Integrated Geophysical Investigation to delineate potential gold (& silver) mineralization in Phom Syarung Permit, Cambodia
Country: Cambodia Region: Ratanakiri, Cambodia, Southeast-Asia Period:2015-16 Commodity: Gold & Silver
A 12 sq. km. permit area has been evaluated for potential gold mineralization in epithermal high sulphidation setting over a porphyry gold deposit by use of geophysical techniques including airborne magnetic & radiometric interpretation, High resolution ground magnetic survey, Self-Potential survey, 2D Electrical Imaging (Resistivity & IP) & 3D modelling of geophysical data.
While radiometric data interpretation led to defining the K-rick areas, airborne magnetic rendered it possible to interpret geological structures & lithological domains including granite, granodiorite, diorite & andesite. High Resolution Ground Magnetic data covering the area in 122 LKM assisted in refining the structures & boundary of lithological domain, that led the focus on a porphyry gold system. Self-Potential survey with cumulative of 52 LKM defined broad zones of sulphide mineralization in 03 pockets that led to planning of 2D Resistivity & IP survey for a cumulative 15 LKM across the zones of interest up to 250 m depth below surface level.
While the resistivity sections indicated structural fabric of the rock unit, IP signatures point towards a high chargeability mineralization zone that occur at a depth of about 100 m below ground surface, complimented with low resistivity values indicating metal presence. Structures features with possible epithermal vein system could also be deciphered in the investigation.
3D Modelling of the 2D Electrical (IP) sections evolved a large mineralization zone in one of the pockets that extend for about 1200 m with a width of about 800 m at a depth of 100 m below ground level. The recommended drill holes for verification yielded mineralization zone of about 80 m thickness with presence of economic grade silver from 100 m below ground level. Correlation of the bore holes with geophysical results reiterated the resource position & dimension interpreted based on geophysical results.
Reconnaissance geo-scientific investigation to assess gold mineralization in a prospect near West Pokot, Kenya
Country: Kenya Region: Rift Valley Province Period:2016 Commodity: Gold & Copper
The program involved reconnaissance investigation in two conjugate assets encompassing 750 sq. km. The objective of the study was to identify mineralization zones based on hydrothermal signatures in regional scape, collection of representative samples & scoping for further exploration. Scope of work entailed the following,
- Extraction of geological features from satellite data using multispectral datasets such as ASTER & LANDSAT and terrain features from satellite-based DEM. Cultural features were mapped using high resolution satellite data.
- Analysis of satellite data for identifying hydrothermal alteration signatures as an aid to targeting zones of mineralization.
- Using Priority Zone Classification scheme to identify probable mineral potential zones in a GIS platform.
- Ground based reconnaissance survey, preliminary assessment of geological conditions, mining practices, collection of surface samples & assaying.
- Recommendations to further investigation on ground based on a comprehensive review of the results.
GIS based priority zone classification scheme was created by distributing entire area in a 500 m x 500 m regular grid. The grids were prioritized according to the mineral abundance of signatures from various routines & its relation to geological structures. Out of the total of 3,339 grids being analysed, 12 grids are categorised under ‘Very High Probability’, 48 under ‘High Probability’, 369 under ‘Moderate’ & 352 under ‘Low probability’. Most of these grids are suitably clubbed to define 27 zones which shall be seeds for further investigations.
A total of 71 samples were collected that returned assay values ranging between <1 ppb to a high of 65736 ppb Au, while Cu concentration was estimated between 0.75% to a high of 28.05%.
Remote Sensing analysis of the multispectral datasets emerged a vital contribution in defining the mineral zones that allowed a qui
Geo-Scientific Assessment of a Gold Prospect near Kwekwe, Midlands Province, Republic of Zimbabwe
Country: Zimbabwe Region: South-central Africa Period: 2019-2020 Commodity: Gold
The project area covered a total of 6.4 sq km with indicative gold mineralization in 02 pockets with active artisanal mining. Broad scope of the program includes,
- Preliminary investigation including pitting/trenching at selective locations.
- High Resolution Magnetic Survey (HRMS) with the aim to identify structural fabric engrossing rock units in the area.
- 2D Electrical Imaging (Resistivity & IP) survey across selective profiles in reference to those interpreted structural & lithological features. A target depth of 90 m with electrode spacing of 05 m was conducted in the program.
- Drilling exploration for the purpose of verification of interpreted chargeability zones in selective location identified in 2D sections.
- Logging, sampling & assaying of bore hole intercepts to analyse the content of chargeability zones, with primary focus on gold mineralization.
- Overall assessment of the property based on outcome of assay distribution in the samples.
The area was first evaluated with Remote Sensing studies to assess regional structures, lithological demarcations & hydrothermal alteration signatures. This was followed with near surface exploration by pitting/trenching at 48 locations. HRMS survey was undertaken to cover the area in 135 LKM at 50 m interval in continuous data acquisition mode. The interpreted magnetic data indicate several structural domain & framework which assisted in planning 2D Electrical imaging across prospective zones of mineralization. The 2D imaging survey indicated chargeability conditions based on which 06 sites were identified across different sections for verification of mineral concentration across the sub-surface chargeability zones. A cumulative of 500 m of drilling was conducted in these core holes followed with logging & sampling (core split sample). Assay was performed on 325 samples, subsequently. The results indicated depleted source of epigenetic gold present which may not account for large scale economic extraction. The study helped in quicker decision making which prevent investor in concluding the feasibility condition of the ore in the prospect.
Ground Magnetic Investigation to evaluate a gold asset Kedougou Region, Senegal
Country:Senegal Region: West Africa Period: 2021 Commodity: Gold
The geo-prospecting services was undertaken for evaluating a prospecting permit spanning 56 sq. km. area located in eastern part of Senegal.
Objective of the investigation was to assess structural framework in permit area in a bid to target zones of possible mineralization related to hydrothermal regime that has evolved due to orogenic deformation experienced in region, particularly in the permit area The service entailed the following scope of work,
- High Resolution Ground Magnetic Survey across entire prospect in a regular pattern of 200 m line spacing in northwest-southeast orientation followed with infilling of line in 100 m spacing in selective portions in the permit.
- Process, analyse & interpret the structural & lithological regime experienced in the prospect & identify potential mineralization zones for further assessment.
- Recommend future prospecting schemes in target areas for detailed mapping & exploration.
A total of 374.70 LKM of on-ground survey was conducted to cover the area using GEM systems GSM19TW Proton Precision Magnetometer (PPM) equipment. Data acquired in the field has been processed to produce anomaly maps and several derivative information pertinent to interpretation of the structural features.
Interpretation drawn from several magnetic datasets led to delineation of structural framework and characterising the interpreted features in Major & Secondary categories. Major structures are aligned in northeast-southwest orientation in tandem to the regional structural trends. Secondary structures orthogonal to the major structures. Based on this interpretation 07 Zones have been recommended for further geophysical prospecting covering about 28.0 sq km (50% of the permit area). Taking reference from these 07 zones, a future prospecting program was conceived to cover target areas in 04 blocks. The future prospecting program would cover 2D Electrical Imaging (Resistivity & IP) followed with core drilling in target locations.
Integrated Geophysical Prospecting for Gold Mineralization in 02 concessions, Mandiana Region, Guinea
Country:Guinea Region: West Africa Period: 2022 Commodity: Gold
The geophysical prospecting program was undertaken to evaluate two prospecting permit spanning 30-hectare & 95 hectares in eastern part of Guinea, bordering Mali. Objective of the investigation was to assess structural framework in the concession to target zones of possible mineralization evolved due to orogenic deformation in the sedimentary formation. The services entailed following scope of work,
- High Resolution Ground Magnetic Survey covering the areas at 50 m line spacing in continuous data acquisition mode
- 2D Electrical Imaging (Resistivity & IP) covering the anomaly areas identified in magnetic results, generating 2D sections to a target depth of 80 m.
- Interpretation of structural features & chargeability zones in sub-surface based on above studies.
- Comprehensive analysis of geophysical data & geological attributes to demarcate zones of potential mineralization.
In this program a total of 25 LKM of Magnetic survey was conducted (cumulative of both the concessions) with 2D Electrical Imaging in cumulative 8 LKM of survey length. The results indicated presence of North-South trending structures; a few of such structures appear to be associated with high chargeability zones (potential gold mineralization signatures) bounded within the sedimentary strata. The results hold importance in identifying the zones for drilling & defining the mineralized body underneath. This study also put forth the groundwater condition for exploitative purposes.
Geoscientific prospecting to evaluate large Gold asset, Tiris Zemmour region, Mauritania
Country:Mauritania Region: West Africa Period: 2021- 2022 (ongoing) Commodity: Gold
This is a long-term asset evaluation program initiated with regional coverage of 8,500 sq km of green field area in the Sharan Desert located towards North-eastern region of Mauritania. Strategic planning for stage wise prospecting was mooted ideal to evaluate the asset considering regional to local level studies. Scope of work included the following tasks,
- Airborne Data Analysis: Airborne magnetic data processing, interpretation & analysis to identify regional structures/shear zone, broad demarcation of lithological units & delineate anomaly signatures related to mineralization.
- Satellite Data Analysis: Procurement, processing, analysis of multi-spectral satellite data (LANDSAT series & ASTER) for lithological, structural & hydrothermal alteration mapping, DEM data for terrain analysis and High-resolution remote sensing data for land feature & accessibility analysis.
- Ground Assessment: Semi-regional & detailed Geochemical sampling (near surface), Ground Geophysical, Drilling, Resource Assessment, Feasibility Studies
Airborne & Satellite data interpretation helped in identifying regional structures, lineaments & 02 major shear zones, target areas of hydrothermal alteration signatures & identification of lithological units. Semi-regional geochemical program in demarcated potential zones led to identification of smaller blocks earmarked for Ground Investigation. Geochemical results are encouraging to undertake further prospecting program. Ground Magnetic Survey in some of the blocks have already been initiated followed with 2D Electrical Imaging (Resistivity & IP). Targeting specific potential zones in the vast terrain was possible in quick time for strategic development.
2D Induced Polarization Imaging survey to delineate and model (3D) of anomalous sub-surface sulphide mineralization zones, Kedougou, Senegal, West Africa
Country:Senegal Region: West Africa Period: 2023 Commodity: Gold
