Mining Intelligence and News

Cerro de Oro Project

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Mine TypeOpen Pit
  • Gold
Mining Method
  • Truck & Shovel / Loader
Production Start... Lock
Mine Life... Lock
SnapshotThe Cerro de Oro oxide gold project in northern Zacatecas has considerable past drilling and metallurgical work completed and is currently being guided through the permitting process by the Company’s permitting consultants.


Minera Alamos Inc. 100 % Indirect
In September 2020, the Minera Alamos finalized definitive option agreements through its subsidiary Minera Mirlos S. De R.L. DE C.V. and an arm’s length parties to acquire 100% of the Cerro de Oro project comprising the Zacatecas I and Zacatecas II concessions near Concepcion del Oro, Zacatecas, Mexico. The agreements convey 100% ownership to the Company with no underlying royalties subject to the Company meeting a schedule of payments.



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Deposit type

  • Porphyry
  • Vein / narrow vein


Mineralization at the Cerro de Oro deposit is typical of a porphyry system and is characterized by the development of A and B veins. These veins developed during an early potassic alteration phase and were later overprinted by silica and sericite (phyllic overprinting) within the inter-mineral porphyritic intrusive phases. These phases form part of the overall intrusive complex.

Mineralization at the Project scale occurs within a granodioritic porphyritic stock and within its calcareous host rocks. Within the calcareous host rock zone are blocks of highly garnetized limestone that are part of the Indidura Formation. These sedimentary rocks have been uplifted by the intrusion of the granodiorite stock.

The current Mineral Resources are contained within a semicircular zone of about 1 km diameter; within this mineralized envelope the ore zones are mixed, with some lower-grade or barren zones. Most of the drilling is shallow, with an average depth of 100 m, roughly corresponding to the depth of supergene oxidation. The upper 70 m to 120 m of the mineralization has been oxidized with pyrite altered to hematite, goethite, and jarosite. The hypogene sulphide mineralization is open at depth, and along all directions.

Mineralization at Cerro de Oro consists dominantly of pyrite that is widely disseminated throughout the porphyritic granodiorite, and in hornfels and skarns developed at the contact with the sedimentary rocks. Occasionally the presence of chalcopyrite has been noted, but its presence is typically minor and erratic. Lead and zinc are associated in varying amounts with the pyritic mineralization and may correlate with gold mineralization within the skarn zones. In areas where gold is hosted within the porphyritic granodiorite, only pyrite is associated with gold mineralization.

Gold resources are primarily hosted by the porphyritic granodiorite, which is characterized by various forms of stockwork-controlled mineralization associated with the development of early potassic alteration that was later overprinted by a sericitic event. The observed veins are typical of porphyry systems including magnetite vein; magnetite and quartz veins developed with potassic alteration; and later veins associated with sericitic alteration.

The porphyry is altered, with strong pervasive silicification and sericite. Fracturing is common, as is seen in the specimen. Minor quartz occurs as vein filling.

The mineralization at Cerro de Oro also occurs in the thinly bedded calcareous shale of the Caracol Formation and in its hornfels equivalent. It comprises iron sulphides like pyrite, now oxidized down to 70 m to 120 m from surface. The mineralization in the Caracol sediments and hornfels is partially disseminated, but is mostly distributed along bedding planes, fractures, and occasional veinlets and veins where it is often accompanied by quartz. The vein-controlled sulphide mineralization was in places so intense and thick (up to at least 10 cm), that iron sulphides were oxidized to gossan.



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Mining Methods


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Crushers and Mills


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Production is shown as loaded carbon concentrate to be shipped for final gold doré production and sale.
CommodityUnitsAvg. AnnualLOM
Gold oz 58,400476,610

Operational metrics

Daily ore mining rate  ....  Subscribe
Daily processing rate  ....  Subscribe
Annual ore mining rate  ....  Subscribe
Annual processing capacity  ....  Subscribe
Stripping / waste ratio  ....  Subscribe
Waste tonnes, LOM  ....  Subscribe
Ore tonnes mined, LOM  ....  Subscribe
Total tonnes mined, LOM  ....  Subscribe
Tonnes processed, LOM  ....  Subscribe
* According to 2022 study.

Production Costs

Cash costs (sold) Gold USD  ....  Subscribe
All-in sustaining costs (sold) Gold USD  ....  Subscribe
Pre-tax break-even price Gold USD  ....  Subscribe
Assumed price Gold USD  ....  Subscribe
* According to 2022 study / presentation.
** Net of By-Product.

Operating Costs

OP mining costs ($/t mined) USD 2.23 *  
OP mining costs ($/t milled) USD  ....  Subscribe
Crushing costs ($/t milled) USD  ....  Subscribe
Processing costs ($/t milled) USD  ....  Subscribe
G&A ($/t mined) USD  ....  Subscribe
G&A ($/t milled) USD  ....  Subscribe
Total operating costs ($/t mined) USD  ....  Subscribe
Total operating costs ($/t milled) USD  ....  Subscribe
* According to 2022 study.

Project Costs

MetricsUnitsLOM Total
Initial CapEx $M USD  ......  Subscribe
Sustaining CapEx $M USD  ......  Subscribe
Total CapEx $M USD  ......  Subscribe
OP OpEx $M USD  ......  Subscribe
Processing OpEx $M USD 204.1
Refining costs $M USD  ......  Subscribe
Transportation (haulage) costs $M USD 17.8
G&A costs $M USD 19
Total OpEx $M USD  ......  Subscribe
Income Taxes $M USD  ......  Subscribe
Gross revenue (LOM) $M USD  ......  Subscribe
After-tax Cash Flow (LOM) $M USD  ......  Subscribe
After-tax NPV @ 5% $M USD  ......  Subscribe
After-tax NPV @ 10% $M USD  ......  Subscribe
After-tax NPV @ 8% $M USD  ......  Subscribe
After-tax IRR, %  ......  Subscribe
After-tax payback period, years  ......  Subscribe

Required Heavy Mobile Equipment


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Mine Management

Job TitleNamePhoneEmailProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Sep 28, 2022
....................... Subscription required ....................... Subscription required ........... Subscription required ........... Subscription required Subscription required Dec 21, 2023
....................... Subscription required ....................... Subscription required Subscription required Dec 21, 2023

Aerial view:


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