Electronic Theses and Dissertation

Kegiatan penambangan batubara dengan metode tambang terbuka menyebabkan peningkatan limpasan permukaan yang berpotensi menimbulkan erosi, sedimentasi, dan penurunan kualitas air. Oleh karena itu, diperlukan perencanaan settling pond yang mampu mengendalikan debit air tambang serta mengurangi kandungan sedimen sebelum dialirkan ke badan air. Penelitian ini bertujuan menentukan curah hujan rencana, intensitas hujan, luas catchment area, debit limpasan, sistem pemompaan, dan merancang dimensi settling pond pada pit Timur PT Nirmala Coal Nusantara, Kecamatan Meurubo, Kabupaten Aceh Barat. Metode penelitian meliputi analisis hidrologi menggunakan distribusi Gumbel dan Log Pearson Tipe III yang diuji dengan metode Kolmogorov-Smirnov dan Chi-Square, perhitungan intensitas hujan menggunakan metode Mononobe, debit limpasan menggunakan Metode Rasional, perencanaan sistem pemompaan berdasarkan analisis hidraulika perpipaan, serta perancangan settling pond berdasarkan debit masuk dan karakteristik sedimen. Hasil penelitian menunjukkan curah hujan rencana periode ulang 2 tahun sebesar 494,46 mm dengan intensitas hujan 51,92 mm/jam. Luas daerah tangkapan hujan terdiri atas lima catchment area dengan debit limpasan terbesar 7,42 m³/detik pada area front penambangan. Sistem dewatering menggunakan pompa Multiflow 180 berkapasitas 550 m³/jam, panjang pipa 655,98 m, dan total head 38,41 m, sedangkan sump memiliki kapasitas 967.420,15 m³. Settling pond dirancang berbentuk trapesium dengan empat kompartemen dan menghasilkan efisiensi pengendapan hingga 85%. Rancangan tersebut dinilai mampu mendukung pengelolaan air tambang secara lebih efektif sesuai kondisi hidrologi lokasi penelitian.

Open-pit coal mining activities increase surface runoff, which can lead to erosion, sedimentation, and deterioration of water quality. Therefore, a properly designed settling pond is required to control mine water discharge and reduce suspended sediments before the water is released into receiving water bodies. This study aimed to determine the design rainfall, rainfall intensity, catchment area, runoff discharge, pumping system, and to design an appropriate settling pond for the East Pit of PT Nirmala Coal Nusantara, Meurubo District, West Aceh Regency. The research employed hydrological analysis using the Gumbel and Log Pearson Type III distributions, which were evaluated using the Kolmogorov–Smirnov and ChiSquare tests. Rainfall intensity was calculated using the Mononobe method, runoff discharge was estimated using the Rational Method, the pumping system was designed based on pipeline hydraulic analysis, and the settling pond dimensions were determined according to inflow discharge and sediment characteristics. The results showed that the 2-year return period design rainfall was 494.46 mm, with a rainfall intensity of 51.92 mm/h. Five catchment areas were identified, with the highest runoff discharge of 7.42 m³/s occurring at the mining face. The dewatering system utilizes a Multiflo 180 pump with a capacity of 550 m³/h, a 655.98 m long HDPE pipeline, and a total dynamic head of 38.41 m, while the sump has a storage capacity of 967,420.15 m³. The proposed trapezoidal settling pond consists of four compartments and achieves a sediment removal efficiency of up to 85%. The proposed design is expected to improve the effectiveness of mine water management under the site's hydrological conditions.