Modeling hydrodynamic regime of the technogenic aquifer within the Noyabrsky site of the Aikhal mine

The Noyabrsky site is used for the injection of highly mineralized drainage waters formed during the development of the Aikhal kimberlite pipe (Republic of Sakha (Yakutia), Russia). The water injected into the wells of the site since 2013 has formed a localized intrapermafrost technogenic aquifer. Taking into account the porosity parameters of the formed permafrost reservoirs, as well as the confirmed useful capacity of the site, its operation is planned to continue until 2044 at the very least. Despite relatively small injection volumes (up to 430 m3/day), forecasting dynamical changes in the hydrodynamic regime of the technogenic water horizon is a challenging task, which is of significant practical importance for the provision of environmental and industrial safety. The assessment of the anthropogenic impact, as well as the subsequent forecasting of the hydrodynamic regime dynamics within the Noyabrsky site, were carried out by modeling methods in the Modflow software. The brine lens formed today is characterized by uneven porosity parameters, which is due to the peculiarities of heat and mass transfer when using permafrost for drainage water injection. Based on the results of predictive modeling a conclusion can be derived that the use of the method of Aikhal mine drainage water injection into the permafrost strata at the Noyabrsky site allows to reduce the influence degree of mining and production operations on the geological environment of the studied area through its localization on an intentionally limited, relatively small area, where injection is carried out, as well as on the environment, by preventing drainage brines from entering surface waters until 2044.