TSXV-listed explorer Orca Gold has released an inferred maiden mineral resource estimate at the Koné prospect, within the Morondo gold project in in Côte d’Ivoire.
The mineral resource estimate for the Koné prospect, undertaken by MPR Geological Consultants of Perth, Australia, comprises 34.1 Mt grading at 1.1g/t for 1.206 Moz of gold at a 0.70 g/t cut-off grade. This resource estimate extends over a strike length of 900 m and to a maximum vertical depth of 260 m.
Drilling to date at Koné totals 17 644 m of reverse circulation (RC) drilling in 115 holes and 528 m of diamond drilling in two holes. Koné was discovered by Red Back Mining in 2010 with 4 284 m of shallow RC drilling completed. Following ministerial approval of Orca’s acquisition of the project from Kinross, Orca has completed 13 888 m of RC and diamond drilling including 13 728 m in the resource area.
The mineralised package at Koné is up to 220 m in true width, dipping 50-55° to the north west. Within this wide mineralised domain drilling has defined a series of lower angle (25-30°), higher grade structures that form a core of mineralisation grading over 1.5 g/t.
The mineral resource estimate has been estimated within the central part of a 2.6 km long gold in soil anomaly, which has been tested by 100 m and closer spaced drill traverses. Mineralisation remains open with several low-grade intercepts received from first pass drilling to the north and little or no exploration carried out to the south. The southern margin of the resource is marked by one of the best intercepts received from Morondo in hole MRC069 which returned 41 m grading 2.11 g/t.
“With only a small amount of drilling in a short period of time, we managed to define a resource exceeding the 1 Moz mark at Morondo,” says Orca Gold president and director Hugh Stuart,
“Mineralisation at the Koné Prospect is remarkably coherent with significant mineralised widths, is easily amenable to open pit mining and shows good leach characteristics. Importantly, there is still a lot of work to do at Koné as it remains open, it is not yet fully explored or understood and is part of a growing mineralised trend that could provide further opportunity,” he adds.
Three composite core samples have been submitted to ALS Ammtec in Perth, Australia for preliminary test work.
Comminution test work confirmed the moderate to soft nature of the rock with BWI values of 3.0, 5.2 and 10.7 kwh/t for oxide, transition and fresh rock, respectively.
Whole rock bottle roll leach tests at -75µm grind returned recoveries of 97.8%, 96.5% and 91.4% for oxide, transition and fresh rock, respectively, with low reagent consumptions of 0.20 kg/t CN and 1.0 kg/t lime.
Heap leach tests (coarse rock bottle rolls) returned recoveries of 95.5% for oxide, 79.1% for transition and 57.4% for fresh using a 5 mm crush size.
The mineral resource estimate and first phase metallurgical test work will form the basis for a preliminary economic assessment, which is expected to be completed in early 2019.
West African portfolio growth
Orca Gold has closed its previously disclosed acquisition from Kinross of a highly prospective land package of 2 268 km2 in Côte d’Ivoire positioned on highly prospective structural trends related to known gold mineralisation and forms a strategic portfolio for Orca’s expansion in West Africa.
The Côte d’Ivoire exploration assets are comprised of: the Morondo licence, located north of the town of Seguela, the Korokaha North licence and Korokaha South application which lie immediately adjacent to the east of Randgold’s Tongon Mine; the Bassawa licence and Satama application, located on the southern extension of the Houndé Belt; and, the Zuénoula Ouest and Zuénoula Est applications, located 40km north west of Perseus’s Yaouré project.