Mineralogical, structural, and geochemical evidence collected at Massawa suggests that the mineralised body represents an epizonal-style orogenic gold deposit (c.f. Groves et al., 1998). Fluid inclusion and stable isotope analyses Treloar et al., 2014) indicate mineralizing pressure and temperature conditions of 220°C to 315°C at 1 kbar to 1.65 kbar, at crustal depths of 3.5 km to 6.5 km, with gold mineralisation directly linked to the intrusion of the felsic porphyries. Massawa shares some features with shallow level orogenic Au-Sb deposits in the Murchison Greenstone Belt of South Africa (Ashley et al., 2000; Jaguin et al., 2012) and Au-Sb mineralization associated with the Himalayan orogen in Tibet (Zhai et al., 2014).

The Massawa deposit occurs over a strike length of 4.5 km and is divided into two zones (Central Zone and Northern Zone) that differ in terms of host rock geology, mineralogy, structural controls, and metallurgy. The Central and Northern zones are separated by a 0.3 km gap zone, where less intense deformation is observed.

Massawa Central Zone
Mineralisation in the Central Zone (CZ) is hosted by an anastomosing brittle-ductile shear network localised by pre-existing gabbro and felsic porphyry intrusive contacts.

There is a deposit scale correlation between increasing brittle-ductile strain and increasing gold grade, with the grade of mineralisation variable along strike and down-dip related to the variable strain associated with the structural framework. The continuity of mineralisation is localised along gabbro and felsic porphyry intrusive contacts with high-grade mineralisation associated with high strain and arsenopyrite.

Numerous vein opening directions and vein styles highlight high fluid overpressure, with differential stress trending toward zero. Previously, a genetic link between quartz-stibnite veins and high-grade mineralisation was made leading to a ‘Phase 1 and Phase 2’ nomenclature. Subsequent review with additional drilling has advanced the understanding of the geological setting and mineralisation style, with quartz- stibnite veins observed parallel to and cross-cut by brittle-ductile shearing related to mineralisation. Subsequent analysis highlighted no significant statistical correlation between gold grade and stibnite content, with a good correlation noted with arsenopyrite. The grade and continuity to mineralisation is now characterised by alteration style, deformation intensity, and intrusive contacts.

Low-grade (+1 g/t Au) mineralisation is associated with weak to moderate shearing with silicacarbonate alteration and disseminated sulphides with weak strain. Arsenopyrite is rare. Highgrade (+3 g/t Au) mineralisation is associated with high strain including brecciation, extensional and shear veins, with moderate to strong silica-carbonate alteration and sulphides. Arsenopyrite is the dominant sulphide associated with gold, with arsenopyrite and pyrite also observed as vein selvedges +/- visible gold.

Veins identified by trenching and diamond drilling vary in style and include extensional, sheared, and boudinage veins. Veining associated with +1 g/t Au mineralisation is sub-parallel in orientation to primary strain (shearing) highlighting the genetic link between deformation and mineralisation.

Massawa Northern Zone
The Northern Zone (NZ) has a strike length of 2.5 km and consists of a main NNE trending mineralised structure with discontinuous footwall (FW) and hanging wall (HW) lodes. Mineralisation is localised in a damage zone adjacent to highly strained bands of fine- to medium-grained felsic and lithic wacke, wacke with subordinate carbonaceous shales, and gabbros. The NZ is sub- divided into two further zones based on structure (Northern Zone 1 and Northern Zone 2).

The southern 1.1 km of the Northern Zone (NZ1) hosts discontinuous, weaker gold mineralisation (average grade of 1 g/t Au to 1.5 g/t Au). The weakly silicified, brittle-ductile, mineralised shear is less than 10 m in thickness and is sub- vertical to steeply dipping to the ESE. The higher-grade but narrow mineralisation is focussed at the margins of a medium-grained greywacke and lithological contacts with contrasting grain size. Northern Zone 2 (NZ2) represents the northern and highest grade (>4 g/t Au) portion of the deposit. Mineralisation is predominately confined to a single, continuous, narrow zone (10 m to 15 m average width), which is sub-vertical to steeply dipping (>70°) to the WNW. The mineralisation is bounded by two prominent carbonaceous shale horizons within the sedimentary sequence.

Mineralisation in the NZ is characterised by disseminated arsenopyrite and arsenian pyrite. No quartz-stibnite visible Au veins are seen in the northern parts of the deposit. High grade is associated with crack seal carbonate veining where arsenopyrite intensifies at the margins. Early silicification is less significant in the NZ, where the alteration is mainly composed of sericite, carbonate, and chlorite alteration affecting both sedimentary rocks and the gabbro unit. Primary and tectonic rock fabrics are often still clearly visible.

Sofia Deposit
Sofia is located approximately 10 km to the west of Massawa, along the more than 30 km long 010° Sofia-Sabodala Shear Zone which hosts the Sabodala gold deposit 27 km to the north. Gold mineralisation has been delineated over a four- kilometre strike length and is controlled by both the host lithology and geometry of strong brittle- ductile structures. The mineralised shear has been differentiated into two zones based on different structural trends along the tectonostratigraphic boundary. At Sofia Main, brittle-ductile structures strike 040°, whereas at Sofia North mineralized structures strike 010° (Sofia North).

Delya Deposit
Three parallel zones of mineralisation have been defined at Delya, over a one-kilometre strike length. The main zone of mineralisation is hosted at the lower margin of the gabbro within highly sheared, silicified and sericitised schist. The mineralized zone varies in thickness from 3 m to 10 m (average of 5 m), contains higher grades (up to 5 g/t Au), and dips to the east at 85°. The other branches are located to the west and have an average dip of 84° to the west. Mineralisation has been drill tested to a vertical depth of 150 m below the surface.

The mineralisation and alteration assemblage consists of sericite-silica-carbonate and chlorite alteration, associated with strong disseminated fine arsenopyrite and pyrite. Arsenopyrite is dominant over pyrite (similar ratios to the Massawa NZ). Gold is largely refractory in nature and locked up in the crystal lattice of arsenopyrite.

The open pit mining operations at Massawa, Sofia, and Delya will consist of multiple open pits, i.e. CZ, NZ, Sofia Main, Sofia North, and Delya. The open pits are being planned to be mined by a mining contractor and a down-the-hole blasting service will be provided by an appropriate blasting contractor. The proposed mining method of conventional 90 t truck and excavator open pit mining is appropriate for the ore body and suitable dilution and ore loss factors have been applied. Randgold has significant experience in other mining operations in the region on similar ore bodies to Sofia, Delya, and NZ and has compared production, modification factors, and costs against these operations to ensure they are suitable. The CZ ore body has execution risk in that the bulk of the gold is hosted within thin lodes containing a large coarse gold component. Higher dilution and ore loss factors have been applied to this ore body to compensate. Any misallocation or misinterpretation of the CZ ore body will result in a loss of value. As such, a detailed GC programme will be an important requirement to successfully mine the CZ ore body.

The proposed WOL and refractory process plant design is based on well-known and established gravity/CIL technology, which consists of crushing, milling, and gravity recovery of free gold followed by leaching/adsorption of gravity tailings, elution, gold smelting, and tailings disposal. The refractory process, which includes sulphide flotation, regrind, and BIOX process, is also a well-known technology that will be supplied by Outotec at a later stage. Services to the process plant will include reagent mixing, storage and distribution, water, and air services.

Ore will be processed in three phases:

Phase 1 – Oxide ore will be processed through primary crushing (mineral sizer), milling, and gravity recovery, CIL, gold recovery stages (acid wash, elution, electrowinning, regeneration), and detoxification of tails prior to disposal.

Phase 2 – Fresh (sulphide) ore will be processed through primary (jaw crusher) and secondary (cone crusher) crushing, mill f ........