Gold Deposits of the World
This case study was written by Ellen Dockery, a lower division undergraduate student who is not an earth science major, as part of the DLESE Community Services Project: Integrating Research in Education
. The pages in this case study reflect the personal views of the student author and not of MSU, SERC or the NSF.
Gold is one of the most economically important metals produced. As of 1991, more than 83% of gold consumption was for jewelry, 6% was used for medals and official coins, 6% was used in electronic equipment, 2.2% was used for dental materials, and 2.8% was consumed in a variety of industrial applications. These markets support an annual gold production of about 2,200 tons worth almost $25 billion ([Kesler, 1994] ). Globally, world gold production exceeded 2478 metric tons, or 79.667 million troy ounces in 2004 (Goldsheet Mining Directory - World Gold Production (more info) ).
Figure 1: Schematic illustration of geologic environments in which hydrothermal gold deposits form. Arrows show sources of water thought to have formed these deposits. Details
There are many types of gold deposits (more info) including epithermal vein deposits, intrusion-related breccia pipes, mesothermal turbidite- and greenstone-hosted deposits, contact deposits (skarns), replacement deposits, disseminated ores, placers, and Archean banded-iron formation deposits. The Homestake Mine near the Pine Ridge Reservation is a banded-iron formation deposit.
To further investigate gold deposits, follow the links below.
Resources containing information on gold deposits.
- Au-Ag-Te Vein Deposits. This resource is a part of the USGS document entitled "Preliminary Compilation of Descriptive Geoenvironmental Mineral Deposit Models". This chapter of the document describes gold, silver and tellurium vein deposits. Topics include a summary of relevant geologic, environmental, and geophysical information, geologic factors that influence potential environmental effects, and environmental signatures. (more info)
- Descriptive Model of Au-Ag-Te Veins. This USGS document provides a summary of characteristics of gold-silver-tellurium vein deposits. The data includes the geological environment of the deposits such as rock types, textures, age ranges, depositional environment, tectonic setting, and associated deposit types. The deposit description includes information about mineralogy, texture/structure, alteration, ore controls, and weathering. Also included is a list of examples where these vein deposits are found. (more info)
- Mineral Commodity Report 14: Gold. This Institute of Geological and Nuclear Sciences document provides information about gold mining and production. Topics include types of ores and minerals, properties, formation, uses, price, world production and consumption, ore processing and refining, production, reserves, and future trends. Also described are the different ways that gold deposits form including placer deposits, mesothermal deposits, banded iron formation deposits, epithermal gold-silver deposits, intrusion related breccia-hosted deposits, and by-product gold. Detailed examples from around the world are given for each type of gold deposit. (more info)
- Technical Resource Document: Extraction and Beneficiation of Ores and Minerals
Volume 2: Gold. This EPA document provides detailed information about the gold mining industry in terms of the wastes associated with gold mining and processing. The report briefly characterizes the geology of gold ores and the economics of the industry. Specific information from EPA site visits is included for the Brewer Mine, Colosseum Mine, Nerco Minerals Cripple Creek, and the Newmont Gold Company in Nevada. (more info)
- Mineral Resources, Economics and the Environment. [Kesler, 1994] This is a textbook that covers mineral resources, economics and the environment. (citation and description)
Gold, 6.8 cm high, Homestake Mine, Salmon River District, Siskiyou County. Details
Homestake Mine, located in western South Dakota, was created in 1876. Since the first production in 1878, almost 28 million troy ounces of gold have been extracted, worth 987 million dollars at present price causing the mine to be the most valuable in the United States.
Homestake Mine consists of several operations: an 8,000-foot deep underground mine, an open-pit mine, a mill, and a gold refinery. Operations turned to uranium mining in the 1950's, and the mine closed in 1989.
The gold deposits are a result of mineralization during the Precambrian period. The Homestake ore bodies are associated with banded iron formations and interlayered metavolcanic rocks. The schists of the Homestake Formation have experienced many stages of very tight folds. The ore bodies are central to zones of cross folding. Gold mineralization occurred in four stages of metamorphism and folding of the schists; the last stage occurred during intrusion of Tertiary dikes. The ore mineralization includes native gold, pyrite, arsenopyrite, pyrrhotite, with minor sphalerite and chalcopyrite. Mineralization occurs in vein and stockwork vein systems (Ridge, 1968 ).
To further investigate gold deposits at the Homestake mine, follow the links below.
Gold Deposits at the Homestake Mine
Resources containing information on the gold deposits at the Homestake mine.
- Ridge, 1968 This book documents the ore deposits of mines throughout the United States. For each mine, the history and production, geology, and tables are provided.
- Goldsheet Mining Directory - World Gold Production (more info) This site provides graphs that illustrate gold production for every five years from 1970 to 2004, and gold production by country. Links are also included to quarterly mine gold and silver production data, and yearly and cumulative gold and silver production.
For ideas on how to use these webpages in a classroom, a Study Guide