Integrated Geophysical Surveys in Support of Environmental Site Assessment at a former Pintsch Gas Plant

Abstract

A Phase II Environmental Site Assessment was performed to investigate a former Pintsch Gas Manufacturing Plant (FPGP) and an artesian well location. This survey is within an operating rail yard that is used for maintenance and fueling. the Phase II ESA was conducted in two work stages including an integrated geophysical Investigation using Geonics EM31, EM38 and EM61 surveys. in addition, a limited magnetometer survey was conducted to assist in determining the location of an abandoned Artesian Well. All work was conducted in the estimated vicinity of the FPGP and the artesian well location identified in a Phase I ESA conducted in June 2010. the second stage of the survey involved a trenching Investigation based upon the geophysical results. the FPGP was within the operational rail yard since development in the early 1900’s and was used for locomotive maintenance and fueling as well as rail car classification. Since development there have been a number of structures at the rail yard including a round house with functional turn table, machine shop, engine shop, car shop, passenger and freight depots, storage buildings and a Pintsch gas manufacturing plant. All surface structures were removed and the area graded allowing little or no evidence of the FPGP structures. the geophysical Investigation surveys covered an approximate 1.8 acre polygonal area that encompasses the estimated locations of the FPGP. the results of the three EM surveys closely matched the historic site plan maps and blue prints. Each survey provided independent and complementary data for the intrusive trenching Investigation. the trenching Investigation confirmed the location of many of the abandoned FPGP structures including tanks, piping and contaminants. This presentation will provide the results of the geophysical surveys and the subsequent intrusive confirmation conducted using trenches in strategic locations at the site. the use of complementary geophysical methods provided significant Information for this Investigation rather than conducting a blind trenching Investigation of the site and saved valuable Investigation budget dollars.