Aerial Photogrammetric Survey

Unmanned Aircraft Vehicles (UAV) are a large, diverse group of aerial craft that have no human pilot on board. This group includes model plane, helicopters, drones and other remotely and/or radio controlled machines. New versions of this class are constantly being designed and upgraded to provide a wide range of commercial aerial photography services (stills and broadcast-quality HD video) for industrial photography, feature films, sports coverage, power & gas pipeline surveys as well as...
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Airborne Radiometric Survey

Radiometric surveys detect and map natural radioactive emanations, called gamma rays, from rocks and soils. All detectable gamma radiation from earth materials come from the natural decay products of only three elements, i.e. uranium (U), thorium (Th), and potassium (K). In parallel with the magnetic method, that is capable of detecting and mapping only magnetite (and occasionally pyrrhotite) in soils and rocks, the radiometric method is capable of detecting the presence of U, Th, and K at t...
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Airborne EM Survey

The general objective of Airborne Electromagnetic surveys is to conduct a rapid and relatively low-cost search for metallic conductors, e.g. massive sulphides, located in bed-rock and often under a cover of overburden and/or fresh water. This method can be applied in most geological environments except where the country rock is highly conductive or where overburden is both thick and conductive. It is equally well suited and applied to general geologic mapping, as well as to a variety of engi...
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Airborne Magnetic Survey

A very large number of airborne geophysical techniques have been developed to assist in mineral and hydrocarbon exploration. Aeromagnetic surveying is one of the most common airborne survey types conducted for both mineral and hydrocarbon exploration. Airborne methods are usually the most cost effective tools available for both large regional reconnaissance surveys used as aids in geological mapping and for locating target areas for more detailed follow-up using helicopter borne platforms. ...
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Topographic Surveying

The purpose of a topographic survey is to produce a three dimensional drawing of a particular piece of land or area. Topographical surveys should include all natural and man-made features which are represented by text, lines and symbols on the drawing. The drawing should also include heights and elevations which are represented by spot levels and contours generated at predetermined intervals. GeoSiam use a combination of high precision GPS, Total Station and Laser Scanning to undertake topo...
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GPR Survey

Ground Penetrating Radar (GPR) systems operate by transmitting polarised pulses of electromagnetic energy into the ground and then recording the energy that is reflected back to the surface. The method responds to variations in the electrical properties of subsurface materials (dielectric constant and conductivity) that are a function of material type, moisture content and pore fluid type. Where a contrast in dielectric properties exists between adjacent materials a proportion of the electro...
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Surface Electromagnetic Survey

The electromagnetic induction method is based on the measurement of the change in mutual impedance between a pair of coils on or above the earth’s surface. Most EM instruments are comprised of two or more sets of coils. These coils are electrically connected and are separated by a fixed distance. The transmitter coil is used to generate an electromagnetic field at a specific frequency. This is known as the primary field. The primary field causes electrical currents to flow in conductive mate...
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Gravity Survey

Gravity profiling is a passive technique that involves highly accurate measurement of relative changes in the Earth's gravitational field. Measurements are made using a gravity meter, which comprises a highly sensitive temperature stabilised spring balance. Subtle changes in gravity result from variations in the density of materials within the subsurface and the method can therefore be used to successfully locate voids or buried features such as underground storage tanks. The effects of tida...
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Ground Magnetic Survey

The basic principles of operation are based upon detecting the disturbance to the Earth's magnetic field by buried magnetised materials. The method is entirely passive in that the instrumentation does not have to generate a field itself. The types of materials that affect the Earth's magnetic field include basic igneous rocks, certain forms of mineralisation, and a wide variety of man-made materials and fabrications such as metal pipes, reinforcement bars, electric cables, types of furnace a...
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Induced Polarization Survey

Induced Polarization (IP) effects were first reported as early as 1912 and the method has been in use since the late 1940s. IP is used primarily for mineral exploration, and is also being developed as a tool for geothermal, hydrological and environmental applications. Essentially IP is an extension of traditional resistivity surveying. The ground is characterised not only by its resistivity, but also by its chargeability (how well it holds electrical charge). This means that the geophysicist...
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