Preliminary geological evaluation of Alihiley Emarald Prospect near Boroma, Somaliland
Country: Somaliland Region: Horn of Africa Period: 2012 Commodity: Emerald
- Historic mining of emerald had been reported in the area; a single crystal of high purity emerald weighing about 1600 gm could be found.
- The prospect is marked with presence of biotite schist traversed across by large pegmatite veins. The pegmatite veins are fairly homogenous with dominance of K-felspar, some quartz & minor mica.
- Within the biotite rich zones, minor pegmatite veins hold emerald crystals.
- The transparency & green colour of Emerald is attributed to infusion of Chromium ion in the beryl crystal lattice; biotite schist appears to be the source of chromium.
- Equipment selection and engineering design to explore the prospect needs to be appropriately evaluated, including probability of underground mining.
- Local miners lack appropriate mining skill, knowledge, and tools for excavation of un-fragmented crystal.
Geophysical prospecting to delineate talc-magnetite schist bearing emerald in 02 prospects under Ndola Rural Restricted Area (NRERA), Zambia
Country: Zambia Region: Central Africa Period: 2015 Commodity: Emerald
The prospect is located in Kafubu Emerald belt in central region of NRERA, about 45 km southwest of Kitwe. The region comprises of Proterozoic age ‘Muva Supergroup’ comprising quartzite, mica schist, and metabasites. Emerald mineralization is hosted within the metabasite comprising Talc-Chlorite-Actinolite & Talc Magnetite Schist. High chromium in these rocks induced green colouration of emerald. At later stages beryllium rich pegmatite & quartz-tourmaline veins intruded thus accentuating metasomatic alteration of the Cr bearing TMS by Be-bearing fluids. Based on this background a broad scope of work has been designed to undertake the following,
- 2D Electrical Resistivity Imaging to trace possibility of identifying TMS & reaction zones targeting a depth of up to 50 m.
- Process & Interpret 2D resistivity sections to decipher vein structures & possible TMS zones.
- Diamond Core drilling prospection to discern geological conditions in reference to the ERI sections.
- Technical Report illustrating the program & overall potentiality of the asset.
A total of 12 ERI sections totalling 6000 m at 05 m electrode spacing was conducted. A few sections showed interesting results which contest to the conceived idea about likely presence of TMS, based on which 04 Diamond Core Drilling targets were evaluated.
The core holes encountered laterite/weathered zone up to about 20 meters followed with metabasites in form of amphibolite schist & intermittent biotitic-phlogopite zone. However, appreciable reaction zones with TMS & QT veins could not be traced. Geological sections based on borehole intercepts & 2D ERI sections led to conclusion that the prospect may not bear near surface geological conditions that signify ideal environment for targeting emerald bearing zones. The investigation helped the investors to judge the possibility of further development/abandonment of the asset.
Geophysical data processing, interpretation & 3D modelling of Emerald asset near Ndola, Republic of Zambia
Country: Zambia Region: Copper Belt Province Period: 2016 Commodity: Emerald
The permit covers about 43 sq. km. under the Ndola Rural Emerald Restricted Area (NRERA) in Kafubu area in the Copperbelt Province of Zambia. 03 claims within the permit area were chosen for processing, interpretation & 3D modelling. Emerald mineralization is hosted by primarily in talc magnetite schist (TMS) within the Proterozoic age Muva Supergroup. Scope of work entailed the following.
- Review & analysis of existing airborne geophysical datasets.
- 3D quantitative modelling using VOXI, MVI and generation of 2D sections.
- Inversion refinement using magnetic susceptibility measurements.
- Model validation by incorporation of drilling data and importing leapfrog geo-models into VOXI environment.
- Demarcation of major lithological units’ (TMS) that holds potential for mineralization along with geological structures and suggest targets for further exploration.
- Prepare & submit detailed report with interpretation, conclusions & recommendations
Magnetic susceptibility values of the significant lithological unit (TMS) have been measured in laboratory & used as a parameter to delineate the magnetic sensitive body in 3D space. Distribution of the magnetic values indicated likely presence of TMS & reaction zones from below the surface up to about 200 m. With this 3D models developed for the 03 claims, it became pertinent to plan for drilling quantum & possible trends to hit the target zones.
Exploration Review, Due Diligence studies & Preliminary Exploration to delineate Kimberlite Pipe intrusion in Orapa Diamond Field in Central District, Botswana
Country: Botswana Region: Central District, Southern Africa Period: 2022 Commodity: Diamond
Orapa Kimberlite field has been a region of immense interest for prospecting high grade diamond mines from historic times; at least 85 Kimberlite pipes have so far been identified, a few of them are currently being exploited for high Cpht diamond. In the current program one of the kimberlite pipe areas AK10 has been under purview. Scope of work in the program include,
- Review of literature & modelling of Historic drill data: Previous exploration data to be reviewed and geological model (using SURPAC) to evolve with the sub-surface configuration of the Kimberlite pipe.
- Undertake High Resolution Magnetic Survey (HRMS) to map magnetic characteristics of the host & kimberlite. HRMS was undertaken with high resolution GEM equipment (0.01 nanoTesla) for a total 26 Line Kilometre (LKM) in a 50-hectare area around the kimberlite body maintaining a 20 m spacing between lines in continuous data acquisition mode. Processing & Interpretation to delineate the spatial extent of the kimberlite pipe within the surveyed area.
- Modelling of Magnetic data: Magnetic data shall be modelled in 3D space to interpret sub-surface configuration of the anomalous body in the subsurface. Approximate vertical extension of the kimberlite body & its disposition shall be deciphered in the process.
- Drilling prospection supervised by CGCL with 03 Diamond Core holes (cumulative 500 m) and percussion drilling with a cumulative total of 1000 m in 5 drill hole locations. Logging & sampling of recovered samples shall be performed by a geologist following standard procedures.
- Drilling samples analysed for mineral composition, grain distribution & presence of Kimberlite Indicative Minerals (KIM) in the recovered samples.
- A technical report that would include detailed discussion on results obtained, geological modelling, HRMS survey, magnetic modelling & sample analysis, all indicating characteristic of the kimberlite pipe.
