Freda Rebecca is lies on the central axis of the synclinal Mazowe-Bindura Greenstone belt. The geology of the area around FRM is characterised by the Shamvaian sediments, diorite and granodiorite. Dolerite dykes cut through the three rock types. The FRM orebodies are largely hosted by the Prince of Wales diorite and the Bindura granodiorite, with limited transgressions into the metasediments. The mineralisation is hosted within two major shear envelopes: the footwall/curvilinear Freda-Promoter which strikes from north east through to east west and dips at 0 to 25° to the south; and the Rebecca which strikes north west and dips at 35°. Individual shears are variable in width and these two systems merge to the south west at depth flattening at around 850m elevation and extending into the metasediments. The shear system is characterized by a set of anastomosing shears separated by relatively undeformed rock units.

At FRM there are two styles of sulphide mineralisation: older disseminated, pervasive sulphides occurring throughout the sediments, diorite and granodiorite, which vary in intensity and grade; and younger mineralisation restricted to shear zones and associated with higher gold grades. In both types of mineralisation, higher grades are associated with fine-grained sulphides. Sulphides include arsenopyrite, pyrite, pyrrhotite and chalcopyrite. Mineralisation is characterised by patchy micaceous chloritic alteration with some silicification and to a lesser degree, carbonatization. Quartz veins generally do not carry gold values but may contain minor amounts of sulphide. Payable gold mineralisation is not visually distinct so assaying is required to outline the ore zones.

The underground mine is accessed by ramps driven from portals in the old open pits and the current depth of mining is some 200m below these portals. A sub-level stoping mining method is predominantly employed and the ore is trucked to surface using a variety of articulated dump trucks. One-way haul distances are of the order of 3-3.7km and the cycle time for trucking is typically 45 min. Adaptations of this mining method as well as room and pillar mining are undertaken depending on the characteristics of the orebody and stope design.

RoM is delivered to the plant by dump trucks and is crushed via one of two jaw crushers. Rock that is too large to be crushed is removed and stockpiled for secondary blasting. After crushing the ore is stockpiled ahead of single stage semi autogenous grinding (SAG) mills in two similar parallel milling circuits. The SAG mills are closed by hydro cyclones and a portion of the cyclone underflow is directed to Knelson centrifugal gravity concentrators. Gravity concentrates are processed by intensive cyanidation in an InLine Reactor ahead of gold recovery by electro-winning. Approximately 20% of the gold recovered is attributed to gravity concentration. Cyclone overflow is pumped to a cluster of dewatering cyclones to increase the percentage solids to that required in the pre-leach and carbon in leach (“CIL”) adsorption circuit. Lime is added earlier in the process at the mill feed. Appropriate lixiviant levels are maintained by the controlled addition of calcium cyanide and oxygen. Loaded carbon is removed from the adsorption circuit for elution and electro-winning in an AARL elution circuit. Loaded cathodes are digested in hydrochloric acid ahead of washing, drying and smelting to doré. Eluted carbon is thermally regenerated before being returned to the adsorption circuit. Adsorption tails are pumped to tailings.