Rancangan Teknis Penambangan Bijih Nikel di PT Tiran Indonesia Kecamatan Langgikima, Kabupaten Konawe Utara, Provinsi Sulawesi Tenggara

Erghiza Tribiani, Zaenal Zaenal, Noor Fauzi Isniarno

Abstract


Abstract. PT Tiran Indonesia is mining industries company which is engaged in the mining of nickel ore deposits which have a mining area in Langgikima Subdistrict, North Konawe Regency, Southeast Sulawesi Province. The company plans to open new pits in the Block 2 area to meet its annual sales target. So that it is necessary to plan mining technical design before the mining activities start in that new area. In the research’s location have done exploration drilling, with a total of 50 drillholes, which will be used as database input to perform geological modelling and resources estimation. Based on the result of grade assessment with ordinary kriging method, there are 560,707.81 tonnes measured resources of nickel ore with average content Ni 1.87 % and Fe 15.28 %. Then based on the result of those resource estimation, will be determining the potentially areas for mining based on economics aspect, economical stripping ratio and cut off grade with used lerchs grossman 3-D algorithm. The cut off grade value used is average content Ni ≥ 1.7 % and economical stripping ratio of 4.6 tonnes waste / tonnes ore, so based on this limitations the nickel is considered as nickel ore is nickel who have the average content Ni ≥ 1.5 %. The result of pit optimization, there are two pits namely Pit X which have dimensions 5.44 Ha and Pit Y which have dimensions 6.03 Ha, so the total dimensions of mining boundary are 11.47 Ha. The mining activities will be used surface mining system, open cast method and selective mining procedure. Mine technical design will be made with geometry of bench is 4 m height, 2 m width and 60° slope. Meanwhile, the road technical design will be made with geometry of road is 15 m road straight width, 26.5 m road bend width, 0.04 m/m superelevation, 14.38 m radius of bend, 0.04 m/m cross slope, 8% road grade and 1.5 m height of safety berm. Mining activities will start with make mining block with dimension of block are 25 m x 25 m, which start from the higher elevation to lower elevation of pits. Based on the results of mining technical design, there are 495,853.16 tonnes mineable reserves of nickel ore with average content Ni 1.86 % and Fe 15.23%, which have non-ore materials are 516,129.65 tonnes overburden and 639,904.30 tonnes waste, so generate stripping ratio is 2.33 tonnes waste / tonnes ore. Production target are planned 40,000 tonnes nickel ore / month for each pit, so the mining will be planned for 6 months.

Keywords: Nickel, Resources, Mineable Reserves, Mining Technical Design, Production Planning.

Abstrak. PT Tiran Indonesia merupakan perusahaan industri pertambangan yang bergerak di bidang penambangan komoditas endapan bijih nikel yang memiliki area pertambangan di Kecamatan Langgikima, Kabupaten Konawe Utara, Provinsi Sulawesi Tenggara. Perusahaan tersebut berencana untuk membuka bukaan tambang baru pada blok 2 untuk memenuhi target penjualan tahunannya. Sehingga diperlukannya rancangan teknis penambangan sebelum dilakukannya kegiatan penambangan pada bukaan tambang yang baru tersebut.Untuk area pengamatan telah dilakukan eksplorasi pengeboran, dengan jumlah titik pengeboran sebanyak 50 titik bor yang nantinya digunakan sebagai input basis data dalam melakukan pemodelan geologi dan estimasi sumberdaya. Berdasarkan hasil penaksiran kadar menggunakan metode ordinary kriging, diperoleh sumberdaya terukur bijih nikel sebesar 560.707,81 ton dengan kadar rata-rata Ni 1,87 % dan Fe 15,28 %. Selanjutnya berdasarkan hasil estimasi sumberdaya tersebut, dilakukan penentuan area yang berpotensi untuk dilakukan penambangan dengan parameter acuan ekonomi, stripping ratio ekonomis dan cut off grade melalui algoritma lerchs grossman 3-D. Nilai cut off grade yang digunakan yaitu kadar rata-rata Ni ≥ 1,7 % dan nilai stripping ratio ekonomis 4,6 ton waste / ton ore, sehingga berdasarkan batasan tersebut nikel yang masih dianggap bijih nikel yaitu nikel dengan kadar Ni ≥ 1,5 %. Hasil dari optimasi bukaan tambang, didapatkan dua buah bukaan tambang yaitu pit X dengan luas 5,44 Ha dan pit Y dengan luas 6,03 Ha, sehingga total bukaan tambang seluas 11,47 Ha.Penambangan dilakukan dengan sistem tambang terbuka, metode open cast dan cara penambangan selective mining. Rancangan bukaan tambang dibuat dengan geometri jenjang tinggi 4 m, lebar 2 m dan kemiringan 60°. Sedangkan rancangan geometri jalan yang digunakan yaitu lebar jalan lurus 15 m, lebar jalan tikungan 26,5 m, superelevasi 0,04 m/m, jari-jari tikungan 14,38 m, cross slope 0,04 m/m, kemiringan jalan 8% dan tinggi tanggul pengaman 1,5 m. Penambangan dilakukan dengan membuat blok penambangan berukuran 25 m x 25 m, yang dimulai dari elevasi tertinggi menuju arah elevasi terendah bukaan tambang.Berdasarkan hasil rancangan bukaan tambang, diperoleh cadangan tertambang bijih nikel sebesar 495.853,16 ton dengan kadar rata-rata Ni 1,86 % dan Fe 15,23%, serta terdapatnya material bukan bijih berupa overburden sebesar 516.129,65 ton dan waste sebesar 639.904,30 ton sehingga menghasilkan stripping ratio sebesar 2,33 ton waste / ton ore. Target Produksi direncanakan sebesar 40.000 ton bijih nikel / bulan untuk setiap bukaan tambang, sehingga penambangan akan direncanakan selama 6 bulan.

Kata Kunci: Nikel, Sumberdaya, Cadangan Tertambang, Rancangan Teknis Penambangan, Rencana Produksi. 


Keywords


Nikel, Sumberdaya, Cadangan Tertambang, Rancangan Teknis Penambangan, Rencana Produksi.

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DOI: http://dx.doi.org/10.29313/pertambangan.v0i0.31148

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