Jurnal Puslitbang tekMira (Teknologi Mineral dan Batubara)
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A REVIEW OF SYN-GAS POLYGENERATION AS ONE OF SOLUTIONS TO SOLVE NATIONAL ENERGY CRISIS
No full textIn the future, Indonesian crisis energy can be overcome by the use of coal as oil substitute. Substi- tuting oil by coal is still a problem due to unfamiliar using coal by Indonesian, inappropriate technology selection and environmental pollution. The use of coal-based syn-gas as various energy resources and chemical material can be conducted in an integrated system called syn-gas polygeneration. Syn- gas polygeneration is efficient and environmental friendly. Its process can be conducted gradually. Yet government policy is needed to start applying syn-gas polygeneration from coal gasification
COASTAL AND SEAFLOOR SANDY AND GRAVELLY SEDIMENTS OF NORTHERN LOMBOK ISLAND AND ITS POTENTIAL AS CONSTRUCTION MATERIALS
No full textBased on grain size analyses as well as microscopic and megascopic observations, coastal and seafloor sediments of northern Lombok Island are subdivided into 6 units : slightly gravely sand, slightly gravelly muddy sand, sand, gravelly sand, silty sand and slightly gravelly sandy mud. The slightly gravelly sand, sand and gravelly sand are of interest for its potentiality for construction material due to its widespread distribution and its low content of muddy and silty materials. Some offshore sediments are possibly landslide in origin as observed from factors such as steep seabottom slope of northern Lombok, graphic presentations of bimodal - polymodal histogram presentations as well as poorly sorted character of frequency curve diagrams and evidence from analog seismic record which demonstrates slumping of seabottom sediments
STUDY OF POISON GAS OCCURRENCE AND WATER QUALITY WITHIN BAUXITE-CARRYING BARGE AT KIJANG ISLAND
No full textAn accident occurred in bauxite-carrying barge at Kijang Island that caused the death of 3 workers urged Mining Business Unit for Bauxite of PT Aneka Tambang to ask RDCMCT to conduct a series research on the barge. Observation on the site sampled gas and water. Results presented that NO2, SO2 and CO contents were still the threshold value as stated in a circular of Minister of Manpower no. SE.01/MEN/1997. Seawater analyses showed that all elements were still below the allowed figures except for nitrogen-ammonia (N-NH3) that exceeded the threshold value (0.213-0.47 mg/l). Based on observation on the site and laboratory analyses, oxygen deficiency within compartment was the caused of the worker death
POTENSI BATUBARA UNTUK PENGEMBANGAN GASIFIKASI BAWAH PERMUKAAN : STUDI KASUS DESA MACANG SAKTI, PROVINSI SUMATERA SELATAN
No full textBatubara yang cocok untuk kegiatan gasifikasi bawah permukaan harus memenuhi persyaratan, antara lain kondisi geologis, ketebalan, kedalaman, kadar air total dan kadar abu. Berdasarkan persyaratan ini, tidak semua batubara dalam bisa dimanfaatkan untuk kegiatan gasifikasi bawah permukaan. Kegiatan eksplorasi batubara perlu dilakukan untuk meminimalisasi risiko geologis dan untuk mengetahui kondisi batubaranya. Berdasarkan hasil permodelan, ditemukan lapisan batubara D dengan kriteria kedalaman 200-300 m, ketebalan >5 m, kadar total air lembab+kadar abu <60%, nilai kalor 4.912-6.275 kkal/kg, reflektansi vitrinit 0,23-0,44 (lignit-subbituminus). Perhitungan sumber daya batubara dengan menggunakan software yang ada dan mengacu pada aturan SNI 5015-2011, menghasilkan sumberdaya tereka 3.316.578 ton, tertunjuk 1.909.560 ton dan terukur 2.479.951 ton.
PERUBAHAN KOMPOSISI MASERAL DALAM BATUBARA WAHAU SETELAH PROSES PENGERINGAN/UPGRADING
No full textSebagian besar sumber daya batubara Indonesia adalah batubara peringkat rendah. Batubara ini dapat ditingkatkan nilai kalornya dengan melakukan proses pengeringan (upgrading). Tujuan penelitian ini adalah mengetahui perubahan komposisi sub-maseral dan reflektan vitrinit setelah proses pengeringan. Penelitian upgrading ini dilakukan menggunakan dua metode, yaitu metode hidrotermal dan oksidasi terhadap percontoh batubara Muara Wahau. Hasil penelitian menunjukkan persentase grup maseral eksinit berkurang dan grup maseral vitrinit bertambah setelah proses pengeringan. Dalam grup maseral vitrinit, akibat proses pemanasan desmokolinit lebih stabil dibandingkan dengan maseral lainnya. Pada suhu pengeringan yang tinggi (>150oC), persentase inertinit lebih tinggi pada kondisi atmosfer teroksidasi dibandingkan persentase inertinit hasil proses hidrotermal. Dalam grup maseral inertinit, sklerotinit lebih stabil oleh proses pemanasan dibandingkan maseral lainnya. Nilai rata-rata reflektan vitrinit meningkat pada proses pengeringan hidrotermal dan konstan setelah proses oksidasi. Perubahan struktur molekul batubara antara lain putusnya ikatan C-C pada senyawa alifatik dan terbentuknya senyawa aromatik terkondensasi diperkirakan sebagai penyebab terjadinya perubahan komposisi maseral dan perubahan nilai rata-rata refelektan vitrinit
BIOOKSIDASI: TEKNOLOGI ALTERNATIF PENGOLAHAN BIJIH EMAS REFRAKTORI
No full textSekitar sepertiga produksi emas dunia berupa bijih emas refraktori. Sifat refraktori umumnya karena bijih emas berukuran halus dan terinklusi dalam mineral-mineral sulfida seperti arsenopirit dan pirit sehingga menyebabkan perolehan emas rendah (20-50%) bila diolah dengan proses sianidasi langsung. Teknologi biooksidasi merupakan teknologi alternatif yang menarik sebagai prapengolahan bijih emas refraktori karena desain dan operasinya lebih sederhana, biaya kapital dan operasi rendah dan tidak menghasilkan bahan pencemar udara sehingga teknologi ini lebih ramah lingkungan. Indonesia mempunyai cadangan bijih emas refraktori yang cukup besar dan sangat berpotensi untuk diolah dengan teknologi biooksidasi karena teknologi ini telah terbukti layak secara teknis dan ekonomis, dan telah diaplikasikan selama 30 tahun terakhir di lebih dari 10 negara di seluruh dunia.Tulisan ini menyajikan informasi dan diskusi mengenai aplikasi teknologi biooksidasi dalam pengolahan bijih emas refraktori, landasan teori dan mekanisme reaksi, aplikasi komersial yang telah ada di dunia, hasil-hasil beberapa penelitian di Indonesia, aspek keekonomian, tantangan dan kendala serta potensi dan prospek aplikasinya di Indonesia. Hasil penelitian biooksidasi bijih emas refraktori Indonesia asal Kalimantan Timur, menunjukkan pada sianidasi langsung tanpa praolahan, perolehan emasnya hanya mencapai 38,7% dan setelah bijih mengalami pelindian bakteri selama 42 hari, ekstraksi emasnya meningkat menjadi 87,1 %. Pada penelitian biooksidasi selanjutnya menggunakan kultur bakteri campuran Acidithiobacillus ferrooxsidans dan Acidithiobacillus thiooxidans, perolehan emasnya mencapai 98% dalam waktu proses yang lebih singkat selama 28 hari. Hasil-hasil tersebut memperkuat prospek penerapan teknologi biooksidasi secara komersial di Indonesia
ASSESSMENT FOR DATA CORRELATION OF THE DOWNHOLE SEISMIC MEASUREMENT RESULTS ON UNDERGROUND COAL GASIFICATION LOCATION USING MULTIVARIATE ANALYSIS
No full textOne of the risk potentials that must be alerted for underground coal gasification(UCG) technology is surface subsidence, although such a technology is potential to be developed in Indonesia. Therefore, the characteristics of rock strata above the coal seam needs to be deliberately considered. Downhole seismic data is one of the data that is needed to determine the geotechnical characteristics of the rock layers near the surface. Previously, it is considered that physical, mechanical and dynamic properties of the rocks at same geological formation have equal characteristics although they come from different locations. However, based on correlation test to downhole seismic data using multivariate analysis showed that no significant correlation between the measured data from Macangsakti-1 and Macangsakti-2 with those of Mahayung from different location, although they are in the same geological formation. This fact is shown by the analysis result which shows a significance value of <0.05. Macangsakti-1 and Macangsakti 2, which are located closely, showed a significant value of >0.05. It means that there are no significant data differences between the two locations. It is very likely since there are a lot of factors that affect such conditions, especially the influence of tectonics at each location. In addition, factors of the surface condition such as infiltrations of ground water from the surface towards the unsaturated zone also affect the difference of wave propagation velocity at each location. Thus, it should be noted that the condition of rock layers are site specific to determine the characteristics of the sites it should be measured at the sites and can not be generalized with other locations, although they are in the same geological formation
