Pengaruh Ukuran Butir terhadap Kadar Nikel Menggunakan Metode Fraksinasi dan Analisis Geokimia di Bukit Wrangler PT ANTAM UBPN Kolaka

Siti Aminah (Program Studi Teknik Pertambangan, Fakultas Teknik, Universitas Jember)
Reza Dyna Daniar (Program Studi Teknik Pertambangan, Fakultas Teknik, Universitas Jember)
Haeruddin Haeruddin (Program Studi Teknik Pertambangan, Fakultas Teknik, Universitas Jember)
Fanteri Aji Dharma Suparno (Program Studi Teknik Pertambangan, Fakultas Teknik, Universitas Jember)

Jurnal Geologi dan Sumberdaya Mineral (Journal of Geology and Mineral Resources)
Vol. 26 No. 4 (2025)

PT ANTAM UBPN Kolaka memiliki beberapa bukit dengan karakteristik mineral yang beragam, salah satunya adalah Bukit Wrangler. Ukuran butir tanah bervariasi di daerah ini, memengaruhi distribusi dan deposit nikel. Penelitian ini bertujuan menganalisis kandungan unsur terkait fraksi ukuran butir nikel pada zona saprolit, hubungan antara ukuran butir dan kadar nikel, serta klasifikasi ukuran butir berdasarkan Cut-off Grade (COG). Metode penelitian meliputi fraksinasi ukuran butir (-20 mm, 20 mm, 40 mm, 80 mm, 100 mm) yang dianalisis dengan metode geokimia XRF (X-Ray Fluorescence) untuk mengetahui kadar bijih nikel. Kandungan rata-rata Ni adalah 1,93% dan Fe adalah 13,75%, tertinggi terdapat pada fraksi ukuran 80 mm. Rasio Fe/Ni optimal ditemukan pada fraksi ukuran 100mm dengan kandungan rata-rata 5,78%. Penelitian padasampel di zona saprolit menunjukkan adanya hubunganberbanding lurus antara kandungan Fe dan Ni, nilai R2 = 2,46% dan MgO dengan kandungan Ni, nilai R2=1,05%, serta hubungan terbalik antara kadar SiO2 dengan kadar Ni, nilai R2 = 35,54% dan Al2 O3 dengan kadar Ni nilai R2 = 0,65%. Dari 42 sampel yang dianalisis berdasarkan COG perusahaan, 17 sampel dengan kadar Ni 1,5% - 1,79% dan Fe < 25% memenuhi kebutuhan pasar dalam negeri, sedangkan 25 sampel lainnya diproses lebih lanjut untuk menghasilkan feronikel. Kata Kunci: Analisis geokimia, Fraksinasi, Kadar nikel,Ukuran butir, Bukit Wrangler Abstract ANTAM UBPN Kolaka has several hills with diverse mineral characteristics, including Wrangler Hill. Soil grain size varies in this area, affecting nickel distribution and deposition. The research aims to analyze the elemental content related to the nickel grain size fraction in the saprolite zone, the relationship between grain size and nickel content, and the classification of grain size based on Cut-off Grade (COG). The research methods included grain size fractionation (-20 mm, 20 mm, 40 mm, 80 mm, 100 mm) analyzed by XRF (X-Ray Fluorescence) geochemical technique to determine the content of nickel ore. The analysis showed elements such as Ni, Fe, SiO2 , Mg, and Al2 O3 . The average content of Ni is 1.93% and Fe is 13.75%, the highest value was found in the 80 mm size fraction. The optimal Fe/Ni ratio was found in the 100 mm size fraction with an average content of 5.78%. The study in the saprolite zone showed a directly proportional relationship between Fe and Ni content, R2 value = 2.46% and MgO with Ni content, R2 value = 1.05%, as well as an inverse relationship between SiO2 content with Ni content, R2 value = 35.54% and Al2 O3 with Ni content, R2 value = 0.65%. Of the 42 samples analyzed based on the company’s COG, 17 samples with Ni content of 1.5% - 1.79% and Fe < 25% meet the needs of the domestic market, while the other 25 samples are further processed to produce ferronickel. Keywords: Geochemical analysis, Fractionation, Nickel content, Grain size, Wrangler Hill