T Rabani; N Taghipour; R Aharipour
Abstract
Gheshlagh district contains coal deposits in a large syncline in Shemshak group sediments in East Alborz. To determine the palaeoenvironmental setting of the coal deposits based on organic and mineral components, eleven samples from coal seams from four active mines are collected. Minerals such as quartz, ...
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Gheshlagh district contains coal deposits in a large syncline in Shemshak group sediments in East Alborz. To determine the palaeoenvironmental setting of the coal deposits based on organic and mineral components, eleven samples from coal seams from four active mines are collected. Minerals such as quartz, kaolinite, pyrite, siderite, biotite, montmorillonite and dolomite are identified in Gheshlagh coal mines. The Ground Water Index (GWI) suggests ombrotrophic hydrological conditions for coal layers in Gheshlagh coal region. K13 and k11 layers have much higher GWI among others due to its higher mineral content than other layers. Vegetation index (VI) of the Gheshlagh coals is less than 3, which could indicative of the dominance of aquatic/herbaceous plants in the formation of coal seams. Petrographic data on organic and inorganic matter with facies diagram suggest evidences of anaerobic to low oxygen, alkaline conditions and variations in water level with relative proximity to the marine environment.
Z Solaymani; N Taghipour
Abstract
The Olang area is located in 70 km of northeast Shahroud. This area is situated in Gheshlagh Olang syncline, which is a member of the EasternAlborzCoalBasin. The optical microscopes and X-ray diffraction (XRD) analysis on coal and coal ash samples and also SEM-EDX results revealed kaolinite, quartz, ...
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The Olang area is located in 70 km of northeast Shahroud. This area is situated in Gheshlagh Olang syncline, which is a member of the EasternAlborzCoalBasin. The optical microscopes and X-ray diffraction (XRD) analysis on coal and coal ash samples and also SEM-EDX results revealed kaolinite, quartz, siderite, pyrite, biotite, chlorite and illite minerals in coal seams at the Olang coal mines. Pyrite is observed as syngenetic (framboidal) and epigenetic (filling of the cell cavity, vein, and veinlet).The abundance of syngenetic siderite and absent sulphate minerals is usually thought to indicate deposition of the coal mainly under nonmarine conditions, or at least under the influence of swamp or formation waters with low sulphate content. The study of 15 potentially hazardous trace elements (PHTEs) includes: (Ba ®1054.7 ppm), (Co ®51.32 ppm), (Cr ®161.1 ppm), (Cu ®129.3 ppm), (Mn ®1600 ppm), (Mo ®19.56 ppm), (Sn ® 4.78 ppm), (Ni ®139.7 ppm), (Pb ® 48 ppm), (Tl ®1.36 ppm), (Th ®27.6 ppm), (U ® 9.45 ppm), (V ® 232.9 ppm), (Zn ®101/78 ppm(, (P® 6500 ppm) in coal ash deposits of the Olang region compared with the average of the world coal ash, shales, soils and also crustal Clarke. The results show that these coals are enriched in Mn, Mo, U, Pb, Zn and P and are dangerous elements.