The metals of primary interest at the Property are gold and silver. These metals are intimately associated with lead, zinc and copper in various forms and concentrations throughout the mineralizing system. Gold and silver enriched mineralization is developed within a northwest trending structural corridor, which is interpreted to have focused fluid flow away from weak porphyry centres related to a Late Cretaceous stock in the southeastern corner of the Property. Several of the mineralized structural zones are continuously mineralized for strike lengths of up to 2,400 m, and at least one of the structures is mineralized to a depth of 520 m down-dip from the current geographic surface. The mineralized structures remain open to extension along strike and down-dip.

Fluid inclusion work reveals that the veins formed at shallow depths (<1 km) and have low to intermediate sulfidation epithermal fluid characteristics (Main, 2015). Textures and mineralogy observed at the Property share a number of similarities with Carbonate Base Metal (CBM) deposits (Tarswell and Turner, 2013).

CBM deposits are a recently recognized sub-class of epithermal deposits that encompass a family of similar deposits located around the world. CBM deposits have mainly been discovered around the Pacific Rim and include multi-million ounce gold deposits such as Porgera (New Guinea), Buritica (Colombia) and Kelian (Indonesia).

The CBM class of deposits has yet to be identified elsewhere in the Yukon, but some researchers have recognized that mineralization on the Property has some of the characteristics of mineralization now categorized as CBM deposits (ex. Smuk, 1999). Given the limited academic research on the Property and the absence of significant syn-mineralization carbonate, more studies need to be undertaken.

The Property lies within the northern part of the Mount Nansen Gold Camp (MNGC), a northwest trending structural belt that hosts more than 30 known mineral occurrences, several of which are categorized as deposits and have produced historically and as recently as 1999 (Hart and Langdon, 1997).

Mineralization within the MNGC is dominated by gold-silver rich structures associated with a zonation model ranging from weak porphyry copper molybdenum centres, outward to transitional anastomosing sheeted veins, and lastly to more cohesive and continuous base and precious metal veins. The age of the mineralizing events within the MNGC is now considered to be Late Cretaceous.

The main mineralized structural zones range from 1 to 100 m wide and are usually associated with feldspar porphyry dykes. Mineralization occurs within veins, sheeted veinlets and some tabular breccia bodies. The host granodiorite exhibits pervasive weak argillic alteration immediately adjacent to, and up to 30 m peripherally from, them. Sericitization and potassic alteration are developed directly adjacent to hydrothermal channel ways. The granodiorite is magnetite bearing except where the magnetite has been replaced by sulphide minerals around and within mineralized structures.

Depth of surface oxidation ranges from 5 to 100 m below surface, depending on fracture intensity, the type of mineralization and local geomorphology. The deepest weathering occurs in wide, pyritic veins located along ridge tops or on south facing slopes.

Detailed evaluation of oriented drill core and measurements taken from trench exposures has identified two main structural orientations that control mineralization. The primary structural set strikes between 135° and 155° and dips 60° to 80° to the southwest. The secondary mineralized trend strikes between 110° and 130° and dips 60° to 70° to the south. The secondary structures may represent either Riedel shears of the primary structural set or a separate structural event altogether. The best gold mineralization is sometimes localized in areas where the two structural trends converge. The plunge of these structural intersections is towards the southeast.

Quartz is the dominant gangue mineral in veins in Work Area 2. It occurs in a variety of textures including chalcedonic, comb, banded, speckled and vuggy. Smoky quartz is the most common colour variation, but milky and clear quartz are locally abundant. Carbonate occurs mainly as ankerite and rhodochrosite and typically ranges between 5 and 20% of the veins by volume.

Breccias form tabular bodies consisting of heterolithic wallrock clasts, which include granodiorite and various volcanic or sub-volcanic lithologies. Matrices are enriched with fine grained, disseminated to blebby pyrite, arsenopyrite, sphalerite and galena. Breccias are mostly observed within drill core from the Klaza zone where they range up to 2 m in width.

Mineralization within most structures is interpreted to be spatially and genetically related to porphyry dykes, which strike northwesterly and dip steeply to moderately toward the south. The dykes pinch and swell in three dimensions and are usually unmineralized. Some faults identified to date likely post-date emplacement of the dykes as they are occasionally cut by mineralized veins.

The known surface mineralization on the Dade claims (Work Area 3) is hosted in two, sinusoidal zones of quartz veining and stockwork (V1 and V2) striking about 040° and dipping 60°-75° north, hosted in coarse-grained hornblende-quartz granodiorite to diorite gneiss (Burrell, 2013). V1 (formerly, the Grizzly Vein) and V2 are epithermal quartz vein and stockwork zones that exhibit pervasive silicification and moderate to strong clay alteration. In 2011, trenching exposed V1 over widths of 9 to 20 m along a 175 m strike length and V2 over widths of 2 to 12 m along a 125 m strike length (Burrell, 2013). The veins comprise white to grey quartz with boxwork limonite and locally 1-3% disseminated arsenopyrite and pyrite.

Mineral Resources occur as a selection of vein systems contained in two distinct zones–Klaza and BRX. Each zone can be further broken down by relative location: Western, Central and Eastern. At Central Klaza and BRX potential exists in the eastern extremity for underground mining. The eastern extent is naturally separated from the Central zone by low grade mineralization. The eastern extent of the Central Klaza zone will be accessed from the Klaza pit and at Central BRX zone via underground level development.

The Klaza and BRX zones lend themselves to open pit mining as the mineralized veins are located close to surface. The surrounding topography is moderately steep with sufficient flat areas suitable for the placement of waste dumps and stockpiles.Open pit mining plans to use conventional drill-and-blast equipment and truck and excavator mining equipment supplied by a contractor.Recommendations for the pit slope design are based on probabilistic kinematic analyses. The bench height was limited to 10 m. The berm width of 6.0 m is considered to be sufficient to ensure retention of bench-scale size failures.

Mineralization has been identified through exploration drilling below the potential open pits to a depth of approximately 450 m below surface. Both zones remain open at depth and along strike. Both the Klaza and BRX zones are amenable to mining by underground methods. The proposed underground mining method is Longhole stoping with waste rock fill. Underground mining is planned to be owner-operator with the equipment owned, and personnel employed by Rockhaven.

In order to determine an appropriate production rate that can be supported by the deposit, AMC has used a combination of Taylor`s rule of thumb and vertical tonnes per metre to determine expected production ranges. AMC recommends that the BRX deposit and Klaza deposit be mined as two virtually independent operations at a combined average peak production rate of 690 kilotonnes per annum(ktpa). This production rate is well supported by the detailed production scheduling.

The Klaza and BRX zones are approximately parallel and 800 m apart, and as such separate declines were designed for Klaza and BRX. Access to the Klaza zone underground mine would be via two independent 5m by 5 m declines for the Western Klaza and Central Klaza zoneswith crosscuts on each level. The Central Klaza zone also has an in-pit portal to access one level of stopes. Levels are spaced at a vertical distance of 25 m floor to floor. Ore development (4 m by 4m) was designed to follow the vein along strike from a central access crosscut. Main access to the BRX zone has a similar design with two independent (5 m by 5 m) access decline for the Western and Central BRX zones. Decline access is designed with a 1:7 gradient.

In general, the rock quality values typically range from Poor to Good.Based on a floor to back height of 25 m, at a 65° dip, stope lengths of 18 m for unsupported walls and 49 m for supported walls will be stable. Dilution for Longhole stopes has been estimated using the equivalent linear overbreak slough (ELOS) technique and was estimated by AMC to be less than 0.5 m from the hanging wall(HW).

For both zones, the mine will be ventilated by a “Pull” or exhausting type ventilation system. That is, the primary mine ventilation fans will be located at the primary exhaust airways of the mine. Fresh air will enter each mine via the decline portals with exhaust to the surface via a dedicated return airway. During the winter, air will be heated by direct propane gas fired heaters at the portal, with the heat ducted to the intake airflow. Based upon the equipment required, a peak of approximately 159 m³/s is planned for ventilation of each of the Central Klaza and Western Klaza zones. Central BRX zone has a peak demand of approximately 189 m3/s and Western BRX zone217m3/s.

Tetra Tech EBA Inc. (Tetra Tech EBA) was retained by Rockhaven to install a groundwater monitoring well network in the area of the identified resource and to conduct a preliminary hydrogeological assessment for the area of the mineralized zones at Klaza. A preliminary monitoring well network consisting of five nested monitoring wells was installed; four additional observations wells were fitted with vibrating wire piezometers (VWPs) to monitor pore pressures at different depths in each of the observation wells.Permafrost appears to act as a confining layer for the deeper bedrock aquifer.The ground water flow regime at the site is controlled by the steep terrain with ground water flow from areas at higher elevations on the mountain slopes toward the valley bottoms.

Based on Tetra Tech EBA'sobservations, AMC has assumed a low ground-water inflow that can be sufficiently pumped from the mine workings using submersible pumps and a four inch (100 mm) discharge pipeline. The majority of the discharge water will be service water for operating equipment.

During development the decline will be equipped with power for distribution underground as well as a six inch (150 mm) compressed air line, a four inch (100 mm) pipeline for mine service water and a four inch (100 mm) pipeline for dewatering. Telecommunications will be provided by a conventional leaky feeder system.

On all levels, the planned main escape route is either the main decline or to the return air raise (RAR). RARs will be equipped with ladder ways for personnel egress. Refuge stations will be placed strategically in the underground mine, they will be portable for flexibility of location.

Typical equipment for a mechanized Longhole stoping underground mine were selected by AMC. Development will be undertaken using 2 boom Jumbo development drills, stope drilling will be undertaken using production drill rigs. Bolters and cablebolters will undertake all ground support installation. Forty tonne articulated trucks will be used to haul mineralized materialfrom the underground mines to surface. Suitable quantities of auxiliary equipment such as a water truck, grader, scissor lifts, personnel transporters, and utility vehicles were also estimated by AMC.

In order to optimize the overall value of the project and the sequence of mining each zone, AMC has determined potential revenue for each pit and each underground zone. The zones were then ranked in order of value. The potential revenue from each source provides a basis for the order in which the pits and underground zones are scheduled. In addition, there is a focus to have the open pits mined early in the mine life in order to allow development of the underground mines simultaneously.

Proposed production from the open pit and underground is stockpiled in YR0, during the construction of the process plant. It was assumed that the process plant will be capable of reaching 90% capacity (610 ktpa) during YR1 and 100% capacity in YR2. The process plant has been designed for a maximum throughput of 1,900 tpd (690 ktpa).

Crushing and stockpiling
The crushing plant consists of a single primary crushing stage for top size control. Material from the mine is hauled by truck and loaded onto a static grizzly. The primary crusher consists of a jaw crusher, and would crush the grizzly oversize. Grizzly undersize and jaw crusher product are combined and delivered to an ore bin with 24 hours’ live capacity (1,900 t). Material from the ore bin is withdrawn using one of two vibrating feeders, which will feed onto a SAG mill feed conveyor belt, equipped with a weightometer.

Milling and classification
The entire mineral processing circuit has been designed with an assumed availability of 92%, indicating a mean operating throughput of 86t/hour.

Crushed ore is reclaimed from the mill feed storage bin and fed to a single SAG Mill driven by a 1MW motor. Lime and a pre-mixed sodium cyanide / zinc sulphate complex is added to the mill feed chute, to promote selective lead flotation in the downstream lead rougher circuit. SAG Mill discharge is screened, with oversize, returning by conveyor to the SAG mill feed without crushing, although space is allowed for a crusher should it be needed in the future. Screen undersize is pumped to the ball mill pump box. Material from the ball mill pump box is pumped to a cluster of hydrocyclones for classification, at a cut size of 90 microns. Cyclone underflow, operating at a 250% circulating load ratio, launders to a 1400kW ball mill. Cyclone overflow launders to the lead rougher float. Balls would be added by overhead crane into the SAG and ball mills using bottom discharging kibbles.

A lead flotation circuit is employed to concentrate lead and silver from the ore. Cyclone overflow from the hydrocyclone cluster is laundered to the rougher where it is combined with flotation reagents:
• Diaryl dithiophosphate Cytec Aero 241 (Aero 241) collector.
• Dithiophosphinate Cytec 3418A (3418-A) collector.
• Methyl Isobutyl Carbinol frother in the feed well.

Concentrate from the lead rougher is collected in a launder system. Tailings from the rougher launders to the lead rougher tails pump box. The concentrate from the lead rougher is pumped to the lead regrind circuit consisting of a mill operating in closed circuit with hydrocyclones at a circulating load ratio of 350%. The regrind mill, sized at 2.4 m x 4.3 m, is powered by a 200 kW motor. It is combined with the lead regrind mill discharge to be pumped to a hydrocyclone cluster where it is classified, with underflow laundered back to the regrind mill feed chute and overflow laundered to the lead f ........