The Otjikoto deposit is located within the Damara Mobile Belt, which forms part of the Pan–African Mobile Belt system. The Damara Mobile Belt consists of two branches, one running approximately parallel to the present Namibian coastline, while the second branch strikes north-eastwards and is referred to as the “Intracratonic Branch”. Otjikoto is located within the northern portion of the Intracratonic Branch.

The Otjiwarongo-Otavi regional area is located in the Northern Central Zone and Northern Zone (“NZ”) of the Damara tectonostratigraphic zones. The Otjikoto exploration properties lie primarily within the NZ. The Otjikoto area is predominantly underlain by lithologies belonging to the Neoproterozoic Swakop Group of the Damara Orogen. The Okonguarri Formation, of the Swakop Group, hosts the gold mineralization and is overlain and underlain by distinctive glacial diamictite horizons, the Ghaub and Chuos formations, respectively. The Okonguarri Formation is principally composed of thick units of dark grey carbonaceous marble, biotite-schist, graphitic schist and calc-silicate horizons.

Gold in the main Otjikoto deposit is hosted by a NNE striking sheeted sulphide (+ magnetite) - quartz+carbonate vein system. The system has been traced over a strike length of 2.3 km, to a depth of 475 metres below surface. The mineralized zones trend NNE, dip 20° to 30° to the SE and contain higher grade shoots which plunge at 10 15° to the SSW. The gold occurs in a series of thin (commonly less than 10 centimetres) sheeted veins in the schist and granofels of the Upper and Middle Okonguarri Formation. The main Otjikoto gold deposit lithology has been divided into three principal mineralized lithostratigraphic units, from top to base, the OTC, OTB and OTA. The albitite-hornfels OTC unit hosts most of the mineralized vein system and is underlain by the six metres to ten metres thick un-mineralized calcitic marble, the OTB horizon. The albitized granofels OTA unit (~30 metres thick), which hosts minor bedding-parallel veins with irregularly distributed gold values, occurs between the OTB marble and the footwall marble (~20 metres thick). The OTA granofels and the OTB marble are part of the Middle Okonguarri Formation and the OTC is the basal unit of the Upper Okonguarri Formation. Shear zones and thrust faults locally disrupt the stratigraphy and veining. Gold mineralization is spatially related to the shear zones. Most of the stronger zones of gold mineralization are situated below an albite marker horizon and associated thrust fault.

Gold occurs within the vein system as coarse native gold with a size variation from 5 microns to 400 microns, with the median at about 100 microns. Gold occurs adjacent to and within sulphides, along fractures, adjacent to and within garnets, within magnetite, on the edges of amphiboles and chlorite, and as free gold in quartz and carbonate.

The Otjikoto open pit operate with traditional equipment and methods. Ore and waste are emulsion blasted, then loaded with hydraulic excavators and shovels into 100 tonne class haul trucks. For 2016, Phase 1 of the Otjikoto Pit is expected to provide most of the ore tonnage, while Phase 2.

The original design of the Otjikoto mill was based on a gravity/whole ore leach flow sheet with a nominal treatment rate of 2.5 Mt/a and a plant availability of 94%. A 25% design factor was included for sizing the primary crusher, conveyors, ball mill, thickeners, cyanide destruction circuit, reagent systems and mainstream pumps which would facilitate a future expansion. A pebble crusher was installed in the SAG mill circuit and two leach tanks were added to the leach circuit in the second half of 2015 to expand the mill capacity from 2.5 to 3.1 Mt/a.

Gold is recovered by gravity concentration/intensive leaching and by a cyanide leach/CIP process for treatment of gravity tailings. The Otjikoto mill design is robust and able to process the three major ore types (XR1 – oxide, XR2 – pyrite-dominant, XR3 – pyrrhotite- dominant) and now Wolfshag over the range of ore grades mined, and with variable materials handling and metallurgical characteristics.

The proces ........