Minerals exploration methods modified for environmental targets

Abstract

In recent years, several traditional mining exploration methods have been successfully modified for use in the environmental geophysics field. In these cases, "successfully modified" refers primarily to acquiring data fast enough, and therefore economically efficiently enough, to accommodate the relatively small budgets that are available in most environmental studies. Modifications also include adjustments for the smaller scales of environmental surveys, often in the size of the project area, size of targets themselves, and required resolution. For example, transient electromagnetics (TEM) methods have been increasingly applied to environmental problems, particularly in unexploded ordnance (UXO), underground storage tank (UST), and utilities detection. A major research effort is now underway to use, among other methods, multi-component, multi-time-gate mobile TEM systems (measuring HX and HY, as well as the standard HZ) in order to discriminate targets of interest (UXO, for example) from other anomalies (such as metallic debris). A second good example is the induced polarization (IP) method. Although resistivity has been used extensively in shallow environmental applications, IP data acquisition has always been too slow, and therefore too expensive, for most environmental targets. Multi-channel receivers, multiplexers, and laptop computers now allow us to acquire IP data at rates of 2500 to 3000 data points per day (in the dipole-dipole configuration, for example), providing low-cost, high-density data. IP data have been shown to be particularly useful in delineating buried waste, such as at old landfills.