Mining Intelligence and News
Mexico

Mulatos Operation

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Overview

Mine TypeOpen Pit
StatusActive
Commodities
  • Gold
  • Silver
Mining Method
  • Truck & Shovel / Loader
Production Start... Lock
Mine Life... Lock
SnapshotMining operations at the Mulatos Mine consist of the Mulatos open pit complex and the Yaqui Grande open pit and heap leach facility.

With the completion of mining at the Mulatos open pit in Q2 of 2023 the company is currently mining from only the La Yaqui Grande open pit.

Stacking of remaining stockpiles at Mulatos was completed in the fourth quarter and residual leaching commenced in December 2023. The operation is expected to benefit from ongoing gold production at decreasing rates in 2024 through residual leaching of the leach pad. Residual leaching of the Mulatos heap leach is expected to continue into 2025.

The increase in high-grade Mineral Reserves at Puerto Del Aire(PDA) is being incorporated into a development plan to be completed during the first quarter of 2024 which is expected to outline a significant mine life extension at Mulatos.
Related AssetsLa Yaqui Grande Mine, Mulatos Mine

Owners

SourceSource
CompanyInterestOwnership
Alamos Gold Inc. 100 % Indirect
Minas de Oro Nacional S.A. de C.V. (operator) 100 % Direct
The Mulatos group of concessions covers the Mulatos deposit and satellite gold systems known as Cerro Pelon, La Yaqui, El Carricito, El Halcon, Las Carboneras, El Jaspe, Puebla, Los Bajios, and La Dura. Mineral rights for all concessions comprising the Mulatos Group of Concessions are controlled by Minas de Oro Nacional, the Mexican subsidiary of Alamos.

Contractors

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Deposit type

  • Epithermal
  • Breccia pipe / Stockwork

Summary:

The Mulatos mineral deposits are large epithermal, high-sulfidation, disseminated gold deposits. Gold mineralization is closely associated with silicic alteration within extensive areas of argillic and advanced argillic alteration. The Mulatos deposit proper is composed of the contiguous Estrella, El Salto, Mina Vieja, and Puerto del Aire Mineral Resource areas. The Escondida deposit is the faulted extension of the Mina Vieja and El Salto sub-deposits and is believed to be continuous to the northeast with the Gap, El Victor, and San Carlos mineralized areas. Although zones are often bounded by post-mineral faults, together they form a trend of 2.7 km of gold mineralization starting at the north end of the Estrella pit to the San Carlos deposit.

Within the larger Mulatos Group of Concessions, and generally within 20 km from the Mulatos deposit, geologically similar high sulfidation gold deposits, occurrences, or prospects are known.

Gold deposits of the Mulatos district are considered to be high sulphidation-state epithermal systems. Epithermal precious metal systems may be classified as high, intermediate, and low sulphidation styles. They are characterized by the sulphidation state of the hypogene sulphide mineral assemblage, and show general relations in volcano-tectonic setting, precious and base metal content, igneous rock association, proximal hypogene alteration, and sulphide abundance. Ore in all occurrences is of the type formed under epizonal conditions, that is, generally within 2 km of the paleo-surface.

Precious metal mineralization at Mulatos is associated with intense silicic alteration (mostly vuggy silica), advanced argillic alteration, and the presence of hydrothermal breccias. The original protolith (dacite porphyry flow/tuff, coarse-grained volcaniclastic rocks, breccias), as indicated by surface mapping and core drilling, may have contained in the order of 2-3% sulphide as pyrite with various amounts of enargite and tetrahedrite. The principal gold-bearing host rock is interpreted as favoured for mineralization due to relatively high primary porosity and its intense fracturing.

Gold mineralization within the Mulatos deposit occurs primarily within areas of pervasive silicic alteration of the volcanic host rocks, and to a lesser extent, within advanced argillic alteration assemblages proximal to silicic alteration. The gold-bearing advanced argillic zones are dominated by pyrophyllite or dickite alteration. Silicic rocks host approximately 80% of the contained gold within the deposit. There are three main mineralization assemblages. From oldest to youngest they are: 1) quartz + pyrite + pyrophyllite + gold; 2) quartz + pyrite + kaolinite + gold + enargite; 3) kaolinite + barite + gold. Free gold is commonly found in hematite-filled fractures. Gold also occurs in pyrite, as gold/silver telluride minerals, and possibly as a solid solution in some copper sulphide minerals. Supergene oxidation and perhaps remobilization and secondary enrichment of gold have been ongoing since the post-mineral volcanic cover was removed (in those specific deposits where it has been removed).

Mineralization of the La Yaqui Grande High-Sulfidation Epithermal Deposit
La Yaqui Grande (LYG) is a new discovery 9 km southwest of the Mulatos Mine. LYG is a high- sulfidation epithermal Au-Ag deposit situated on the northern end of the Mexican Au-Ag belt along the southern arm of the Laramide porphyry belt in the Sierra Madre Occidental volcanic province.

Gold mineralization is hosted by residual vuggy quartz and quartz-dickite-alunite advanced alteration in the upper Mulatos Dacite. This silicic alteration formed by intense hypogene acidic leaching of porphyritic rocks, below a cap of barren massive silica. 40Ar/39Ar age determinations of coarse crystalline hydrothermal alunite from LYG yielded a plateau age of 57.34±0.09 Ma, and a fine-grained alunite matrixsupported silica breccia returned total gas age of 55.20±0.06 Ma. Hydrothermal alunite is common at LYG, in contrast to pyrophyllite-dominant alteration at the Mulatos Mine.

Puerto del Aire
The Puerto del Aire sulphide hosted gold deposit currently consists of four zones: PDA, PDA Extension, GAP-Victor and Estrella. The deposit is located between the current Mulatos deposit and the past producing Victor Deposit. Of the four zones, PDA, is the largest, hosting 78% of the current mineral resource.

The zones are generally stratiform, dipping gently to the north-east. PDA has a strike length of approximately 1100 m and has a pinch-and-swell geometry due primary and post mineralization faulting. The zone thickness ranges from 20 m to over 120 m. GAP – Victor has a strike length of approximately 850 m and thickness ranges from 15 to 50 m.

Lithologically, the mineralization at PDA is hosted in either a porphyritic dacite unit or a phreatic breccia below the Tplt rhyolite. Alteration consists of vuggy silica in the center and advanced argillic alteration at the borders of the system. Hydrothermal breccias are centered around faults, which are interpreted as the conduits for gold.

Gold mineralization is associated with multiple alteration styles, including:
• Vuggy silica and advanced argillic alteration with dickite filling vugs and fractures,
• Advanced argillic alteration in hydrothermal breccia with a silica-dickite cement, and strong dickite in fractures, and
• Advanced argillic alteration with dickite crystals and dickite in fractures.

The best mineralization is also associated with barite infilling vugs and fractures.

Reserves

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Mining Methods

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Comminution

Crushers and Mills

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Processing

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Production

CommodityUnits2024202320222021202020192018201720162015
Gold koz  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe142 176 160 154 140 
All production numbers are expressed as metal in doré. ^ Guidance / Forecast.

Operational metrics

Metrics202320222021202020192018201720162015
Daily processing rate  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe20,000 t18,900 t19,000 t18,300 t17,500 t
Ore tonnes mined  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe7,166,679 t8,527,983 t8,586,634 t7,157,494 t7,011,714 t
Waste  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe7,095,650 t6,037,427 t6,443,971 t9,184,468 t7,678,864 t
Total tonnes mined  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe14,262,329 t17,316,741 t15,666,866 t16,518,596 t14,690,578 t
Tonnes processed  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe7,289,811 t6,886,855 t6,929,483 t6,686,462 t6,371,053 t
Stripping / waste ratio  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe0.73 0.71 0.76 1.31 1.12

Production Costs

CommodityUnits20242023202220212020201920182017
Total cash costs (sold) Gold USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 784 / oz **   786 / oz **   775 / oz **  
All-in sustaining costs (sold) Gold USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 868 / oz **   855 / oz **   835 / oz **  
^ Guidance / Forecast.
** Net of By-Product.

Financials

Units20242023202220212020201920182017
Capital expenditures (planned) M USD  ....  Subscribe
Growth Capital M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 46,400   25.2   25.9  
Sustaining costs M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 6.5   7.2   5.5  
Capital expenditures M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 54.2   35.3   31.4  
Revenue M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 194.4   223.3   201.4  
Operating Income M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 51.9   42.7   41.7  
Operating Cash Flow M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 41.5   71   64.3  

Heavy Mobile Equipment

Fleet data has not been reported.

Personnel

Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Jul 18, 2024
....................... Subscription required ....................... Subscription required Subscription required Jul 18, 2024
....................... Subscription required ....................... Subscription required Subscription required Jul 18, 2024
....................... Subscription required ....................... Subscription required Subscription required Jul 18, 2024
....................... Subscription required ....................... Subscription required Subscription required Jul 18, 2024
....................... Subscription required ....................... Subscription required Subscription required Jul 20, 2024

EmployeesContractorsTotal WorkforceYear
...... Subscription required ...... Subscription required ...... Subscription required 2023
...... Subscription required ...... Subscription required ...... Subscription required 2021
...... Subscription required ...... Subscription required ...... Subscription required 2020
...... Subscription required ...... Subscription required ...... Subscription required 2019
...... Subscription required 2018
...... Subscription required 2017

Aerial view:

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