The Mission deposit is a porphyry copper skarn deposit located southwest of the city of Tucson in Pima County, Arizona. A series of Paleozoic sedimentary rocks.

Mineralization is a skarn-related copper porphyry deposit with seams and disseminations of copper carbonates and sulfides with minor zinc, lead and molybdenum minerals in a pyrometasomatic deposit in altered, complexly folded, and faulted Paleozoic limestone and Triassic sedimentary and volcanic formations intruded by Laramide and Tertiary intrusives. There is a thin secondary enrichment zone. The host rock unit is the Scherrer Formation.

The Mission Complex, an open-pit mine composed of the Mission, Eisenhower, Pima, Mineral Hill and South San Xavier properties and the nearby North San Xavier mine.

The treated ore is first crushed with a primary crusher to less than 20 centimeters and then crushed by a fine crushing plant to less than 16 millimeters using seven large vibrating screens and five crushers. To extract the ore from the tepetate, a combination of six circuits is used. The ground ore is pumped into one of the six flotation sections, where chalcopyrite and bomite are separated from the tepetate using the sulfide flotation process.