The Rosebel concession lies within the Paleoproterozoic Guiana Shield. The Suriname portion of the shield is characterized by discrete corridors of low grade metamorphic rocks (greenstone belts), separated by large granite gneiss terranes.

The local greenstone belt stratigraphy comprises a basal mafic to felsic volcanic package (Paramaka Formation) and two overlying volcano-sedimentary sequences (Armina and Rosebel Formations). The Armina Formation includes intermediate to mafic volcanics and volcaniclastics, trubidite and minor conglomerate whereas the unconformably overlying Rosebel Formation is mainly comprised of coarser grained sandstone and conglomerate with subordinate mudstone. The entire sequence has been deformed by east-southeast to east-west striking folds and faults. A large tonalitic pluton occurs in the southern part of the property (Brinks Granite). Metamorphism is greenschist to lower amphibolites facies.

The Rosebel property contains eight orogenic gold deposits distributed along three major structures. The northern mineralized trend has a strike length of 12 kilometres and hosts the Pay Caro, East Pay Caro, Koolhoven and J-Zone deposits. The southern mineralized trend has a strike length of 15 kilometres and hosts the Mayo, Royal Hill and Roma deposits. The Rosebel deposit occurs at the eastern extremity of the central mineralized trend.

Primary gold mineralization occurs in several different styles on the property but is typically associated with multiple generations of quartz, quartz-carbonate and quartz-carbonate-tourmaline veining. Vein arrays are thought to have developed preferentially along pre-existing structural heterogeneities such as lithological contacts, fold closures and sub-vertical shear cooridors during major deformation phases. For example, gold mineralization at the Rosebel deposit is associated with north dipping quartz and quartz carbonate vein sets localised along shear corridors developed at contacts between sandstone and siltstone units of the Rosebel Formation. Low grade gold mineralization is widely dispersed in sericitic alteration halos surrounding these structures. Diamond drilling has intersected economic gold mineralization to a vertical depth of 200 metres below surface and the continuity of the mineralization can be traced for over two kilometres along strike. The deposit, like most others on the property, remains open on strike and at depth.

Gold mainly occurs in its native form as free grains, often precipitated close to vein selvages or as intergrowths in pyrite crystals within veins and adjacent country rocks. Mineralized quartz veins range from a few centimetres up to 4 metres in thickness and are typically associated with a wall-rock alteration assemblage comprising sericite, chlorite, carbonate, tourmaline, pyrite, pyrrhotite and plagioclase. Alteration halos range from 0.25 metres around individual veins to over 20 metres around major vein sets.

Mining at Rosebel has been carried out at eight open pits to date: Royal Hill, Pay Caro, East Pay Caro, Koolhaven, Rosebel, Roma, J-Zone and Mayo. Mining is by conventional open pit methods, using excavators and trucks. Material is designated as soft rock, transition or hard rock with the latter two types requiring blasting.

CRUSHING, STOCKPILING AND RECLAIM
Run-of-mine from the hard rock stockpile is delivered to the primary crushing facility by haul trucks and front-end loaders. Ore delivery from the mine is on a 24 hour per day schedule. The primary crusher incorporates a 1.37 m x 1.88 m gyratory crusher, followed by a vibrating grizzly and a 2.1 m secondary crushing system that produces the required feed for SAG mill. The crushing product sizing is set at minus 63 mm (2.5”). An active hard rock stockpile is maintained at approximately 50,000 tonnes.

Soft rock feed is maintained through two grizzlies using one dozer and two backhoes, with an active stockpile maintained at approximately 200,000 tonnes. Hard rock/soft rock blending to the SAG feed conveyor is maintained by two 1.8 m x 6.9 m apron feeders respectively.

GRINDING AND CLASSIFICATION
The two stage grinding circuit produces 80% passing 74 microns from the cyclone overflow. The first stage includes a 9.1 m x 4.0 m SAG mill driven by a 7,500 hp variable speed motor controlled by a Power Flex drive. The SAG mill is operating in an open circuit feeding two 2.4 m x 4.8 m vibratory screens. Screen oversize is processed through a cone crusher with ½” product returning to the SAG mill. Undersize from the SAG mill discharge screen is pumped to the pressure distributor where it is combined with the ball mill discharge and process water.

The second grinding stage consists of two 5.0 m x 8.2 m ball mills driven by 4,500 hp motors and one 5.0 m x 9.3 m ball mill driven by 5,200 hp fixed speed motor that operate in parallel closed circuit and receive the SAG discharge screen undersize. The ball mills operate in closed circuit with each cyclone cluster consisting of eight 660 mm diameter cyclones. The cyclone cluster is fed by a combination of the SAG mill discharge, the ball mill discharge, and process water. The cyclone underflow reports back to the ball mill for further grinding, while the cyclone overflow, at 35 wt% solids and 80% passing 75 microns (200 mesh) flow by gravity to the four 25 m2 linear screens to remove trash from the slurry.

The nameplate capacity of the process plant is 12.5 Mtpa. The plant has been operating near this capacity on a sustained long term basis.

The metallurgical process has; a conventional grinding (including gravity) circuit, dewatering circuit, leach circuit, carbon in leach (CIL) circuit, elution circuit, and refinery. Gold recovery facilities include acid washing, carbon stripping, and electrowinning, followed by bullion smelting and carbon regeneration. The process was developed to accommodate varying ratios of soft rock, transition, and hard rock ores.

GRAVITY CIRCUIT
Approximately 20% of the cyclone underflow from each cyclone cluster reports to the Sizetec 2.1 m x 4.9 m vibratory screens fitted with 10 mesh panels. Oversize reports to the ball mill discharge pump boxes, and undersize reports to the gravity circuit via a magnetic drum separator at a rate 400 tph. The plant has a gravity circuit consisting of three Falcon concentrators, a Consep Acacia int ........