Introduction

The Geophysical and Geochemical Section (GGS), under the Geoscience division of the Department of Mines and Geology (DMG), is responsible for mineral prospecting and geo-hazard assessment using various geophysical tools. This section conducts various geophysical and Geochemical survey methods (electrical, Magnetic, seismic, and Gravity) as appropriate.

Main objective geophysical and geochemical section

1. To conduct geophysical and geochemical methods for prospection and exploration of various mineral resources.
2. Data acquisition and interpretation of sub-surface information (soil depth, shear wave velocity, soil layer, soil type, etc.) for geoscientific research and geo-hazard assessment.
3. Conduct ERT, GPR, Microtremor, etc. surveys for foundation studies and hazard assessment.
4. Prepare high-resolution Digital Elevation Map for various use by Drone survey.

 Existing geophysical equipment with brief description                

1. WCZ Proton Magnetometer: -

WCZ-3 proton magnetometer is a new generation of fully digital proton magnetometers having complete GPS navigation ability. It is applicable for mineral prospection (iron ore, lead-zinc mine, copper mine), engineering application such as buried pipeline tracing, assess diurnal variation of the magnetic field, and so on.

2. Electrical Resistivity and Induced Polarization Imaging System -

The instrument GD 10 Supreme can conduct Electrical Resistivity Tomography (ERT), Induced Polarization (IP), and Spontaneous Potential data acquisition of subsurface material.  It has the ability to conduct both 2D and 3D surveys as necessary.

3. GPR Survey: -

Ground Penetrating Radar (GPR) is a non-invasive method of material analysis based on transmitting electromagnetic signals. GPR survey is used in geological application and engineering applications, based on the frequency of transmitting signal: In geological applications, it is more useful if the frequency is less than 500 MHz In engineering applications, low depth of penetration and high resolution would be possible if the frequency is more than 500 MHz). DMG has GEOSCANNERS AB, GPR set with 100 MHz transmitting frequency. This set is more applicable for relatively high depth of penetration.

4. Drone Survey: -

A drone survey is the cheapest and latest technique to develop high-resolution Digital Elevation maps of selected areas. These maps are applicable for various uses of geosciences, such as landslide study, neotectonics study, land use planning etc.

5. Microtremor Survey: -

The microtremor survey method is the latest developed technique, used to acquire the natural period of geologic material, seismic vulnerability index, shear wave velocity, sub-sediment layer, etc. These parameters are useful to assess the seismic hazard for urban planning.