Advanced Airborne Geophysics for Environmental and Engineering Solutions

The application of airborne geophysics to provide solutions for environmental and engineering problems has increased in recent years. This paper will present data collected via helicopter-borne magnetic and electromagnetic surveys (HEM). Airborne geophysics measures the electrical properties of the earth and its constituents as well as man made objects buried in it. Surveying the ground with a helicopter has always offered the ability to overcome physical barriers such as inaccessibility or hazardous environments. Compared with ground surveys, helicopter surveys can offer significant cost reductions for surveys over large areas with typical hourly production rates of approximately 500 acres/hour). Advances in the last 5 years in instrumentation, software, GPS and map products have brought about growing acceptance of HEM by the engineering community. This is due primarily to the ability of today's systems to make accurate, high resolution, precisely positioned measurements. HEM is proven as a technology to: Locate contaminant plumes, characterize industrial sites, measure the extent of salt water invasion, detect buried metal structures and UXO, locate brine leaks from abandoned oil wells, assess groundwater resources and recharge areas, characterize rock and soil along Rights of Way, locate illegally abandoned or lost radioactive sources, map sand and gravel deposits for aggregate resource exploration, measure soil conductivity near oil pipelines to assess corrosion risk, delineate burnt and un-burnt coal and locate igneous dikes in coal mines. A range of data presentations and final products are available to satisfy the various mapping needs of the scientific community such as 2D and 3D presentations of geophysical data and vertical conductivity sections. Integration of information from the complementary datasets is a powerful part of interpretation that leads to a comprehensive understanding of the structural history and geological evolution of an area - a vital part of any exploration or land care management program. Through the recognition of the many advantages provided by HEM, engineers and scientists with a need to map the earth's subsurface are gaining a better understanding of geology, hydrology, natural hazards and the impacts of mankind. This paper will present HEM data acquired for a variety of environmental and engineering projects. This data has contributed significantly to an understanding of the subsurface while providing cost and time efficiencies.