Advanced Technical Report — Mana Property, Burkina Faso

This report presents an independent technical review of resources and reserves for the Mana gold deposits in Burkina Faso, based on drilling completed to the end of 2011.

Report context

This technical report was prepared by SGS Geostat for Semafo to support the annual disclosure of mineral resources and reserves for the Mana property following the 2011 exploration campaign. The report describes the basis and methodology used for modeling and estimation of the gold deposits on the Mana property, with an effective date of July 11, 2012. The report covers mineral processing and metallurgical testing, mineral resource estimates, mineral reserve estimates, mining methods, and recovery methods for the Mana property.

Processing route

Current mine processing

The Mana mine began operation in March of 2008 with a 2,000 tpd mill which was progressively upgraded up to a current capacity of 8,000 tpd in blended ores. Installations include a carbon in leach mill with crusher, SAG mill, two ball mills, reactive cells, gold room and ancillary services. Since the opening of the Mana mine, Semafo has progressively upgraded the capacity from 2,000 tpd to the current output of 8,000 tpd for blended ores.

A total of 2,448,170 tonnes was processed to the mill in 2011, with an average head grade of 2.76 g/t Au, and an overall gold recovery of 88%. The ore processed was a blend of Wona, Nyafe (North, Center and Filon 67) and low grade ore stockpiled on the run of mine (ROM) pad. The process plant always treats a blend of various ore types to maximize its throughput and gold production. Most of the ore treated during 2011 was in saprock and bedrock.

Crushing

The crushing circuit forms part of the carbon in leach mill with crusher, SAG mill, two ball mills, reactive cells, gold room and ancillary services.

Grinding and classification

The grinding circuit includes a semi-autogenous grinding (SAG) mill that was added in 2010 to increase the mill throughput to 6,000 tpd. In February 2011 a fourth phase of plant expansion to attain up to 7,200 tonnes per day in bedrock and up to 8,000 tpd in blended ore was launched. The primary changes to the processing plant included: addition of a pebble crusher, utilization of the third ball mill previously used as back-up, addition of two CIL tanks, addition of a thickener, additional generators, critical spares and some equipment capacity upgrades.

Leach and adsorption circuit

The leach and adsorption circuit uses carbon in leach technology. Two additional carbon in leach tanks were added in 2010 to optimize gold recovery. The plant includes reactive cells as part of the CIL circuit.

Elution and gold room operation

The gold room operation includes carbon acid wash, carbon stripping via a Zadra elution circuit, carbon regeneration, electrowinning and gold room facilities. These components form part of the processing plant infrastructure.

Tailings disposal and water management

Water for processing is collected from a network of wells, collected from the tailings and accumulated behind an earthen dam constructed to collect seasonal runoff. A 58 km pipeline between the Mana water dam and the Mohoun River was under construction and should be operational before year end. It is designed to pump up to 450 m³/hour, or a maximum of 3.5 Mm³ of water per year. This, in addition to the water captured from the rainy season, should be sufficient to feed a 14,000 tpd operation.

South sector metallurgical testwork

The metallurgical testing for the South sector (Yaho, Fofina, and Fobiri) was based on 111 representative core and RC composite samples. SGS South Africa executed a variety of tests using current mill process conditions. Testwork included: comminution including JK Drop weight (9 samples), Bond Abrasion (9 samples), Bond Crushability (9 samples) and Bond Ball Mill Work Index (9 samples), Gravity Recoverable Gold (3 samples) test and Carbon-in-leach (CIL) (72 samples). The core/RC composite samples were carefully chosen to represent roughly 90% of ore body tonnage. Individual samples were diluted when necessary with core waste to respect averaged ore body head grades. Variability of the ore was also evaluated with specific samples. Variability in the South sector indicating higher localized zones of sulphide such as pyrite, pyrrhotite, arsenopyrite and graphitic zones were individually sampled (12 special samples) and tested by SGS to verify their response to the current Mana CIL process.

Based on these results, a standard CIL process showed good response when the ore is fully oxidized (saprolite) but mitigated response in partially oxidized (saprock) and sulphide ore (bedrock). Consequently, Semafo decided to investigate other process routes such as sulphide flotation, sulphide concentrate regrinding and ultimately, oxidation to seek better gold recoveries. Representative samples were sent to HRLTesting Laboratories in Queensland-Australia to investigate these process options. Preliminary testwork indicated good potential to improve recovery rates but final results were still pending.

Key reported parameters

Technical qualifications

The Nyafe deposit appeared to have low recoveries within the parts of the sulphide zone (3 samples with less than 20% recovery). A more comprehensive study was ongoing to better define the limits of the sulphide mineralization. Reserves reported herein have been adjusted downward to account for the losses resulting from the refractory ore.

New metallurgical tests had shown that the sulphide portions for the Fofina, Fobiri and Yaho deposits had low recoveries with traditional CIL treatment (19%-48% recovery). Consequently, Semafo undertook a new series of metallurgical tests to define a treatment method that would enable higher recoveries for this material, with results pending at the time of reporting.

No reserves were reported for the Fobiri, Maoula and Yaho deposits. The Yaho deposit had a significant impact on the resource base, although at a lower average grade than other deposits on the Mana Property.

The resource estimate was completed using a database containing 4,394 holes and trenches totaling 546,305 metres which were completed almost entirely since 1997. Most of the drilling in 2011 was focused on expanding and refining the resources in the Fofina, Fobiri, Yaho and extensions to Wona-Kona.

Source: Advanced Technical Report, Mana Property, Burkina Faso, Reserve and Resource Update as of December 31, 2011, effective date July 11, 2012, Sections 13 and 17.