AN ASSESSMENT TO THE POST MINING SURFACE WATER MANAGEMENT ON THE PART OF THE INACTIVE PARINGIN AREA IN PT. ADARO INDONESIA

• Main Author: PRADIPTA (NIM : 22108007), SENA
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/20519
• Institution: Institut Teknologi Bandung

The impact to the surface water quality is one of the most significant impacts from the mining sector. Also need to be recognized is that every mine have their lifespan and sooner or later the valuable resources will eventually ran out. Therefore the mining company should have a self sustained surface water management plan during that kind of time which is more known as the post mining phase in order to ensure that the managed impacts during the operational phase will still be delivering positive results. Another significant impact is the potential occurance of massive voids at the end of the <br /> <br /> <br /> mining operation if the mining conducted in an open mine method. Without a proper planning, these voids have the tendency to be a large non-useable hole and even maybe <br /> <br /> <br /> holds a great danger to the surrounding environment. Since there is a significant possibility of unintended filling these voids with water from rainfall and runoff so it is clear that these voids are also have the potential to be a new resource especially water resources at the time of the post mining phase. One of the inactive mine area in PT. Adaro Indonesia is parts of the Paringin area. In this area, the company has made a mine closure pilot project as a preliminary test in <br /> <br /> <br /> order to obtain inputs to plan the total mine closure plan in the next future. The most important part of the project is a pit lake occurred as a result of water filled void. The company has made few plans to use this pit lake as a water resource. This research will cover an assessment to the pit lake in terms of the quantity, quality and conforming the planned water use so that the proper steps to conduct a mine closure preparation plan <br /> <br /> <br /> since the operational phase of the mining can be formulated. By conducting such plan, it is expected to have a well and sustained post mining condition. <br /> <br /> <br /> The assessment result exhibits that the Paringin pitlake has already feasible for in-situ type of use based on the quantity aspect with the water volume available are 2,5 billion m3. However it is not yet optimally feasible enough for ex-situ type of use due to the limited amount of spill volume of about 72.000 m3 per month. Based on the quality aspect, problem is found only if the standard for class II water applied as the benchmark to determine water quality. By doing so, the TSS value is above the granted limit which is 123 mg/L. Therefore, class II water use application plan need to be reviewed. Nevertheless, DO modeling results gives the range of DO fluctuation between 2,5 – 12 mg/L at the surface of the reservoir and from 1,7 to 6 mg/L at the 6 m depth of the reservoir. Therefore using the reservoir as a fishery area is very probable.