The San Martín Mine was operated by Grupo México until mid-2007 when it closed due to labour unrest. It reopened in mid-2018 after metal prices rebounded and labour issues were resolved. The San Martín Mine exploits the southeastern part of the same skarn orebody actively exploited by Industrias Peñoles through their Sabinas Mine. The property boundary between the two companies dovetails irregularly through the western part of the skarn body, and the mineralogy is essentially identical on both sides of the boundary, so there is no material geological difference between the two mines. However, the San Martín Mine got started going deep 25 years before Sabinas and has operated at much deeper levels at any given time. This means minerals characteristic of the upper levels of the system (apophyllite, stilbite, and stibnite) came out of Sabinas 20 years or so after they came out of San Martín. While San Martín was closed (2007-2018), all specimens from the district came from Sabinas.

Most of the minerals seen from San Martín are primary species, but oxidation affected the deposit from the surface to about the 150 m level. Most of the oxides were mined out long ago, but small prospects and high-grade pits dot the surface, and oxide minerals can be found there. These oxide minerals reflect their sulphide precursors, with chrysocolla and azurite seen around the peripheries and adamite and conichalcite and cerussite towards the intrusive contact. In 2025-2026, small numbers of wulfenite specimens were found.

Prior to 1948, the San Martín Mine exploited narrow high-grade veins that cut the skarn and extended beyond it. These structures continue to deepen and appear to coincide with the principal feeders for the skarn/sulphide mineralisation stage. At great depth (below the 18th level), these structures contain massive sulphide mineralisation consisting of almost pure chalcopyrite and bornite, locally laced by late native silver. They can also be traced upwards to the top of Cerro La Gloria, where they show classic epithermal brecciation and mineralisation textures such as quartz pseudomorphs after bladed calcite. Some of these mines produced some of the richest silver ores ever produced in Mexico outside of Batopilas, and the district was recognised as the source of the wealth that allowed Mexico to free itself from Spanish rule in the early 1800s.

Many specimens from the Sabinas Mine and probably San Martín as well bear an erroneous "Noria Mine" or "La Noria de San Pantaleon" label, often from Blue Sky Minerals, which brought out a lot of material from the district in the 90s. Specimens younger than 1975 cannot have come from La Noria, and since the Sabinas shaft and ramp lie over a kilometre from the Noria shaft and the Sabinas mine workings have never been accessible through the Noria workings, there is no justification for labelling them as Noria. La Noria de San Pantaleon was the small mine colony at the headframe of the Noria Mine. This settlement shows on government maps but was largely abandoned by the 1980s. In 1999 there were only one or two habitable buildings left. If one desires a nearby community for location attribution, "San Martín", which is the miners' town of several hundred people 2 kilometres from the Sabinas installations, is a better choice than San Pantaleon. (Revised 2026)

Other Regions, Features and Areas containing this locality

References