The zinc-lead-silver mineralization of the Florida Canyon deposit occurs as sulfides hosted in dolomitized zones of the Chambara 2 Formation. Dolomite paragenesis and later sulfide mineralization are controlled by a combination of porosity, permeability and structural preparation. Metals occur in sphalerite and lesser galena, which contains silver. Minor mineralization is hosted in limestones, but the bulk of sphalerite and galena is hosted in dolomite.

In a number of core samples, the mineralization has very sharp contacts along the dolomitization boundary. Characteristic mineralization textures include massive and disseminated mantos, mineralization in dissolution breccias, collapse breccias and pseudobreccias. The different breccias and vein types are structurally controlled by faults of north-south and northeast- southwest direction.

The mineralization is characterized by the presence of sphalerite, galena and locally pyrite. Sulfide replacements occur in dolomitized limestone of variable grain sized and in solution breccias with white dolospar and lesser amounts of late generation calcite. Pyrite content is generally low, with percentages averaging less than 2% by volume. Sphalerite in mineralized sections has variable grain size from 0.1 to greater than 5 mm, with colors ranging from dark brown through reddish brown to light brown. It occurs as individual crystals or in massive form, sometimes displaying colloform textures with bands of slightly differing color zoning, indicators of polyphase hydrothermal deposition.

Early fine-grained sphalerite has evidence of later deformation and reactions to secondary mineralizing fluids. A second phase of more massive sphalerite mineralization is observed within the core of the deposit. These crystals are coarse-grained, regular, euhedral and show very little evidence of any post-depositional deformation. The sphalerite is contemporaneous with fine to coarse grained galena and is often overprinted with a later stage coarse-grained, euhedral galena.

The presence of zinc oxides, locally to considerable depths, is due to syngenetic oxidation, with later contributions of basin- derived connate water and movement of rainwater through fractures that leached the limestones and formed significant karst cavities.

The areas of current exploration interest are the Karen/Milagros, San Jorge and Sam Fault deposits. These mineralized zones are hosted in the dolomitized Chambará 2 sub-unit of the Pucará Group carbonates, bracketed by the Coquina and Intact Bivalve Marker beds. Geologic mapping and modeling includes refining the extents of Chambará 2, and further defining the steeply dipping feeder structures to predict additional zinc-lead-silver mineralization.

Local and regional geologic mapping, geologic drillhole logs, and the dome-shaped geometry of the deposit suggest the mineralization is hosted in a broad anticline structure. Florida Canyon is the collective name of the deposits in the Project area in Florida Canyon, and includes the Karen- Milagros, San Jorge, Sam Fault zones and similar mineralized strata between these areas.

Modeled manto zones are between 1 m and 9 m thick and occur over an area of about 1 km x 3 km and are open in all directions. Unmineralized gaps exist within the mineralized manto zones, as is typical for hydrothermal replacement deposits. Irregular steeply dipping replacement bodies also occur, frequently at the intersection of vein-like feeder structures and in karst-controlled mineralization.

Mineralization outcrops locally in a number of areas, and have been drilled at depths of up to about 450 m below ground surface. Zinc mineralization occurs as massive sphalerite (ZnS), and is locally oxidized to smithsonite (ZnCO3) and hemimorphite (Zn4Si2O7 (OH)2). Lead occurs in galena (PbS), cerussite (PbCO3) and anglesite (PbSO4).

An area of 20 km x 100 km extending from Mina Grande to north to 80 km south of the Florida Canyon deposit has become the focus of what is an emerging Mississippi-Valley Type (MVT) zinc and lead province, with many surface occurrences and stream sediment anomalies distributed throughout the Pucará Group. The main host rock of zinc and lead occurrences in the mineral district and Project area is dolomitized limestone, which may show karst or collapse breccia textures.

The structure at Florida Canyon is dominated by a N50º-60ºW trending domal anticline (or doubly plunging anticline) (SRK, 2014b). This anticlinal structure results in potential mining blocks of the manto deposits oriented along shallow dipping footwall/floors with dips ranging from 0° at the hinge to 25° near the middle to outer edges of the dome. The dip is as steep as 50° in the south of the deposit near the San Jorge exploration adit. Additionally, two steeply dipping mineralized bodies have been interpreted to exist. The first, known as San Jorge (zone F1), is located at the southern end of the deposit, and the other, known as SAM (zones 2 and 3), is located on the southwest edge of the deposit. The dip of these bodies ranges from 60° to 85° in San Jorge and 55° to 80° in the SAM body.

Approximately 26% of the mining resource will be mined using longhole stoping in the SAM and F1 areas with the remaining mined using mechanized drift and fill and cut and fill. Cemented paste fill and cemented rock fill will be used to backfill primary stopes. Mine development waste will be used in secondary stopes with some secondaries backfilled with low-content cemented paste fill where required.

Longhole Stoping
Sublevels in the longhole areas will be developed at 16 m intervals. Stopes less than 8 m wide will be mined longitudinally (along strike) with stopes greater than 8 m wide mined transversely (perpendicular to strike). Ramp, main haulage, and cross-cut development will be in the footwall. Haulage drifts have been offset from the stopes by 20 m. Sill development in the mineralized zones will provide access for drilling, blasting, ground support, and mucking. Blasthole drilling will be from the top sill using top hammer drills. Broken material will be mucked from the bottom of the stopes using remote controlled Load Haul Dump units (LHD). Typical blast patterns will be drilled using 2.5 m (burden) x 2.0 m (spacing) ring patterns. It is expected that water will be present requiring blastholes to be charged with ANFO/emulsion blends as required for water resistance. Cut and fill mining blocks exist in the hangingwall and footwall in the F1 area. Consideration for good ground control and the influence of mining induced stresses has an impact on the sequence of mining in these areas. The production schedule described in this study has mining occurring from the hangingwall to footwall with cut and fill blocks in the footwall mined on retreat.

Drift and Fill, Cut and Fill
Mining of shallow dipping (less than 27°) accounts for 70% of mine production. Mining cuts measuring 4 m wide x a minimum 3 m high will be used to minimize dilution in thin areas. Stopes within a given manto or group of mantos will be developed from the bottom-up with each subsequent 3 m level developed above the mined-out and backfilled cut below. It will be possible to develop ramps and haulage drifts in the mineralized material where the dip of the mineralized zone allows a maximum 12% gradient. Stopes will also be able to follow the grade of the footwall up to a maximum allowable gradient of 15%.

Drill jumbos will be used to drill 45 mm holes with each round advancing 4 m. Blasting will primarily use ANFO/emulsion blends will be used as required.

Areas that require footwall waste development for stope block access will utilize access ramps with a maximum grade of 15%. Blocks of 12 to 16 m high will be mined using cuts of 3 to 4 m depending on the geometry of the mineralized material. Mining of cuts within a stope block will progress from the bottom to the top with lower cuts filled with cemented paste fill, cemented rock fill or development waste.

Large karst caverns have been encountered during the excavation of the San Jorge adit, and karstic features have been observed in drilling. Additional geotechnical and hydrogeological information and study is required to better understand the potential impact on mining and risk mitigation measures that may be required to ensure a safe working environment.

Mineralized material will be mucked using LHDs (4.5 to 6.5 m3), loaded onto 30 tonne trucks and hauled to the appropriate portal. The material will be crushed at the portal and transported to the processing facility via conveyor.

Given the location of the deposit, it is anticipated three underground portals will be producing mineralized material at any given time. Because the challenging topography and road conditions, trucking Run-of-Mine (ROM) material would demand a lengthy route from the underground portals to the plant’s location. Instead, SRK has designed a set of conventional overland conveyors with a maximum slope of 20° to simplify the operation and significantly reduce the cost of transferring mill feed from the mine portals to the process plant. A portable, 75 hp primary jaw crusher is to be installed at each underground mine portal to ensure the ROM is adequately sized for the conveying system.

Crushed material produced by the primary jaw crushers is transferred to a 2,500 t silo located at the process plant area. A secondary-tertiary crushing plant using 150 hp cone crushers in closed-circuit with vibrating screens will reduce the mill feed to approximately 80% passing 12 mm. The product from the crushing plant will be transferred to a mill feed silo (fine ore silo) capable of holding 2,500 t.

The single stage 1,800 kW conventional ball mill operating in closed-circuit with a classification screen will produce a product sizing approximately 80% minus 44 microns that will feed the differential flotation stage.

Florida Canyon mineralized material will be processed using a conventional concentration plant consisting of three stage crushing, grinding using a single-stage ball mill to 80% minus 44 microns, and differential flotation to produce two final products: a zinc concentrate and a lead concentrate containing payable silver. The concentrate will be truck transported to the point of sale. Tailings will be used as backfill or filtered and conveyed to a dry stack tailings storage facility.

The mill will process 2,500 t/d of fresh mineralized material, and produce approximately 287 t of zinc concentrate grading 50% Zn, 1% Pb, and 0.6 g/t Ag and approximately 46 t of lead concentrate grading 50% Pb, 8.4 g/t Ag, and 6% Zn.

The flotation will have two multi-stage flotation circuits, the first will produce a lead concentrate. The second multi-stage flotation circuit, the zinc circuit, receives tails from the lead circuit to produce a zinc concentrate. Both final concentrates ........