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Batubara telah menjadi salah satu sumber alternatif unsur-unsur tanah jarang (UTJ) seiring dengan meningkatnya permintaan terhadap kebutuhan unsur-unsur tersebut. Kondisi geologis spesifik menyebabkan pengayaan konsentrasi UTJ pada batubara. Keterdapatan lapisan tipis material vulkanik (tonstein) pada Lapangan Batubara Muara Tiga Besar Utara, Formasi Muara Enim, Cekungan Sumatera Selatan menjadi salah satu indikasi terdapatnya pengayaan UTJ. Penelitian dilakukan menggunakan metode petrografi sayatan poles, analisis-analisis X-Ray Diffraction (XRD), proksimat, dan geokimia; Inductively Coupled Plasma-Mass/Atomic Emission Spectroscopy (ICP-MS/AES). Analisis geokimia menunjukkan pola distribusi UTJ didominasi oleh tipe UTJ Berat (Heavy Rare Earth Elements, HREE). Plot diagram nilai Coutl dan REOash menunjukkan prospek pengayaan UTJ termasuk ke dalam daerah prospek. Pola distribusi UTJ dan anomali redox sensitive dan redox non-sensitive menunjukkan tipe genetik pengayaan UTJ adalah tufaan. Pengayaan UTJ terjadi oleh proses pencucian alkaline tonstein yang terendapkan pada fase penggambutan dalam pembentukan batubara.

Karakteristik batubara dari dua wilayah prospek batubara di Sumatera dievaluasi dengan menggunakan metode kimia dan petrografi batubara. Penelitian terfokus pada evaluasi peringkat (tingkat pembatubaraan di daerah penelitian), tipe (komposisi material organik dan lingkungan pengendapan batubara) serta grade (kandungan material inorganik yang bisa berpengaruh terhadap proses utilisasi) batubara. Lapangan X memiliki lapisan batubara yang merupakan bagian dari Formasi Muaraenim dan Kasai Cekungan Sumatera Selatan sedangkan batubara pada lapangan Y merupakan bagian dari Formasi Petani Cekungan Sumatera Tengah. Sebanyak enam conto batubara dari lapangan X dan 8 conto dari lapangan Y digunakan dalam penelitian ini. Hasil penelitian menunjukkan bahwa kedua lapangan memiliki batubara dengan karakteristik yang berbeda. Walaupun batubara di kedua daerah termasuk dalam kategori lignit, nilai rata-rata reflektansi huminit batubara Lapangan Y sedikit lebih tinggi dari lapangan X. Hal ini mengindikasikan bahwa batubara lapangan Y mengalami pengaruh peningkatan termperatur dan pembebanan yang lebih tinggi dari lapangan X. Berdasarkan hasil analisis komposisi maseral, batubara lapangan X dapat dibedakan ke dalam 3 fasies: fasies 1 (huminit >90%, kandungan inertinit dan liptinit 90% dan liptinit serta inertinite 50%) menunjukkan bahwa conto tersebut bukan batubara. Sebagai kesimpulan, perbedaan karakteristik batubara lapangan X dan Y mendukung teori bahwa batubara dengan sejarah pengendapan yang berbeda akan menghasilkan karakteristik yang berbeda.

Carbon and hydrogen isotope compositions of CH 4 generated via methanogenesis in cultures of South Sumatra Basin (SSB) coalbed methane (CBM) formation waters grown on coal, acetate and H 2 + CO 2 were investigated. CH 4 production and molecular analysis confirmed the presence of active microbial communities that are able to convert coal into CH 4 using both acetoclastic and hydrogenotrophic pathways. The representative bacterial sequences were dominated by Bacteroidetes , Firmicutes and Deltaproteobacteria , while Methanosaeta and Methanosarcina were the most prevalent archaeal methanogens present in the cultures. CH 4 produced in this study's culturing experiments has δ 13 C values in the range of − 50 ‰ to − 20 ‰, with most values falling outside the current understanding of the carbon isotopic boundaries for biogenic CH 4 (− 110 ‰ to − 30 ‰). However, the corresponding apparent carbon isotopic α factor ( α c = 1.02 ± 0.006), and isotopic effect ( e c = − 20.1 ‰ ± 15.3) showed that CH 4 in SSB cultures was predominantly produced by acetoclastic methanogenesis, which is consistent with the results of molecular DNA analysis. In addition, the calculated contribution of CO 2 reduction from the δ 13 C values of coal-treated cultures was overall 4 production in the SSB cultures. The outcome of this experimental study also suggests that δ 2 H-CH 4 values may not provide a reliable basis for distinguishing methanogenic pathways, while apparent carbon isotopic fractionation factor ( α c ) and isotope effect ( e c ) are considered more useful indicators of the methanogenic pathway. The high δ 13 C-CH 4 values (≥ 30 ‰) and the dominance of Methanosaeta over Methanosarcina indicate that methanogens within the SSB cultures were operating at low substrate concentrations. An unusually positive δ 13 C-CH 4 suggests a substrate depletion effect, which is thought to be related to a decrease in the relative abundance of key bacterial coal degraders with formation water inoculum storage time. Closer observation of δ 13 C-CH 4 values during the growth of cultures within a single experiment also showed a 13 C-enrichment trend over time. At log phase of growth, the CH 4 produced was 13 C-depleted when compared to the stationary phase that also indicates substrate depletion effects. Finally, the δ 13 C-CH 4 values encountered in this study (as high as − 20 ‰) highlight the possible positive extension of δ 13 C-CH 4 values of acetoclastic methanogenesis from those currently reported in the literature for natural and experimental samples (as high as − 30 ‰).

A simple laboratory experiment has been conducted in order to demonstrate the ability of bacteria to leach the metal elements from insoluble ores or solid substrates. The experiment was conducted in a leaching column that was set up using 5 cc syringe that contained 1 cc of glass wool and 3.5cc of mine tailings. The basal salt was used as an inoculation media while mine tailing was used as a leaching subject and a source of bacterial leaching. Bacterial leaching was isolated using the most probable number (MPN) technique. Overall, the results of the experiment showed the capability of bioleaching process to recover metals from the mine tailings.

The nature and mode of occurrence of the non-mineral inorganic fractions in coal from the Bukit Asam coalfield South Sumatra Basin Indonesia were analysed using a combination of selective leaching, low temperature ashing, XRD, XRF and electron micropobe techniques. Geologically the rank of coal at Bukit Asam was influenced by igneous intrusion. Fourteen coal samples were used in this study. Samples are chosen to represent different rank levels as well as seam horizons. The inorganic elements, in the form of dissolved salts, exchangeable ions and organometallic complexes, although present in small proportions, contribute significantly to the mineral matter components of Bukit Asam low rank coal. Electron microprobe analysis showed small but significant concentrations of inorganic elements (Al, Ca and Fe) occurring in the individual macerals in two sub bituminous and twosemi anthracite samples. There is a tendency for some of the elements, particularly Ca and Al to be lost from the organic matter with rank advance. The concentrations of elements indicated by the microprobe are relatively in good agreement with the levels of element mobility indicated by selective leaching of the same whole-coal samples. The results of this study also suggest that non-mineral inorganic was likely act as a precursor for the reactions resulting in the formation of new minerals in the high rank coals at Bukit Asam.

The term “mineral matter” in coal is defined as all inorganic, non-combustible material that is in or associated with coal which include discrete crystalline mineral particles, dissolved ions and other inorganic components in the pore water or surface water of the coal, and inorganic elements combined within the organic compounds of the coal macerals. The minerals existing in coal are aresult of processes that occur throughout the entire history of coal formation. Its distribution is influenced by biological, hydrological and geochemical factors. Quartz and the clay minerals are the most widespread and abundant mineral found in coal. Another common minerals are feldspars and carbonate in the form of siderite, calcite and dolomite and sulfide minerals such as pyrite. Coal mineral matter analysis and characterization are useful for various reasons, particularly to take as much as benefit from coal utilization and to avoid any negative influence of coal inorganic components to the environment.

Refereed/Peer-reviewed Temporal changes in microbial community structures during methanogenesis were investigated in cultures of South Sumatra Basin (SSB) coalbed methane (CBM) formation water (SSB5) grown on three coals of different rank (Burung sub bituminous Rv 039%, Mangus sub bituminous Rv 0.5%, Mangus anthracite Rv 22%). Methane production accelerated from day 6, peaked around day 17 and then levelled off around day 20. The initial bacterial community from the SSB formation water was predominantly Aceto bacterium, Acidaminobacter, Bacteroides and Pelobacter species, while the archaeal community consisted of Methanosaeta, Methanosarcina and Methanobacterium members. A general pattern was observed in all cultures with the three coals. Over time the bacterial members decreased in proportion whereas the archaeal component increased. The increase in the proportion of archaeal methanogens corresponded with an increase in methane production yield.Enrichment cultures produced similar communities when grown on coals from the same seam (Mangus sub bituminous and Mangus anthracite), rather than from different seams of similar type (Burung sub bituminous and Mangus sub bituminous). Methanosaeta was the dominant methanogen species in the sub-bituminous Burung coal culture, but was a lesser proportion in cultures of both Mangus sub bituminous and anthracite coals where Methanosarcina species were a greater proportion. Interestingly, obligate hydrogenotrophic methanogens from the genera of Methanobacterium, which were present at low levels in culture enrichment of all coal substrates, increased in proportion only in the absence of coal in the no-coal control enrichment cultures. These results suggest that the low rank Burung sub bituminous coal favours methane production by the obligate acetoclastic Methanosaeta members while both Mangus coals also favour metabolically versatile Methanosarcina members, and the absence of coal favours hydrogenotrophic methanogens. Despite the similarity of communities grown on coals from the same seam, greater quantities of methane were generated from the lower rank coals when compared to higher rank coals. (C) 2014 Elsevier B.V. All rights reserved. usc

usc Refereed/Peer-reviewed Formation water samples collected from five South Sumatra Basin (SSB) coal bed methane (CBM) wells were investigated for the presence of active microbial communities capable of converting coal to methane using culture enrichment studies and molecular phylogenetics techniques. All water samples contained communities capable of methanogenesis using both acetoclastic and hydrogenotrophic pathways. In addition, viable coals to methane communities were detected in four of the water samples. Molecular analysis further confirmed the presence of active microbial methanogen consortia in the tested water samples. Taken together these results highlight the potential of SSB coals to be developed as real time methane bioreactors that may contribute to Indonesia's future energy supply.

Indonesia has abundant coal resources at depths suitable to contain substantial volumes of naturally occurring methane, which are currently being explored. Most Indonesian coals are thermally immature, but are composed of hydrogen-rich organic components that are presumed to make them excellent substrates for biogenic methane production. Gas isotope results from pilot wells in South Sumatra, reported in this study, are interpreted to indicate biogenic origins for the methane. Corresponding formation water samples were collected and incubated, and show the presence of indigenous microbial communities capable of producing methane from Indonesian and Australian coal. Although these results are only preliminary, they are promising and support the possibility of Indonesia developing bio renewable energy from coal seams.

A laboratory experiment was set up to demonstrate the capability of microbe to remediate petroleum hydrocarbon contaminated beach sand. Oil contaminated soil was used as a source of inoculum for hydrocarbon degrading bacteria (HDB) while oil contaminated beach sand was used as remediation object. The growth of HDB in the inocula was enriched and stimulated through the addition of nutrient in the form of vitamin and mineral as well the addition of oil waste as a source of carbon. Experiment took place in the course of approximately five weeks. Microscopic observation clearly showed the interaction between microbe and oil contaminant both in enrichment and bioremediation samples. The result of the experiment also suggests that approximately 25% of the petroleum hydrocarbon mass in the contaminated beach sand was biodegraded over the course of one month. Overall, the results of this experiment suggest the potential of bioremediation method to treat petroleum hydrocarbon polluted environment.Keywords: bacteria, bioremediation, hydrocarbon DOI: 10.33332/jgsm.2019.v20.1.1-7

Batubara dikenal sebagai salah satu barang tambang yang bernilai ekonomi tinggi. Bersamaan dengan keterdapatan batubara, bisa pula dijumpai komoditi lain yang kemungkinan memiliki nilai ekonomi untuk diusahakan bersama-sama dengan pengusahaan batubara. Sebagai contoh, gas methane yang terperangkap dalam pori-pori lapisan batubara, telah terbukti memiliki nilai ekonomi. Eksplorasi gas methane memberikan keuntungan tidak hanya karena menghasilkan sumber energi yang lebih ramah lingkungan dibandingkan dengan batubara, tetapi juga dapat mengurangi kemungkinan terjadinya ledakan dalam tambang bawah tanah. Selain gas methan, sisa pembakaran batubara berupa abu batu bara, sebaiknya tidak selalu diperlakukan sebagai sarnpah, karena abu tersebut kemungkinan bisa dimanfaatkan untuk bahan baku dalam industri semen, campuran beton, dan batako.Dalam eksplorasi batubara, perhatian sebaiknya juga diberikan pada komoditas ekonomi lainnya yang kemungkinan ditemukan bersamaan dengan keterdapatan batubara. Sehingga keberadaan seluruh potensi ekonomi bahan tambang yang ada dapat dimanfaatkan secara optimal.

Biogenic coal bed methane (CBM) has gained considerable interest because of its potential to be regenerated. The research reported in this thesis evaluated the potential to develop Indonesian coals as CH4 bioreactors using culture enrichment, molecular phylogenetic and isotopic composition analysis methods. The results increase the current understanding on microbial methanogenesis in coal, with a specific focus on Indonesian coals. Indonesian coals range in rank from lignite to bituminous, with anthracites occurring in specific areas. The coals are low in ash yield and dominated by vitrinite group macerals, with abundant liptinite group macerals, which is thought to make them good targets for methanogenesis. Stable isotope analysis of gas from pilot production wells confirmed the hypothesis that Indonesian CBM is partly biogenic in origin. Culture enrichment studies of formation water from these CBM pilot wells also indicated the presence of active coal to CH4 consortia that has the capability for degrading native South Sumatra Basin (SSB) coals and foreign Surat Basin coal from Australia. Among the Indonesian coal basins, the SSB currently has the greatest CBM potential and good accessibility for gas, water, and coal sampling that is required to assess the biogenic CH4 potential of Indonesian coal. Therefore, SSB was targeted for the experiments conducted in this thesis. Detailed laboratory experiments assessing both acetoclastic and hydrogenotrophic pathways for formation waters from five SSB CBM wells confirmed the presence of microbial communities capable of methanogenesis in all. The representative bacterial sequences were dominated by Bacteroidetes, Firmicutes and Deltaproteobacteria while the archaea sequences by members of Methanobacteriales, Methanosarcinales and Methanomicrobiales. When grown on Muaraenim SSB coal, under ideal laboratory conditions, SSB cultures yielded a maximum net CH4 production of 130 Scf t–1, warranting further study to confirm mechanisms. Although the application of the laboratory results to field conditions remains a challenge, the results are still promising. Considering the large amount of deep subsurface unutilized SSB coal, the conversion of only a small fraction of that coal to CH4 could significantly increase the SSB CBM field reserves and reservoir lifetime. The investigation of the microbial methanogen community structure grown on different coal substrates showed temporal changes in community structure over time, and suggested some influence of coal substrate on the microbial community composition. The community structure exhibited greater similarity when grown on coal from the same seam but of different ranks (Mangus iii sub-bituminous (SB) Rv 0.5% and Mangus Anthracite (A) Rv 2.2%) than for coal of similar types (Mangus SB Rv 0.5% and Burung SB Rv 0.39%). The obligate acetoclastic Methanosaeta members favor Burung SB coal, while metabolically versatile Methanosarcina members favor the Mangus coals and the obligate hydrogenotrophic methanogens are significant in the control cultures without coal. Regardless of the community structure similarities across all coal cultures, more CH4 was generated from the lower rank sub-bituminous coal cultures relative to the one high-rank semi anthracite coal. These results suggest a potential relationship between coal type and rank, microbial community composition and CH4 production, which warrants further investigation. While CH4 measurements and molecular phylogenetic analysis confirmed the production of biogenic CH4 in the cultures, the gas sampled from the culture headspace had δ13C-CH4 values ( 52.2‰ to 22.6‰) that mostly fell outside the range currently considered to indicate a biogenic origin. In this study, the apparent carbon fractionation factor (αc=1.02±0.006) and isotope effect (ec= 20.1‰±15.3) were found to be more useful indicators of methanogenic pathways than the absolute δ13C-CH4 values. Both values agreed with the calculated contribution of CO2 reduction pathway (ƒmc=18%±24%) and molecular analysis results that showed the dominance of acetoclastic over hydrogenotrophic methanogens. In contrast, the δD of H2+CO2 and acetate derived CH4 were relatively similar, suggesting that in this study δD isotopic measurement may not provide a reliable basis for distinguishing methanogenic pathways. The high δ13C-CH4 values found in this study indicate that the methanogens are operating at low substrate concentration. Substrate depletion is thought to strongly affect the SSB cultures δ13C-CH4 composition and may relate to a decrease in the relative abundance of the key bacterial coal degrader with formation water inoculum storage time. Overall, the research output demonstrated that Indonesian coals in the SSB contain an active CH4-forming microbial community, which adds to the known basins where microbial communities can form CH4 from coal measures and their formation waters. The results also emphasize the potential of Indonesian coal to be developed into CH4 bioreactors that could contribute to Indonesia's future energy supply. From a scientific point of view, the results underline a possible positive extension of δ13C-CH4 values for biogenic origin beyond that currently available in the literature. The research results also highlight the need for further more detailed studies on coals of different type and rank, to assess the potential for microbes to form CH4 directly from the coal itself.

A deep sleep in coal beds Deep below the ocean floor, microorganisms from forest soils continue to thrive. Inagaki et al. analyzed the microbial communities in several drill cores off the coast of Japan, some sampling more than 2 km below the seafloor (see the Perspective by Huber). Although cell counts decreased with depth, deep coal beds harbored active communities of methanogenic bacteria. These communities were more similar to those found in forest soils than in other deep marine sediments. Science , this issue p. 420 ; see also p. 376

The coal of the Miocene Bukit Asam deposit in south Sumatra is mostly sub-bituminous in rank, consistent with regional trends due to burial processes. However, effects associated with Plio–Pleistocene igneous intrusions have produced coal with vitrinite reflectance up to at least 4.17% (anthracite) in different parts of the deposit. The un-metamorphosed to slightly metamorphosed coals, with Rvmax values of 0.45–0.65%, contain a mineral assemblage made up almost entirely of well-ordered kaolinite and quartz. The more strongly heat-affected coals, with Rvmax values of more than 1.0%, are dominated by irregularly and regularly interstratified illite/smectite, poorly crystallized kaolinite and paragonite (Na mica), with chlorite in some of the anthracite materials. Kaolinite is abundant in the partings of the lower-rank coals, but is absent from the partings in the higher-rank areas, even at similar horizons in the same coal seam. Regularly interstratified illite/smectite, which is totally absent from the partings in the lower-rank coals, dominates the mineralogy in the partings associated with the higher-rank coal beds. A number of reactions involving the alteration of silicate minerals appear to have occurred in both the coal and the associated non-coal lithologies during the thermal metamorphism generated by the intrusions. The most prominent involve the disappearance of kaolinite, the appearance of irregularly interstratified illite/smectite, and the formation of regular I/S, paragonite and chlorite. Although regular I/S is identified in all of the non-coal partings associated with the higher-rank coals, illite/smectite with an ordered structure is only recognised in the coal samples collected from near the bases of the seams. The I/S in the coal samples adjacent to the floor of the highest rank seam also appears to have a greater proportion of illitic components. The availability of sodium and other non-mineral inorganic elements in the original coal to interact with the kaolinite, under different thermal and geochemical conditions, appears to be the significant factor in the formation of these new minerals, and distinguishes the mineralogical changes at Bukit Asam from those developed more generally with rank increases due to burial, and from the effects of intrusions into coals that were already at higher rank levels.

The increasing price of oil in the world market andthe depleted national oil reserves while on the otherhand there is a high dependency on oil as nationalmain source of energy, promote the development ofnew energy alternative in Indonesia. Apart from oil,Indonesia is also known to have contained enormousresources of conventional gas, coal, hydropower andgeothermal. Furthermore due to its significant coalresources, coal bed methane becomes one of the newpromising alternative energy in Indonesia.

Metadata dapat didefinisikan sebagai data tentang data atau data yang menjelaskan tentang data. Dokumen metadata berisikan informasi yang menjelaskan karakteristik suatu data, terutama isi, kwalitas, kondisi dan cara perolehannya. Metadata digunakan salahsatunya untuk mendokumentasikan produk data yang dihasilkan serta menjawab pertanyaan mendasar tentang siapa, apa, kapan, dimana dan untuk apa sebuah data dibuat atau disiapkan.Metadata memegang peranan penting di dalam mekanisme pencarian maupun pertukaran suatu data. Sejak tahun 2002, Pusat Sumber Daya Geologi telah melakukan pekerjaan pembuatan metadata untuk produk data spasial yang dihasilkannya. Pekerjaan tersebut difokuskan pada pembuatan metadata peta potensi sumberdaya geologi Indonesia (mineral logam dan non logam, batubara serta panas bumi) berdasarkan lembar peta skala 1:250.000 serta dilaksanakan dengan tujuan utama untuk memelihara serta mempublikasikan data geospasialyang dimiliki Pusat Sumber Daya Geologi. Tulisan ini berisi penjelasan tentang pengertian, manfaat dan kegunaan, maupun cara penyusunan metadata. Sedangkan secara lebih spesifik, tulisan ini juga akan menjelaskan tentang pekerjaan pembuatan metadata peta potensi sumberdaya geologi Indonesia yang dilakukan oleh Pusat Sumber Daya Geologi.