Mining Intelligence and News
Mexico

San Martin Mine

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Overview

Mine TypeUnderground
StatusActive
Commodities
  • Zinc
  • Copper
  • Silver
  • Lead
Mining Method
  • Mechanized Cut & Fill
Backfill type ... Lock
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SnapshotThe San Martin mining complex includes an underground mine and a flotation plant. The ore body contains lead, copper and zinc concentrates, with significant amounts of silver.
Related AssetIMMSA Operation

Owners

SourceSource
CompanyInterestOwnership
Grupo Mexico, S.A.B. de C.V. 88.87 % Indirect
Ownership Tree
Industrial Minera Mexico, S.A. de C.V. (together with its subsidiaries, the “IMMSA unit”) operates five underground mines that produce zinc, lead, copper, silver and gold, a coal mine and a zinc refinery.

IMMSA’s principal mining facilities include Charcas, Santa Barbara, San Martin, Santa Eulalia and Taxco.

Contractors

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Deposit type

  • Skarn
  • Vein / narrow vein
  • Intrusion related

Summary:

The Zn-Pb-Cu (- Ag ± Au) San Martín deposit in northwestern Zacatecas is one of the most economically important and largest skarns in México. Mineral associations in this deposit belong to the sulfide skarn type (with rather "classical" prograde and retrograde zones) and contain peripheral sub-epithermal to epithermal veins.

The San Martín skarn deposit was formed by a hydrothermal system associated with intrusion of the 46-m.y.-old Cerro de la Gloria quartz monzonite stock into the middle Cretaceous Cuesta del Cura limestone. The deposit is exploited by two major mines. The San Martín mine extracts Cu-Zn-Ag ore from veins and replacement bodies hosted by skarn, and the Sabinas mine extracts Zn-Pb-Ag (+ or - Au) ore from veins hosted by skarn and recrystallized limestone.

The vein system represents a series of intrusion-related fractures that roughly parallel the intrusive contact and that served as major conduits for the ore-forming fluids. Formation of both the vein system and sulfide-hosting in skarn probably was aided by volume loss during metasomatism. Other retrograde phases include wollastonite, vesuvianite, epidote, and chlorite; fluorite and calcite are common, and minor quartz is also present.

In the area of San Martín the Cretaceous Cuesta del Cura and Indidura Formations consist of limestones with thin interbeds of flint and shale. It has been observed in the lower levels of the San Martín mine, as well as in deep diamond holes of exploration, that the Cuesta del Cura Formation is approximately 900 m thick, presents changes such as: the presence of carbonaceous shale horizons and almost absence of flint. The Peña formation are intensely folded and faulted by the Laramide orogeny of (40 to 80 Ma), and discordantly covered by tertiary conglomerates, and by Rhyolites and Basalts of the Quaternary across the region.

The mineralization (replacements) inside the mantles/layers is variable and irregular. The length of the mineralization downdip reach 800-850 m and drilling has found that the mineralization is still open at depth, including areas where the mineralization extends for an additional 400 m. The
width of the mantles varies from few meters up to 50-60 m or more locally.

Mineralization is related to the retrograde alteration event overprinting the skarns. This retrograde event is thought to have occurred during the cooling of the porphyry intrusions is related to the retrograde alteration that accompanied the porphyry feldspathic quartz. Fluid inclusions show that sulfide mineralization was associated with high and low salinity fluids (46 %wt Na Cl eq. and 3-8 %wt NaCl eq. Gonzalez Partida, 1997) and temperatures between 250°-300°C, suggesting magmatic and meteoric sources respectively.

Alteration veins associated with porphyries include: early quartz-chalcopyrite-molybdenite, quartzchalcopyrite-arsenopyrite, fluorite-arsenopyrite with sphalerite and quartz, quartz-sericite pyrite veins. In the central part of the deposit there is a horizontal zone with respect to the intrusive contact, presenting Ag, Cu and As enrichment close to the contact. Sphalerite tends to be deposited later and in greater quantity than Fe, Mo, As, Cu, but it is strongly associated with marmatite and chalcopyrite. At depth, there is an increase of pyrrhotite and marmatite, with a horizontal zonation similar to that described. In the NE portion of the deposit structures concentric to the intrusive “Ibarra, Gallo – Gallina”, there is an increase of Pb, Zn, Ag in the Skarn.

Reserves

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Mining Methods

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Comminution

Crushers and Mills

Milling equipment has not been reported.

Processing

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Production

San Martin restarted operations during the second quarter of 2019.
CommodityProductUnits20232022202120202019
Lead Concentrate kt  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe2
Zinc Concentrate kt  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe14
Copper Concentrate kt  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe7.1
Zinc Metal in concentrate M lbs  ....  Subscribe  ....  Subscribe  ....  Subscribe13
Copper Metal in concentrate M lbs  ....  Subscribe  ....  Subscribe  ....  Subscribe2.9
Lead Metal in concentrate t  ....  Subscribe

Operational metrics

Metrics202320222021202020192018201720162015
Annual milling capacity  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe1,606 kt1,606 kt1,606 kt1,606 kt1,606 kt
Ore tonnes mined  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe653.7 kt
Tonnes milled  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe653.7 kt
Daily milling capacity  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe4,400 t4,400 t

Production Costs

Commodity production costs have not been reported.

Financials

Units2023202220212020201920182017
Book Value M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 71.3   20.4   28.2  

Heavy Mobile Equipment

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Personnel

Mine Management

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EmployeesYear
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Aerial view:

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