Geonics EM63 Multichannel EM Data Processing Algorithms for Target Location and Ordnance Discrimination

摘要

The Department of Defense (DoD) is currently involved in a number of unexploded ordnance (UXO) site remediation efforts where rapid transition of advanced technologies can save substantial sums of money and significantly expedite the transfer of lands for re-use. One of the most prominent of these efforts is the ongoing UXO cleanup of the Kaho olawe, Hawaii, bombing ranges. The difficulty with this site is that the significant magnetic anomalies from geologic sources and near-surface fragments make traditional magnetometer-based surveys impractical. Standard EM61 metal detection surveys have also performed poorly in these conditions due to the very high magnetic susceptibility response of basalt and basaltic soils. As of March 1, 2000, contractors at Kaho olawe had detected 12,121 subsurface anomalies, and after digging, they found that only 4% are UXO, 32% are false positives due to geologic variations, and 64% are due to buried metal from both UXO and non-UXO-related materials (Reference 1). The focus of this project was to evaluate the Geonics EM63 multigate time domain metal detector to quantify its detection, discrimination, cost, and production rates. This project was designed to incorporate the lessons learned from previous UXO technology demonstrations and to extend the results of the Jefferson Proving Ground (JPG) Phase IV Demonstrations that were completed during FY 97. NAEVA Geophysics was contacted by the Environmental Security Technology Certification Program (ESTCP) under Contract Number 200035 to demonstrate detection and discrimination abilities of Geonics EM63 multichannel (multitime gate) instrument through the development of algorithms and decay curve analysis. The purpose of this advanced technology is to reduce the cost and time spent in UXO remediation. To achieve this goal, the contract was divided into three main tasks.