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Mexico

El Castillo Mine

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Summary

Mine TypeOpen Pit
StageResidual leach
Commodities
  • Gold
  • Silver
Mining Method
  • Truck & Shovel / Loader
Production Start... Lock
SnapshotThe El Castillo open pit heap leach gold mine is a part of San Agustin complex (formely El Castillo complex).

In late 2022, the previous owners of El Castillo placed the mine under care and maintenance, with metals production continuing from re-leaching of residual leach pads.

Since acquisition of the mine on November 7, 2024 Heliostar continued re-leaching the residual leach pads.

Reclamation work during Q1 2025 included rinsing of the east leach pad, reforestation initiatives in the vicinity of the mine, pit lake modelling and studies addressing water quality.

Further reclamation work will continue to be performed in 2025.

Owners

SourceSource
CompanyInterestOwnership
Minera Real del Oro S.A. de C.V. (operator) 100 % Direct
Heliostar Metals Limited 100 % Indirect
The El Castillo Mine is owned and operated by Minera Real del Oro, S.A. de C.V., which is a wholly-owned Heliostar Metals Ltd subsidiary.

Heliostar announced notice of the acquisition of the Mine on July 17, 2024, from Florida Canyon Gold Inc., an interim successor to the former operator Argonaut Gold Inc., and completed the acquisition on November 8, 2024.

Deposit type

  • Porphyry
  • Intrusion related
  • Epithermal

Summary:

Deposit Type
El Castillo is interpreted to be a porphyry-style gold system related to Eocene granodiorite– diorite porphyries that intrude Cretaceous clastic and carbonate sediments in an extensional tectonic setting. Gold mineralization occurs throughout the magmatic-hydrothermal system in space and time and is related to sulphide mineralization spatially associated with early potassic development and genetically related to an overprint of phyllic alteration. Supergene alteration, formed as a product of acid leaching, has resulted in argillic-quartz alteration assemblages within the oxide zone of the deposit. The main gold event is believed to be associated with magmatic hydrothermal fluids corresponding to phyllic alteration.

Supergene oxidation of shallow (<200 m) pyrite-gold mineralization is the most important factor affecting mine viability at El Castillo. Oxidized or partially oxidized transition and sulphide material located relatively near surface is a main component of the Mineral Resources and mine plan. The depth of oxidation has been strongly influenced by the density and depth of natural rock fracturing, total pyrite content of hypogene mineralization and the thickness of post-mineral cover. The deeper sulphide portion of the mineral system remains open at depth.

Mineralization
The moderately dipping granodiorite–diorite sills, siltites and argillites are the most favourable host lithologies. Argillic–quartz alteration is often closely associated with the intrusive contacts and can be indicative of higher-grade zones of mineralization.

The dominant controls on the gold mineralization include structural channeling along contacts between intrusive sills and metasedimentary units and a broad zone of northeast-striking, steeply-dipping faults and fractures that acted as conduits to help spread mineralization. Gold precipitation may be somewhat dependent on a chemically-favourable environment within the sediments but does not appear to be strongly influenced by rock composition. The hydrothermal fluids and their contained metals are believed to have been derived from a magmatic source and are a primary volatile component of the porphyry intrusion that is host to much of the mineralization.

Gold is spatially and genetically associated with pyrite occurring as disseminations, fracture fillings and stockworks often occurring within areas of hydrothermal brecciation. Within the mine the host environment for gold mineralization is dominated by an alternating pattern of sediments and parallel intrusive sills that strike to the northwest and dip moderately to the northeast. The sedimentary units generally vary from 20 m to 40 m thick, as do the intrusive sills. Many of the sills appear to have intruded along bedding planes by splitting the tabular sedimentary blocks into their present positions. This geologic event resulted in the unique alternating pattern of sediments and intrusive sills that are observed throughout the mine area. Extensive fracturing and brecciation of the sedimentary blocks, especially along contacts, created favourable secondary permeability for the deposition of gold mineralization predominately associated with pyrite. As a result, the northwest-striking sediments are often better mineralized than the surrounding intrusive rocks.

There is typically a transition zone of partially oxidized mineralization that lies between the fully oxidized material and lower non-oxidized, sulphide material. The transition zone varies from 5 m to 50 m thick and is generally influenced by degree of fracturing and level of erosion.

The sulphide zone is generally identified by the presence of pyrite mineralization. The occurrence of sulphides, either fracture-related or disseminated, is usually a good indicator of gold mineralization. The sulphide veinlets are most commonly 0.5 cm to 4.0 cm wide.

There are two preferred trends to mineralization. The most obvious of these reflects the generally stronger mineralization within the sedimentary units. The favourable permeability related to increased fracturing within the sediments enhanced the distribution and broader geometry of mineralization. The second trend of mineralization is to the northeast and reflects the dominant structural controls to mineralization. These structures are considered to be important conduits that helped channel the mineralizing system. The combination of these geologic controls resulted in a northeast-elongated gold zone that measures approximately 1,800 m by 1,500 m.

Reserves

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Mining Methods

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Heavy Mobile Equipment

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Comminution

Crushers and Mills

Milling equipment has not been reported.

Processing

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Commodity Production

2024: On November 7, 2024, Heliostar acquired 100% of the El Castillo mine. The previous owner reported production data for the period January 1 to June 30, 2024. Heliostar submitted production data from the date of acquisition onward. Consequently, the 2024 production figures do not include four months (July–October).
CommodityUnits2024202320222021202020192018201720162015
Gold oz  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe65,14547,85759,00062,23579,751
Gold Equivalent oz  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe66,50948,31159,540
Silver oz  ....  Subscribe  ....  Subscribe
All production numbers are expressed as metal in doré.

Operational metrics

Metrics20222021202020192018201720162015
Stripping ratio  ....  Subscribe  ....  Subscribe  ....  Subscribe1.49 1.4 1.28 1.48 1.53
Ore tonnes mined  ....  Subscribe  ....  Subscribe  ....  Subscribe8,914 kt8,801 kt8,140 kt11,139 kt10,787,049 t
Waste  ....  Subscribe  ....  Subscribe  ....  Subscribe13,293 kt12,303 kt10,407 kt16,450 kt16,506,926 t
Total tonnes mined  ....  Subscribe  ....  Subscribe  ....  Subscribe22,207 kt21,104 kt18,547 kt27,589 kt27,293,975 t
Tonnes processed  ....  Subscribe  ....  Subscribe  ....  Subscribe8,867 kt8,840 kt8,164 kt
Daily mining rate  ....  Subscribe  ....  Subscribe  ....  Subscribe75 kt75 kt

Production Costs

CommodityUnits2023202220212020201920182017
Cash costs (sold) Gold USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 1,201 / oz **   1,016 / oz **   918 / oz **  
All-in sustaining costs (sold) Gold USD  ....  Subscribe  ....  Subscribe
** Net of By-Product.

Operating Costs

Currency2022
OP mining costs ($/t milled) USD  ....  Subscribe
Processing costs ($/t milled) USD  ....  Subscribe
G&A ($/t milled) USD  ....  Subscribe

Mine Financials

Units202220212020201920182017
Capital expenditures M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe 13.2   16.7   35.3  
Sustaining costs M USD  ....  Subscribe
Revenue M USD
Operating Income M USD
Gross profit M USD

Personnel

Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Aug 14, 2025
....................... Subscription required ....................... Subscription required Subscription required Aug 14, 2025
....................... Subscription required ....................... Subscription required Subscription required Aug 14, 2025

Workforce

EmployeesContractorsTotal WorkforceYear
...... Subscription required ...... Subscription required ...... Subscription required 2023
...... Subscription required ...... Subscription required ...... Subscription required 2022
...... Subscription required 2021
...... Subscription required 2020

Aerial view:

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