Saucillo (municipality) in the context of Municipalities of Chihuahua

The Naica Mine of the Mexican state of Chihuahua, is a lead, zinc and silver mine. Located in Naica in the municipality of Saucillo, the Naica Mine is owned by Industrias Peñoles, the world's largest silver producer. Caverns discovered during mining operations contain gigantic crystals of CaSO
₄ · 2 H
₂O (calcium sulfate dihydrate, gypsum, also sometimes called selenite). Peñoles announced in October 2015 that it was indefinitely suspending operations due to uncontrollable flooding at the Naica Mine.

The peak underground air temperature was 58°C (136°F) with 100% relative humidity, which rapidly exposed the visitors to hyperthermia hazard and caused breathing difficulties. Because of the heat, unprotected researchers could only stay up to 10 minutes inside the cave. Longer visits required the use of a special suit fitted with a cooling system (ice reserve in a backpack with cooled water recirculating in polymer tubes installed over all the body surface) and delivering fresh air for easier breathing. The visits were limited to about half an hour, the time needed to melt the ice reserves.

Naica is a town in the Mexican state of Chihuahua. It is located in the municipality of Saucillo. As of 2010, the town of Naica had a population of 4,938, up from 4,775 in the 2005 INEGI Census.

It is a mining town and the location of the renowned Naica Mine.