The Project’s vein deposits and the several associated veins within the mine are classified as volcanichosted epithermal base and precious metal vein type deposits. These deposits are sometimes referred to as intermediate sulfidation epithermal deposits typically characterized as high in silver and gold with or without base metals, associated with andesite volcanism and structurally controlled.

At Virginius, chalcedonic quartz and cockscomb textures have been observed and late euhedral calcite is found in places. Fluid inclusion studies suggest that boiling did not occur in the system.

Mineralization in the District is found primarily in sub-vertical fissure veins and is classified as a telescoped epithermal quartz vein type deposit. The veins are characterized by somewhat constrained vertical extents generally less than 1,000 ft) and a vertical zoning that favors precious metals in the upper levels grading into more base-metal rich mineralization with depth.

The mineralogy found at the Project is consistent with this type of mineralization and includes galena, sphalerite, tetrahedrite, polybasite, chalcopyrite, pyrite, arsenopyrite, marcasite as well as ferroan rhodonite, calcian-ferroan rhodochrosite, quartz and chlorite.

Virginius Vein System
The most historically productive vein system at the Project is the Virginius and its northern extension, which is sometimes referred to as the Monongahela Vein. Reference to the Virginius Vein in this report will include the Monongahela. Between 1875 and 1906, this vein system is estimated to have produced over 15 Moz of silver with “significant lead and gold credits”.

The Virginius Vein in the north-northwest heading from the Revenue Tunnel is continuous over long strike (11,700 ft based on mapping) and dip distances and historic stoping occurs extensively within a zone 3,600 ft along strike and 2,500 vertical ft. The vein is typically averages about 1.5 ft or less in width although it can be as thick as 3 ft. The largest intercept on the vein recorded in the database was approximately 7 ft. It is reported to be a galena bearing vein, with perhaps 2 ft of altered and weakly mineralized rock on either side. Wallrock beyond that total width is weakly altered to unaltered and makes for relatively stable walls for mining purposes. More recent exposure by OSMI shows the vein widths can be more variable and reach widths of over 2 ft to 3 ft on a local scale in exposures during test stopes mined in 2016. The average width of the vein within the current Mineral Resources is estimated at approximately 1.3 ft.

The vein strikes from N45°W (near the 3rd Level portal) to N25°W in the northwest part of the mine (Coxe, 1985). In the upper workings, the vein is nearly vertical or even steeply northeast dipping in places. The vein is reported to outcrop at surface but is difficult to trace with confidence due to the rugged nature of the topography, snow cover and talus. An interpreted trace of the vein at surface has been used by SRK during the geological modelling stage. An inflection occurs at approximately the 6th level where the vein establishes a southwest dip that persists to the lowest workings, varying from 45° to 75° but typically dipping 65° to 75° southwest.

The vein tends to be narrow but continuous and typically consists of quartz with variable amounts of galena, tetrahedrite, polybasite. sphalerite, chalcopyrite and pyrite. The mineralogy of the vein is remarkably constant over the very large vertical and horizontal span, although the silver grade is variable (Benham, 1980). Tetrahedrite and polybasite are the principal silver minerals in the mine and can reach concentrations of 15% silver by weight.

Yellow Rose Vein
Development of the Revenue Tunnel provided deep access to several veins in the District including the Yellow Rose Vein. The Yellow Rose is a northwest trending vein sub-parallel to the Virginius located more than 5,000 ft to the northeast. The Yellow Rose was mined to a minor extent in the early years following development of the Revenue Tunnel and was explored by Ranchers, Sunshine and Star Mines over a length of approximately 3,800 ft and a down dip extension of approximately 550 ft. The vein zone has been mapped over 16,000 ft at surface. Like the Virginius, the Yellow Rose Vein dips steeply to the southwest and consists of several anastomosing veins within a broader structural zone. The mineralogy of the Yellow Rose is similar to the Virginius, but in general it is a wider vein averaging approximately 3 ft. The widest vein intercept sampled is approximately 10 ft with the smallest intercept at 0.1 ft. The Yellow Rose is considered to be a lower grade target than Virginius.

Terrible Vein System
The Terrible Vein has an overall N60°W strike with a steep southwesterly dip. Historical production came from workings with portals on three levels spaced at about 100 vertical feet with adits along the south slopes of Governor Basin ranging in elevation from 12,050 to 12,270 ft. A 4th and 5th Level were reached by means of internal shafts, but stoping only occurred above the 4th Level or above 11,950 ft elevation. The Terrible Vein system is intersected by the Revenue Tunnel and followed by a drift to the northwest of the tunnel for 1,202 ft and to the southeast for 850 ft. The vein tends to be narrow but continuous and typically consists of quartz with variable amounts of galena, tetrahedrite, polybasite. sphalerite, chalcopyrite and pyrite, similarly to the Virginius Vein and other veins in the vicinity.

The resource models were constructed in such as way so as to model just the high grade vein structures without including mineralized material outside of the structures. In the Revenue area, the main vein and footwall veins have been modeled. The Terrible and Yellow Rose areas each have a single modeled vein. In the mining areas, the veins typically have dips around 70° but vary locally from approximately 50° to 85°.

The Virginius area 2000 level is accessed from the portal. Lower levels were historically accessed by a shaft/winze located at the 0 north/south point. Previous operators partially constructed two declines in 2014 to 2015 (Virginius South decline and Terrible decline) in an attempt to reach the 2210 level from the 2000 level; however, neither was completed. The main areas targeted for potential underground mining based on current drilling and geology. In the mining areas, the Virginius Vein widths typically range from 0.5 to 2.5 ft.

The Terrible area is located to the north of the Virginius area and has a bearing approximately 20° more westward than the Virginius area. Current identified mineralization is above the 2000 level. In the mining areas the Terrible Vein widths typically range from 0.5 to 1.5 ft.

The Yellow Rose area has been somewhat developed historically from the Revenue Virginius Tunnel. Though this vein had been mined historically with significant production at the Yellow Rose Mine, over 10,000 ft away along strike from current workings, records indicate that no significant production had occurred from the Revenue tunnel. The level nomenclature used in the Yellow Rose area is similar to that used for Revenue. The 0 north/south point is located where the Yellow Rose vein meets the main development coming from the portal. All identified mineralized areas are above the 2000 level. In the mining areas, the Yellow Rose Vein widths typically range from 1.0 to 5.0 ft.

Based on the orientation and width of the mineralization, review of historic mining, and available geotechnical information, a resue mining method is appropriate where waste rock serves as backfill as the stope is advanced in an overhand manner. This method is highly selective and allows for mining narrow widths down to 0.5 ft. There is a significant amount of high grade Ag ore carried in narrow vein structures.

More specifically, the resue mining method is explained as follows:

A stope block is identified having minimum approximate dimensions of approximately 500 to 1,000 ft along strike and up to 300 ft in height. Stope block widths vary according to the mineralization. Typically, an off-ore access drift is developed on the footwall along the length of the stope. Two-compartment raises known as cribbed manways, are developed on each end of the stope from the level below providing access to any level of the stope. In the center of the stope a three ompartment service raise with a manway, ore pass, and equipment slide is constructed as the primary access. Each raise will have utilities run up into the stope so that miners can pull water or air from either side of the stope or from the middle service raise.

The bottom portion of the stope, approximately 25 ft in height, is left in a pillar (sill pillar), which is partially recoverable from the stope below. A 3.5 ft wide scram drift is developed along the length of the stope above the pillar. Finger raises with ore chutes at the access level connect the scram drift to the development access below and are used to remove ore material from the stopes. Once the scram and finger raises are established, upholes are drilled into the vein, both in ore and waste. Ore material is blasted first and then removed using slushers operating on a conveyor belt muck sheet to the finger raise for transportation to the process facility. Prior to blasting the waste material, cribbed timbers are placed to raise the ore passes (similarly to the manway and service raises) to the next level. Waste material is then blasted and left in the stope as fill material for accessing the next level of the stope. Where necessary, additional waste can be drilled and blasted to ensure fill volume in the stope is appropriate as mining progresses.

The process plant consists of the following principal process areas (each described in more detail in the subsequent sub-sections). While the detailed design of the process upgrade completed by Barr in 2017 was for an instantaneous feed to the rod mill of 13.0 mt/h (14.4 st/h), values in this report have been adjusted for an annualized design throughput of 91,390 st/y.
• ROM Storage and Crushing;
• Primary Rod Milling;
• Secondary Ball Milling;
• Bulk Lead Rougher Flotation;
• Zinc Rougher Flotation;
• Lead Cleaner Flotation;
• Zinc Cleaner Flotation;
• Lead Concentration Thickening and Filtration;
• Zinc Concentration Thickening and Filtration;
• Tailings Thickening and Filtration;
• Reagent Mixing, Storage and Distribution;
• Raw Water Storage and Distribution;
• Process Water Storage and Distribution; and
• HP and LP Air Services.

The primary products from the process plant include:
• A lead conce ........