# A New Method for Haul Road Design in Open-Pit Mines to Support Efficient Truck Haulage Operations
## 4 Case Study
### Three-Dimensional Modeling and Visualization of Road Design Result
Finally, the haul road of the open-pit mine was designed by using the terrain model of the mine together with the haul road layout as the input for AutoCAD Civil 3D and was visualized in three dimensions. The application of the proposed method to an area containing gold deposits made it possible to determine the slope limit of the haul road layout for the proposed open-pit mine as 10\({}^{\circ}\) (18%). Furthermore, it was possible to estimate the approximate work time, travel distance, and speed associated with haulage on the roads designed for the trucks. The proposed method can resolve the problems (e.g., the zigzag path problem, the inability to consider the radius of curvature constraint) that occur when the haul road layout is determined with the conventional LCPA method only. As a result, our method enables us to not only analyze the optimum path for trucks moving along an existing road in open-pit mines at the production stage of their lifecycle, but also to design a haul road for an open-pit mine that is still in the planning and design stage and for which no road exists. In open-pit mines, there are many obstructions such as trees, rocks, or other equipment, which reduce the drivers' visibility. The reduced visibility often incurs hazard situations for truck drivers. Therefore, in future work, it would be interesting to develop an extended method to consider the stopping and sight distances in designing the radius of curvature. The stopping distance of each vehicle is served by manufacturers, and methods for calculating sight distance can be found in the literature [1; 2; 3; 4; 5]. To construct haul roads in open-pit mines in the real world, it is crucial to select available construction materials for the pavement of a surface layer (i.e., the uppermost layer of the haul road). If the road pavement features are not suitable for driving, it may cause a decrease in the safety, efficiency, and productivity of haulage operations and an increase in the cost of maintaining the road. In other words, most of the benefits that are gained with the layout optimization will be lost. Several guides provide methods for selecting construction materials for the road pavement in open-pit mines [1; 2; 3; 44; 45; 46; 1]. The haul road layout determined by using our method can be used as the input data for road design by existing mining software. Furthermore, the estimation result for haulage operation time can be used to select the optimum type, number, and combination of haulage equipment, thus enabling the establishment of specific haulage operation plans for an open-pit mine in the production stage. Therefore, the proposed method can improve the road design and haulage operation planning functions for open-pit mines provided by existing mining software applications. Furthermore, the proposed method can be used as a tool for the haul road layout design of civil engineering and construction sites in the planning and design stage, i.e., where no road exists, as well as for mining sites. This work was supported by (1) the Korea Energy and Mineral Resources Engineering Program funded by the Ministry of Trade, Industry, and Energy and (2) the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education (2015R1D1A1A01061290). [PERSON] conceived and designed the experiments; [PERSON] performed the experiments; [PERSON] and [PERSON] analyzed the data; [PERSON] contributed reagents/materials/analysis tools; and [PERSON] and [PERSON] wrote the paper. The authors declare no conflict of interest.