Treasure Vault Mine

The Treasure Vault mine is located in the upper part of Agua Caliente Canyon at an elevation of about 6,650 feet. It was discovered in 1899 and is owned by the Santa Rita Mining Co., of Tucson. It is on a fault fissure which strikes N. 75° E, and stands about vertical in altered porphyritic diorite which is intruded by granite porphyry on the southeast. The diorite is fine grained and consists of andesine, hornblende, and orthoclase, with a little quartz, biotite, and magnitite. Next to the fault it contains phenocrysts of hornblende three-fourths of an inch in maximum length.

The fissure filling consists principally of about 4 feet of hard sheared and altered diorite and quartz. It is separated from the walls by a thick selvage. The ore consists mainly chalcopyrite, galena, tetrahydride (gray copper), and sphalerite in association with quartz and some calcite. It occurs principally as pockets or stringers in the selvage and is only sparingly disseminated in the main filling. Some of it is said to average 18 per cent in copper and 100 ounces of silver and $29 of gold to the ton.

The mine is developed by two tunnels and a shaft. The tunnels are driven eastwards in a ridge that separates the head forks of Agua Caliente Canyon. They are 80 feet apart vertically. The lower tunnel is 135 feet long, and from it a 30-foot crosscut has been driven to the south. It makes considerable water, which is rapidly depositing limonite on the walls and floors. The shaft, which 100 feet deep, is located above the upper tunnel, which is 80 feet long and considerably caved.²

USGS 1981 map

Mineral Assessment plan¹

Alternate Names

None

Company

Santa Rita Mining company².

Mining District and Mines

Tyndall District

Arizona Geological Survey Mining data

https://data.azgs.arizona.edu/api/v1/collections/ADMM-1552440859503-200/TreasurevaultmineSantacruz52c.pdf

Location

31 DEG 42MIN 05SEC , W 11 ODEG 53MIN 28SEC

31.70111,-110.89111²

Mineral Products

Ag, Au, Pb, Zn ⁵

Geology

Mineralization involves a fault fissure which strikes N.75ºE. and stands about vertical in altered porphyritic diorite which is intruded by granite porphyry on the SE. The diorite is fine-grained and consists of andesine, hornblende, and orthoclase, with a little quartz, biotite, and magnetite. Next to the fault it contains phenocrysts of hornblende ¾ of an inch in maximum length.

The fissure filling consists principally of about 4 feet of hard sheared and altered diorite and quartz. It is separated from the walls by a thin selvage. The ore contains sulphides with quartz and some calcite. It occurs principally as pockets or stringers in the selvage and is only sparingly disseminated in the main filling. Some of it is reported to average 18% Cu and 100 oz. Ag/T and $20 Au/T (period values).¹

Type of Operation and Production

Workings include a shaft and 2 tunnels separated by 80 feet vertically. The tunnels are driven eastward in a ridge that separates the head forks of Agua Caliente Canyon. The lower tunnel is 135 feet long, and from it a 30 foot long crosscut has been driven to the south. The shaft is 100 feet deep and is located 100 feet above the upper tunnel, which is 80 feet long and caved.⁵

Photos

Upper Tunnel, 2/14/2022

Mineralization, 2/14/2022

Notes

Mine not in Keith. Route description in Tubac Nature Center book inadequate. Not in Tomasi book. Ref. 1 is best plan of the area

References

1. Mineral Appraisal of Coronado National Forest, Part 12, Santa Rita Mountains Unit, MLA11-94 (1994). SR 591-609
   http://repository.azgs.az.gov/sites/default/files/dlio/files/nid1813/usbm_mla_011-94.pdf
2. Mining in the Santa Rita and Patagonia Mountains of Arizona, F. C. Schrader, U.S. Department of Interior, 1915. Republished 2014 by Kerby Jackson.
3. Mike Bertram,
4. USGS Mineral Resources Data System - using WGS84 (https://mrdata.usgs.gov/mrds/map-commodity.html#home)
5. Index of Mining Properties in Santa Cruz County by Stanton B. Keith, bulletin 1991, Arizona Geological Survey, 1975
6. Arizona Geological Survey Mining data