Potential Contamination of Shallow Aquifers by Surface Mining of Coal

Authors
Mark Trudell
Stephen Moran
Terry Macyk
Resource Date:
1990
Page Length
63

This is one of a series of reports that presents the findings of the Plains Hydrology and Reclamation Project (PHRP), an interdisciplinary study that focuses primarily on hydrologic aspects of the reclamation of surface coal mines in the Plains of Alberta. The focus of the PHRP is to develop a predictive framework that will permit projection of success for reclamation and impact of mining on water resources on a long-term basis. The predictive framework is based on an understanding of processes acting within the landscape so that, in the future, mine sites that are not totally analogous to those that have been studied can be evaluated as well. The project involves a holistic approach to reclamation by integration of studies of geology, hydrogeology, and soils, not only in the proposed mining area, but also in the adjoining unmined areas. This approach permits the assessment of impacts and of long-term performance, not only in reclaimed areas, but also in the surrounding area. This report addresses PHRP Subobjective B-1, \"to assess and evaluate the long-term alteration of quality of groundwater in cast overburden and surface water fed from mine spoil as a result of the generation of weathering products\". It is fair to say that this particular investigation had not been conceived at the onset of the project. Conventional thinking clearly indicated that reclaimed surface coal mines would act as hydrologic sinks, certainly for a period of many years or decades after mining. The migration of spoil groundwater into unmined areas at the Battle River site arises from a collection of favourable geologic and hydrogeologic features that are presently unique to the Vesta Mine site. The key features required to produce this off-site migration, an elevated, ponded reclaimed landscape and adjacent permeable unmined aquifer, are potentially available at a number of mine sites. It is hoped that an awareness of the potential for off-site movement of spoil groundwater will have some influence on the design and construction of reclaimed landscapes in the future.