The hydrogeological situation after salt-mine collapses at Solotvyno, Ukraine

Leonard Stoeckl,Vanessa Banks,Stella Shekhunova,Yevgeniy Yakovlev

doi:10.1016/j.ejrh.2020.100701

Abstract

Study regionThe study site is located in the south-western part of the Ukraine, in the area of the historical rock-salt mining town Solotvyno. The former mining area is situated in close vicinity to the River Tisza, the main tributary of the Danube River, the largest river in Europe. Study focusAfter uncontrolled flooding of several salt mines, a one month advisory mission was launched by the European Commission to estimate the impact of the abandoned salt mines (containing large quantities of salt water) on the environment. As a consequence of the flooding, dozens of sinkholes formed and sinkhole forming processes are ongoing, with sinkhole diameters reaching 250 m. As river contamination by the release of large quantities of saltwater would lead to an international disaster, hydrogeological measurements were taken on-site to study the system. New hydrological insights of the regionAt the study site, saturated (hyper-saline) water as well as fresh surface and groundwater were encountered in close vicinity to each other. Electrical conductivity, as a proxy for salinity, and temperature were measured on-site and water samples taken from surface-, ground- and mine waters were analyzed for chemistry and stable isotopes, providing new insights into groundwater flow dynamics. A conceptual model shows the salt dome, and potential flow paths from the mining area to the Tisza River, in the context of the mines and associated sinkholes potentially impacting the river water quality.

Highlights

Solotvyno is a historical rock-salt mining town, situated above a salt dome structure in the south west of Ukraine, close to its border with Romania
Field investigations in September and October 2016 have contributed to the conceptual understanding of the present hydrogeological situation at Solotvyno
It shows several potential flow paths that could discharge saline water derived from contact with the salt dome towards the Tisza River

Summary

Introduction

Solotvyno is a historical rock-salt mining town, situated above a salt dome structure in the south west of Ukraine, close to its border with Romania. Flooding occurred due to mine collapse triggered by underground mining operations. Huge surface collapses developed, similar to the sinkholes in Berezniki, Russia, after flooding of the potash mining area in 2006 (Ashrafianfar et al, 2011). An official request was presented to the European Commission by the Hungarian authorities, as a consequence of elevated salt concentrations in the Tisza River in 2008 (OLHGC, 2009). Sourced in the Carpathian Mountains, around 400 km upstream of the Solotvyno mining area, the Tisza River enters Hungary at Tiszabecs, around 104 km downstream. Chloride concentrations of 504 mg/l were measured in 2008 This concentration exceeds the proposed surface water quality standard (SWQS) of 200 mg/l (OECD, 2008), alarming the Hungarian authorities. The hydrogeological situation and the impact of anthropogenic mining activities on the area was not previously well understood

Methods

Results

Conclusion