History
The La Venturosa silver mine was the site of underground mining operations for silver, lead and zinc from 1929–1936, 1948–1955 and 1990-2002. Mining was on a very small scale in the 1929-1936 period. More extensive mining took place in the latter two periods when both oxide and sulphide resources were exploited. Historically the mine produced 14.37moz silver, 32,550t lead (produced from 1.16mt mined oxide/sulphide material) and 43,530t zinc (from just sulphide material).
Mining has taken place over a strike length of just 1,250m and to a depth of only 250m (in places) and generally down to 100m. Mining ceased in 2002 due to flooding and low metal prices.
La Venturosa silver mine’s Princessa Shaft head frame and ore bin
Geology
The Namiquipa Project area is hosted by Tertiary age volcanics deposited in the Early to Middle Miocene. Namiquipa is one of a series of deposits hosted in the rocks of Northern Mexico’s Upper Volcanic Series and lies within the Ag-Pb-Zn epithermal belt. The mineral assemblages present and the associated hydrothermal alteration suggest that mineralisation is a low to intermediate sulfidation type. As such and considering the levels of silver at Namiquipa it is strongly analogous to the Fresnillo-style of polymetallic vein systems which are silver rich and gold poor. Fresnillo in Zacatecas State in north central Mexico is the world’s largest primary silver producer and Mexico’s second largest gold producer, with substantial lead and zinc credits.
