Maverick Springs project, Mud Springs Mining District, Elko County, Nevada, USAi

Regional Level Types
Maverick Springs project	Prospect
Mud Springs Mining District	Mining District
Elko County	County
Nevada	State
USA	Country

Structure: The Maverick Springs Range is an east-tilted fault block.

Commodity: Ore Materials: silver, gold

Deposit: Maverick Springs hosts a large silver-rich system that may be amenable to low unit cost bulk mining, similar to Carlin-type deposits. The Maverick Springs Project is underlain primarily by Upper Paleozoic calcareous and siliciclastic sediments covered by local basin-fill Tertiary volcanic rocks. Silty limestone and fine-grained calcareous clastic sediments of the Permian Rib Hill Formation are the dominant hosts to the silver-gold mineralization at Maverick Springs. These units generally strike to the north and dip to the east. Intrusives of felsic and intermediate composition have been intersected in drill holes and these are believed to be feeder systems for the Tertiary basin fill volcanics. The target mineralization does not crop out and has been delineated by programs of reverse circulation (RC) and diamond core (DD) drill holes. The target trends NNE and occurs as a gently-folded sub-horizontal zone, of dimensions of approximately 8,000 ft along strike and 2,500 ft wide. The zone of mineralization is approximately 200 ft thick and occurs at depths of 500 ft to 600 ft below surface. The silver-gold mineralization forms an arch-shaped zone of about 8,000 feet in length, with a width of 2,500 feet and a thickness of approximately 200 feet. Mineralization is open to the south and north-northwest. The Maverick Springs gold-silver property contains a large, flat-lying, Carlin-type system with gold-silver mineralization occurring in a zone 100 to 400 feet in thickness.

Deposit type: Sediment-hosted Au

Development: The property was first staked in 1986 by Artemis Exploration Company. Vista Gold Corp. acquired a lease on the property in December 2001 and subsequently formed a joint venture with the company in 2002. Silver Standard Resources, Inc. will own the silver resource while Vista Gold will own the gold resource. A seven-hole drill program, completed in November 2002, extended mineralization at least 2,000 feet north and 1,200 feet west of the area used for present resource calculations. Results of the 2002 program indicated that the mineralized system is not closed and the resources could be increased by a minimum of 50% with infill drilling. Higher-grade gold and silver mineralization were also encountered in this program. A 14-hole drill program, completed in October 2003, confirmed gold-silver mineralization within a zone measuring 2,500 feet by 2,000 feet. One step-out hole drilled 1,400 feet from the infill area intercepted anomalous gold mineralization, significantly expanding the potential for the project. Higher grade gold intercepts included 10 feet of gold mineralization in drill hole MR-147 assaying 0.134 opt gold. The project is subject to an option/joint venture earn-in agreement between Vista and Silver Standard Resources Inc. in which Silver Standard will acquire all silver mineralization hosted at Maverick Springs while Vista will retain all gold mineralization. In order to earn its interest, Silver Standard has paid US$300,000 in cash and will contribute an additional total of US$1.2 million toward exploration programs, land holding costs and option payments. A total of 159 holes have been drilled on the property, including 16 by the joint venture in 2003. Plans are to continue drilling to increase the resource, carry out further metallurgical studies to refine a recovery process and improve silver recoveries, and complete a scoping study to define the project economics. Drilling in 2003 improved the resource, and mineralization in holes 1,450 feet northwest and 2,000 feet south of the current resource body indicates good potential for further improvements to the resource.

Geology: The geology in the region is dominated by limestones and dolostones of the Permian Pennsylvanian Rib Hill Formation, limestones of the Permian Pequop Formation, and carbonate strata of the Permian Park City Group that were deposited along a continental margin. The sediments have been intruded locally by Cretaceous acidic to intermediate, biotitic igneous rocks and have been overlain by Tertiary rhyolites, Late Tertiary tuffs and sediments. The Carlin Trend marks a deep penetrating fault that separates relatively thick and stable continental crust to the east from a zone of thinned transitional crust to the west. Late Basin and Range faulting has left a northeast lineation to the topography and structural setting. This trend is offset by northwest trending structures that locally produce horsts of pre-Cenozoic units that are bounded to the northeast and southwest by Tertiary units.

Other Databases

Link to USGS MRDS:	10310453

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References