First used in the mining industry in the 1920s, mise a la masse (which means “excitation at the source”) is a technique helpful in mapping mineral deposits. Because it’s an electrical application, it is typically used for conductive materials like metal ores. We have also employed this method to map targets such as conductive (ionic) leachate plumes, flooded mine workings, and mineralized fault zones.
While initially developed to map conductive materials, RETTEW/Enviroscan has adapted the mise a la masse process to also delineate resistive bodies such as light non-aqueous phase liquid (LNAPL) plumes floating on groundwater surfaces. Using mise a la masse to delineate these features helps to site recovery wells within the plume to allow maximum product recovery.
RETTEW/Enviroscan has also employed mise a la masse to delineate the surface orientation of water-producing fractures in nearby wells, facilitating placement of other production and/or monitoring wells in that same feature.
Since mise a la masse studies provide only footprints (not cross sections) of electrical anomalies, they are generally employed for reconnaissance in advance of drilling or geoprobing, or to estimate the boundaries of known plumes.