Identifikasi Zona Boulder pada Lapisan Saprolit Menggunakan Data Bor dan Metode Electrical Resistivity Tomography (ERT): Studi Kasus Blok "X", Sulawesi Selatan

Zahran, Yurcel Satria (2026) Identifikasi Zona Boulder pada Lapisan Saprolit Menggunakan Data Bor dan Metode Electrical Resistivity Tomography (ERT): Studi Kasus Blok "X", Sulawesi Selatan. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Keberadaan boulder bawah permukaan (subterranean boulders) pada lapisan saprolit endapan nikel laterit menjadi kendala teknis dalam operasional tambang open pit, terutama dalam kegiatan pemboran, peledakan, dan pengerukan. Penelitian ini menerapkan metode Electrical Resistivity Tomography (ERT) dengan konfigurasi gradient pada 21 lintasan pengukuran dengan panjang berkisar antara 200 hingga 650 meter, guna mengidentifikasi profil resistivitas bawah permukaan dan memetakan sebaran zona boulder pada lapisan saprolit di Blok "X", Sulawesi Selatan. Data bor (borehole log) digunakan sebagai validator hasil interpretasi ERT, dan seluruh model resistivitas diintegrasikan ke dalam perangkat lunak DataMine untuk menghasilkan pemodelan pseudo-3D bawah permukaan.
Hasil pengolahan data menunjukkan bahwa profil laterit di lokasi penelitian tersusun atas zona limonit (>100 Ωm) pada kedalaman 0–7 meter, zona saprolit (100–300 Ωm) pada kedalaman 7–19 meter, serta zona bedrock di bawahnya. Zona boulder teridentifikasi sebagai sisipan di dalam matriks saprolit pada kedalaman 2–32 meter, dengan dua tipe utama: boulder kompak (>300 Ωm, teridentifikasi pada 9 lintasan) yang dicirikan oleh nilai resistivitas tinggi akibat rendahnya tingkat rekahan, dan boulder terekahkan (<300 Ωm, teridentifikasi pada 2 lintasan) yang menunjukkan respons resistivitas lebih rendah akibat tingginya densitas rekahan (fracture). Selain itu, tipe boulder campuran ditemukan pada 10 lintasan dengan variasi nilai resistivitas. Validasi terhadap data borehole log menunjukkan tingkat keselarasan yang tinggi antara model ERT dan kondisi bawah permukaan aktual, membuktikan bahwa integrasi metode ERT dan data bor sangat efektif untuk memetakan sebaran zona boulder secara lateral maupun vertikal.
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The presence of subterranean boulders within the saprolite layer of nickel laterite deposits poses significant technical challenges in open pit mining operations, particularly in drilling, blasting, and ore excavation activities. This study applies the Electrical Resistivity Tomography (ERT) method using a gradient configuration across 21 survey lines ranging from 200 to 650 meters in length, to characterize subsurface resistivity profiles and map the distribution of boulder zones within the saprolite layer at Block "X", South Sulawesi. Borehole log data served as a validator for the ERT interpretation, and all resistivity models were integrated into DataMine software to generate subsurface pseudo-3D modeling.
The results indicate that the laterite profile at the study area consists of a limonite zone (>100 Ωm) at 0–7 meters depth, a saprolite zone (100–300 Ωm) at 7–19 meters depth, and a bedrock zone below. Boulder zones were identified as intercalations within the saprolite matrix at depths of 2–32 meters, comprising two primary types: compact boulders (>300 Ωm, identified on 9 lines), characterized by high resistivity values due to low fracture density, and fractured boulders (<300 Ωm, identified on 2 lines), exhibiting lower resistivity responses due to high fracture density. A third type, mixed boulders, was identified on 10 lines with variable resistivity values. Validation against borehole log data demonstrated a high degree of consistency between the ERT model and actual subsurface conditions, confirming that the integration of ERT and borehole data is highly effective for mapping boulder zone distribution both laterally and vertically.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Boulder, Bor, ERT, Resistivitas, Saprolit, Boulder, Borehole, ERT, Resistivity, Saprolite
Subjects:	Q Science > QE Geology Q Science > QE Geology > QE538.5 Seismic tomography; Seismic waves. Elastic waves
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geophysics Engineering > 33201-(S1) Undergraduate Thesis
Depositing User:	Yurcel Satria Zahran
Date Deposited:	28 Jul 2026 06:30
Last Modified:	28 Jul 2026 06:30
URI:	http://repository.its.ac.id/id/eprint/138599

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