Chief Mine, Empire District

Mining District and Mines

Empire District.

AKA: Hiltano group, State of Maine

Location

18S 17E NE¼ 18⁷

Owners

Dick & Sullivan, Hilton, U. S. Magnetite⁷

Mineral Products

Pb, Zn, Ag, Cu-, Au-⁷

Geology

Irregular replacement orebodies and chimneys containing cerrusite, anglesite, smithsonite, malachite, aurichalcite, galena, plumbojarsite, and azurite in a gangue of calcite, aragonite, siderite, and quartz in badly faulted Permian limestone beds, overlying a Laramide dioritic dike and associated with a rhyolite porphyry dike. Orebodies controlled by intersecting fissures and faults.⁷

Light-colored rhyoliticand alkalitic lava and tuff.

Silitic volcanics - tufff, volcanic conglomerate, and brecia.

Hematite, limonite, silexite

Complex system of fissure veins including NW-trending Flux veinand general structure common to regional formations is a sheeting which dips

Alum Gulch Fault Block

N60E trending silexite dyke

Volcanics locally much altered to quartz, sericite, epidote, pyrite, carbonate⁵

Type of Operation and Production

Incline shaft operations. Worked intermittenly from early 1900’s to 1963, producing over 500 tons of ore averaging about 25% Pb, 8 oz. Ag/T, 0.5% Cu, and minor gold and zinc.⁷

Area of mine which has been reworked.

References

1. Mindat.org - small amount of data
2. MRDS records: 31.44904, -110.78538
3. Mineral Appraisal of Coronado National Forest, Part 7 - Patagonia Mountains - Canelo Hills Unit by Mark Chatman, 1994, No entry
4. Arizona Department of Mines report: http://docs.azgs.az.gov/OnlineAccessMineFiles/C-F/ChiefgroupSantacruz112.pdf
5. The Mineral Deposits of the Santa Rita and Patagonia Mountains by Frank C. Schrader, 1914 - p. 251
6. Index of Mining Properties in Santa Cruz County by Stanton B. Keith, bulletin 1991, Arizona Geological Survey, 1975
7. Index of Mining Properties in Pima County by Stanton B. Keith, bulletin 189, Arizona Geological Survey, 1974