Ecological assessment of Uncle Sam Gulch Creek water quality under conditions of acid mine drainage

The current stage of subsurface use development is accompanied by an annual increase in post-mining territories. This is partly due to a change in funding priorities in this area and their widespread reorientation to the search for alternative sources of raw materials to ensure the development of modern high-tech industries. One of the biggest threats to the environment in this development is the deterioration of the freshwater quality due to poor management of abandoned mining areas. And one of the most significant problems is often created by acid mine drainage. As a part of the study, information on the current environmental state of a past American mining territory located near Basin, Montana, USA, was analyzed and summarized; a conceptual exposure model was created regarding the studied natural and technogenic interactions; systematization and data updating on temporal and spatial changes in the qualitative characteristics of surface waters that are in direct contact with the abandoned mine were carried out; the level of efficiency of implemented reclamation works on the territory was determined. The results of the water quality environmental assessments proved that the measures taken thus far are absent of a sufficient level of effectiveness for its full rehabilitation. To accelerate the process of changing the water quality of the investigated water object, both in terms of condition and degree of purity, a combination of a passive treatment system coupled with an artificial reduction of acid mine drainage volumes was suggested.