearing gold is associated with quartz-adularia pyrite veins containing arsenopyrite, magnetite, and chalcopyrite.

Visible gold has been identified throughout Mesquite. Small flakes, less than 50 µm, of free “flour” gold have been found within the oxidized gouge and clay fault zones. The flour gold is thought to be a result of remobilization during oxidation and is supergene in nature. Gold is typically associated with titanium oxides (rutile) and hematite. These zones are limited in extent (one inch to three feet wide, with three feet to 50 ft of strike length), but can be extremely high grade. Selective sampling indicates typical gold values of 1.0 opt to 2.0 opt Au, with a high of 35.9 opt Au recorded in Big Chief.

Coarse-grained hypogene gold has also been noted with more frequency and larger size in the unoxidized portion of the deposits. Recent test work on non-oxidized ore indicates that 65% to 78% of the gold is liberated free milling gold, 13% is associated with refractory sulphide minerals, and the remainder is associated with iron oxides and carbonates. Grain size ranges from 10 µm to 600 µm, with no textural indications of re-mobilization. Coarse gold generally occurs as electrum within quartz veins (occluded and void fill), while the refractory portion is found within overgrowth rims of arsenopyrite, chalcopyrite, and pyrite.

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

CommodityUnits202320222021202020192018201720162015
Gold koz  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe126155169111135
All production numbers are expressed as metal in doré. ^ Guidance / Forecast.

Operational metrics

Metrics20222021202020192018201720162015
Stripping / waste ratio  ....  Subscribe  ....  Subscribe  ....  Subscribe1.31 1.63 1.83 2.1 1.94
Ore tonnes mined  ....  Subscribe  ....  Subscribe  ....  Subscribe25,221 kt24,600 k tons20,828 kt18,969 kt19,987 kt
Waste  ....  Subscribe  ....  Subscribe  ....  Subscribe32,925 kt40,200 k tons38,023 kt39,782 kt38,791 kt
Total tonnes mined  ....  Subscribe  ....  Subscribe  ....  Subscribe

Production Costs

CommodityUnits2023202220212020201920182017
Cash costs (sold) Gold USD  ....  Subscribe  ....  Subscribe 857 / oz   723 / oz   727 / oz  
Cash costs (sold) Gold USD  ....  Subscribe  ....  Subscribe
Total cash costs (sold) Gold USD
All-in sustaining costs (sold) Gold USD  ....  Subscribe  ....  Subscribe 933 / oz   819 / oz   727 / oz  
All-in sustaining costs (sold) Gold USD  ....  Subscribe  ....  Subscribe
^ Guidance / Forecast.
** Net of By-Product.

Operating Costs

Currency202220212020201920182017
OP mining costs ($/t mined) USD 1.48  1.47  1.42  1.48  1.31  1.3  
Processing costs ($/t milled) USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe
G&A ($/t milled) USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe

Financials

Units202320222021202020192017
Capital expenditures (planned) M USD  ....  Subscribe
Sustaining costs M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe 7.1   12.8  
Capital expenditures M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe 15.8  
Revenue M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe 178.2   215.7  
Operating Income M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe 32.8  

Heavy Mobile Equipment

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Personnel

Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required May 30, 2023
....................... Subscription required ....................... Subscription required Subscription required Dec 31, 2019
....................... Subscription required ....................... Subscription required Subscription required Dec 31, 2019
....................... Subscription required ....................... Subscription required Subscription required May 30, 2023
....................... Subscription required ....................... Subscription required Subscription required May 30, 2023
....................... Subscription required ....................... Subscription required Subscription required May 30, 2023
....................... Subscription required ....................... Subscription required Subscription required May 30, 2023

EmployeesContractorsYear
...... Subscription required 2022
...... Subscription required 2021
...... Subscription required 2020
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...... Subscription required 2017
...... Subscription required ...... Subscription required 2016

Aerial view:

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