the closure of the steep rock iron mines near atikokan, ontario, canada in the late 1970's left behind an area of severe environmental concern. the subsequent flooding of the pit mines resulted in the formation of two adjacent pit lakes, hogarth and caland. as water levels in the two pit lakes continue to rise, the water columns are exposed to differing proportions of various wall rocks. the geochemical influence is likely the major control on the unique and dynamic water chemistries of the two pit lakes.