Characterizing groundwater resources is a critical step when analyzing potential mining areas. A vital component of the mining process, water is used for mineral processing, metal recovery, dust mitigation, and the basic needs for on-site workers. Even more importantly, a thorough understanding of groundwater resources is a major factor in understanding the environmental impact of the mine on those resources.
One such groundwater characterization project was led by Knight Piésold and company hydrogeologist Jared King. The project entailed the characterization of a decommissioned gold and silver mine in preparation for permitting future mining scenarios.
Over the course of six months, reverse circulation drilling was conducted throughout the proposed future mining areas. At each borehole, a well was installed and groundwater measurements were taken via an electronic water level indicator. All drilling samples, primarily volcanic and sedimentary rock, were characterized onsite by Knight Piésold geologists.
Developing a relationship between the surface elevation and the groundwater elevation was an important step for Mr. King and the team. The site was located in the Atacama region of Chile, an area with historic faulting and wide ranging surface topography with approximately 500 meters of elevation change. Additionally, the high altitude desert climate experienced significant precipitation variation which in turn impacted the shallow and deep groundwater flow. As such, a basic surface elevation map of the site was plotted using Golden Software’s contouring, gridding, and surface mapping software, Surfer.
Due to the highly variable topography of the mine area, Mr. King could not create a groundwater surface using a normal interpolation method as the gridded surface would not match what was observed in the field. Instead, the groundwater level was estimated using an empirical relationship from the data collected during drilling.