The Namdini has many characteristics typical of mesothermal Birimian gold deposits.

The Namdini gold deposit is a large, structurally controlled, orogenic gold deposit within the Nangodi Greenstone Belt, with numerous features similar to deposits found elsewhere in late Proterozoic Birimian terranes of West Africa. To date the Namdini gold deposit has been delineated over a strike length of 1.15 km, up to 300 m wide and 700 m deep.

The rock types comprising the Namdini Gold Project included a steeply west dipping Birimian sequence of interbedded, foliated, metasedimentary and metavolcanic units which have been intruded by a medium-grained granitoid and diorite. The southern part of the Project is covered by flat-lying Voltaian Basin clastic sedimentary rocks that have been deposited unconformably on the Birimian sequence and postdate mineralization and the host sequence.

Underneath the weathering profile, the Birimian units include metasedimentary, metavolcanic, granitoid (tonalite) and diorite. The metasedimentary and volcaniclastic lithologies have been intensely altered with a resulting pyrite-carbonate-muscovite-chlorite-quartz assemblage. Alteration is most prevalent in the volcaniclastic units. Similarly, the tonalite is extensively altered and has been overprinted by silica-sericitecarbonate assemblages.

In all rock types, the mineralization is accompanied by visible disseminated sulfides of pyrite and very minor arsenopyrite in both the veins and wall rocks. In diamond drill core, the mineralized zones are visually distinctive due to the presence of millimetre to centimetre wide quartz carbonate veins that are commonly folded and possess yellow-brown sericite-carbonate selvages. Rare visible gold occurs in strongly altered granite and is associated with sub-millimetre wide silica-sericite shears.

Typical shallow weathered zone:
- Average base of strong oxidation: 7m
- Average depth to fresh bedrock: 15m

Gold mineralisation:
- Localised in the 300-400m wide Namdini mineralised “corridor”
- Dominantly hosted by the three main lithologies located within it: Metavolcanics, granitoid and diorite.

Gold at Namdini is dominated by electrum (80% of measured grains) with the remainder as native gold.

Gold grains are generally fine; QEMScan analysis indicates 89% <10 microns.

Visible gold is rare and usually occurs as a vein selvage with chlorite in late-stage remobilised veins.

Gold dominantly occurs as inclusions and fractures in;
- Pyrite (75%)
- Arsenopyrite (8%)
- Quartz and other silicates (6%)
- Chalcopyrite (2.5%).

Circa 5% of gold grains are free gold.

Sulphides in decreasing order of abundance are:
- Pyrite, arsenopyrite, chalcopyrite, galena
- Trace sphalerite, molybdenite, pyrrhotite, gersdorffite and tennantite
- Rutile, ilmenite and magnetite are alsob associated with gold mineralised zones
- Pyrite mostly exhibits grain sizes in the 20 to 140 micron range.

Drilling has outlined mineralization with three-dimensional continuity, with a size of approximately 1,500 m long, 550 m wide, and 450 m in depth.

The primary rock is a muscovite rich phyllite that shows extensive carbonate replacement. The phyllite hosts a major sulfide content and significant gold. The fine-grained muscovite shows a moderate preferred orientation and is heavily impregnated with ankerite carbonate.

The dominant ore minerals are pyrite and arsenopyrite that occur relatively commonly through much of the phyllite matrix. Tennantite, chalcopyrite, pyrrhotite, galena, and sphalerite all occur as fines within some pyrites. Magnetite was also detected once.

About 25 occurrences of gold were detected optically. The vast majority occur as inclusions in pyrite. The gold appeared low in silver. These included golds in pyrites that were predominantly under 5 µm, with the exceptions of a linear nature, reaching 25 µm. Most were single particles plus a rare trio.

The host pyrites had a wide range of grainsizes from 50 to 600 µm. Two occurrences of gold were single, fine grains of 2 µm within silicate.

Mining will comprise a conventional hydraulic shovel operation typically using 400 t class excavators in backhoe configuration for mining ore and face-shovel configuration for mining waste. Rigid body Cat 785 (134 t) class dump trucks will be used for hauling ore and waste on designed access roads. An auxiliary mining fleet of dozers, graders, water carts and utility vehicles will support the mining operation.

Mining will be carried out using staged cut-backs with five identified Phases incorporated within the LOM Final Pit. The mining schedule defines movement of ore and waste on 10 m mining benches, by year, for each of the Phases. It is proposed to mine three flitches in the ore (allowing for blast heave), within 10 m benches.

The Namdini Project will be mined on an outsourced contract.

The maximum peak fleet requirements for the Namdini Project are shown in Table 146 with an expected maximum 27 (134 t capacity) rigid haul trucks and four shovels, three in face shovel configuration and 1 in backhoe configuration.

The mine design for the Namdini Gold Project consists of a series of nested conventional open pit layouts with orebody access provided through a series of ramps. For mining purposes, the Namdini orebody can be considered a layered sequence from top down of the following material types:

* Oxide zone, comprising:
- strongly oxidized upper weathered zone
- moderately oxidized zone with total oxidization of sulphides extending to approximately 10 m average depth from surface

* Transition zone with partial oxidization of sulphides extending to approximately 18 m average depth from surface

* Fresh non-mineralized meta-sediment sequence

* Fresh mineralized host sequence of meta-volcaniclastics, granitoids (tonalite), and diorites.

In the Oxide and Transition zones, a mixture of free-digging, ripping and blasting (after drilling) will be used. In the Fresh zone, competent material at depth will need conventional pre-splitting, drilling and blasting to fragment the rock for excavation. The Oxide and Transition zones are limited in extent with the Oxide zone seldom greater than 20 m below surface. The Transition layer appears more pronounced at the southern end of the Final Pit and is of limited thickness throughout the remainder of the planned mining area.

The process plant design was based on a nominal capacity of 9.5 Mtpa. The feed will comprise blended ore from the pit consisting predominantly of three rock types being approximately 56% Metavolcanics, 29% Granite and 15% Diorite over the LOM. Oxide material will be fed at the end of the LOM once all Fresh + Transition material is depleted.

The process plant design incorporated the following unit process operations:

*Single stage primary crushing with a gyratory crusher to produce a P80 150 mm.
* Crushed ore feeding a coarse ore stockpile (12 hours live).
* Stockpile reclaim by two apron feeders.
* Two stage SAG / ball milling in closed circuit with cyclones to produce a P80 grind size of 106 µm, including recycle and crush of pebbles from the SAG mill (SABC grinding).
* Gravity recovery includes scalping screens, centrifugal concentrators and an intensive leach reactor and dedicated electrowinning cell to recover gold.
* Rougher flotation to produce a gold-rich sulphide concentrate.
* Thickening of the flotation tails for water recovery prior to disposal in a separate non cyanide tailings storage facility.
* Thickening of the flotation concentrate for water recovery.
* Maelgwyn’s Aachen high shear oxidation process on the regrind product before CIL.
* High intensity regrind of the flotation concentrate to a P90 grind size of 9 µm.
* A concentrate CIL circuit incorporating one pre-aeration tank and seven CIL tanks for gold and silver adsorption. Aachen technology will be utilised prior to the CIL.
*A 4.5 tonne split Anglo American Research Laboratory (AARL) elution circuit, electrowinning and smelting to recover gold and silver and produce doré.
* CIL tailings treatment incorporating cyanide destruction by sulphur dioxide and oxygen and arsenic precipitation.
* Concentrate CIL Tailings disposal in a lined tailings storage facility.

The primary crusher was sized on the basis of achieving 75% utilisation. The mine design is based on direct feed to the crusher with minimum rehandle. The crusher will be sized on this basis and to provide capacity for maintenance of the crusher without interrupting mill operation.

Ore will be trucked and direct tipped into the ROM feed pocket for entry into the gyratory crusher. A fixed rock breaker will be used to handle oversize ore. A gyratory crusher was selected to allow direct tipping of ore from 150 t trucks and to achieve the target reduction ratio required for mill feed. As the abrasion index of the ore is moderate no significant wear issues are expected.

Crushed ore will feed a 12-hour live capacity stockpile. The live coarse ore stockpile was selected to ensure adequate surge capacity in the event of a crusher breakdown. Crushed ore will be reclaimed by two apron feeders, each capable of providing 100% of the mill feed.

The milling circuit was sized to reduce the crusher product to the nominal P80 size of 106 µm. The SABC facility provides a more uniform product while minimising operating cost. Pebble crushing was included to reduce any critical size build-up. The SAG mill will be equipped with a variable speed drive allowing a range of mill speed with a nominal design of 75% of critical speed. The ball mill will also be variable speed. The variability in ore competence can be addressed by varying the speed of the mills.

A gravity circuit was included as some of the ore types tested, in the Starter Pit samples in particular, appear to have a reasonably high gravity recoverable gold component.

Inclusion of a flotation concentrate thickener before the regrind facility will achieve a higher regrind feed slurry solids. Thickening also recycles water that is not cyanide bearing for re-use in the grinding and flotation sections of process plant.

The higher regrind feed slurry solids allows CIL tailings decant to be used as process water dilution to meet the regrind mill vendor’s requirements for limiting the mill feed slurry solids content without compromising the plant water balance. The thickener was sized to allow for potential froth management.

A surge tank is installed to store concentrate thickener underflow slurry prior to delivery to the regrind circuit. This allows the primary grinding and flotation circuit to remain operational in the event of a short-term maintenance stoppage or breakdown in the regrind area.

The testwork indicated a simple roughing circuit with a residence time of 30 minutes was adequate without a cleaning stage. Given the significant slurry flow from the grinding facility at 35% solids, tank cells were selected with six cells each with individual level control. All flotation concentrate will report to a single concentrate hopper and be pumped to the concentrate thickener before transfer to the regrind circuit.

Metallurgical testwork indicated that pre-oxidation improved both the gold leaching kinetics and overall dissolution. As a result, a pre-aeration tank was included in the design. Cardinal nominated a leach residence time of 48 hours for design.

A configuration of one pre-aeration tank and seven CIL tanks was selected. The pre-leach and CIL tanks will be the same size. As well as the pre-aeration tank oxygen addition facility, extra oxygen may be added to all CIL tanks to oxidize any cyanicides and maintain an adequate dissolved oxygen level. Cardinal have conducted metallurgical testwork and based on positive results have selected the Aachen technology as the method to add oxygen into the pre-CIL slurry.

The average daily movement of carbon was calculated based on the design feed grade and maximum gold and silver extraction. On this basis a 4.5 t capacity split AARL elution circuit was selected requiring just under seven strips per week. The AARL circuit was selected as it offers the flexibility to run more than one elution per day if needed.

Tails from the flotation circuit will be dewatered in a high rate thickener to recover cyanide-free process water for re-use in the grinding and flotation circuits.