GBG GROUP NEWS

Geophysical Investigation to Locate and Map Contamination and Footings Within an Old Gas Works, Central NSW

GBG Australia undertook a non-destructive geophysical investigation to locate and map the location of contamination and footings within an old gas works in Central, NSW. For this investigation Ground Penetrating Radar (GPR), Frequency Domain EM (FDEM) and Earth Resistivity Tomography (ERT) were used.

The GPR data was collected using the GSSI SIR3000 GPR data collection system. Both a 400MHz and 200MHz shielded antennas were utilised for this investigation. The use of two different antenna frequencies enabled data to be collected to a depth beyond 2.5 meters.

The FDEM survey was conducted using the GSSI Profiler EMP-400 attached to a high accuracy DGSP. The ERT survey was conducted with using a 48 channel GF Instruments ARES Switch Resistivity System. All survey instruments used in this investigation were supplied by GBG Australia.

Geophysical Investigation at Plain of Jars Archaeological Project, Laos

GBG Australia has pledged $60 000 worth of geophysical data collection and processing toward the Plain of Jars Archaeological Project, a joint Australian/Laos research project led by Archaeologists from ANU and Monash University. The research hopes to determine the role of the jars during the Iron Age, and eventually contribute to the site achieving UNESCO World Heritage status..

The first phase of geophysical work was completed in February 2016. Ground Penetrating Radar (GPR), electromagnetic induction and metal detection surveys were undertaken around the existing exposed jars.

Rocks buried in the soil were detected by the GPR survey and the subsequent archaeological excavation revealed these were marker stones locating buried remains. Skulls, limb bones, teeth and pottery have since been dug up.

Electromagnetic induction and metal detector surveys mainly found anomalies associated with fragmentation from the ordnance used in the area during the military conflict of the Vietnam war years.

A second phase of geophysical work at a different archaeological jar site is planned for late 2016.

Geophysical Investigation to Map the Bedrock Depth for Planning Purposes, Kyushu Island, Japan

GBG Australia undertook a geophysical investigation to map the depth to bedrock for planning and construction purposes. For this investigation seismic refraction was utilised to gain information on the depth of bedrock in addition to velocity information for each layer observed.

The seismic refraction data was collected using the Gemetrics Geode seismic recorder. An array length of between 12 channels to 24 channels was used depending on avaliable space with the seismic source being created using a sledgehammer.

All geophone and shot locations were taken using a high accuracy DGPS and levels along the lines were taken using a laser level.

 

Geophysical Investigation to Map Tree Roots, Northern Sydney, NSW

GBG Australia undertook a non-destructive geophysical investigation to locate and map tree roots eminating from a number of trees along a kerb line.

Data was collected using a GSSI SIR3000 GPR data collection system attached to a 400Mhz shielded antenna. A tight line spacing of 0.5 m was used to gain high quality data.

 

Geophysical Investigation to Locate Mine Shafts and Mine Infrastructures, Central NSW

GBG Australia undertook a non-destructive geophysical investigation to locate and map the location of mine shafts and mine infrastructure. For this investigation Ground Penetrating Radar (GPR), Frequency Domain EM (FDEM) and Earth Resistivity Tomography (ERT) were used.

The GPR data was collected using the GSSI SIR3000 GPR data collection system. A 200Mhz shielded antenna was utilised for this investigation with 2 m line spacing being used. The FDEM survey was conducted using the GSSI EMP-400 Profiler attached to a high accuracy DGSP. Using a low-frequency set up a maximum depth of 15 m was acheived with the FDEM.

The ERT survey was conducted with using a 48 channel GF Instruments ARES Switch Resistivity System. All survey instruments used in this investigation were supplied by GBG Australia.

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