## 6 Discussion
The geomembrane's probability of nominal failure for the specific exposure time and the conditions of SP1, SP2, and SP3 was 0%, 0%, and 0.4%, respectively. These probability values were calculated by integrating the area under the PDF for tensile strength values less than 26.5 kN/m; according to the densities of SP1 and SP2, the probability was zero, whereas with the density of SP3, the probability was non-zero. This can be observed according to the shaded area under the PDF curve in Figure 9c. This means that assuming SP1, SP2, and SP3 together are representative of the geomembrane covering the reservoir of the dam, even with conservative estimation, the probability of the geomembrane reaching nominal failure is 0.4% as a function of tensile strength. It is important to note that the studied samples were either above the tailings or at elevations influenced by the variation in the tailing elevation. Therefore, this assessment of geomembrane durability cannot be directly applied to sections of it that are completely submerged in the dam reservoir. Regarding the representativeness of the samples and considering their tensile strength (for which the non-parametric statistical analysis was conducted), it is substantially adequate considering the literature data for similar situations [44, 46]. Variations and uncertainties are inherent to the samples, especially after an exposure period. Therefore, it would be necessary to replicate the experiments to identify distribution patterns and consequently analyze behavioral representativeness. This approach would lead to a better understanding of the variables involved and contribute to the robustness of the obtained results. Another point of analysis is the performance of the seam. Although the peel strength exhibited satisfactory values when compared to the minimum requirement established by the [82] standard, the peel separation showed values higher than the maximum allowable values, even when considering its variability (Figure 10). According to [62], unsatisfactory peel separation does not necessarily imply loss of the bonded area, but it does not exclude this possibility. Depending on the geomembrane/seam combination, it could induce grazing, which serves as a precursor to stress cracks. Even though the SCR tests were conducted outside the CRIT zone, comparing samples SP2 and SP3 (Figure 8), which were installed with geomembranes from the same batch and under similar exposure conditions, shows no statistically significant difference in the SCR values. This likely contributes to the understanding that even if crazing has been induced in the CRIT zone, it has not influenced the behavior of the geomembrane sheet in terms of SCR performance. Additionally, ref. [62] also mentions that the separation of a seam during testing may indicate that at some point during the geomembrane's service life, this seam could come  
Figure 10: Variation in peel separation with weld for sample SP2, comparing the average values obtained with that presented in the GRI GM19a standard and with statistical errors shown. apart if it is located over a subsided subgrade, on a fold, or even at waves caused by thermal expansion/contraction. If the seam comes apart, the geomembrane will no longer be able to serve its function as a hydraulic barrier in the reservoir of the dam. It is noteworthy that the company conducting the mining operations in question, aiming to comply with the requirements of the Brazilian National Mining Agency (ANM), conducted environmental analyses to assess whether there were any signs of significant contamination in the area, as the SCR and peel separation test values were unsatisfactory. These analyses indicated no significant indications; however, the authors were not granted permission to publish them. When considering the possibility of catastrophic consequences due the geomembrane failure within the context of mining operations, analyzing the probability of failure becomes essential for decision-making regarding preventive or corrective actions.