United States

Commonwealth Project

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Mine TypeOpen Pit
StagePreliminary Economic Assessment
  • Gold
  • Silver
Mining Method
  • Truck & Shovel / Loader
Mine Life... Lock
SnapshotThe Commonwealth Silver-Gold Project is a low sulphidation epithermal precious metals project located in Cochise County, Arizona. It hosts the past-producing Commonwealth mine on patented claims and an updated mineral resource estimate (2021) containing 12.6 million oz of silver and 131,000 oz of gold in the Measured and Indicated categories plus another 7.1 million oz of silver and 100,000 oz of gold in the Inferred category.


Wexford Capital LP. 100 % Indirect
All Commonwealth Silver-Gold project assets are controlled by Wexford or funds controlled by Wexford via ownership of Marlin Gold Mining USA Ltd. (former Commonwealth Silver and Gold Mining Inc.), which is the sole owner of CSG.

In accordance with the terms of a binding letter of intent entered into between 1278398 BC Ltd. (“398”) and Wexford (US) on 6 October 2021, the parties have agreed to complete a plan of arrangement whereby, among other things, Wexford (US) shall sell all of the shares of Marlin Gold Mining USA Ltd. (“Marlin”), the holder of the Commonwealth Silver-Gold project, to 398 in exchange for 13,821,429 common shares of 398. As a result of the transaction, Marlin will become a wholly-owned subsidiary of 398. Upon completion of the transaction, 398 intends to change its name to “Swordfish Silver Corp.” or such other names as is acceptable to the parties.



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Deposit type

  • Epithermal
  • Vein / narrow vein


The conceptual geologic model that best applies to the Commonwealth Silver and Gold Project is a variation of the rift, low sulfidation, epithermal chalcedony-ginguro model of Corbett (Corbett, 2002). The characteristics of this model are mineralogy derived primarily from dilute, near neutral pH fluids, an extensional, dilatant structural setting, competent host rocks that fracture well, and abundant banded chalcedonic quartz.

The mineral deposits within the Commonwealth Project area are typical of silver dominant, low sulfidation, epithermal veins and stockworks emplaced in a near surface environment. The veins are best developed in the andesite to rhyolite units of the Pearce Volcanics. These volcanic rocks fracture well, are densely fractured to shattered, and host dense quartz stockworks, breccia zones and banded quartz veins. Cretaceous marine sediments of the Bisbee Group also host mineralization and are chemically favorable hosts. The calcareous sandstones and siltstones of the Bisbee Group are very similar to the “dirty carbonate” host rocks of many sediment hosted disseminated gold deposits in Nevada and in northern Mexico. These rocks seem to be especially favorable hosts for gold mineralization and there is a higher Au:Ag ratio in the assay results from mineralized Bisbee Group samples as compared to the mineralized volcanic rocks at the Commonwealth Project. The Bisbee Group sediments are soft enough that they do not fracture well on faulting.  Mineralization within the Bisbee Group sediments occurs as both vein type mineralization and some disseminated mineralization.

At least seven major quartz veins were actively mined in the Commonwealth Mine between 1895 and 1927. The two most important veins are the Main Vein and the North Vein. The Main Vein strikes approximately N70°W and dips 65 to 85°to the southwest. The Main Vein is interpreted to be an extension fracture related to the North Vein, which has greater fault displacement. The Main Vein ranges from 3 m to over 8 m in true width and is composed of quartz cemented breccias, colloform banded very fine grained quartz, and chalcedony. Characteristic green chalcedonic quartz locally termed “talc quartz” is common in the Main Vein. This green color may be due to finely disseminated embolite (silver chloro-bromide). Late events within the Main Vein exhibit comb and cockade textures and drusy open space filling. Some of the late quartz is amethyst. The North Vein strikes N80°W to N90°W and dips 45 to 65° to the southwest. The vein is up to 15 m wide and is characterized by abundant white colloform banded chalcedony and banded grey silica, which is almost opaline in texture.  

Much of the mineralization on the Commonwealth Project occurs in the silicified and shattered structural wedge between the Main Vein and the North Vein. This mineralized zone is at least 550 m long and expands eastward from a point where the veins coalesce reaching a mineralized exposed width of 125 m before extending beneath alluvial cover.

Subsidiary veins in the mineralized wedge that were named by Smith (1927) are, from the footwall of the Main Vein and proceeding north, the Footwall Vein, the Fischer Vein, the Smith Vein, the Hartery Vein and the Renaud Vein. Each of these veins varies from 1 to 4 m in width, with the Renaud Vein being the widest. These veins are generally sheeted veins sub-parallel to the Main Vein. They may also be considered the thick, high fluid flow arteries within the stockwork zone between the Main and North Veins.



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Mining Methods


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Crushers and Mills


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Silver M oz 11
All production numbers are expressed as payable metal.

Production Costs

Cash costs Gold Equivalent USD 800.97 / oz *  USD
Cash costs (sold) Gold USD 1,281 / oz *  USD
Cash costs (sold) Gold USD 492 / oz * **  USD
Total cash costs Gold Equivalent USD 831.23 / oz *  USD
Total cash costs (sold) Gold USD 528 / oz * **  USD
All-in sustaining costs (AISC) Gold Equivalent USD 945.09 / oz *  USD
All-in sustaining costs (sold) Gold USD 708 / oz * **  USD
Assumed price Silver USD 22.5 / oz *  USD
Assumed price Gold USD 1,350 / oz *  USD
* According to 2014 study / presentation.
** Net of By-Product.

Operating Costs

OP mining costs ($/t mined) USD 2.97 *  USD
OP mining costs ($/t milled) USD  ....  Subscribe
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* According to 2014 study.

Project Costs

MetricsUnitsLOM Total
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Net revenue (LOM) $M USD  ......  Subscribe
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After-tax NPV @ 5% $M USD  ......  Subscribe
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Heavy Mobile Equipment


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Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Jan 2, 2023

...... Subscription required 2014

Aerial view:


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