Gold grade variation and stream sediment geochemistry of the Vaimba-Lidi drainage system, northern Cameroon (West Africa)

Abstract

Stream sediment geochemistry remains a versatile tool in exploration especially in regionswhere knowledge of the primary mineralization is lacking and the exploration activities are still at reconnaissance stage. In this study, we investigate the concentrations of gold and associated elements in stream sediment samples from the Vaimba-Lidi drainage system in northern Cameroon; a relatively remote area where alluvial gold is worked locally, and exploration activities are at early stage. The main river and its principal first and second order tributaries were sampled, panned for gold grain recovery and the 100 μm size fraction analyzed for Au by fire assay with Ni finish. A suite of other elements were analyzed for by inductively coupled plasma mass spectrometry (ICP-MS). Gold grades estimated by the panning and weighing technique rarely exceed 1 g/t while the Au concentrations from chemical analysis range from 3.0 to 354.0 ppm. The spatial distribution of gold and all the other elements are presented as point symbol maps and the data analyzed using multivariate statistics. From the principal component analysis (PCA), the As-Mo-W-Ag as well as the Au-Zn factors point to the presence of primary hydrothermal gold-sulphide mineralization in the area and this can be further investigated. These results highlight the importance of multielement analysis and multivariate statistical interpretation of sediment geochemical data in inferring the nature of the underlying primary mineralization in any region.No represents the number of samples with concentrations above their detection limit used to calculated the statistics, Min, Max, Std. D represents the Minimum, Maximum concentration value and standard diversion, respecively, / represents no value. t

Regional Geochemical Stream Sediment Survey for Gold Exploration in the Upper Lom Basin, Eastern Cameroon

“…Their weight was related to the weight of the bulk sample and expressed in g/t. The ≤100 microns fraction was dried, pulverised and shipped to the analytical laboratory where gold was analyzed by fire assay with a nickel finish and a range of other elements analyzed by ICP-MS [12]. The statistical treatment of the data laid emphasis on the production of the distribution maps for the various elements as well as the determination of elements association through correlation coefficient and PCA.…”

“…Although several exploration efforts including airborne regional surveys and restricted soil geochemical sampling [6]- [12] have been undertaken in this area, finding economically viable primary deposits in the bedrock has remained elusive. This is particularly true of the Lom region where although alluvial gold is worked by small scale artisanal miners and semi mechanized industrial operations, the primary source of the gold is not yet well constrained.…”

Microchemical signature of alluvial gold from two contrasting terrains in Cameroon

“…Chapman et al, 2009). In Cameroon alluvial gold is mined from the Lom river drainage system and its tributaries (Fon et al, 2012;Embui et al, 2013) and from tributaries of the Nyong river (see www.legendmining.com, for example). Despite intensive mapping, ground geophysical surveys and soil geochemical programmes in the catchment regions of these rivers, the primary mineralization that is the source of gold in the alluvia has not been uncovered.…”

Geochemical investigation of stream sediments from the nlonako area; littoral, Cameroon: implications for Au, Ag, Cu, Pb and Zn mineralization potentials

“…The use of stream sediments in mineral exploration in Cameroon has so far received little attention. However some examples include Embui et al, (2013), Soh et al, (2014), Mumbfu et al, (2014) and Omang et al, (2014). These works have investigated the concentrations of gold and associated elements in stream sediment in some areas of Cameroon with some giving clues on future exploration guides (e.g.…”

“…These works have investigated the concentrations of gold and associated elements in stream sediment in some areas of Cameroon with some giving clues on future exploration guides (e.g. Embui et al, 2013). More so, the areas have had a history of at least some legal artisanal mining and somehow explored.…”