MINE DRAINAGE FACILITIES PLANNING ON ULTIMATE PIT LIMIT OF CLAYSTONE AND LATERITE OPEN MINE AREA ON PT XYZ

• Main Author: Kurnia Lie, Rama
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/86224
• Institution: Institut Teknologi Bandung

PT XYZ is a limestone mine company that use surface mining method operating in Kotabaru Regecy, South Kalimantan. Currently, PT XYZ is preparing a mining scheme for production in the claystone and laterite commodities mine permit area. Generally, hydrological condition of the operation area will affect the mining operation over time, therefore a mine dewatering planning is needed to ensure the mining process to go as planned. The planning start with analyzing the rainfall depth data that is recorded by a station from 2013-2021 using Log Pearson III data distribution type, obtaining planned rainfall depth of 130.07 mm and planned rainfall intensity of 21.68 mm/hr for 15 years return period. Based on given topographic data, a total of 136.36 ha catchment area is divided into 22 sub-catchment areas. In accordance with the requirements for dewatering and existing sedimentation facilities, analysis for two scenario of mine dewatering is being conducted, concluding with the plan to separate the mine dewatering system of claystone and laterite mine area. Therefore, dewatering infrastructure is needed in the form of open channel, drop structure, culvert, retention pond, and sedimentation pond built on the mine area. Designed open channel is categorized into four type with the shape of trapesium with the dimensions of bottom cross section width, top cross section width, and cross section height as follow 1,08x0,5x1 m; 1,61x0,8x0,7 m; 1,92x1x0,8 m; 2,35x1,2x1 m. 4 drop structure is built on steep bench, 2 type of culvert with diameter of 1,5 m typically located under mine haulage road and diameter of 1,2 m typically located under ramp. Water treatment scheme for claystone mine area is done by building retention pond with volume requirement of 111,710.25 m3 and using existing Sediment Pond C with total volume of 36,730 m3, while water treatment scheme for laterite mine area is done by building retention pond with volume requirement of 58.454.68 m3 and sediment pond with volume requirement of 8,208,67 m3.