Pemodelan dan Estimasi Sumberdaya Nikel Laterit Berdasarkan Kandungan Ni dan Fe dengan Menggunakan Metode Kriging di PT Putra Perkasa Abadi, Kecamatan Langgikima, Kabupaten Konawe Utara, Provinsi Sulawesi Tenggara (original) (raw)

Bandung Conference Series: Mining Engineering

Nickel laterite is a metallic mineral resulting from the chemical weathering process of ultramafic rocks which results in residual and secondary enrichment of Ni, Fe, Mn, and Co elements (Syafrizal et al.,2011). With the cutoff grade Ni, modeling and estimation of resources is important to obtain a block model of Ni resources. The distribution of Ni levels is heterogeneous, so mining is carried out by selective mining referring to model blocks that have been mapped to meet the cutoff grade Ni. Based on this, it is possible for low and high Ni levels to be optimized, because if you only take Ni levels above 1.6%, Ni levels below the cutoff grade are not utilized. The resource estimation method used is kriging. Because kriging is the best linear unbiased estimator, many parameters are considered in kriging one of which is the variogram model. The variogram model is a geostatistical analysis by considering the location of the sample point, so that information on the relationship of one point with another point is expressed in the range/radius of information points that still have a spatial relationship. Based on statistical analysis, Block North and Block South data distribution are abnormal, with coefficient of variation values of 0.494 and 0.410. Resources that meet the cutoff grade Ni for blending needs are obtained low nickel, medium and high grade ore nickel. The total laterite nickel resources of the North Block amounted to 36,757 tons with an average Ni content of 1.64%, the total laterite nickel resources of the South Block amounted to 178,186 tons with an average Ni content of 1.62%. When viewed from the average rate per block, both blocks meet the cutoff grade Ni.