Maderposson Feldspar Occurrence
Keystone, South Dakota
The Maderposson Feldspar Occurrence is near Keystone, South Dakota. Historically the site has been associated with the Keystone Mining District which is now part of the Black Hills National Forest. The site was first discovered in 1941. Ore mineralization has been found at this location and the size of the deposit is estimated to be small, however the precise grade, tonnage, and extent of the mineralization are not known. There has been no production and little to no activity other than routine claim maintenance since the mineral discovery. The ore mined is composed of feldspar and beryl. The ore is found in dikes 4 meters (14 feet) in width. The mineralization at this location is from the Neoproterozoic era 1.00 to 0.54 billion years ago. The Black Hills of the Interior Plains characterize the geomorphology of the surrounding area.
Additional textual information about a site or mine.
Formal or informal mining district names.
UNPATENTED LODE CLAIM
A SINGLE SMALL EXPLORATION PIT
Characteristics of the ore body.
Geological materials at the site.
Physiographic area where the resource is found.
Other deposits in the same region.
Mountain Lion Mine
Soda Spar Lode
Big Smoke Group
Glendale Gp Beryllium Prospect
Glendale Tin Mine
Beryllium Feldspar Mine
* Mine bounds on map indicate the general area that a mine occupies. For an detailed map, refer to the overseeing BLM field office.
** The mine central point is based on an average of the mine's bounding box(es) and does not necessarily fall on the claim itself.
1 World-class significance is determined by total endowment of the contained commodity. This includes all past production and remaining reserves. Each commodity is considered separately and commodities cannot be combined to arrive at a significant size. The tonnage thresholds are from the mine model grade-tonnage studies. As of June 2008, many entries were classified as significant under less strict rules.
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