The Paracatu deposit is a metamorphic gold system with finely disseminated gold mineralization hosted within metasedimentary rocks. Very fine and evenly distributed gold is disseminated throughout a thinly bedded, highly deformed phyllite of Upper Proterozoic age. The deposit is part of a northwest-southeast lineament of gold occurrences including Cabeça Seca and Luziânia.

Gold mineralization was introduced syn-tectonically as the result of metamorphic alteration during thrusting of the Morro do Ouro Sequence over the rocks of the younger Vazante Formation. Structural interpretation suggests that mineralization was precipitated within a high strain zone where silica and carbonate were depleted from host phyllites, resulting in an increase in graphite content that may have acted as a chemical trap, precipitating out gold and sulphide mineralization remobilized during the metamorphic alteration of the Morro do Ouro Sequence.

The deposit has extraordinary lateral and longitudinal continuity. The majority of exploration efforts have sought to better define the continuous longitudinal continuity of mineralized phyllites at depth west of Rico Creek and the lateral limits of the economic mineralization.

The Paracatu mineralization is subdivided into four horizons defined by the degree of oxidation, surface weathering and sulphide mineralization. These units are, from surface, the C, T, B1 and B2 horizons. Figure 7-6 presents the conceptual pre-mining weathering surface and establishes the relative relationship between the various zones. Mining to date has exhausted the C and T horizons. The remaining mineral reserves are hosted exclusively in the B1 and B2 horizons. For this geological model, the interpreted geologic profiles combines the C, T and B1 horizons into a single unit.

Type C mineralization occurs at surface and extends to a depth of 20 m to 30 m. Type C mineralization is completely altered with no remaining sulphides. It also features localized laterite development.

The T horizon is generally only several metres thick, and marks the transition from the C horizon to the B1 horizon.

The B1 horizon is dark in colour and carbonaceous, with less oxidation than the C horizon. Sulphides have been completely oxidized but some fresh sulphide material is visible in the quartz boudins.

B2 mineralization was originally described as unweathered or fresh mineralization with primary sulphides.

The contact between unmineralized host rock (Type A – Oxide and Fresh) and the various mineralized horizons is gradational, occurring over a 10 m thick interval that is characterized by arsenic values of 200 ppm to 500 ppm and gold values of up to 0.2 g/t.

The mineralization at Paracatu is indicative of metamorphic alteration of lower and sericite make up 80% of the rock mass. Carbon occurs in the form of a fine opaque dust disseminated within the individual sericite bands. Carbon content varies from 5% to 20%. Minor amounts of ilmenite, tourmaline, anatase, rutile and limonite are also commonly observed.

Petrography indicates that 60% to 90% of unoxidized phyllites were composed of variable amounts of quartz and sericite to produce a distinctive banding. Individual bands are typically less than two centimetres thick. The phyllites also contain up to 20% carbonate (calcite and ankerite). Fine grained carbon was also observed in the less weathered samples. Accessory minerals included muscovite, biotite, albite, tourmaline, ilmenite, chlorite, zircon and rutile.

The amount of sulphides present does not typically exceed 3% to 4%. The most common sulphides observed are arsenopyrite, pyrite and pyrrhotite. Galena is relatively common and may be accompanied by sphalerite. Chalcopyrite occurs locally in fractures within the main sulphide minerals listed above. The sulphides typically occur as individual crystals or coarse crystalline aggregates. Arsenopyrite is the most common sulphide and occurs as a fine grained (<1 mm) to coarse grained (>3 mm) aggregates. Crystals up to one centimetre in size are not uncommon. Arsenopyrite crystals increase in size to the southwest.

The mineralization at Paracatu exhibits distinct mineralogical zoning with the arsenopyrite content increasing towards the center and west and in the zones of intense deformation. Gold grade increases with increasing arsenopyrite content.

Pyrrhotite occurs in the western part of the deposit and gold grades are elevated where pyrrhotite increases. There is evidence for a pyrrhotite-rich deposit at depth, which has been intersected in a number of drill holes.

The deposit formation model proposed for Paracatu suggests that gold and arsenopyrite were introduced concurrently during the deformation event.

The quartz boudins typically observed in the higher grade portions of the Paracatu deposit represent original, attenuated quartz veins. The boudins crosscut bedding at a shallow angle. The boudin thickness likely represents the original thickness of the quartz veins, which have been stretched considerably, implying moderately high to very high strain in the system (Holcombe, 2005). The boudin formation has been interpreted as a two-stage process. First, quartz veins are emplaced early in the deformation event. As stress builds, these veins are folded, boudinaged and separated. Mineralized boudins are parallel to foliation. A final barren quartz stockwork phase cross cuts foliation in the low grade hanging wall.

Gold occurs either as free gold or electrum. Microscopic analysis indicates that 92% of the gold at Paracatu is free-milling with less than 8% encapsulated by sulphide grains or silica.

The Paracatu Mine is a traditional open pit truck/shovel operation.

The production fleet consists of ten Caterpillar 777 haul trucks and thirteen Caterpillar 793 haul trucks. In 2014, the Caterpillar 793 fleet will expand to fifteen haul trucks.

The loading fleet consists of three Caterpillar 992 loaders, three Caterpillar 994 loaders and two Bucyrus 495HD shovels.

The diesel-powered drill fleet is comprised of two Atlas Copco DM45 rigs, two Atlas Copco DM50 rigs, one Bucyrus 35R and one Atlas Copco ROC D7. Shovel and drill fleets will be replaced with comparable units upon retirement.

Paracatu has two mineral processing plants known as Plant I and Plant II with extraction of gold using gravity/ flotation/ carbon-in-leach (CIL) recovery processes.

Plant I treats the softer near-surface B1 ore at a design throughput of 20 Mt/a, while Plant II treats the harder B2 ore at a design throughput of 41 Mt/a.

In Plant I, ore is crushed through two stages and ground in ball mills prior to gold recovery by jigs and flotation. The concentrate is treated by gravimetric methods first and the coarser gold is recovered. The flotation and gravity concentrate is then leached with cyanide in a carbon-in-leach (CIL) circuit, followed by carbon elution and electrowinning to recover gold which is then smelted to form gold bars.

Currently, Plant II consists of an in-pit MMD crusher, a 1.8 km conveyor to a covered stockpile area, an 11.6 m diameter SAG mill, and four ball mills. The ore recovery process uses gravity flotation to produce concentrate which is ........