Jurnal Puslitbang tekMira (Teknologi Mineral dan Batubara)
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GEOTECHNICAL INVESTIGATION FOR EVALUATING COAL MINING DESIGN OF PIT A AT KUTAI KERTANEGARA, EAST KALIMANTAN
No full textDue to the occurrence of slope failure at Pit A, on both side-wall and low-wall geotechnical study had been con- ducted to evaluate the slope stability whether the mining can be continued through the end of mine life or not. Slope stability modeling using Limit Equilibrium method shows that coal mining is feasible to reach the depth of ± 50m as stated in a previous plan. The previous design for sidewall has the overall slope of 400. This is not a stable condition with Safety Factor (SF) =1.050. As a result, evaluation of slope design must be conducted. The simulation shows that the slope must be changed to 300 in terms of reaching stable condition with SF=1.539. Previous design of the low wall that has the overall slope of 300 is stable with the SF=1.359 however, as the area is near settlements and Mahakam River, the pit slope must be reduced to 250 with SF=1,523. Slope stabil- ity simulation at the high-wall shows that the previous design with the overall slope 450 is stable for SF=2.418. It is not necessary to change previous design. However, to guaranty safety condition along mining area, it is recommended to make safety-berm to prevent the rocks enter the area
PROCESSING ZIRCONIA THROUGH ZIRCON SAND SMELTING WITH NaOH AS A FLUX
No full textZirconia had been made through smelting the zircon sand along with NaOH as a flux. The zircon sand as the smelter feed was taken from CV. Kurnia Alam Sejati mine at Palangkaraya, Middle Kalimantan. Major content of the zircon sand was 28.04% ZrO2 and SiO2 51.22% with several minor oxides such as 0.54% HfO2, 2.53% Fe2O3, 10.53% TiO2, 3.27% Al2O3 and less than 1% of alkali, alkaline earth and rare earth elements. In order to economizing the process, zircon sand upgrading was conducted prior to zirconia production. The upgrading process was conducted using several comprehensive equipments, consist of shaking table, magnetic separator and high tension separator (HTS).The upgraded sand contained 65.35% of ZrO2+HfO2 with 73.25% recovery, which was then used for smelting process at 650C for 2 hours using NaOH as a flux. The product was then leached with water and sulphuric acid then crystallized to get precipitated zirconium hydroxide. The precipitated product was calcined at 900C for 1 hour to get the zirconia and analyzed for its content. The zirconia content was 97.27% of ZrO2+HfO2 with 65.13% recovery
FACTORS CONTROLLING PETROGRAPHIC COMPOSITION OF NEOGENE TENGGARONG COALS-KUTAI BASIN-EAST KALIMANTAN
No full textPetrographic composition of the Neogene Tenggarong coals in the Kutai Basin-East Kalimantan indicates its geological setting. The aim of this study is to obtain an understanding of the geologic aspects controlling the petrographic composition of the coals.Variation of type and rank in the coals was determined by petrographic examination of twenty-two samples. The coals are absolutely dominated by vitrinite, common liptinite and rare inertinite and mineral matter. Vitrinite macerals are dominated by detrovitrinite and telovitrinite. Cutinite and resinite are the dominant liptinite macerals in the coals. The inertinite macerals include semifusinite, inertodetrinite and sclerotinite. Clay and pyrite are the dominant mineral matters in the coals. The type differences largely reflect climatic influence and differences in peat conditions. Rank of the coals, in general, depends largely on the stratigraphic position. Reflectance measurements on the coals indicate that there is a slightly difference in rank. The coals are sub-bituminous rank (Rvmax of 0.40-0.47%). The change in vitrinite reflectance of the coals is due to the thicker cover/overburden on the high rank coals. Nevertheless, the vitrinite reflectance is higher in some coals in the Loa Kulu area (Rvmax of 0.48-0.57%) due to its stratigraphic position that is at the bottom of the sequence. The type and rank characteristics of the coals clearly influence the utilization. The coals are suited to utilize for direct combustion and therefore, the major utilization potential would be for power generation
POTENTIAL STUDY OF INDONESIA COAL FOR ADSORBED NATURAL GAS
No full textLow rank coal was used as a precursor for the preparation of adsorbed natural gas by chemical activation with KOH-NaOH mixtures. Chemical activation process is commonly used and involves two major steps, which are heating process and chemical treatment process. The experiments were used in the various of temperatures, contact times, and rasio of sample and chemical compound. The result of process was obtained of the iodine number around of 1004 mg/g and 1198 mg/g . Based on the other study, the iodine number at 1004 mg/g and 1198 mg/g have surface area between 1000 mg/g up to 1200 mg/g. These surface area provide a methane capacity between 75 mg/g up to 80 mg/g
THE USE OF 1-METHYL NAPHTHALENE AS COAL ASH REMOVAL SOLVENT
No full textSolvent extraction method is one of the methods to reduce ash content in coal to improve the energy efficiency and reduce negative environmental impacts. The use of 1-methyl naphthalene (1-MN) as a solvent in the weight ratio of coal to solvent of 1: 3, 1: 6 and 1: 9 using three coal samples obtained from a coal washing plant, namely ROM (run of mine), DC (dirty coal) and RC (reject coal) was performed. Results show that the ash content of the extracted coals no or significantly low amount (<0.3%) ash contents. The highest extraction yield was obtained at 15.38 % (daf) at DC coal sample and coal to solvent ratio of 1:9, while the lowest at 3.09 % (daf) at ROM coal sample and coal to solvent ratio of 1:3. In addition, the extraction process with a solution of 1-MN also able to reduce moisture content of the coals, as a result the calorific value of the coals were significantly increased
COAL GEOCHEMISTRY OF THE UNCONVENTIONAL MUARAENIM COALBED RESERVOIR, SOUTH SUMATERA BASIN: A CASE STUDY FROM THE RAMBUTAN FIELD
No full textMuaraenim coalbeds in Rambutan Field have typically high vitrinitic coal geochemical features that indicates the main target for CBM development. The presence of vitrinite coals in South Sumatra Basin is indicated by high huminite concentration (up to 83 vol.%). The coalbeds are of sub-bituminous rank (Ro<0.5%). They are geochemically characterized by high moisture content (up to 21%) and less than 80 wt.% (daf) carbon content. Minerals are found only in small amounts (<5 vol.%), mostly iron sulfide. Cleat fillings are dominated by kaolinite. This behavior can either be related to the increase coal moisture content to the depth or significant variation in vitrinite content within the deeper seam
