Electrical Resistivity Tomography (ERT) Surveys at the Callahan Mine Superfund Site in Brooksville, Maine: May 2017

On May 10, 2017 an electrical resistivity tomography (ERT) profile was collected on the land along the gravel path between the water and the slime impoundment associated with the former mine activities. A total of 56 electrodes, spaced 1 m apart, extended along the base of the slope. Electrode 1 was near monitoring well MW-701 and electrode 56 was near MW-702. In the ERT measurement current is injected through two current electrodes and voltage is measured sequentially across multiple pairs of potential electrodes, which is used to determine the apparent resistivity of the subsurface. In addition, induced polarization (IP) was measured to assess the presence of chargeable layers. Two surveys were collected in dipole-dipole and combined [...]