From October 2016 to July 2018, the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers and Maine Department of Transportation, collected surface, marine and borehole geophysical surveys to characterize the subsurface materials on land and under the water at a former mine facility in Brooksville, Maine. Three water-based geophysical methods were used to evaluate the geometry and composition of subsurface materials. Continuous seismic profiling (CSP) methods provide the depth to water bottom, and, when sufficient signal penetration can be achieved, delineate the depth to bedrock and subbottom materials. Continuous resistivity profiling (CRP) and frequency domain electromagnetics (FDEM) methods were used to define the electrical properties of the shallow subbottom. All data points were located using global positioning systems (GPS), and the GPS data were used for real-time navigation. The stage of Goose pond was monitored with pressure transducers during the water-borne geophysical surveys. On land, electrical resistivity tomography (ERT), FDEM, shear-wave velocity (Vs) seismic refraction and horizontal-to-vertical spectral ratio (HVSR) seismic methods were used to characterize the subbottom materials and to evaluate the surveys collected on the water. Borehole geophysical logs were collected in five boreholes to identify fluid and electrical properties as well as natural gamma emissions.

The collection of borehole geophysical logs and images and continuous water-level data was conducted by the U.S. Geological Survey South Atlantic Water Science Center in the vicinity of the GMH Electronics Superfund site near Roxboro, North Carolina, during December 2012 through July 2015. The study purpose was part of a continued effort to assist the U.S. Environmental Protection Agency in the development of a conceptual groundwater model for the assessment of current contaminant distribution and future migration of contaminants. Previous work by the U.S. Geological Survey South Atlantic Water Science Center at the site involved similar data collection, in addition to surface geologic mapping and passive diffusion bag sampling within monitoring wells (Chapman and others, 2013). The continued data compilation efforts included the delineation of more than 900 subsurface features (primarily fracture orientations) in 10 open borehole wells. Geophysical logs, borehole imagery, pumping data, and heat-pulse flow measurements were collected and are presented within this data release. The data on this page consists of .csv files that contain vertical flow measurements within the borehole and the associated depth below land surface. Measurements recorded under both ambient and stressed conditions are contained in each file.

The collection of borehole geophysical logs and images and continuous water-level data was conducted by the U.S. Geological Survey South Atlantic Water Science Center in the vicinity of the GMH Electronics Superfund site near Roxboro, North Carolina, during December 2012 through July 2015. The study purpose was part of a continued effort to assist the U.S. Environmental Protection Agency in the development of a conceptual groundwater model for the assessment of current contaminant distribution and future migration of contaminants. Previous work by the U.S. Geological Survey South Atlantic Water Science Center at the site involved similar data collection, in addition to surface geologic mapping and passive diffusion bag sampling within monitoring wells (Chapman and others, 2013). The continued data compilation efforts included the delineation of more than 900 subsurface features (primarily fracture orientations) in 10 open borehole wells. Geophysical logs, borehole imagery, pumping data, and heat-pulse flow measurements were collected and are presented within this data release. The data on this page consists of .csv files that contain vertical flow measurements within the borehole and the associated depth below land surface. Measurements recorded under both ambient and stressed conditions are contained in each file.

The collection of borehole geophysical logs and images and continuous water-level data was conducted by the U.S. Geological Survey South Atlantic Water Science Center in the vicinity of the GMH Electronics Superfund site near Roxboro, North Carolina, during December 2012 through July 2015. The study purpose was part of a continued effort to assist the U.S. Environmental Protection Agency in the development of a conceptual groundwater model for the assessment of current contaminant distribution and future migration of contaminants. Previous work by the U.S. Geological Survey South Atlantic Water Science Center at the site involved similar data collection, in addition to surface geologic mapping and passive diffusion bag sampling within monitoring wells (Chapman and others, 2013). Geophysical logs, borehole imagery, pumping data, and heat-pulse flow measurements were collected and are presented within this data release. The data within this page contain .csv files with caliper, natural gamma, resistivity, fluid temperature, fluid specific conductance, and heat-pulse flow measurements (ambient and stressed conditions).

From October 2016 to July 2018, the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers and Maine Department of Transportation, collected surface, marine and borehole geophysical surveys to characterize the subsurface materials on land and under the water at a former mine facility in Brooksville, Maine. Borehole geophysical logs were collected in five boreholes from May 2-3, 2017 to identify geophysical properties, including the electrical properties and natural gamma emissions, which can be related to geologic materials behind casing. In addition, fluid electrical conductivity and temperature were collected through the water column in the well. Results can be used to identify the water level and the lithologic contacts in the subsurface. Natural gamma, fluid electrical conductivity, temperature and electromagnetic induction logs are provided in a series of files within a compressed (zip) file. Equipment used, measurement units and calibration information are described in the log files.

From October 2016 to July 2018, the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers and Maine Department of Transportation, collected surface, marine and borehole geophysical surveys to characterize the subsurface materials on land and under the water at a former mine facility in Brooksville, Maine. Borehole geophysical logs were collected in five boreholes from May 2-3, 2017 to identify geophysical properties, including the electrical properties and natural gamma emissions, which can be related to geologic materials behind casing. In addition, fluid electrical conductivity and temperature were collected through the water column in the well. Results can be used to identify the water level and the lithologic contacts in the subsurface. Natural gamma, fluid electrical conductivity, temperature and electromagnetic induction logs are provided in a series of files within a compressed (zip) file. Equipment used, measurement units and calibration information are described in the log files.

In October 2016 and May 2017 frequency domain electromagnetic (FDEM) methods were used to image the electrical conductivity of the shallow subsurface. Electrical conductivity can be caused by changes in the soil, overburden, saturation, and water quality. Two multi-frequency tools were used at the site. One of the tools has a 1.6-meter (m) long antenna that was used in the vertical-dipole mode to collect data in stepped-frequency mode at seven user-selected frequencies ranging from 1530 to 47,970 Hertz (Hz). The GEM2HG tool has an antenna that is 2.1 m long, and it was used in vertical dipole mode with five stepped frequencies ranging from 90 to 24,000 Hz. In general, the lower frequencies penetrate to deeper depths, but the data are an average over a larger volume; whereas higher frequencies penetrate only to shallow depths but provide a smaller volume-averaged measurement. A plastic-pipe frame was used to keep the antenna at a fixed distance of 1.0 m above water surface to minimize noise induced by variation in tool position. Profiling data were collected at walking speeds of approximately 3 kilometer per hour(km/hr), with a full suite of seven frequencies measured every 0.5 seconds (s), which translates to a complete measurement suite about every 0.4 m along the profile. All measurement positions were mapped with a global positioning system (GPS). Both the primary and secondary fields were measured at the receiver coil, and the ratio of the secondary to primary magnetic fields was recorded as in-phase and quadrature. The in-phase part of the EM field relates to the magnetic susceptibility, and the quadrature component relates to apparent conductivity (aEC) . Raw data for each frequency and Q Sum (a summation of quadrature values) were recorded in parts per million (ppm). In post processing, EM data were converted to magnetic susceptibility and aEC, which can be inverted to get the actual depth of the electrical conductivity value. This data release provides the raw ppm values, the magnetic susceptibility, and the apparent electrical conductivity values.

In October 2016 and May 2017 frequency domain electromagnetic (FDEM) methods were used to image the electrical conductivity of the shallow subsurface. Electrical conductivity can be caused by changes in the soil, overburden, saturation, and water quality. Two multi-frequency tools were used at the site. One of the tools has a 1.6-meter (m) long antenna that was used in the vertical-dipole mode to collect data in stepped-frequency mode at seven user-selected frequencies ranging from 1530 to 47,970 Hertz (Hz). The GEM2HG tool has an antenna that is 2.1 m long, and it was used in vertical dipole mode with five stepped frequencies ranging from 90 to 24,000 Hz. In general, the lower frequencies penetrate to deeper depths, but the data are an average over a larger volume; whereas higher frequencies penetrate only to shallow depths but provide a smaller volume-averaged measurement. A plastic-pipe frame was used to keep the antenna at a fixed distance of 1.0 m above water surface to minimize noise induced by variation in tool position. Profiling data were collected at walking speeds of approximately 3 kilometer per hour(km/hr), with a full suite of seven frequencies measured every 0.5 seconds (s), which translates to a complete measurement suite about every 0.4 m along the profile. All measurement positions were mapped with a global positioning system (GPS). Both the primary and secondary fields were measured at the receiver coil, and the ratio of the secondary to primary magnetic fields was recorded as in-phase and quadrature. The in-phase part of the EM field relates to the magnetic susceptibility, and the quadrature component relates to apparent conductivity (aEC) . Raw data for each frequency and Q Sum (a summation of quadrature values) were recorded in parts per million (ppm). In post processing, EM data were converted to magnetic susceptibility and aEC, which can be inverted to get the actual depth of the electrical conductivity value. This data release provides the raw ppm values, the magnetic susceptibility, and the apparent electrical conductivity values.

In October 2016 and May 2017 frequency domain electromagnetic (FDEM) methods were used to image the electrical conductivity of the shallow subsurface. Electrical conductivity can be caused by changes in the soil, overburden, saturation, and water quality. Two multi-frequency tools were used at the site. One of the tools has a 1.6-meter (m) long antenna that was used in the vertical-dipole mode to collect data in stepped-frequency mode at seven user-selected frequencies ranging from 1530 to 47,970 Hertz (Hz). The GEM2HG has an antenna that is 2.1 m long, and it was used in vertical dipole mode with five stepped frequencies ranging from 90 to 24,000 Hz. In general, the lower frequencies penetrate to deeper depths, but the data are an average over a larger volume; whereas higher frequencies penetrate only to shallow depths but provide a smaller volume-averaged measurement. Data were collected at walking speeds of 3 kilometers per hour (km/hr), with a full suite of seven frequencies measured every 0.5 seconds (s), which translates to a complete measurement suite about every 0.4 m along the profile. All measurements were georeferenced with a global positioning system (GPS). Both the primary and secondary fields were measured at the receiver coil, and the ratio of the secondary to primary magnetic fields was recorded as in-phase and quadrature. The in-phase part of the EM field relates to the magnetic susceptibility, and the quadrature component relates to apparent conductivity (aEC) . Raw data for each frequency and Q Sum (a summation of quadrature values) were recorded in parts per million (ppm). In post processing, EM data were converted to magnetic susceptibility and aEC, which can be inverted to get the actual depth of the electrical conductivity value. This data release provides the raw ppm values, the magnetic susceptibility, and the apparent electrical conductivity values.

In October 2016 and May 2017 frequency domain electromagnetic (FDEM) methods were used to image the electrical conductivity of the shallow subsurface. Electrical conductivity can be caused by changes in the soil, overburden, saturation, and water quality. Two multi-frequency tools were used at the site. One of the tools has a 1.6-meter (m) long antenna that was used in the vertical-dipole mode to collect data in stepped-frequency mode at seven user-selected frequencies ranging from 1530 to 47,970 Hertz (Hz). The GEM2HG has an antenna that is 2.1 m long, and it was used in vertical dipole mode with five stepped frequencies ranging from 90 to 24,000 Hz. In general, the lower frequencies penetrate to deeper depths, but the data are an average over a larger volume; whereas higher frequencies penetrate only to shallow depths but provide a smaller volume-averaged measurement. Data were collected at walking speeds of 3 kilometers per hour (km/hr), with a full suite of seven frequencies measured every 0.5 seconds (s), which translates to a complete measurement suite about every 0.4 m along the profile. All measurements were georeferenced with a global positioning system (GPS). Both the primary and secondary fields were measured at the receiver coil, and the ratio of the secondary to primary magnetic fields was recorded as in-phase and quadrature. The in-phase part of the EM field relates to the magnetic susceptibility, and the quadrature component relates to apparent conductivity (aEC) . Raw data for each frequency and Q Sum (a summation of quadrature values) were recorded in parts per million (ppm). In post processing, EM data were converted to magnetic susceptibility and aEC, which can be inverted to get the actual depth of the electrical conductivity value. This data release provides the raw ppm values, the magnetic susceptibility, and the apparent electrical conductivity values.