Geologically Molo is situated in the Bekikiy block (Tolagnaro-Ampanihy high grade metamorphic province) of southern Madagascar. The Molo deposit is underlain predominantly by moderately to highly metamorphosed and sheared graphitic (biotite, chlorite and garnet-rich) quartzo-feldspathic schists and gneisses, which are variably mineralised. Near surface rocks are oxidised, and saprolitic to a depth, usually of less than 5m.

The Molo deposit occurs within the regional Ampanihy Shear Zone. The most conspicuous feature of rocks found within this shear zone is their well-developed north-south foliation and vertical to sub-vertical nature. Martelat et al. (2000) state that this observed bulk strain pattern is clearly related to a transpressional regime during bulk horizontal shortening of heated crust, which resulted in the exhumation of lower crustal material.

The Molo Project area is underlain by supracrustal and plutonic rocks of late Neoproterozoic age that were metamorphosed under upper amphibolite facies, and deformed with upright north-northeast-trending structures. The supracrustal rocks involve migmatitic (± biotite, garnet) quartzo-feldspathic gneiss, marble, chert, quartzite, and amphibolite gneiss. The metaplutonic rocks include migmatitic (± hornblende / diopside, biotite, garnet) feldspathic gneiss of monzodioritic to syenitic composition, biotite granodiorite, and leucogranite.

The surficial, lateral expanse and the massive nature of the Molo deposit make it suitable for open-pit mining methods. It is a typical pipe shaped and steeply dipping ore body, with an extended mineral outcrop along the strike (north-south direction) of the deposit. In this mining method, the following activities are executed:

• The land is cleared, topsoil is removed and stockpiled at designated sites for use in future land rehabilitation. Depending on the extent of the base of weathering, any further waste, or ore that can be removed by free-digging is removed and stockpiled accordingly. The topsoil is planned to be used as a berm around the pit to prevent water flow into the pit and to minimise transportation costs

• In a number of cyclic processes the waste and/or mineralised material is drilled, charged with explosives and blasted, excavated, hauled and dumped in designated sites

• At strategically planned periods the waste around the boundary of the pit is removed in order to mine out deeper ore.

The conventional open pit mining activities are carried out with small to medium sized mining equipment including 30t dump trucks, a 2 m3 excavator and a 8 m3 Front End Loader.

The process design is based on an annual feed plant throughput capacity of 240 kilotonnes at a nominal head grade of 7.04% C(t) producing an estimated average of 15-17 kilotonnes per annum (ktpa) of final concentrate.

The ore processing circuit consists of three stages of crushing which comprises jaw crushing in the primary circuit, followed by secondary cone crushing and tertiary cone crushing; the secondary and tertiary crushers operate in closed circuit with a double deck classification screen. Crushing is followed by primary milling and screening, graphite recovery by froth flotation and concentrate upgrading circuit, and graphite product and tailings effluent handling unit operations. The crusher circuit is designed to operate 365 days per annum for 24 hours per day at ±55% utilization. The crushed product (P80 of approximately 13 mm) passes through a surge bin from where it is fed to the milling circuit.

The milling and flotation circuits are designed to operate 365 days per annum for 24 hours per day at 92% utilization. A single stage primary ball milling circuit is employed, incorporating a closed circuit classifying screen and a scalping screen ahead of the mill. The scalping screen undersize feeds into a flash flotation cell before combining with the mill discharge material. Scalping and classification screen oversize are the fed to the primary mill.

Primary milling is followed by rougher flotation which, along with flash flotation, recovers graphite to concentrate from the main stream. Rougher flotation employs six forced-draught trough cells. The primary, fine-flake and attritioning cleaning circuits upgrade the concentrate to the final product grade of above 94% C(t). Concentrate from the main stream feeds into the primary cleaning circuit consisting essentially of a dewatering screen, a polishing ball mill, a column flotation cell and flotation cleaner/cleaner scavenger trough cells.

The primary cleaner column cell concentrate gravitates to a 212 µm classifying screen, from where the large-flake oversize stream is pumped to a high rate thickener located in the concentrate attritioning circuit whilst the undersize is pumped to the fine-flake cleaning circuit.

The fine flake cleaning circuit consists primarily of a dewatering screen, a polishing ball mill, a column flotation cell and flotation cleaner/cleaner scavenger trough cells. The attritioning cleaning circuit employs a high rate thickener, an attritioning stirred media mill, a column flotation cell and flotation cleaner/cleaner scavenger trough cells. Fine flake column concentrate is combined with the +212 µm primary cleaner classifying screen oversize as it feeds the attritioning circuit thickener. Concentrate from the attrition circuit is pumped to the final concentrate thickener.

The combined fine flake cleaner concentrate and the +212 µm may also be processed through the secondary attrition circuit which consists of a dewatering screen, an attrition scrubber, column flotation cell and cleaner/cleaner scavenger trough cells. Concentrate from this circuit is pumped to the final concentrate. The secondary attrition circuit is optimal.

Combined rougher and cleaner flotation final tailings are pumped to the final tailings thickener. Thickened final concentrate is pumped to a filter press for further dewatering before the filter cake is stockpiled prior to load and haul.

The concentrate thickener underflow is pumped to a linear belt filter for further dewatering and fed to a diesel-fired rotary kiln for drying. The dried concentrate is then screened into four size fraction:
• +48 mesh
• -48 + 80 Mesh
• -80 +100 mesh
• -100 mesh

The various product sizes are bagged and readied for shipping.