Mining Intelligence and News

San Martin Mine

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Mine TypeUnderground
StatusCare and Maintenance
  • Silver
  • Gold
Mining Method
  • Cut & Fill
Backfill type ... Lock
Production Start... Lock
SnapshotThe San Martin mine operated until July 2019 when it was placed on temporary suspension due to increased insecurity in the area caused by organized criminal groups and safety concerns for the First Majestic's workforce. the First Majestic removing all of its remaining workforce from the area in 2021 and the mine and plant are currently occupied and under the de facto control of an organized criminal group.

The First Majestic has repeatedly requested all applicable governmental authorities to take action to secure the area but, to date, the Mexican government has failed to take any such action and the Company's own efforts have been unsuccessful. Due to this situation the First Majestic has been unable to carry out proper care and maintenance of the mine and plant and tailings storage facilities and the First Majestic has limited information as to the current state of repair at the mine, including the tailing storage facility.


First Majestic Silver Corp. 100 % Indirect
Minera El  Pilón S.A. de C.V. (operator) 100 % Direct
The San Martín Silver Mine owned by the First Majestic Silver Corp's wholly owned indirect subsidiary, Minera El Pilón, S.A. de C.V.

Deposit type

  • Epithermal
  • Vein / narrow vein


The San Martín mine is considered to be a typical example of a low sulfidation epithermal deposit, and the geological model used for exploration as well as the mineral resource estimation is that of a low sulfidation vein type deposit. Epithermal deposits form at shallow depths in volcanic-hydrothermal and geothermal environments, typically at temperatures between 160°C and 300°C (White and Hedenquist, 1995). They define a spectrum with two end members, low and high sulfidation (Hedenquist et al., 1998).

Fluid inclusion microthermometry carried out in sphalerite, quartz and fluorite for the Zuloaga vein indicates average homogenization temperatures and salinities of 297°C and 4.1 wt% NaCl eq (Albinson et al., 2001). The homogenization temperatures and low salinities (diluted fluids) in the Zuloaga vein and the alteration-mineral assemblage (interstratified illite/smectite in Zuloaga and Rosario) are consistent with low sulfidation vein-type deposits described by White and Hedenquist (1995) and Hedenquist et al. (1998). The presence of epidote in Zuloaga, Rosario and Other Veins is also consistent with the homogenization temperatures around 300°C determined for Zuloaga by Albinson et al (2001).

In the opinion of the QP, the deposits in the San Martín mine area are considered to be examples of low sulfidation epithermal deposits. The Miocene age of the mineralization and its association with volcanic rocks of the Upper Volcanic Series is also found for other low sulfidation deposits in Mexico. Additionally, structural-textural features, such as hydrothermal breccias cemented by quartz-calcite, stockworks and cymoid loops, are also common in other low sulfidation epithermal vein-type deposits in Mexico.

Mineralization in the San Martín mine occurs in east–west, northwest–southeast, northeast southwest and north–south fault structures in the form of stockworks, sheeted veinlets, veins, and breccias. The veins in the San Martín mine can be described as fault veins or mineralized faults, given that the amount of gangue minerals such as quartz, calcite, fluorite, epidote, ankerite and adularia are very limited, i.e., they do not form massive or banded veins typical of open space-filling veins.



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Silver Metal in doré oz 555,5951,746,1391,822,2971,902,9632,296,965
Gold Metal in doré oz 1,6115,2266,7974,1345,745
Silver Equivalent Metal in doré oz 692,5412,169,3382,322,8352,209,0352,722,059

Operational metrics

Daily milling capacity 1,300 t1,300 t1,300 t1,300 t1,300 t
Ore tonnes mined 101,362 t284,656 t
Waste 113,264 t
Tonnes milled 101,362 t284,656 t278,252 t297,802 t349,193 t
Daily mining capacity 900 t
Daily milling rate 816 t1,000 t

Production Costs

Credits (by-product) Silver USD -4.58 / oz  
Cash costs Silver USD 10.7 / oz  
Total cash costs Silver USD 17.2 / oz   13.2 / oz   11.3 / oz  
Total cash costs Silver USD 13.5 / oz **   9.42 / oz **   6.69 / oz **  
All-in sustaining costs (AISC) Silver USD 18.7 / oz **   12.3 / oz **   9.06 / oz **  
** Net of By-Product.

Operating Costs

UG mining costs ($/t milled) USD 25.1  20.9  
Processing costs ($/t milled) USD  ....  Subscribe  ....  Subscribe
Total operating costs ($/t milled) USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe


Sustaining costs M USD 2.1   4.5   3.6  
Capital expenditures M USD 4.9   9.3   10.8  
Revenue M USD 10.6   33.9   39.7  
Operating Income M USD -9.6   2.4   12.1  

Heavy Mobile Equipment


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Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Apr 29, 2024

EmployeesContractorsTotal WorkforceYear
...... Subscription required ...... Subscription required ...... Subscription required 2021
...... Subscription required ...... Subscription required ...... Subscription required 2019
...... Subscription required ...... Subscription required ...... Subscription required 2013


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