GBG GROUP NEWS

Non-Destructive Investigation to Map the Location and Depth of Tree Roots, Eastern Suburbs, Sydney, NSW

GBG Australia undertook a non-destructive investigation to map the location and depth of tree roots eminating from a number of trees on a residential property. The property investigated was located in the eastern suburbs of Sydney, NSW.

The geophysical data was collected using a GSSI SIR-3000 control unit and a 400MHz Ground Coupled Antenna.

 

Geophysical Investigation to Delineate the Location of USTs, Southern Sydney, NSW

GBG Australia undertook a geophysical investigation to map the location of Underground Storage Tanks (UST) at an operating service station in southern Sydney. For this investigation ground penetrating radar was used to map the USTs onsite as well as any associated services.

The geophysical data was collected using a GSSI SIR-3000 unit with a variety of ground coupled antennas at different frequencies.

Geophysical Investigation to Map Bedrock Profile and Determine the Location of a Historic Drainage Ditch, Sydney, NSW

GBG Australia undertook a geophysical investigation to map the depth to bedrock and the location a histroric drainage ditch under a major road in the North Shore of Sydney, NSW. The project was undertaken as part of the planning processing associated with a HDD bore.

MASW was utilised for the investigation with a Gemetrics Geode seismic recorder being used to record the data. An array of 24, 4.5Hz geophones was utilised for the survey. A sledgehammer striking a rubber plate was used to generate the seismic energy. The work was conducted during daylight and night times hours to maximise data coverage.

All shot locations were taken using a high accuracy DGPS.

Geophysical Investigation to Map the Bedrock Depth for Planning Purposes, Iwate Prefecture, Japan

GBG Australia undertook a geophysical investigation to map the depth to bedrock for planning and construction purposes in two sites in the Iwate Prefecture, located on the main island of Japan. For this investigation seismic refraction was utilised to gain information on the depth of bedrock in addition to velocity information for each layer observed.

Seismic refraction data was collected using the Gemetrics Geode seismic recorder. An array length of 24 channels was utilised for most of the survey. A sledgehammer striking a metal plate was used to generate the seismic energy.

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 in Papua New Guinea

GBG Australia staff recently spent several weeks in a remote part of PNG to conduct a geophysical investigation for a proposed tailings dam. The conditions experienced onsite were hot, humid and muddy but the staff enjoyed the challenge amongst the jungle.

Initially a number of techniques were trialled which included resistivity, shallow and deep ReMi (refraction micro-tremor). Processing was carried out on site concurrent to the field acquisition to save on time, and to adequately assess each technique’s effectiveness. Upon examination of the results of all the techniques it was decided to exclude the use of resistivity as the results being returned were not of a high standard.

In addition to the surface geophysics described above, a number of downhole VSSP (vertical seismic shear-wave profiling) and crosshole seismic surveys were conducted at strategic points throughout the tailings dam to correlate the results of the ReMi.

This is the fourth project undertaken by GBG Australia in PNG.

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