scholarly journals Sequencing of ore columns for planning of large underground mines

Mining Scince ◽  
2019 ◽  
Vol 26 ◽  
Author(s):  
Hylke Glass ◽  
Gert Van Hout
Keyword(s):  
Net Present Value ◽  
Underground Mining ◽  
Underground Mines ◽  
Systematic Design ◽  
Present Value ◽  
Block Caving ◽  
Initiation Point ◽  
Mining Technique ◽  
Mine Economics ◽  
Large Deposits

Block caving is an underground mining technique which extracts ore from the base, rather than from the top, of typically massive deposits. Mining infrastructure is developed below the deposit before extraction commences. A network of tunnels provides access to a collection of drawpoints from which ore is hauled. With large deposits, not all drawpoints are developed simultaneously and the opening of drawpoints is sequenced to facilitate orderly extraction of ore columns above drawpoints. Sequencing fixes the initiation point for the entire block cave, or a part of it, as well as identifying the direction of cave advancement. The drawpoint opening sequence exerts influence on the block cave mine economics. This paper discusses the optimisation of sequencing based on the net present value associated with extraction over the life-of-mine. It is shown that the maximum attainable net present value is obtained by a sequence in which ore columns are ranked in descending order of value. If significant variation of grade is present inside columns, an iterative procedure is given which corrects the sequence which yields the maximum net present value. The sequence with maximum net present value may not be practical or attractive from a caving perspective. Systematic design of sequences which permit orderly development of a block cave is discussed. To provide context, the net present value obtained from these feasible sequences is compared with the maximum attainable net present value. It is shown that the best feasible sequences are preferentially initiated in zones with columns of high-grade ore.

scholarly journals ANALISIS PENENTUAN KADAR BATAS OPTIMAL (OPTIMUM CUT-OFF GRADE) DENGAN METODE LANE: STUDI KASUS PENAMBANGAN EMAS BAWAH TANAH

2020 ◽  
Vol 1 (1) ◽  
pp. 1-8
Author(s):  
Sari Uly Uly Sibarani ◽  
Fadhila A Rosyid ◽  
Aryo P Wibowo ◽  
Lilik E Widodo ◽  
M Nur Heriawan
Keyword(s):  
Net Present Value ◽  
Underground Mining ◽  
Commodity Prices ◽  
Open Pit ◽  
Present Value ◽  
Open Pit Mines ◽  
Vein Type ◽  
Result Show ◽  
Cut And Fill ◽  
Mineral Reserves

ABSTRAKKonservasi mineral akan tercapai manakala semakin banyak cadangan mineral tertambang dan meninggalkan sesedikit mungkin material waste. Untuk mencapai hal tersebut salah satu cara yang dapat ditempuh adalah menentukan jumlah cadangan berdasarkan kadar batas yang optimal (optimum cut-off grade). Dalam penentuan optimum cut-off grade, model matematis yang dapat dipergunakan adalah model/persamaan Lane. Metode Lane akan memaksimalkan nilai Net Present Value (NPV) dengan mempertimbangkan 3 variabel, yaitu; variabel ekonomi (harga komoditas dan biaya), distribusi kadar pada endapan, dan kapasitas maksimum pada tahapan penambangan (mining, milling, and refinery). Model Lane biasa diterapkan dalam tambang terbuka, namun dalam penambangan bawah tanah sulit untuk diterapkan. Dalam peper ini akan dikaji penerapan Model Lane dalam penentuan optimum cut-off grade pada penambangan urat (vein) emas bawah tanah dengan metode cut-and-fill. Hasil simulasi menunjukkan nilai optimum cut-off grade yang dinamis dalam memaksimalkan NPV dan nilainya lebih besar dari break even cut-off grade.Kata Kunci: model Lane, optimum cut-off grade, tambang bawah tanah ABSTRACTMineral conservation will be obtained if more mineral reserves are extracted and leaves less waste as possible. One of the methods to achieve those condition is determining the total minable reserves based on the optimum cut-off grade. Optimum cut-off grade can be estimated using Lane Model. Lane Model will maximize the Net Present Value (NPV) by considering 3 variables, i.e; economic variables (commodity prices and costs), grade distribution of deposit, and maximum capacity of each stage of production (mining, milling, and refinery). Lane models are usually applied in open-pit mines, unfortunately it is difficult to apply for underground mining unless some there are some modifications. This paper will examine the application of the Lane Model in determining the optimum cut-off grade in underground gold mine using cut-and-fill method to extract vein type deposit. Simulation result show dynamic optimum cut-off grade which maximizing NPV and generally greater than the break-even cut-off grade.Key Words: Lane model, optimum cut-off grade, underground mine 

scholarly journals Technical Planning of Ventilation System to Support Development W Undercut in 2021 at PT. Freeport Indonesia Underground Mining

2020 ◽  
Vol 1 (1) ◽  
pp. 1-6
Author(s):  
Yudho Dwi Galih Cahyono
Keyword(s):  
Underground Mining ◽  
Ventilation System ◽  
Underground Mines ◽  
Design Criteria ◽  
Minimum Level ◽  
Block Caving ◽  
Heavy Equipment ◽  
Clean Air ◽  
Technical Planning ◽  
Main Components

Ventilation is an attempt to drain clean air into the mine and remove dirty air out of the mine. The main components of a mine ventilation system are intake, working, and exhaust. Intake is a tunnel and wells system where air flows from the surface into the mine. The purpose of the ventilation system in an underground mine is to provide and drain clean air into the mine for breathing and comfort of mine workers. Based on the Ventilation Design Criteria used by PTFI, the minimum airflow level required for every mine worker is 0.033 m3 / s / worker. Based on PTFI Ventilation Design Criteria, the minimum level in diluting smoke of heavy equipment diesel engine is 5 m3 / min or 0.08 m3 / s / kW. PT Freeport Indonesia is currently developing new underground mines namely Grasberg Block Caving (GBC) and Deep Mill Level Zone (DMLZ) which will be mined using the block caving method.

ANALISIS KELAYAKAN FINANSIAL INDUSTRI PENGOLAHAN KECAP ANEKA GUNA DI KOTA LANGSA

2017 ◽  
Vol 2 (1) ◽  
pp. 21-30
Author(s):  
Muhammad Jamil ◽  
Januari Frizki Bella
Keyword(s):  
Net Present Value ◽  
Rate Of Return ◽  
Internal Rate Of Return ◽  
Present Value ◽  
Internal Rate

Adapun tujuan dari Penelitian ini adalah untuk mengetahui kelayakan usaha industri pengolahan kecap Aneka Guna apabila dilihat dari segi kelayakan finansial. Penelitian ini menggunakan metode studi kasus. Lokasi penelitian yaitu di Kota Langsa dengan pertimbangan bahwa lokasi tersebut merupakan daerah yang terdapat industri pengolahan kecap asin dan mudah di jangkau oleh penulis. Waktu penelitian dilaksanakan pada Bulan Juni - Oktober 2014. Tenaga kerja yang digunakan berjumlah 27 orang, 20 tenaga kerja pria dan 7 orang tenaga kerja wanita. Jumlah penggunaan tenaga kerja selama 5 tahun sebesar 3759 HKP. Total biaya produksi yang dikeluarkan oleh pengusaha dalam usaha pembuatan kecap didaerah penelitian selama 5 tahun adalah Rp. 2.076.988.000,-. Pendapatan kotor yang diperoleh pengusaha sebesar Rp. 8.199.690.000,- dan pendapan bersih yang diperoleh sebesar Rp. 6.122.702.000,-                 Kota Langsa hanya memiliki 1 pengusaha pengolahan kecap asin dan dijadikan sebagai pengusaha sampel yaitu usaha industri pengolahan kecap asin Aneka Guna. Hasil perhitungan di peroleh Net Present Value (NPV) sebesar Rp. 263.281.290 (lebih besar dari nol), sedangkan Internal Rate of Return (IRR) sebesar 84% lebih besar dari tingkat bunga yang berlaku (D.F. = 18%), sedangkan Net B/C Ratio sebesar 3,27 (lebih dari pada 1) dan Pay Back Priod (PBP) 1 Tahun 6 Bulan (lebih kecil dari umur ekonomis).  

UNIFICATION OF STANDS SELECTION FOR FINAL FELLING IN STRATEGIC AND TACTICAL PLANNING

2015 ◽  
Author(s):  
Ainārs GRĪNVALDS
Keyword(s):  
Strategic Planning ◽  
Net Present Value ◽  
Strategic Plan ◽  
Regression Function ◽  
Tactical Planning ◽  
Present Value ◽  
Black Alder ◽  
Value Maximization ◽  
Annual Changes ◽  
Selection For

The stand selection for cutting in tactical planning should be done according to the same principles like in strategic planning – to maximize net present value. The simple way of how to transfer the net present value maximization principle from strategic planning to tactical planning was created in Sweden. The method is based on annual changes in the net present value by postponing final felling. Forest inventory data and forestry modelling system was used for calculation of changes in net present value for pine, spruce, birch, aspen and black alder stands. And changes in net present value were described by regression function with factors from stand parameters. The regression function allows calculating annual changes in net present value for each stand. And stands with higher decrease in net present value have higher cutting priority. Stands selected for the final felling in strategic plan were compared with the stands selected in tactical plan with two methods, first, by using annual changes in the net present value, second, by traditional planning principles. Stands selected by annual changes in the net present value were similar to stands that were selected for cutting in strategic plan, but stands selected by traditional planning principles – not.

EVALUASI TERHADAP PENGELOLAAN SAMPAH DALAM MENINGKATKAN PELAYANAN ASET DI KOTA PEMATANGSIANTAR

2017 ◽  
Vol 13 (3) ◽  
pp. 240
Author(s):  
Novdin M Sianturi
Keyword(s):  
Net Present Value ◽  
Payback Period ◽  
Rate Of Return ◽  
Cost Ratio ◽  
Internal Rate Of Return ◽  
Present Value ◽  
Benefit Cost Ratio ◽  
Internal Rate ◽  
Benefit Cost

Abstrak: Pengelolaan sampah di Kota Pematangsiantar masih bertumpu pada pendekatan akhir (kumpul-angkut-buang), dengan tingkat pelayanan yang rendah, sehingga untuk meningkatkan pelayanan sampah, perlu dilakukan pemilahan di tempat penampungan sementara (TPS). Penelitian ini bertujuan untuk mengkaji sistem pengelolaan sampah dengan melakukan pemilihan di TPS dapat meningkatkan pelayanan aset persampahan sampai tahun  2015 secara teknis operasional dan dari aspek keuangan. Analisa teknis operasional aset pengelolaan sampah mulai dari pewadahan, pengumpulan dan pengangkutan sedangkan analisa keuangan dan analisa kelayakan menggunakan Net Present Value, Internal Rate of Return, Benefit/Cost Ratio, dan Payback Period. Dari hasil analisa tersebut diperoleh suatu sistem pengelolaan sampah dengan pemilihan di TPS berdasarkan zona pelayanan dengan skala prioritas secara bertahap daritahun 2013-2017, dapat meningkatkan cakupan pelayanan sampah eksisting rata-rata 6,69 %, cakupan pelayanan TPS eksisting rata-rata 8,29 %, dan cakupan pelayanan truk pengangkut sampah eksisting rata-rata 12,03 %. Investasinya layak, diperoleh Net Cashflow pada tahun 2020 sebesar Rp 1.720.242.284,-, NPV suku bunga 15 % bernilai positif, IRR > MARR 15 %,  B/C Ratio > 1, dan PP 4,7 tahun, lebih pendek dari periode investasi 10 tahun. Dari Metode penelitian ini maka pengumpulan data, observasi lapangan dan pengukuran contoh timbulan sampah dengan sampel 4 TPS perumahan yang terlayani pengangkutan.

KELAYAKAN USAHA PENANGKAPAN IKAN MENGGUNAKAN JARING INSANG (GILL NET) DI WADUK JATIGEDE KABUPATEN SUMEDANG

2018 ◽  
Vol 2 (1) ◽  
pp. 8-14
Author(s):  
Wahyu Setiawan ◽  
Atikah Nurhayati ◽  
Titin Herawati ◽  
Asep Agus Handaka
Keyword(s):  
Net Present Value ◽  
Cost Ratio ◽  
Present Value ◽  
Literature Study ◽  
Benefit Cost Ratio ◽  
Period 2 ◽  
Gill Net ◽  
Business Analysis ◽  
Benefit Cost ◽  
Profit Value

Gill net is one of the fishing gear used by Jatigede Reservoir fisherman. The purpose of this research is to analyzed the feasibility of fish catching business with gill net in Jatigede Reservoir. This research was conducted by used data collection method (observation, questioner, literature study) and method of data analysis (feasibility business analysis). The benefits of this research is expected to be informations and references for the research who will expand a fishing business with gill net at Jatigede Reservoir. The result of feasibility of fish catching business with gill net at Jatigede Reservoir is profit value Rp. 70.890.000, Break Event Point price and production (all species of fish) Rp. 4.154/kg and 2.136kg in a year, Benefit Cost Ratio 3,37, Payback Period 2 months and Net Present Value >1 Rp. 52.820.243, the fish catching business using gill net at Jatigede Reservoir is feasible to be developed.

PENINGKATAN KINERJA SIMPANG MELALUI MANAJEMEN HAMBATAN SAMPING DAN PENGATURAN ARUS LALU LINTAS

2017 ◽  
Vol 16 (2) ◽  
pp. 38
Author(s):  
Rama Dwi Aryandi ◽  
Ari Sandhyavitri ◽  
Reni Suryanita
Keyword(s):  
Net Present Value ◽  
Cost Ratio ◽  
Present Value ◽  
Traffic Light ◽  
Benefit Cost Ratio ◽  
Benefit Cost

Penelitian ini bertujuan untuk menganalisis tingkat pelayanan simpang berdasarkan data lalu lintas simpang tersebut apakah derajat jenuhnya sudah melewati ambang batas DS = 0,75, jika nilai DS>0,75, akan dikaji penerapan beberapa alternatif penanganan untuk meningkatkan tingkat pelayanan simpang, untuk kemudian dipilih lagi alternatif terbaik untuk jangka pendek, menengah dan panjang. Metode pengumpulan data yang digunakan dalam penelitian ini adalah metode traffic counting, sedangkan untuk pengkajian alternatif penanganan simpang secara teknik menggunakan metode MKJI 1997, secara ekonomi menggunakan metode LAPI ITB, analisa nilai waktu dengan nilai waktu hasil penelitian Dirjen Bina Marga dan analisa biaya investasi dengan analisa Benefit Cost Ratio dan Net Present Value.  Dari tiga alternatif manajemen lalu lintas yang diajukan, hanya alternatif ke-3 yaitu kombinasi peniadaan hambatan samping, pelarangan belok kiri dan optimasi traffic light  yang menghasilkan nilai DS<0,75 untuk kondisi eksisting, sedangkan untuk tahun 2020 nilai DS-nya adalah 0,79 untuk Hari Selasa dan 0,83 untuk Hari Rabu. Sedangkan dengan alternatif pembangunan flyover, untuk jangka pendek atau 5 tahun nilai BCR dan NPV-nya 1,25 dan 48,9 milyar rupiah, tahun ke-10  2,29 dan 256,4 milyar rupiah, serta tahun ke-15 3,35 dan 472,19 milyar rupiah, sehingga dapat disimpulkan bahwa pembangunan flyover adalah solusi penanganan terbaik untuk menignkatkan kinerja Simpang Pasar Pagi Arengka.

TINJAUAN STUDI KELAYAKAN USAHA BADAN USAHA MILIK DESA (NAGARI) KAMANG HILIA SEJAHTERA KENAGARIAN KAMANG HILIA, KECAMATAN KAMANG MAGEK, KABUPATEN AGAM, PROVINSI SUMATERA BARAT

2018 ◽  
Vol 3 (2) ◽  
pp. 160
Author(s):  
Halkadri Fitra ◽  
Salma Taqwa ◽  
Charoline Cheisviyanny ◽  
Abel Tasman ◽  
Nurzi Sebrina
Keyword(s):  
Cash Flow ◽  
Net Present Value ◽  
Average Rate ◽  
Flow Analysis ◽  
Payback Period ◽  
Rate Of Return ◽  
Internal Rate Of Return ◽  
Present Value ◽  
Internal Rate

Penelitian ini bertujuan untuk melihat kelayakan aspek keuangan usaha grosir sembako Badan Usaha Milik Desa (Nagari) Kamang Hilia Sejahtera di Kenagarian Kamang Hilia Kecamatan Kamang Magek Kabupaten Agam Provinsi Sumatera Barat yang dilakukan pada tahun 2018. Penelitian bersifat deskriptif kuantitatif dengan menggunakan metode cash flow analysis, payback period, net present value, profitability index, internal rate of return, dan average rate of return. Hasil penelitian menunjukkan bahwa nilai net cash flow Badan Usaha Milik Desa (Nagari) Kamang Hilia Sejahtera adalah positif yaitu Rp.21.774.000, nilai payback period adalah 1,15 tahun, nilai net present value positif sebesar Rp.10.680.034,47, nilai profitability index adalah positif 1,37, sedangkan nilai internal rate of return adalah 46,7% dan nilai average rate of return adalah 57,23%. Berdasarkan standar penilaian maka semua metode yang digunakan memberikan kesimpulan bahwa usaha grosir sembako milik Badan Usaha Milik Desa (Nagari) Kamang Hilia Sejahtera dalam kategori layak untuk dilaksanakan.

Analisis Kelayakan Finansial Usaha Ternak Ayam Kampung Super (Studi Kasus pada Peternakan Suparlan di Desa Jojog Kecamatan Pekalongan Kabupaten Lampung Timur)

1970 ◽  
Vol 3 (1) ◽  
Author(s):  
Fikri Fathurahman Aziz
Keyword(s):  
Return On Investment ◽  
Net Present Value ◽  
Secondary Data ◽  
Payback Period ◽  
Rate Of Return ◽  
Primary Data ◽  
Cost Ratio ◽  
Internal Rate Of Return ◽  
Present Value ◽  
Internal Rate

This study aims to analyze financially (net present value, revenue cost ratio, internal rate of return, break event point, return on investment and payback period) feasibility of kampung super chicken farming Mr. Suparlan in Jojog village, district Pekalongan, East Lampung regency. The data used in the form of quantitative and qualitative data sourced from the primary data and secondary data which is then analyzed descriptively. Based on the analysis, it is known that kampung super farm is financially feasible to cultivate. This is indicated by the positive value of net present value (NPV) of Rp 186,568,517, revenue ratio (RCR) 1.59, internal rate of return (IRR) of 135.82%, return on investment (ROI) of 43%, and the value of payback period (PP) of 0.50. Keywords: financial feasibility, kampung chicken, chicken farm

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