Localities - Ojuela Mine, Mapimí, Durango, Mexico

The Ojuela mine is located northeast of Mapimí in the state of Durango, on the edge of the Bolsón de Mapimí, and is associated with carbonate host rocks of an arid highland region. The deposit was discovered around 1598 and mining operations began in the early 17th century; the main period of operation was in the 19th century.

The mine was operated by various Spanish, British, and Mexican companies, including the Mapimí Mining Company. The mine workings consisted of an extensive system of shafts and tunnels extending over several hundred meters in elevation; access was provided in 1892 by a large suspension bridge.

Geologically, it is a polymetallic hydrothermal ore deposit with metasomatic ore replacement in limestone and dolomite rocks, as well as vein-like mineralization along faults. Pronounced oxidation and supergene zones characterize the upper part of the deposit.

The mine primarily extracted lead and zinc ores (galena, sphalerite) with silver inclusions, and to a lesser extent, copper. It is internationally renowned for its wide variety of secondary minerals, including adamite, legrandite, smithsonite, hemimorphite, cerussite, and anglesite.

Mining ceased at the beginning of the 20th century for economic reasons. Today the mine is closed; limited archaeological finds exist in spoil heaps, and underground access is largely prohibited.