The CLP is a district-scale land package in central Cameroon, covering 4,091km2 of previously unexplored Paleo-Proterozoic to Pan-African age rocks that are highly prospective for a range of commodities, including orogenic-style gold mineralisation and lithium. Located to the west of the regional capital, Ngaoundéré, the package comprises the Eastern CLP licences (Tenekou, Niambaram, Pokor, Ndom and Mbe), the Western CLP licences (Mana, Dogon and Sanga), both prospective for gold, and Gamboukou which is prospective for lithium; Oriole has 90% ownership of all nine licences. A further licence, Maboum, is currently under application to the east of the Eastern CLP.
As of January 2024, BCM is earning up to a 50% interest in Mbe in return for a US$1 million signature payment, US$4 million exploration expenditure and resource-linked success-based payments.
The eight Eastern CLP and Western CLP licences, all of which were granted in February 2021, were applied for following an in-house, country-wide prospectivity analysis that deemed the district as having significant potential to host orogenic-type gold mineralisation. This assessment was made on the basis of host-rock geology, structural location – targeting the regional Tcholliré-Banyo shear zone (TBSZ) which is a major splay off the larger scale Central African Shear Zone. The TBSZ and its associated shears, thrusts and faults are (according to academic literature) thought to be one of the significant structural controls for gold and other mineralisation in the region. Remote sensing work on the CLP has interpreted that the TBSZ passes through at least six licences; all of the Oriole licences in the east of the package and at least one of the BEIG3 licences (Sanga) in the west, with the potential for it to be hidden by the Cenozoic cover rocks in the Mana and Dogon. Following the identification of anomalous lithium-in-soil values (up to 84 ppm) within multi-element data from the Ndom licence, a ninth licence, Gamboukou, was applied for immediately to the south of Ndom. Gamboukou, granted in November 2022.
Eastern CLP
In Q3 2021, the Company completed regional mapping and stream sediment sampling over the Eastern CLP. The results identified multiple areas of elevated gold in distinct drainage basins, associated with the northeast-trending TBSZ corridor and related structures. Best results of 291 ppb Au and 95 ppb Au were returned from the Ndom and Tenekou licences respectively and a total of 18 areas graded >30 ppb Au. Follow-up semi-regional soil sampling (400m by 200m spacing) over six initial grids confirmed anomalous gold in all five licences and has delineated multiple 2-3km long gold-in-soil anomalies across the Ndom, Pokor and Niambaram licences, as well as a broad zone of gold anomaliasm within the Mbe licence, where en-enchelon, structurally-controlled trends are now confirmed to occupy a c.12.5km long by 3km wide corridor. Best results included 838 ppb Au (0.84 g/t Au), 520 ppb Au and 463 ppb Au.
During late Q4-2022 and H1-2023, the Company completed 1:15,000 scale mapping (lithology and regolith) and rock-chip sampling over a c.48km2 area at Mbe to help constrain the source of the gold anomalism. A total of 76 rock-chip samples (including QAQC) were taken over selective outcrops, predominantly quartz veins, within a 3km-long geological zone that is up to 700m-wide. The zone is underlain by a northeast to north-northeast trending, shear-related porphyritic unit (provisionally recorded as quartz-feldspar-porphyry (‘QFP’)) that is highly altered along its central core and is silicified and gold-mineralised. Results of up to 134.10 g/t Au were returned from sulphide-rich and locally brecciated quartz veins that occur within or at the contact of pervasively altered (albite, silica and carbonate) and sulphide-rich QFP.
Subsequent artisanal workings/pits exposed narrow (3-4m wide) trench-like profiles that enabled the collection of 19 channel samples (22 including QAQC) on six parallel lines covering a c.200m strike length of a shear-parallel main quartz vein within the broader 70m corridor. The profiles do not test the full width of the mineralised zone and as such are considered ‘partial’ trenches. Best intervals from the partial trenching included 2.20m grading 8.47 g/t Au (MBTR001), 5.00m grading 2.03 g/t Au (MBTR004) and 2.10m grading 3.69 g./t Au (MBTR005) with all profiles ending in mineralisation in either one or both directions. Mineralisation was confirmed in steeply-dipping, shear parallel (north-east trending) massive silica veins up to 3m wide that show anastomosing, pinch and swell structures. Narrow (up to 1m wide) extensional quartz veins that were typically steeply dipping and trending northwest were also confirmed to grade. Additionally, significant gold grades were returned from the strongly altered wall rock material tested in the near surface, including a 0.90m at 5.94 g/t Au interval ending in mineralisation.
In December 2023, BCM completed a three-week long site visit to Mbe and collected a further 639 samples over the 3km-long zone, each weighing 2-5 kilograms. Of these, 542 samples were collected from pits (5-10 metres deep and exclusively dug by artisanal miners) and 97 samples were collected from outcropping rocks. All of the pit samples were collected from in-situ (weathered saprolite or saprock) material, with composite channel-chip sampling being applied over the exposed pit wall (and perpendicular to the dominant vein set, where apparent) to ensure sample representivity. Results returned 155 samples grading ≥1 g/t Au, 13 of which have graded ≥10 g/t Au. Of these higher-grading samples, best results include 256.74 g/t, 133.44 g/t, 75.09 g/t, 33.66 g/t and 22.89 g/t Au from outcrop sampling, and 25.16 g/t, 23.97 g/t, 9.98 g/t, and 8.75 g/t Au from pit sampling. A further 232 samples graded between 0.20 and 0.99 g/t Au.
The highest grades have been returned from smoky quartz veins and strongly silicified QFP host rocks, which commonly display stockwork veining and boxwork textures after pyrite. These samples also have an abundance of fine-grained aggregations of pyrite encapsulated by silica. The results provide further support for targets at MB01-N and MB01-S, where increased dilation (on the sites of structural intersections) has resulted in enhanced levels of gold deposition. These zones extend over strike lengths of at least 650m and 750m respectively, and over widths of more than 500m. Importantly, the data shows that the plus 1 g/t Au grades persist outside of the discrete veins, extending well into the more weakly-altered QFP host rocks to create wider halos of pervasive mineralisation and alteration
Work programmes are currently being designed for the next phase of exploration at the project.
CLP Lithium
A review of stream and soil multi-element data has also identified the potential for lithium within the Ndom licence. Two lithium-in-soil anomalies trending east northeast, parallel to the regional shear, and extending up to c.9km in length were identified in the south-eastern Ndom licence area with lithium-in-soil values up to 84 ppm.
The southernmost anomalous trend overlies an east-northeast trending massive granitoid outcrop, confirmed to be highly fractionated and likely S-type granites (derived from sediments) known globally for their association with lithium deposits. Preliminary mapping of the Li-in-soil anomalies delineated the extent of the granitoid body and confirmed the presence of numerous pegmatite veins in granitoid outcrops, and within the Pan-African basement rocks (greenschist to amphibolite facies, tonalite- trondhjemite-granodiorite ‘TTG’), with widths ranging from a few centimetres to several metres.
While lithium bearing minerals have not been identified in the field, given abundance of white micas in some specimens, and the geochemistry to date, the presence of lithium bearing minerals (petalite, lepidolite) and cassiterite (tin-bearing mineral that commonly occurs in pegmatites) are suspected.
Rock chip samples from a range of pegmatites from Ndom have been collected for geochemical analyses and other technical studies to help resolve the mineralogy of the pegmatites.
A reconnaissance visit to Gamboukou was conducted, confirming the presence of similar pegmatite and granitoid outcrops to those at Ndom. A first-pass stream sediment campaign is being planned to help with targeting with the licence.
Western CLP
At the Western CLP, the structural control is interpreted to be dominantly north-northeast-south-southwest, associated with more recent (Cenozoic) bimodal volcanism that is believed to overlie the older Paleo-Proterozoic to Pan-African rocks and may represent a reactivation of older structures. Variably deformed orthogneiss units dominate the licence package, intercalated with amphibolite, quartzite and migmatite units and shearing and quartz vein development is parallel to the TBSZ, with the veins typically forming at the contact zones between the granite and amphibolite. Locally these units are cut by younger, basaltic rocks, supporting the interpretation for bimodal volcanism. In addition to the orogenic mineralisation being targeted within the licence package, this more recent volcanism highlights the potential for other styles of gold mineralisation (e.g. high-sulphidation), which may overprint the older system locally. Work is yet to commence at these licences.
Mbe JORC Table 1
CLP (not incl. Mbe) JORC Table 1