Characteristics of Laterite Nickel Based on Geochemical Data and Electrical Resistivity Tomography (ERT) of Ultramafic Rocks in the Sorowako Area, East Luwu Regency

Erika Patadungan; Busthan Azikin; Hendra Pachri

doi:10.58227/jge.v3i2.179

Authors

Erika Patadungan Universitas Hasanuddin
Busthan Azikin Universitas Hasanuddin
Hendra Pachri Universitas Hasanuddin

DOI:

https://doi.org/10.58227/jge.v3i2.179

Keywords:

Sorowako, Laterite Nickel, Saprolite, Bedrock, ERT

Abstract

In laterite nickel exploration, PT.Vale Indonesia Tbk, initialy relied solely on drilling methods to define profile boundaries based on mineral content and rock characteristics, but discrepancies of around 2% between reserve estimates and actual mining outcomes led to the adoption of geophysical methods as a complementary approach in 2014. This study aims to determine the characteristics of laterite nickel profiles by correlating resistivity values with geochemical data. Using Datamine and Leapfrog software, a 3D model of laterite nickel profiles was generated, identifying limonite (0–10 m depth, 201–250 Ohm.m resistivity), saprolite (0–10 m depth, 101–200 Ohm.m resistivity), and bedrock (>10 m depth, 101 to >801 Ohm.m resistivity). Variations in resistivity are influenced by factors such as mineral content and morphology. The volume estimated from resistivity correlation and drillhole data is 1,625,300 m³ for limonite and 1,902,600 m³ for saprolite, compared to 1,523,100 m³ and 1,390,100 m³ based on drillhole-only data, showing discrepancies of 6% and 27%, respectively. This study provides a clearer understanding of geological modeling using drillhole and ERT data to support laterite nickel ore mining and correlation modeling.

References

Ahmad, W. (2002).Nickel laterites-A Short Course : Chemistry, Mineralogy and Formation of Nickel Laterites. Unpublished

Ahmad, W. (2002).Laterites- Fundamentals of chemistry, mineralogy, weathering, proses and laterite formation. Unpublished

Ahmad, W. 2006. Laterite : Mine Geology at PT. International Nickel Indonesia. Sorowako. Unpublished

Ahmad, W. (2009).Nickel laterites-A Short Course : Chemistry, Mineralogy and Formation of Nickel Laterites. Unpublished

Boldt, J.R. (1967). The Winning of Nickel, The Hunter Rose Company. Longmans, Canada.

Bankes. 2003 . Estimation of mineral resources and mineral reserves best practice guidelines. Ensiklopedi Pertambangan Edisi 3, Puslitbang Teknologi Mineral.

Darijanto, Totok. (1986). “Pengaruh morfologi terhadap pembentukan dan penyebaran nikel lateritik.

Elias M. (2002). Nickel laterite deposits – geologic overview, resources and exploitation in Giant ore Deposits: characteristics, genesis, and exploration, Cooke, D.R., Pongratz, J.,eds Centre for ore deposits research. special Publication 4. University of Tasmania, P 205-220,.

Evans, A.M. (1993). Ore Geology and Industrial Minerals. Blackwell Scientific Publications, Oxford, p 390.

Fitrian, E. B. (2021). Identifikasi Sebaran Nikel Laterit dan Cadangan Bijih Nikel Menggunakan Korelasi Data Bor. Paulus Civil Engineering Journal, 3, 113-119.

Golightly, J. P.1979. Geology of Soroako nickeliferous laterite deposit. INCO Metals Company, Ontario: Canada.

Golightly, J. P. 1981. Nickeliferous Laterite Deposits. Economic Geology (75th Anniv.), pp. 710-735

Hamilton, W. (1979). Tectonics of Indonesian region. United States Government Printing Office. Washington.

Kumarawarman, B. 2016. Engineering Geology Of Sorowako and Petea. (PT. Vale Indonesia Tbk.)

Looke, M.H. 2004. Tutorial: 2-D and 3-D Electrical Imaging Surveys. Geotomo Software. Penang, Malaysia.

Lowrie, W. 2007. Second Edition: Fundamentals of Geophysics. Cambridge University Press: Cambridge.

Maulana Adi. (2017). Endapan Mineral. Penerbit Ombak 2017: Yogyakarta

Pearl, R,M. (1988). Geology, 4th Edition, A Division of Harper Amd Row. Publisher, New York, Hagerstown, San Francisco, London

Ringwood, A.E., 1975. Composition and Petrology Of The Earth’s Mantle. McGraw-Hill, Inc: New York.

Simandjuntak, T.O., 1986, Sedimentology and Tectonics of the Collision Complex in the East Arm of Sulawesi, Unpub. PhD thesis RHBNC University of London, 374 pp

Simandjuntak, T.O., Rusmana, E., Surono dan Supandjono, J.B. 1991. Geologi Lembar Malili, Sulawesi. Departemen Pertambangan dan Energi, Direktorat Jenderal Geologi Dan Sumber Daya Mineral, Pusat Penelitian Dan Pengembangan.

Simanjuntak, T.O. 1993. Neogene Plate Convergence in Eastern Sulawesi.Jurnal Geologi dan Sumberdaya Mineral, no. 25 v.VIII, hal. 2-15.

Simandjuntak, T.O., Rusmana, E., Surono dan Supandjono, J.B. 1994. Geologi Lembar Bungku, Sulawesi. Departemen Pertambangan dan Energi, Direktorat Jenderal Geologi Dan Sumber Daya Mineral, Pusat Penelitian Dan Pengembangan.

Sukamto, R. 1975. Geologi Sulawesi. Departemen Pertambangan dan Energi, Direktorat Jenderal Geologi Dan Sumber Daya Mineral, Pusat Penelitian Dan Pengembangan.

Telford, W. M., Geldart, L. P., & Sheriff, R. E. (1990). Applied geophysics. Cambridge university press.