Orca executed a share purchase agreement in early 2017 with two subsidiaries of Kinross to acquire the Morondo and Korokaha North exploration licences and five other exploration license applications (see Company News Release on February 1, 2017). The Korokaha North licence and Korokaha South application lie adjacent to the east of Randgold's Tongon Mine. The Bassawa and Satama applications are located on the southern extension of the Houndé Belt. The Zuénoula Ouest and Zuénoula Est applications are located north west of Perseus's Yaoure project.
The 300km2 Morondo exploration Permit is located in central Northern Côte d’Ivoire and is the most advanced of the Company’s projects. Gold mineralization at Morondo was discovered by Red Back Mining in 2010 who completed 4,284m of shallow RC drilling before the company was acquired in the same year.
Following approval by the Minister of Industry and Mines of the Republic of Côte d'Ivoire for the portion of the Transaction related to Morondo (see Company News Release on November 6, 2017), the Company completed a 2,211m drill programme on this permit in late 2017. This drilling confirmed that the mineralisation intersected in the earlier drilling extended to depth.
During 2018, Orca completed a further 11,667m of RC and 528m of diamond drilling leading to the estimation of a maiden resource at the Koné prospect in the Morondo Exploration Permit.
Mineral Resource Estimate at Koné Prospect
The Mineral Resource Estimate was undertaken by MPR Geological Consultants of Perth, Western Australia ("MPR") who estimated mineral resources using Multiple Indicator Kriging ("MIK") based on mineralised domains interpreted by MPR.
The Mineral Resource Estimate is shown below at a range of cut-off grades and by oxidation category at cut of grade of 0.70g/t:
Table 1: Koné Mineral Resource Estimate as at October 3, 2018
Table 2: Koné Mineral Resource Estimate at 0.7g/t cut off by Oxidation Category
The Mineral Resource has been prepared in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum "CIM Definition Standards for Mineral Resources and Mineral Reserves" (CIM, 2014). Numbers may not add up due to rounding.
Drilling to date at Koné totals 17,644m of reverse circulation ("RC") drilling in 115 holes and 528m of diamond drilling in two holes.
The mineralised package at Koné is up to 220m 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 (Figure 3) that form a core of mineralisation grading over 1.5g/t.
Mineralisation is hosted within a variably foliated diorite intrusive and is associated with biotite alteration, minor silicification, disseminated pyrite and quartz-carbonate-pyrite-chalcopyrite veining.
The Mineral Resource Estimate has been estimated within the central part of a 2.6km long gold in soil anomaly, which has been tested by 100m and closer spaced drill traverses (Figure 3). 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 41m grading 2.11g/t.
Metallurgical Test Work
In Q2/2018 three composite core samples were 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 10.7kwh/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 0.20kg/t CN and 1.0kg/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 5mm crush size.
Preliminary Economic Assessment
The Mineral Resource Estimate and first phase metallurgical test work will form the basis for a Preliminary Economic Assessment ("PEA") which is expected to be completed in early 2019.