The Sleeper deposit is located on the western foothills of the Sleeper range, in NW Nevada. It consists of an epithermal Au-Ag vein system controlled by an extension-related system of NW, NS and bed-parallel structures affecting stratified rocks.

Bed parallel structures related to the base of the rhyolite porphyry and the contact also act as control for Lower grade, disseminated mineralization.

NW structures act as discontinuities for the main N-S veins, as well as hosts for lower grade mineralization.

Four main types of gold mineralization are found within the Sleeper deposit and may represent a continuum as the system evolved from a high level, high sulphidation system dominated by intrusion related fluids and volatiles to a low sulphidation meteoric water dominant system (Corbett, 2005, Utterback, 2005, Histed, 2005). In this setting the paragenetic relationships of the differing mineralization styles are as follows:
* Early - quartz-pyrite-marcasite stockwork
* Intermediate - medium-grade, silica-pyrite marcasite cemented breccias localized on zones of structural weakness
* Late - high-grade, banded, quartz-adularia-electrum-(sericite) veins
* Post - alluvial gold-silver deposits in Pliocene gravels.

The Sleeper Gold Property is located in Desert Valley and the adjoining Slumbering Hills, Awakening Mining District, Humboldt County, Nevada, U.S.A. The Sleeper Project represents an opportunity as a mine that might be put back in to operation in the current gold price environment.

On March 26, 1986 AMAX poured its first gold bar from the Sleeper Gold Property The Sleeper operation was designed to treat oxide mineralization by both milling and heap leaching. There was no flotation circuit in the mill to recover gold bearing sulphides. The early pit mill feed was oxide material, but zones of sulphide mineralization were present in the pit. Reported gold production from the mill was 1,219,880 ounces and 438,609 ounces from heap leaching. Silver production totaled approximately 2.3 million ounces. The mine ceased production in 1996.

The Sleeper gold-silver deposit represents a project with a great deal of potential for being an important gold producer in Nevada once again.

Existing infrastructure at the Sleeper mine site will require upgrades for the projected large mine configuration, however, the basic components remain in place. The site is currently connected to the regional electrical grid, although substantial capacity upgrade would be required. Gravel road access, connecting the Sleeper mine site to paved, all weather Highways 140 and 95 is in place.

According to 2017 PEA The mining operation was assumed to employ conventional surface mining methods, with drill and blast rock breakage and truck and loader materials handling. According to 2017 PEA The mining operation was assumed to employ conventional surface mining methods, with drill and blast rock breakage and truck and loader materials handling.

Reclamation of the Sleeper Mine excavation included the placement of waste materials in the pit to isolate them from the air, and termination of the dewatering operations to allow the mine excavation to form a lake. In historic Sleeper dewatering, the majority of the water production came from an alluvial aquifer to the West of the mine excavation, and exposed in the west wall. The alluvium thins to the East and the topography gently rises along the hill slope above the Facilities Zone. This suggests that initial mining in the Facilities Zone should not require dewatering, and it has been assumed in the PEA that dewatering of the mine lake and re-establishment of the cone of depression around the surface mine can be spread over a 3 year period.

Mining of the Sleeper Zone requires the dewatering progress to reach the bottom of the historic mine, and requires dewatering of the mine waste and alluvium placed in the mine before the lake was allowed to form. This will required operation of a pump barge in the lake, re-creation of an interceptor well field to the West, and installation of dewatering wells in the waste material placed in the mine. Further expansion of the mining footprint would result in an increase in the required dewatering rate beyond that achieved in the historic Sleeper Mining.

The process facilities in the PEA were assumed to be standard cyanide heap leaching with carbon-in-column and ADR recovery plant. Heap leach material would be crushed to P80-3/4 inch (19 mm) using a primary and secondary crushing circuit. It was assumed that agglomeration would be required for the heap leach. For the heap leach only system, the crushing circuit would be sized for 30 ktpd throughput, with a stockpile of mineralized material developed to level the process rate.

The process facilities would produce a dore’ for direct sale to a regional refinery.