A Groundwater Monitoring Well is a purpose-built, specially constructed borehole fitted with a screened casing and sealed annulus that allows the collection of representative groundwater level measurements and water quality samples from a specific depth interval or aquifer within the subsurface, used to track changes in groundwater conditions associated with mining activities and other land uses. Monitoring wells are a fundamental component of environmental monitoring programs at bauxite, gold, iron ore, and diamond mining operations, providing the primary means of detecting potential groundwater impacts before they propagate to sensitive receptors such as drinking water sources, wetlands, rivers, or ecosystems.
A groundwater monitoring well typically consists of a steel or PVC casing with a perforated screen section positioned opposite the target aquifer or water table, surrounded by a gravel pack to facilitate water flow into the screen, sealed above and below by bentonite clay or grout to prevent contamination between different water-bearing zones, and capped at the surface with a lockable protective cover.
Wells are installed using rotary air or mud drilling rigs, and their construction is documented in detailed well completion reports submitted to regulators. Monitoring wells are strategically located upgradient and downgradient of potential contamination sources such as tailings storage facilities, processing plants, fuel storage areas, and waste dumps to enable detection of any groundwater quality impacts.
Each well is surveyed for precise position and elevation to enable accurate water level measurement and hydraulic gradient calculations. Development pumping removes drilling fluids before regular monitoring commences.