EPITHERMAL GOLD DEPOSITS OVERVIEW
Epithermal gold deposits
Low sulfidation epithermal deposits in the Great Basin are very similar to deposits of this classification located throughout the world. Importantly, these near surface deposits have strong vertical zonation, and in the Great Basin these occurrences developed during very strong extension of the Earth's crust. This is significant for exploration because in a single project area one can often see different levels of the deposit due to faulting and changes in elevation. This exposure provides a tremendous advantage to those engaged in exploration activity and helps increase the success rate in Nevada.
Epithermal deposit types can be very high grade, but if not oxidized can be refractory. Nevada has the enormous benefit of infrastructure with multiple mills competing for feed to maintain efficient ore processing facilities. This is a tremendous advantage in Nevada because it allows small sulfide resources to become economic.
On a global scale, Nevada is home to some of the better quality epithermal deposits such as Round Mountain (RM in the lower right of the graph).
Two other examples of this type of deposit are the high grade Midas Mine in northern Nevada which produced over 2 Moz. Au through 2011. In 2013, the project was sold to Klondex with an expected endowment of over 4 million ounces of gold.
The other example is Sleeper, also located in Northern Nevada. When originally discovered, armed guards were employed to keep miners and robbers from pocketing the very high grade gold specimens. Sleeper is located along one of the Miocene-aged continental rifts and on the northern part of the F2 lineament. Renaissance Gold realized the importance of this projection and has located several projects along this trend. For detailed geology and references read the section on the F2 Mineral Belt.