Donate now to keep mindat.org alive!Help mindat.org|Log In|Register|
Home PageMindat NewsThe Mindat ManualHistory of MindatCopyright StatusManagement TeamContact UsAdvertise on Mindat
Donate to MindatSponsor a PageSponsored PagesTop Available PagesMindat AdvertisersAdvertise on Mindat
The most common minerals on earthMineral PhotographyThe Elements and their Minerals
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
Keyword(s):
 
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
StatisticsThe ElementsMember ListBooks & MagazinesMineral MuseumsMineral Shows & EventsThe Mindat DirectoryDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day Gallery

Kofa District, Kofa Mts (S.H. Mts), Yuma Co., Arizona, USA

This page is currently not sponsored. Click here to sponsor this page.
 
 
A Au-Ag-Mn-W-Cu-Pb-F mining district located in T1-2S, R15-17W, in the southern/SW margin of the Kofa (S.H.) Mountains.

Mineralization within the district varies: (1) Spotty, but often high-grade, fine-grained, gold and silver mineralization in lensing quartz-calcite, brecciated rock, fissure veins cutting Cretaceous or Tertiary andesite and Mesozoic schist or slate. Minor copper and lead, and often considerable manganese and local fluorite. Wall rocks are strongly silicified; (2) Erratic and irregular manganese oxides in fracture zones in fragmented Cretaceous or Tertiary andesitic volcanics; and, (3) Spotty stringers, pods, and disseminated grains of scheelite, associated with quartz and iron oxides, in fracture zones in fragmented volcanics and schist.

Workings include 2 major mines and numerous prospects and small mines operated mainly in the late 1800's and early 1900's, with small, intermittent operations until 1954. Total estimated and recorded production of precious and base metals through 1974 would be some 779,500 tons of ore containing about 227,500 oz. Au, 103,700 oz. Ag, 3 tons of lead and one ton of copper. Over 1,000 oz. of placer gold were recovered. Manganese production was about 230 long tons of 27% Mn and about 94 short ton units of WO3. Total production s set at some $5,000,000 (period values).

Mineral List

Mineral list contains entries from the region specified including sub-localities


38 entries listed. 24 valid minerals.

Localities in this Region


The above list contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.

References

Blake, W.P. (1898) Distribution of metallic wealth in Arizona, in Report of the Governor of Arizona to the Secretary of the Interior for fiscal year ending June 30, 1898: Washington, D.C.: 19-86.

Jones, Jr., E.L. (1915), A Reconnaissance in the Kofa Mountains, Arizona, USGS Bull. 620: 164.

Thompson (1925), Arizona Mining Journal, Nov 1925: 9(12): 7.

Wilson, E.D. (1933) Geology and Mineral Deposits of Southern Yuma County, Arizona. Arizona Bureau of Mines Bulletin 134: 106-116;

A.I.M.E. Ore deposits of the western states (1933): 629.

Wilson, E.D., Cunningham, J.B., and Butler, G.M. (1934), Arizona Lode Gold Mines and Gold Mining (revised 1967), Arizona Bureau of Mines Bull. 137: 136-143.

Hewett, D.F. (1964), Veins of hypogene manganese oxide minerals in the southwestern United States, Economic Geology: 59: 1429-1472.

Keith, Stanton B. (1978) State of Arizona Bureau of Geology and Mineral Technology, Geological Survey Branch Bull. 192, Index of Mining Properties in Yuma County, Arizona: 154 (Table 4).

Hankins, D.D. (1984), Geologic setting of precious metals mineralization, King of Arizona district, Kofa Mountains, Yuma County, Arizona, San Diego State University M.S. thesis.

Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd. ed.: 225, 354.

Arizona Bureau of Mines file data.

Mineral and/or Locality  
Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2017, except where stated. Mindat.org relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: December 16, 2017 03:31:51 Page generated: January 21, 2015 02:10:21
Go to top of page