Jurnal Puslitbang tekMira (Teknologi Mineral dan Batubara)
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THE NATURES OF ZINC SULFIDE CONCENTRATES AND ITS BEHAVIOR AFTER ROASTING PROCESS
No full textThe sample used for this study was a sulfide flotation concentrate that came from PT Lumbung Mineral Sentosa.The phase changes that occur in the particles of zinc sulfide concentrate during roasting in a muffle furnace were investigated using light microscopy, X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDS) while its chemical composition was analyzed using atomic absorption spectroscopy (AAS) and X-ray fluorescence (XRF) methods. Characterization also employed DTA-TGA instrument to provide data on the transformations that have occurred while the TGA data presents information about physical and chemical phenomena. Mineral composition of the sample included sphalerite, galena, chalcopyrite, and pyrite. Sphalerite was the most dominant one. Roasting sphalerite samples was intended to release the sulfur from its sulfide, Such a release was made easier for further treatment of the zinc such as a leaching process. Roasting temperature varied from 200 - 1,100 °C. Sphalerite starts to change when the temperature was raised to 650 °C performing the formation of zincite, franklinite, quartz and sphalerite as well. This composition did not change although the temperature increased to 1,100 °C. The Zn content within the original sample was 59.00% and then increased with the increasing of temperature but the improved in line with the increased temperature. The highest Zn was 78.98% achieved at 1,100 °C
EVALUATION OF COMBUSTION BEHAVIOUR FOR INDONESIAN LOW-RANK COALS TREATED HYDROTHERMALLY
No full textHydrothermal dewatering process has been made to produce dry-processed coals, which are comparable to bituminous coal. Two types of coals, i.e. low rank and high-rank coals. The low-rank coal came from West Papua while the high one was from Central Kalimantan. The behaviour of raw and processed coals were observed using thermogravimetry and differential scanning calorimetry techniques The change in chemical properties that are based on proximate, ultimate, calorific value and Fourier-transform infrared spectroscopy analyses are studied. Those are closely related to some combustion problems. This process was conducted in a laboratory scale using an autoclave with 5,000 ml/batch in capacity at the temperature of 300 and 330°C for one hour. The results indicate that the processed coals generally have a better combustion behaviour than that of the raw coals. The processed coals have a lower reactivity than that of raw ones, due to the higher ignition temperature (Tig), char burnout temperature (Tbo) as the end of combustion and maximum combustion rate (Rmax) of processed coals. The processing temperature of the process was a slight effect on combustion behaviour. The process is very effective to improve the quality of low-rank coal, nonetheless to high-rank coal, which has low moisture content and high calorific value, and the combustion behaviour of processed coals was not significantly changed
ANALISIS PENENTUAN HARGA JUAL BATUBARA PT BERAU COAL UNTUK PEMBANGKIT LISTRIK TENAGA UAP MULUT TAMBANG LATI
No full textPerusahaan batubara dalam hal menjual batubara harus mengikuti peraturan yang dikeluarkan oleh Kementerian Energi dan Sumber Daya Mineral yang kewenangannya ada di bawah Direktorat Jenderal Mineral dan Batubara. PT Berau Coal sejak 2003 menjual batubara berupa reject coal kepada Pembangkit Listrik Tenaga Uap Mulut Tambang Lati di Kabupaten Berau, Kalimantan Timur. Berdasarkan kajian Pusat Penelitian dan Pengembangan Teknologi Mineral dan Batubara, harga jual batubara tersebut ditetapkan sebesar USD 0,85 per ton atau senilai bagi hasil bagian pemerintah, dengan pertimbangan untuk memajukan daerah. Dengan berjalannya waktu, cadangan reject coal perusahaan tambang tersebut semakin tipis. Di samping itu, penggunaan reject coal untuk pembangkit listrik menimbulkan permasalahan bagi boiler. Untuk memenuhi kebutuhan pembangkit listrik tersebut, sebagai alternatif digunakan batubara non reject coal yang tersedia di pasar batubara. Harga batubara untuk steam (thermal) coal ditetapkan berdasarkan Harga Patokan Batubara. Kondisi tersebut menjadi kendala, khususnya untuk periode 2012-2015, yaitu belum adanya kesepakatan harga jual beli dari kedua belah pihak. Berdasarkan analisis, harga tersebut tidak ekonomis bagi pembangkit listrik tersebut (PT Indo Pusaka Berau) maupun PT PLN. Di lain pihak, berdasarkan simulasi cash flow PT Indo Pusaka Berau, jika harga batubara senilai bagian pemerintah, biaya produksi lebih ekonomis, tetapi tidak sesuai lagi dengan peraturan. Untuk mencari win-win solution terhadap persoalan tersebut, maka berdasarkan Pasal 2 dan 3 Peraturan Direktur Jenderal Mineral dan Batubara Nomor 1348.K/30/DJB/2011, bahwa harga batubara untuk pembangkit listrik mulut tambang dengan kalori lebih besar atau sama dengan 3.000 kkal/kg gar dapat dijual dengan harga di bawah Harga Patokan Batubara dengan menyampaikan kajian. Berdasarkan hasil analisis diperoleh satu harga alternatif, yaitu USD 19,96 per ton
ANALISIS PENGENAAN PAJAK PERTAMBAHAN NILAI TERHADAP KONTRAKTOR PERJANJIAN KARYA PENGUSAHAAN PERTAMBANGAN BATUBARA GENERASI III
No full textPengenaan Pajak Pertambahan Nilai terhadap kontraktor Perjanjian Karya Pengusahaan Pertambangan Batubara Generasi III telah menimbulkan sengketa di pengadilan pajak. Persoalan tersebut terjadi karena terdapat perbedaan pemahaman terhadap perlakuan Pajak Pertambahan Nilai atas peraturan perundang-undangan di bidang pertambangan mineral dan batubara. Metodologi yang digunakan di dalam kajian ini berdasarkan pada pendekatan keilmuan kebijakan dengan menerapkan metode analisis data sekunder. Hasil analisis data sekunder selanjutnya dimanfaatkan untuk merumuskan dan menjawab pokok persoalan kajian. Berdasarkan analisis data sekunder terdapat perbedaan perlakuan pengenaan Pajak Pertambahan Nilai. Pada kontraktor Perjanjian Karya Pengusahaan Pertambangan Batubara yang ditandatangani sebelum diberlakukan Undang-Undang Nomor 4 Tahun 2009, maka penerapannya diatur sesuai ketentuan Undang- Undang Nomor 11 Tahun 1967 dan produk hukum turunannya, yaitu batubara yang telah mengalami proses pengo- lahan. Sementara itu, peraturan perpajakannya mengacu kepada Undang-Undang Nomor 8 Tahun 1983 tentang Pajak Pertambahan Nilai Barang dan Jasa dan Penjualan Barang Mewah dengan aturan pelaksanaannya Peraturan Pemerintah Nomor 22 Tahun 1985. Setelah berlakunya Peraturan Pemerintah Nomor 144 Tahun 2000, perubahan atas Peraturan Pemerintah Nomor 22 Tahun 1985, maka pengaturannya didasarkan kepada proses pengolahan batubara menjadi briket. Periode setelah diberlakukan Undang-Undang Nomor 4 Tahun 2009, pengenaan Pajak Pertambahan Nilai didasarkan kepada Peraturan Pemerintah Nomor 77 Tahun 2014, perubahan atas Peraturan Pemerintah Nomor 23 Tahun 2010, bahwa pengertian pengolahan meliputi: peningkatan mutu batubara, pembuatan briket batubara, pencairan batubara, gasifikasi batubara, coal slury/coal water mixture. Artinya, batubara yang belum mengalami beberapa jenis pengolahan tersebut masih dianggap sebagai barang tambang yang diambil langsung dari sumbernya, atau belum mengalami pen- ingkatan nilai tambah, atau merupakan golongan barang yang tidak terkena Pajak Pertambahan Nilai
APPLICATION OF MULTI-ARRAY ELECTRICAL RESISTIVITY TOMOGRAPHY IN PT. BUKIT BAIDURI ENERGI COAL MINING-EAST KALIMANTAN
No full textMulti-array Electrical Resistivity Tomography survey was conducted in coal mining concession of PT. Bukit Baiduri Energi at the Marandai pit, Loa Janan District, Kutai Kartanegara-East Kalimantan. Data acquisition has been done using the MAE-X612 unit with 48 electrodes and 5 meters interval and the maximum length of the survey was 235 meters. The aim of the survey is to analyze resistivity images from three different electrodes configurations for interpreting coal seams and other lithologies. We deployed three configurations, including Wenner-Schlumberger, Dipole-Dipole, and Pole-Dipole in one traverse. The resistivity images analyses were constrained using geological and geophysical logging. The result shows that the Wenner-Schlumberger array is the reliable result comparing to the dipole-dipole and pole-dipole arrays. This technique will apply for further assessment to provide the reliable result in this coal mining concession. Electrical Resistivity Tomography offers rapid mapping for shallow mine working up to 45-meter depth. This method can be applied to one or two hour’s measurements with 48 electrodes with maximum 5-meter electrodes interval. This method offers the possible saving of drilling cost by using resistivity profile for coal seam correlation instead of conducting more drilling
CEMENT MATERIAL DEVELOPMENT USED FOR CEMENTING UNDERGROUND COAL GASIFICATION WELL
No full textR&D Centre for Mineral and Coal Technology, the Ministry of Energy and Mineral Resources developes an underground coal gasification (UCG) technology including its UCG test in a coal mine at Musi Banyuasin regency, South Sumatra. The UCG is safer than the underground mine since there is no worker underground however there is a concern in risk of ground water pollution. One of the mthods to reduce the risk is a proper instalation of well casing and cementing that seal aquifer from contact with UCG product gas. Development of special cement for cementing UCG well is needed due to its high process temperature (up to 1300°C). The objective of this research is to develop a cement material that can withstand high temperatures environtment. Domestically available an oil well cement (OWC) and a castables (CT) were used for the experiments. Single material of OWC is not suitable for cementing UCG well since the OWC compressive strength reduced drastically at heat treatment above 300°C due to decomposistion of portlandite and calcium silicate hydrate. On the other hand, there was a synergistic effect that resulted of higher compressive strength sample if 60% weight of OWC and 40% weight of CT was blended. The absence of portlandite and the presence of inert filler materials in the blend is believed to improve thermal and mechanical properties of the blend