Optimization of Physical Properties for Ditches–Case Study: Kankberg, Maurliden and Renström-Petiknäs.

Abstract: It is important for practical and legal reasons that water and sediments in disturbed areas around the mining operation should be controlled. The construction of a well-designed drainage system that controls erosion and thus restores the proper hydraulic function of the surface is one of the most important post-disturbance features which should be done as part of the mining activities. However, even with the best planning and design, unless proper construction practices are adapted; both the disturbed and reclaimed areas are very much likely to be susceptible to erosion, sedimentation and stability problems. In order to tackle the problem, guidelines on how to design and construct the drainage system should be well prepared. The main objective of this study was to prepare guidelines for the proper design, construction and monitoring of the water drainage management system in the study areas (Kankberg, Maurliden and Renström-Petiknäs). This report has analysed the results from the outcome of HEC-RAS software for the case study of the new ditch around the Maurliden mine site and integrated with different guidelines. Based on the results of the HEC-RAS, the most common problems in the drainage system have been identified. Moreover the thesis project identified important physical parameters such as cross-sections and slopes of the representative ditch which affect the function of the ditch in the study areas. Hydraulic parameters such as velocity which is very important for designing the type of lining and also Froude number which is very important in identifying the type of flow whether it is super-critical, critical or sub-critical were identified. The latter helps to select the type of guideline to be used between steep slope and mild slope.