The Tocantinzinho deposit is best classified as a granite-hosted, intrusion-related gold deposit. It is underlain by igneous rocks of older magmatic arcs of the Tapajós (Cuiú-Cuiú/Creporizão). Textural evidence and contact relationships suggest that the host granitic rocks at Tocantinzinho intruded as elongate bodies along a northwest-striking fault zone that cut through more regionally extensive quartz monzonites and granites. The granitoids were likely emplaced synchronous with faulting, and both intrusive contact and vein orientations suggest the host fault zone was active during this period as a sinistral, dominantly strike-slip feature. The presence of abundant aplites, miarolitic cavities, and blebby quartz textures implies that the host granitic intrusions represent late, volatile-rich components of the parent magma. Vein textures suggest that at least some of the veins, and possibly gold mineralization, were introduced during or just after solidification of the host rocks.

The Tocantinzinho deposit forms a sub-vertical, northwest-trending elongate body approximately 900 metres long by 150-200 metres wide. It has been drilled to approximately 450 metres depth and remains open below this depth.

The gold mineralization is bound on the hangingwall and footwall sides by structural zones which mark the contact with the surrounding barren granite/monzonite. This structural corridor is an outer geological constraint on the estimation domain. The andesitic body close to surface is largely unmineralized and is used as an internal constraint on the estimation domain.

Mineralized granites at Tocantinzinho are divided into two sub-units, smoky and salami granite. Grade distribution is similar in both units and therefore they have been grouped for resource estimation purposes.

The green-grey colour of the smoky granite is due the alteration of plagioclase to sericite with lesser chlorite, calcite and pyrite particularly in the core of the feldspar. Salami mineralized granites are distinctively bright red due to hematite dusting on the feldspars. But the red-pink colour is not indicative of potassic alteration. Anastomosing veinlets are common and similar in scale to those in the smoky granites but are generally filled with a distinct black chlorite and lesser sericite-calcite-pyrite-quartz. Quartz textures in the salami and smoky granites commonly have curvilinear grain boundaries with feldspar. Chlorite-sericite-calcite veins are typically wormy rather than planar and appear to cut feldspar but develop along the margins of the quartz grains suggesting this was a relatively late magmatic-hydrothermal phase. Contacts are diffuse between smoky and salami granites and a complete gradation exists between the two units.

Pyrite is the main sulfide phase and commonly contains inclusions of minor chalcopyrite and pyrrhotite. The presence of pyrrhotite is genetically significant because it indicates that the ore at least locally formed under reduced conditions despite the abundance of hematite-dusting on feldspar and hematite-alteration of magnetite in the outer red granite. Gold grains were observed in close association with pyrite along grain boundaries, within fractures and locally as inclusions within pyrite. A white-grey mineral was also observed associated with gold and is likely a bismuth mineral (bismuthinite or bismuth). Multi-element data for samples with anomalous gold (> 0.1ppm) show a strong correlation pair between gold and bismuth (0.87).

The Tocantinzinho mine will be developed as a conventional open pit using excavators and trucks with wheel loader support. Near surface saprolite material and old tailings will be mined using a fleet of articulated 40 t capacity trucks and 6 m3 excavators in pioneering areas. Some saprolite and fresh granite, quartz monzonite and andesite will be drilled, blasted and loaded by 17 m3 excavators and an 11.6 m3 capacity wheel loader into 90 t rigid frame off road haulage trucks.

The mine will be developed in two phases. Pre-stripping will be undertaken in Phase 1 over a two year period. Road and drainage development will be undertaken initially as well as stripping of a borrow pit which will provide fresh rock for construction and site preparation. Stockpile and waste dump preparation will take place west of the open pit area. A total of 22.7 Mt will be excavated in the mine during the pre-production period. The mine will deliver 4.37 Mt of ore annually to the processing facility. Peak production years will be Year 1 and Year 2 with a total mining rate of 26.7 Mt. The open pit will operate to Year 9 of the plan. Stockpile recovery and processing will continue into Year 10.

The mine was designed as a single open pit operation using two pit phases mined over 11 years, including two years of development and pre-stripping, with a peak mining rate of 26.7 Mt of material per year. The open pit is designed to a depth of 350 m using variable wall slopes. The mine will operate on 10 m benches using truck and excavator fleets. The average cost of mining a tonne of material is estimated to be US$2.47/t based operating with three crews of operators and quotes for major equipment maintenance components, diesel, explosives and tires.

The mine design takes into consideration the proposed 10 m bench height and the size of the equipment in the fleet. The mine will operate two fleets of equipment. Saprolite pioneering and mining of tailings will be undertaken by 6 m3 excavators and articulated 40 t trucks. Waste rock and ore will be moved by 17 m3 excavators, an 11.6 m3 wheel loader and 90 t trucks.

The designs for the hard rock slopes vary by sector, as recommended by Golder. Controlled blasting techniques will be used including buffer blasts and pre-splits. The pre-split is planned for a double bench (20 m) application and will be drilled once every 2 benches. The inter-ramp slope angles per sector are the same as the Golder recommendations, however the bench face in all sectors was set at 70 degrees.

Haulage ramps were designed with consideration for the size of equipment. The larger haulage units are 90 t trucks which have an operating width of 6.2 m and a tire height of 2.6 m.

Ramp design considerations included the following:
• A berm height equal to at least half the tire height;
• A passing width between trucks equal to ½ the operating width;
• A ditch along the toe of the wall.

Based on these factors two designs were created. Main haul roads will have 30 m wide road allowance with a maximum 10% gradient. A 25 m wide road allowance was used to access the final 40 m of the pit from bench -130 to -170.

A waste rock disposal area was designed to permanently store the waste rock that will be mined from the Tocantinzinho open pit. The following design criteria were used:
• Storage capacity of approximately 82.6 million m3 on a footprint of 126 ha;
• Maximum height of 142 m – elevation 265 m;
• Lift height of 20 m with angle of repose slopes of 37 degrees;
• Berm width 10 m and overall slope of approximately 28 degrees;
• A surface water drainage plan that allows for collection and settling of all water run-off;
• A detailed system of drains to be constructed in the base of the storage facility;
• An offset distance of 300 m horizontally and 5 m vertically from the Tocantinzinho River.

Primary Crushing
Ore from open pit mining operations will feed a primary jaw crusher system which produces a product size P80 of 148 mm. Saprolite ore and artisanal mining (garimpeiros) tailings will be stockpiled in designated areas near the ROM bin. A front end loader will transfer these ores from their designated stockpiles into the ROM bin with granite ore at specific blend ratios required at the processing facility.

Haul trucks will dump ROM ore onto a static grizzly with 700 mm openings overtop the ROM bin. The ROM bin will have a 300 t live storage capacity which corresponds to two dump truck loads. A mobile rock breaker will break any oversized material captured at the static grizzly. An apron feeder will draw material from the ROM bin and discharge onto a vibrating grizzly feeder with 102 mm spacing. The oversized material will discharge directly into the primary jaw crusher. The undersized material will bypass the jaw crusher and combine with primary crusher discharge onto the primary jaw crusher discharge conveyor. The primary jaw crusher discharge conveyor will feed the stockpile feed conveyor. The jaw crusher will have opening dimensions of 1,600 x 1,200 mm with installed motor power of 250 kW.

Fresh water will be used to mist the ROM bin, the vibrating grizzly and the jaw crusher to lower dust emissions generated at these locations.

Crushed Ore Stockpile
The stockpile feed conveyor will feed the crushed ore stockpile. The crushed ore stockpile will be uncovered. There will be two reclaim apron feeders located in the concrete reclaim tunnel under the stockpile. The apron feeders will transfer ore to the SAG mill feed conveyor with each feeder capable of providing total throughput to the plant when required.

The crushed ore stockpile will have 6,600 t live capacity that can support milling operations for 12 hours when the crushing plant is not operating.

Grinding
The SAG mill feed conveyor will transfer ore to the SAG mill from the crushed ore stockpile. An automated SAG mill media addition system will meter the required steel charge to the SAG mill feed conveyor. The transfer size produced from the SAG mill will be approximately 1000 µm.

The SAG mill will be 8.5 m in diameter by 4.0 m (effective grinding length) driven with installed 5,500 kW variable speed motor. The SAG mill discharge will pass through to a SAG mill trommel screen attached to the end of the SAG mill with trommel undersize going directly into the SAG/ball mill discharge pumpbox. Trommel oversize will be recirculated back into the SAG mill using a trommel water-jet system.

From the SAG/ball mill pumpbox the cyclone feed pump will pump a combined slurry into the ball mill cyclone cluster which will classify the feed slurry into coarse/underflow and fine/overflow fractions. The designed recirculation rate through this classification system is 300%. The cyclone overflow will have particle size P80 of 125 µm and will flow via gravity to the rougher flotation conditioning tank prior to sulphide flotation. The underflow will feed the ball mill for further grinding with a portion of the coarse fraction feeding the gravity separation circuit for coarse gold recovery. Tailings from the gravity separation will also report to the ball mill. The cyclone cluster will have a total of seven cyclones; five operating, two standby.

Copper sulphate will be added to the SAG/ball mill pumpbox. Milk of lime can be added to the SAG mill to adjust pH if required.

The ball mill will be 6.4 m in diameter by 9.75 m (effective grinding length) driven with installed 7,500 kW fixed speed motor. Slurry will overflow from the ball mill to a trommel screen, attached to the ball mill discharge end. Trommel undersize will discharge into the SAG/ ball mill discharge pumpbox.

The process selected for the Tocantinzinho Project is based on testwork and is a flotation concentrate cyanide leach and carbon adsorption flowsheet comprising crushing, grinding, gravity concentration, flotation, cyanide leaching, carbon adsorption, cyanide detoxification, carbon elution and regeneration, gold refining, and tailings disposal.

The Tocantinzinho process plant will process run of mine (ROM) granite ore, along with minor amounts of saprolite and garimpeiros tailings, and produce gold doré bars and tailings.

The mill is designed with a nominal capacity of 4.3 Mtpa at a planned average feed grade of 1.41 g/t Au, producing 174,000 oz of Au annually with a life of mine of 9 years. The plant is designed to treat ore with a maximum head grade of 1.76 g/t Au.

The plant will consist of the following unit operations:

• Primary crushing – A vibrating grizzly and jaw crusher in open circuit producing a final product of 80% passing (P80 ........