The drainage flows of metal loads into drainage and infiltration waters of mine dumps of enterprises have a dramatic effect on small rivers in industrial regions. The paper considers the outcomes of geochemical monitoring of the Karagaily River and assesses the transformation of acid-base conditions depending on the influence of the facilities of the enterprise. The results of engineering and environmental surveys, including sampling of bottom sediments, laboratory preparation, chemical elemental analysis of samples and X-ray diffraction analysis of mineral composition, are presented. A complex technogenic alkaline sorption-hydroxide barrier was found at the mixing point of acidic river waters (the influence of dump and quarry waters) and alkaline wastewater of treatment facilities, where the deposited iron hydroxide adsorbs ore minerals, which reduces their outflow into larger rivers and increases the self-purification potential of the river. Further interaction of iron hydroxide with the acid mine drainage and calcium bicarbonate of wastewater results to pyritization of bottom sediments. Excavation and dewatering of pyrite-containing bottom sediments will allow their joint use with tailings and ore-processing waste for re-extraction useful components.