# Review of the Failure at the Flotation Tailings Storage Facility of the \"Stolice\" Mine (Serbia)
## 5 Measures Taken After the Accident  
Remediation measures of the TSF and its surroundings were carried out in three phases [10,11]:  
* The cleaning of houses and yards was started in the first phase, which was carried out by the locals themselves. Through the United Nations Office for Project Services and the then Ministry of Construction, Transport, and Infrastructure of the Republic of Serbia, the Korenita-Krupanj road (road no. 139) was rebuilt and reopened in July 2014. At the same time, work began on the cleaning of the Kostajnicka River and the Korenita River, which was mostly carried out by local residents whose households were located on the banks of the rivers. In the upper part of the course of the Kostajnicka River, several flood barriers were constructed on the Kostajnicka River and its tributaries. Upstream from the landfill, a catch basin was built with the intention of receiving the waters of the Bezimeni Stream and introducing them into the drainage system in order to reduce erosion and thus reduce the washing of tailings into the Kostajnicka River.
* In the second and third phases, organized measures to rehabilitate the TSF and flooded terrain initiated by the Government of the Republic of Serbia were carried out. Within a zone of 100 m from the TSF, spilled tailings were removed where deposits were thicker than 5 cm, biological remediation measures were applied through controlled  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Microelements** & **Concentrations from 2018** & **Allowed Concentration** \\  & **(mg/kg), Data from [25]** & **(mg/kg) [27]** \\ \hline Zn & 50.33–1999.87 & 70–400 \\ As & 0–4936.16 & 15–50 \\ Cd & 0.1–11.26 & 3–8 \\ Hg & 0–1.46766 & 0.3–5 \\ Pb & 15.26–468.29 & 100–400 \\ Sb & 0–1467.77 & 5–10 \\ Mn & 145.98–1265.73 & 1500–3000 \\ Cr & 7.92–46.58 & 75–100 \\ Ni & 11.98–60.26 & 100 \\ Cu & 11.4–36.44 & 60–125 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Found concentration ranges during soil testing in the vicinity of the flotation TSF of the “Stolice” Mine in 2014 and allowed concentration ranges of microelements.  
production and the use of biomass on flooded surfaces, and monitoring of the cleaning effects was planned for a period of at least 3 years.  
The reconstruction of the TSF included the following [11]:  
* Reprofiling of the TSF, which included the excavation, moving, and backfilling of the existing tailings which resulted from the cleaning of the downstream flooded terrain, amounting to about 110,000 m\({}^{3}\);
* Formation of settling tanks downstream of the TSF for leachate with a system for recirculation and evaporation in order to prevent leakage of leachate from the TSF into downstream watercourses;
* The formation of a stone dam in front of the TSF and before the settling tank, which has the function of additionally supporting the reconstructed embankments of the TSF;
* The creation of a space for the disposal of additional amounts of tailings that were caught during the cleaning of the flooded terrain;
* Reconstruction of the peripheral embankments.  
The stability of the reconstructed TSF is ensured according to the criterion for large dams with respect to precipitation with probability of occurrence 0.1% (once in 1000 years). The costs of removing tailings from the riverbed of the Korenita and Kostajnicka rivers, the reconstruction of the TSF itself, and the cleaning of the flooded surrounding terrain amounted to 1,072,101,000.00 dinars [11], i.e., according to the middle rate of the National Bank of Serbia fir euros and US dollars from September 2016 [29], when the rehabilitation was completed, about 8,695,060.00 euros, i.e., 9,755,241.00 dollars. Figure 2(c) shows the current state of the TSF after all rehabilitation measures have been taken.