Gold mineralization in the main Bullfrog and North Bullfrog sub-districts is characterized as volcanic-hosted lowsulfidation epithermal type. Two styles of epithermal precious metal mineralization are present: 1) disseminated mineralization associated with sulfidation of iron in the volcanic host rocks; and 2) open-space filling quartz and/or carbonate veins, which are controlled by boiling. Pervasive quartz-adularia alteration of volcanic rocks is intimately associated with the disseminated mineralization and is an important ground preparation process for later vein forming events. Epithermal deposits form at shallow depth, from the surface to generally <2 kilometers. Temperatures of formation range between 150 to 300°C. Mineralization at NBP is typical of other low-sulfidation type gold systems in and around the Walker Lane trend such as: Bullfrog, Round Mountain, Rawhide, Aurora, Bodie and Comstock. These deposits commonly contain higher gold grades in vein and stockwork zones surrounded by zones of lower grade disseminated mineralization.

Corvus and previous operators exploring in the northern Bullfrog Hills have defined targets in areas of historic mines or prospects, as well as targets associated with high level epithermal alteration. Mineral Resources have been identified in several areas including: Jolly Jane, Sierra Blanca, YellowJacket, Air Track Hill, Air Track West, and Mayflower.

SIERRA BLANCA
The greater Sierra Blanca area includes th ........

The proposed mining method is conventional open pit mining. Mineralized material and waste are drilled and blasted, then loaded into 133-t payload haul trucks with ~ 20 m3 bucket capacity wheel loaders. The loading and haulage fleet would be supported by track dozers, motor graders, and water trucks. Waste would be hauled to Waste Rock Management Facilities (WRMF) near each pit. Mill resources would be hauled to the mill stockpile while runof-mine (ROM) resources would be hauled and placed directly on the heap leach pad. Mill tailings would be hauled and placed directly on the heap leach pad and mixed into the ROM material by dozing.

Pit slope designs have been based on an overall 50-degree inter-ramp angle. Preliminary pit slope geotechnical evaluations at YellowJacket (Knight Piésold, 2020) indicated a 58-degree inter-ramp angle with 80-degree bench faces would be stable. Preliminary pit slope geotechnical evaluations have been performed for Sierra Blanca/YellowJacket, for Mayflower (Engineering Analytics, 2013b) and for Jolly Jane (Engineering Analytics, 2013a).

The Waste Rock Management Facilities (WRMF) were based on the current mine plan, which predicts that approximately 206.8 Mt of waste rock will require placement and management. The waste rock would be placed in four WRMFs at an overall reclaimed slope of 3H:1V (18.4°). Approximately 91.5 Mt (YellowJacket, Sierra Blanca and Savage pits) would be placed in the East WRMF, approximately 80.9 Mt (S ........

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