Evaluasi rekonsiliasi penambangan bijih nikel antara blok model dengan aktual di site Pulau Pakal, Antam UPBN Maluku Utara
B Berdasarkan data hasil pemboran tim Eksplorasi PT Aneka Tambang pada tahun 1989-1990 telah ditemukan cadangan bijih nikel di daerah Halmahera Timur khususnya di Tanjung Buli dan Pulau Pakal. Dimana hasil dari penambangan bijih nikel ini memiliki grade berupa High Grade Saprolite Ore (HGSO) dengan kadar Ni ≥ 2.0%, Medium Grade Saprolite Ore (MGSO) dengan kadar 1.8% ≥ Ni ≤ 1.99%, dan Low Grade Saprolite Ore (LGSO) dengan kadar 1.5% ≥ Ni ≤ 1.79%. Rekonsiliasi merupakan perbandingan yang dilakukan antara blok model tertambang dengan aktual penambangannya. Evaluasi rekonsiliasi penambangan bijih nikel antara blok model dengan aktual perlu dilakukan untuk meminimalisir kerugian yang disebabkan karena perbedaan kadar nikel (Ni) dan juga perbedaan tonase. Pada bulan Januari 2018 diperoleh hasil blok model tertambang untuk LGSO sebesar 62.079,5 ton, MGSO sebesar 31.085,17 ton, dan HGSO sebesar 76.097,07 ton. Sedangkan pada aktual penambangan diperoleh hasil untuk LGSO sebesar 50.550 ton, MGSO sebesar 34.125 ton, dan HGSO sebesar 64.675 ton. Sehingga diperoleh nilai Mining Recovery pada LGSO, MGSO, dan HGSO sebesar 81,43%, 109,78%, dan 84,99%. Selain perbandingan tonase dilakukan juga perbandingan kadar nikel antara blok model tertambang dengan aktual penambangan. Pada blok model tertambang didapatkan hasil kadar Ni LGSO sebesar 1,64%, kadar Ni MGSO sebesar 1,893%, dan kadar Ni HGSO sebesar 2,436%. Sedangkan pada aktual penambangan didapatkan hasil kadar Ni LGSO sebesar 1,647%, kadar Ni MGSO sebesar 1,892%, dan kadar Ni HGSO sebesar 2,425%. Sehingga diperoleh nilai dilusi (dilution factor) pada LGSO, MGSO, dan HGSO sebesar (-0,43%), 0,03%, dan 0,47%. Dari hasil keseluruhan ini didapatkan bahwa terdapatnya perbedaan tonase dan kadar nikel antara blok model dengan aktual penambangan.
B Based on the data from the drilling of the Exploration Team of PT Aneka Tambang in 1989-1990, nickel ore reserves in East Halmahera area were found, especially in Tanjung Buli and Pakal Island. Where the results of nickel ore mining have a grade of High Grade Saprolite Ore (HGSO) with Ni ≥ 2.0%, Medium Grade Saprolite Ore (MGSO) 1.8% ≥ Ni% 1.99%, and Low Grade Saprolite Ore (LGSO) with levels of 1.5% ≥ Ni ≤ 1.79%. Reconciliation is a comparison between blocks of mined models and actual mining. The actual reconciliation of nickel ore mining between blocks model needs to be done to minimize losses caused by differences in nickel (Ni) levels and also tonnage differences. In January 2018, the results of the mined model block for LGSO were 62,079.5 tons, MGSO was 31,085.17 tons, and HGSO was 76,097.07 tons. While the actual mining results obtained for LGSO amounted to 50,550 tons, MGSO amounted to 34,125 tons, and HGSO amounted to 64,675 tons. So that the value of Mining Recovery was obtained on LGSO, MGSO, and HGSO by 81.43%, 109.78%, and 84.99%. In addition to tonnage comparisons, the ratio of nickel levels between the mined blocks model and actual mining is carried out. In the mined model block, the results of Ni LGSO were 1.64%, Ni MGSO levels were 1.893%, and Ni HGSO levels were 2.436%. Whereas in actual mining, the results of Ni LGSO levels were 1,647%, Ni MGSO levels were 1,892%, and Ni HGSO levels were 2,425%. So that obtained dilution values (dilution factor) on LGSO, MGSO, and HGSO are (-0.43%), 0.03%, and 0.47%. From these overall results it was found that there were differences in tonnage and nickel content between the block model and actual mining.