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Geophysical Capabilities |
- Aggregate Mining Exploration
- Aggregate developers need a reliable estimate of yield in a potential gravel pit. Contrasting sand and gravel deposits from finer grained tills and alluvium is easily accomplished using geophysical techniques. Electrical and electromagnetic techniques such as DC Resistivity and Transient electromagnetics (TEM) are well suited for measuring gravel deposit thicknesses and areal extent, particularly in the Puget Sound Lowland where well sorted glacial outwash cover much of the basin surface. These surveys are capable of estimating deposit volumes without the expense or intrusion of drilling test wells.
- Aquitard Mapping
- Wellhead protection plans, infiltration studies and other environmental problems require a hydrogeological assessment to determine the fate of groundwater flow. Determining if groundwater will percolate into deeper systems or collect above fine grained, impermeable beds can often be a site specific problem, particularly in glacial sediments. Electrical and electromagnetic surveys can detect and measure the depth to the conductive fine-grained sediments, such as clay beds, shales, glacial till, etc.
- Buried Channel Detection
- Locating productive wells in some areas requires precision drilling in sediments known to make water. Geophysical techniques can locating coarse grained channel and paleochannel deposits in unproductive environments such as lake bottom sediments and mountainous areas. This is usually accomplished by surveying in lines across a property in order to find buried features.
- Fracture Mapping in Bedrock Aquifers
- Some of the most complex hydrogeological problems occur in bedrock aquifers where groundwater flow is controlled by fracture systems. Several geophysical techniques, including VLF, HLEM, seismic and others, are capable of detecting fracture zones in bedrock, even beneath overburden. These surveys can also be used to verify the existence of fractures below linear features found using aerial photographs.
- Measuring the Depth to Bedrock in Shallow Basins
- Most geophysical techniques can be used to detect the depth to bedrock in shallow basins. Seismic and gravity surveys are more suited for measuring bedrock depths in deeper sediments. Finding the deepest sediments in a valley bottom can often improve the likelihood of drilling a productive well. Also, groundwater can be controlled by irregular bedrock topography; geophysical techniques can be used to map these buried features.
- Saltwater Intrusion Mapping
- Saltwater is extremely conductive; electrical and electromagnetic surveys can directly detect saline intrusions in coastal aquifers. This application can be extremely useful for coastal and island water purveyors who need to monitor intrusion and determine depths to the saltwater/freshwater interface when constructing new wells.
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3011 South Huson Street, Suite A
Tacoma, WA 98409
Telephone: (253) 475-7711
Fax: (253) 472-5846
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