Search

Geological modeling is an essential step in mineral resource assessment. Geologists typically use deterministic methods to create interpreted models, which ignore the uncertainty in the geological domain layout. This study explores a hierarchical approach for simulating a categorical variable (lithological domain) and a continuous variable (iron grade) in a deposit located in Cameroon, enhancing confidence and accounting for geological uncertainty in resource evaluation. To achieve this, lithological domains are simulated using a non-stationary variant of the plurigaussian model, followed by the simulation of iron grade while accounting for its spatial correlation within and across domains. Cross-validation is used to validate the model, and the simulated block models are processed to assess in-situ and recoverable resources and their uncertainties. [ABSTRACT FROM AUTHOR]

Modeling the spatial dependence structure of metal grades in the presence of soft boundaries between geological domains is challenging in any mineral resource estimation strategy. The aim of this work was to propose a structural model adapted to this type of geological boundary, based on a multivariate Matérn model that fits the observed direct (within domain) and cross (between domains) correlation structures of metal grades. The methodology was applied to a case study of an iron deposit located in southern Cameroon. Cross-validation scores show that accounting for the grade correlation across domain boundaries improved the traditional workflow, where the grade was estimated in each domain separately. The scores were significantly better when we also ensured that the mean grade was locally invariant from one domain to another to reflect the grade continuity across the domain boundary. [ABSTRACT FROM AUTHOR]

The Lom volcano-sedimentary formation belongs to the Adamawa-Yadé (AYD) domain of the Pan-African fold belt in Cameroon. It is a geological formation presenting mineral deposits of economic potential such as gold and diamonds. The area is under small-scale and many artisanal gold mines. A geophysical study was carried out in the village Yassa, a locality situated within this geological formation, close to an artisanal mining excavation in order to define and propose a model of potential mineralized targets. The geophysical study involved the combination of electrical resistivity tomography (ERT), induced polarization (IP), and self-potential (SP) methods. The acquisition of data consisted of 15 electrical tomography lines in Schlumberger arrangement and a collection of SP data along these profiles in the absence of injected current. The anomalies of possible sulfide mineralization were found at a depth of about 10–25 m with a major NE–SW trend by applying the Euler deconvolution to the SP data. The ERT and IP data allow the production of the 2D inversion which is interpolated to obtain pseudo-models of the isosurface of potential mineralization. The correlation of geological information and the 3D isosurface pseudo-models indicates the characterization of zones with sulfides, with high chargeability values (≥ 30 mV/V). A body exhibiting this high chargeability correlating with a low resistivity (≤ 60 Ω m) is observed south of the study area. This body linked to a sulfurized zone presents its roof at an average depth of 13 m with a lateral extension in depth and a NE–SW orientation in agreement with the overall orientation of the area's major tectonic lines. Another polarizable body, located in the near surface to the north of the study prospect over an average depth of about 10 m, correlates with high resistivity (4500 Ω m), thus characterizing a probable zone of silicification. [ABSTRACT FROM AUTHOR]