# Impact of Mining Disturbance on Highway Sustainability:
## 3 A Case Study
### Historical Background (Northern District of the Morava Pit)  
The movement and deformation of the undermined terrain, along with the protection of buildings above mining works, have posed challenges at the Aleksinac coal mine for years. In response to terrain damage in the Northern District of the Morava Pit, a subsidence prognosis was conducted in 1983 using the Pataric-Stojanovic stochastic method [84]. This method for calculating surface subsidence is based on the established extraction dynamics within the excavation field and the original formulas, combined with a graphical representation of subsidence contour lines. The excavation field in the Northern District consists of 31 excavation panels (EPs), which have been mined sequentially since 1978 (Figure 5). To calculate the subsidence parameters, the average values of seam dip for each EP are used. The seam depths (H) are determined through geological interpretation of the deposit, utilizing terrain isohypses and layer isolines for each EP individually. These depths range from 480 to 580 m. The coal seam thickness, derived from the geological interpretation and the isolines of the main seam, varies from 3 to 5 m, with dip angles ranging between 30\({}^{\circ}\) and 50\({}^{\circ}\). The rate of caving (q) is determined based on previous studies of the displacement process of the undermined rock massif, with a value of q = 0.70 accepted [84]. The angular parameters of the subsidence process are geometric characteristics of a conditional and physical nature, which determine the state of the undermined massif. They serve as the basic data in the design of observation networks for the undermined terrain and in the determination of protective pillars beneath natural and technical structures. They are determined at vertical cross-sections along characteristic subsidence planes, i.e., based on the strike and dip of the coal seam [35]. Since angular parameters are geometric characteristics of the same process and depend on physicochemical and mining-geological factors in the rock massif, certain dependencies can be established between them [75; 76; 77; 78; 79; 80]. The prognosis of mine subsidence using the stochastic Pataric-Stojanovic method shows that the central area of the subsidence trough experienced a collapse, reaching a maximum value of \(U_{\text{max}}=-1342\) mm (Figure 5) [84]. To verify the prognostic calculation, a network of profile lines with benchmarks was established. The observation network comprised 220 benchmarks across eight profile lines, three along the seam strike (ranging from 1067 to 1955 m in length) and five along the seam dip (ranging from 822 to 905 m), including a section of the E75 (A1) Belgrade-Nis highway within the range disturbed by mining works. Figure 5: Prognostic subsidence contour lines for completed planned excavation in the Northern District of the Morava Pit [84]. The profile lines for coal seam strike and coal seam dip with the benchmark network are shown in Figure 6[84]. The grid is designed to meet the requirements for long-term subsidence monitoring, ensuring that the stability of the benchmarks remains intact. Benchmarks are installed in areas expected to be affected by subsidence, allowing for periodic position determinations to monitor the intensity and progression of subsidence over time. Geodetic surveys along profile lines track the overall progression of the subsidence process, using data that marks key phases: the onset of displacement, its intense phase, its completion, and its regression. Geodetic surveying along the profile lines involved determining subsidence through high-accuracy leveling. Measurements were systematically conducted from June 1978 to September 1989, when the mine was suddenly closed. A total of 14 series of measurements were conducted across all profile lines, facilitating a comprehensive interpretation of the results.