GSA Annual Meeting in Denver, Colorado, USA - 2016

Paper No. 41-13
Presentation Time: 4:45 PM


PFANNKUCH, Hans-Olaf, Earth Sciences, University of Minnesota, Twin Cities, 310 Pillsbury Dr. S.E, Minneapolis, MN 55455,

Two silver mining districts, Freiberg, Saxony (FS), and the Comstock Lode (CL), are compared because of similarities in ore formation, parallel developments, and approximately equal cumulative production of silver over their lifetimes. FS approximate 220 million oz Ag over 800 years, The CL 192 million oz Ag, plus 8.25 million oz Au over 150 years. This combined with a historical analysis of legal and administrative practices allows to evaluate the mining laws in the two districts under consideration. FS is dominated by the collision of the African and European continental Plates, whereas the CL reacts to subduction processes along the western margin of the American Plate. For both the heat source driving the epithermal ore formation process are relatively young granitic intrusive complexes. Mineralization occurs within complex vein and fissure systems formed in response to tectonic stress fields: the variscan orogenic belt for FS, and Miocene eruptive activity for the CL. The results of hydrothermal ore formation are quarz-polymetal and carbonate silver sulfide associations for both districts. The CL also showed considerable amounts of Electrum, an Ag-Au alloy hence the high Au production in the CL.

German Mining Laws are based on the peculiarities of mining vein deposits in underground mines, a long history of exploitation, documented from the 12th c to the end of the 20th c, the oldest codification is from 1520, and the crown’s claim to underground resources and imposition of royalties. It also produced a strict and competent mining administration with a military hierarchic structure and police powers to issue withdrawal orders. Modern formulations are laid down in the General Mining Act for the Prussian States of 1865, and that of the Kingdom of Saxony in1868.

 In the western U.S. the self-government model of the California mining districts following the 1849 Gold Rush led to local, territorial and state legislation. The U.S. Mining Act of 1866 opened access to public lands, followed by the General Mining Act of 1872 signed into law by President U. S. Grant, to promote the development and settlement of publicly-owned lands in the western United States. However, federal safety and health legislation has not been very successful in protecting miner’s welfare or building an effective supervisory administrative structure.