Evaluasi Perhitungan Debit Pada Open Pit Mining

Kurniawan, Ivan (2023) Evaluasi Perhitungan Debit Pada Open Pit Mining. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Penelitian ini membahas tentang perhitungan debit limpasan pada area tambang terbuka di PT Maruwai Coal, Kalimantan Tengah. Perhitungan debit limpasan dilakukan dengan menggunakan beberapa metode yaitu FJ Mock, HEC-HMS dan Simulasi HEC-RAS 2 Dimensi. Sistem drainase tambang terbuka di PT Maruwai Coal memiliki sump pit dengan volume 12.574 m3 dan pompa pembuang dengan debit 0,22 m3/s. Kehilangan air hujan pada model HEC-HMS dan HEC-RAS dimodelkan dengan menggunakan Curve Number (CN). Pemilihan nilai CN dilakukan dengan mempertimbangkan kondisi lereng yang curam pada lokasi pengamatan. Elevasi muka air pada sump pit dan operasional pompa pada 10 kejadian hujan diamati dan digunakan sebagai validasi model. Hasil perhitungan menunjukkan masing-masing metode mampu memodelkan kejadian hujang dengan cukup baik. Koefisien limpasan yang diperoleh bervariasi dari 0,72 untuk metode FJ Mock dan 0,63 untuk metode HEC-HMS. Metode FJ Mock memberikan nilai rata-rata harian, sehingga mengabaikan kemungkinan debit puncak yang terjadi saat banjir. Pemodelan dengan HEC-HMS dan HEC-RAS mampu memberikan gambaran terhadap debit banjir dikarenakan analisis yang dilakukan untuk aliran tidak tetap. Nilai koefisien limpasan untuk tiap pemodelan digunakan untuk mengevaluasi performa sump saat kondisi hujan kala ulang 5 tahun. Dari hasil evaluasi, sump akan mengalami banjir selama 26 jam untuk FJ Mock, 15 jam untuk HEC-HMS dan 14 jam untuk HEC-RAS.
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This study presents the discharge calculation of open pit mining drainage system in open pit mine at PT Maruwai Coal, in Central Kalimantan. Several calculation methods are compared, including FJ Mock, HEC-HMS, and 2D HEC-RAS simulation. The open pit mine drainage system consists of sump storage with volume of 12.574 m3 and discharged using 0,22 m3/s pump. The loss method for HEC-HMS and HEC-RAS is modelled using Curve Number (CN) approach. CN value choice needs to consider steep slope condition at the site. Storage elevation and pump operation at 10 rainfall events is observed and used as model validation. The calculation shows each method is capable of modeling the event reasonably well. The average run-off coefficient varies from 0.72 for FJ Mock and 0.63 for HEC-HMS. However, FJ Mock method gives daily average value and may underestimate the run-off discharge. Indeed, HEC-HMS and HEC-RAS model are more suitable for flood modelling because of the unsteady nature of the flow. Run-off coefficient value for each model is used to evaluate sump performance during rainy conditions at a 5-year return period. From the evaluation results, the sump will experience flooding for 26 hours for FJ Mock, 15 hours for HEC-HMS and 14 hours for HEC-RAS.

Item Type: Thesis (Masters)
Uncontrolled Keywords: pertambangan, evaluasi perhitungan debit, pemodelan, metode FJ Mock, open pit mining, HEC-HMS, HEC-RAS, mining, evaluation, water discharge calculation, modelling, FJ Mock method, open pit mining
Subjects: T Technology > TC Hydraulic engineering. Ocean engineering > TC530 Flood control
Divisions: Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Civil Engineering > 22101-(S2) Master Thesis
Depositing User: Ivan Kurniawan
Date Deposited: 09 Feb 2024 06:00
Last Modified: 09 Feb 2024 06:00
URI: http://repository.its.ac.id/id/eprint/106423

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