Defining long term groundwater monitoring programs for mining operations is a major challenge. Understanding groundwater patterns over long periods of time, at all stages of mine life, and during hydrologically important events is critical to effectively monitor, identify, and manage environmental impacts.
As per standard risk-based management practices, groundwater monitoring programs are informed by a source-pathway-receptor (SPR) framework. However, changing weather and climate variables such as seasonality and longer-term temporal trends may alter recharge and discharge areas, groundwater levels, hydraulic gradients and ultimately the contaminant flux that would have informed the monitoring program design. These changes in hydrodynamics on site may alter the SPR linkages over short or longer time periods.
Climate variations need to be reflected in the selection and flexibility of groundwater monitoring locations as well as the timing and frequency of monitoring events. Where appropriate, the monitoring program may need to be amended to ensure that data critical to evaluating environmental impact are captured. Variability in climate impacts such as long-term drought and extreme weather events also needs to be considered in the design of the monitoring program and reviewed throughout its execution. In most cases, the site will require conceptual and, sometimes, numerical hydrogeological and geological models that consider the groundwater system under a range of climate conditions.
Climate change presents further challenges to the closure of mining operations. Regional-scale changes in groundwater systems may alter the background conditions of a site, changing the applicability of the baseline assessment data that informs closure management.
Developing and implementing a groundwater monitoring program that is responsive to climate variables and climate change issues can build confidence in mine performance under a range of conditions, particularly during and after closure. This paper presents key considerations for future-proofing groundwater monitoring programs to provide this flexibility. Examples are provided to illustrate the importance of these considerations when constructing a program.