Jurnal Puslitbang tekMira (Teknologi Mineral dan Batubara)
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BENEFICIATION OF BOREHOLE IRON ORE SAMPLES THROUGH MULTI-STAGES MAGNETIC SEPARATION
No full textThis study investigates the effectiveness of magnetic concentration techniques for the beneficiation of borehole samples of Arasuko - West Sumatera iron ore. It is a low-grade type of ore sample (±35% Fe) with high silica and calcium content (±36%). Based on the fact, that there are appreciable differences in magnetic susceptibility between the desired iron minerals and the gangue minerals, hence, it was suggested that multi-stages magnetic separation may be useful to concentrate this type of ore. Because of the fine dissemination of the iron minerals and the most abundant gangue mineral, the particles size of ore was set at 80% passing 150 meshes. Rougher tests of magnetic separation produced concentrates with iron content of about 58.2% Fe; the tailing of rougher stage was then scavenged using higher magnetic intensity. Further, the rough and scavenged concentrates were mixed and fed into a cleaner stage with low magnetic intensity. Results indicate that the final iron concen- trate assaying of 68.1% Fe at a recovery of about 80% is achieved and reckoned as an iron premium-grade concentrate
ANALYSIS OF REGENCY READINESS LEVEL IN IMPLEMENTING AUTONOMY OF MINERAL RESOURCES MANAGEMENT IN WEST PAPUA PROVINCE
No full textReformation in Indonesia has resulted in a new policy, which is widely known as regional autonomy. In imple- menting this decentralisation concept, provinces, regencies and cities as governmental units are being given huge authorities and wider opportunities in terms of managing and developing their areas. This policy, however, could not be interpreted that the central government is transferring an absolute authority. It has to be viewed and be functioned properly as an instrument to accelerate regional developments and to contribute comprehensively to national development as well. In West Papua, natural resources management including mining sector has been a crucial part affecting the implementation of decentralisation. Managerial aspects that consist of planning, organising, monitoring and evaluating seem to be more complicated in practical actions. Therefore, a question usually appearing to be answered is that has West Papua been prepared and capable to face this policy with considering that this long-term policy might have numerous external and internal factors constraining its success. To determine the level of regional capability in facing mining sector autonomy, data regarding mining resources, human resources and regional income of mining activities had been collected from four samples of regencies, namely Fak-Fak, Sorong, Raja Ampat and Teluk Bintuni. These date were then evaluated using factor analysis to be rated and interpreted. The results show that the capability level of Teluk Bintuni is low. Sorong and Fak-Fak have medium levels, and Raja Ampat is in high level
STUDY ON ASHES OF BLENDED COAL-BIOMASS FOR CO-FIRING SYSTEM IN A COAL FIRED BOILER
No full textBiomass and coal blend combustion or co-firing is a promising combustion technology. However, significant development work is required before large-scale implementation can be realized. Issues related to successful implementation of coal biomass co-firing mainly for power generation should be identified. This paper presents the results of the study on blended coal-biomass characterisation, particularly the ash chemical composition and ash fusion temperature to predict the slagging and fouling propensity in a coal fired boiler. The coal used in this research has a calorific value of 5,067 cal/g and the ash fusion temperature of softening temperature in oxidation condition (softening temperature-ox) is 1,228ºC, while the biomass used was baggase, straw and rice husk with the calorific value of 4,144; 3,545; 3,301 cal/g and the softening temperature-ox of 1,303; 1,420 and >1,500ºC, respectively. Experimental results for some varieties of fuel blends indicate that the proportion of 95%-5% of coal and baggase has the highest softening temperature-ox of 1,225ºC. The blend of coal and straw resulted in the highest softening temperature-ox of 1,240ºC at 95%-5%, while the blend of coal and rice husk, the highest softening temperature-ox of 1,235ºC was reached at the proportion of coal and rice husk at 90%-10%. According to the slagging and fouling index, blended coal and straw shows the best performance compared to that of blended coal either with baggase or rice hus
COMPREHENSIVE ENVIRONMENTAL EVALUATION OF BUKIT ASAM POWER PLANT COAL ASH
No full textIndonesian government regulation No 85 year 1999 regarding management of hazardous material states that in order to identify and to define coal ash as hazardous material or non hazardous material, the coal ash should be evaluated by characteristic and toxicity tests. In this study, the properties of coal ash sample from Bukit Asam power plant were evaluated using chemical analyses and bioassay of Lethal Concentration (LC50-96 hour) and Lethal Dose (LD50-96 hour). The chemical analyses shows that the main chemical compositions of Bukit Asam coal ash were SiO2 (60.6 %) and Al2O3 (22.8%). Bukit Asam coal ash was categorized as non toxic criteria as its LC50-96 hour value exceeded 100,000 ppm. Meanwhile, the result of LD50-96 hour shows that mortality of mice was not found in every dose given (500; 5,000; 15,000; 30,000; 50,000 mg/kg BW) for 0-96 hours of observation so it can be classified as a non hazardous material based on the Indonesian government regula- tion. The results of TCLP test reveal that the concentrations of all the heavy metals were invariably well below the permissible limits for discharge of effluents according to Indonesia regulation and US. EPA standard. Thus, it was also categorized as non hazardous material. Radiation dose of Bukit Asam coal ash was 0.41 mSv/year and it was under standard limits for human being (1 mSv/year). The mean heavy metal contents in Brassica chinensis tissues with three times cultivation were above the WHO limits level. However, the addition of 17.5% coal ash in growth media drastically decreased heavy metals content (Cu: 25.6; Pb: 66.6; Cd: 48.8 dan Cr: 8.29%) into the lowest content. The results generated from this study indicated that Bukit Asam coal ash has a vast potential for reclamation of degraded coal mining land
