Features of the formation of natural-technical systems within the injection areas of the Daldyn kimberlite field (Western Yakutia)

Abstract

Relevance. Primary diamond deposits mined by PJSC ALROSA in Western Yakutia have widespread watering of varying intensity with sub-permafrost and inter-permafrost strong and very strong brines. Currently, the resulting drainage waters are pumped back into the depths of the permafrost, which leads to the formation of natural-technogenic aquifers that require constant control, monitoring and study. Aim. Identification of the features of the formation of natural-technogenic systems within the injection areas of the Daldyn kimberlite field, determination of the volume of permafrost waters involved in this process, as well as their characteristics to confirm the environmental friendliness of the method of handling drainage brines. Methods. Field work consisted of quarterly routine testing of observation and injection wells. Assessment of technogenic influence, as well as subsequent forecasting of the dynamics of changes in cryohydrogeological conditions and hydrodynamic regime, was carried out using modeling methods in Feflow software. An additional method was analytical balance calculation based on the parameter of changing mineralization. Results and conclusions. The interaction of drainage waters with permafrost waters leads to areal changes in mineralization without significant changes in the dominant anions and cations within the studied objects, forming an equilibrium natural-technogenic system in the peripheral parts relative to background temperature conditions. The volume of formed man-made aquifers will exceed 300 million m3. The process of involving cryogenic waters, despite the significant volumes, has a positive impact on the ecological state of the territory, because in the peripheral parts of the resulting aquifers, equilibrium cryohydrogeological conditions are formed, characteristic of natural cryopegs in the region of study.