The Relationship of Structure, Alteration and Stratigraphy to Formation of the Deep Star Gold Deposit, Eureka County, Nevada

Abstract Deep Star is a compact, high-grade gold deposit located in the northern Carlin Trend, Eureka County, Nevada. The deposit is a significant underground gold producer for Newmont Gold Company with an average daily gold production of over 500 ounces. Deep surface exploration drill holes and the first year of close spaced underground definition drilling have defined an insitu undiluted resource of 1,428,329 ounces of gold averaging 0.949 oz/st. Although Deep Star shares some similarities with other disseminated gold deposit;, it is not a typical “Carlin-Type” and represents the structural end-member of this important class of deposits. The calc-silicate hornfels, skarn and intrusive host rocks are replaced by quartz, clay and gold-rich iron sulfides. Surface core holes and underground mapping supported by petrography and XRD data result in an interpretation of alteration assemblages that is related to grade. The geochemical signature is typical of “Carlin-Type” systems with the pathfinder elements arsenic, antimony, mercwy, and thallium, in addition to tungsten showing strong enrichment within the Deep Star ore body.