Petrographic characteristics and depositional conditions of Eocene coals of platform basins, Meghalaya, India

Energy Exploration & Exploitation

et al. 2012

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In Tiru valley region of Mon district coals occur in Barail Formation and are of Oligocene age. This study is the first investigation on the petrographic and geochemical characterization of these coals. These thinly bedded seams (<2 m) need systematic exploration for proper evaluation of the resource.The coals are bright to moderately bright in appearance and at places look moderately dull. The study reveals that Tiru valley coals are sub-bituminous to bituminous-D in rank. The chemical study reveals that these coals are perhydrous in nature with moderately high volatile matter content. The sulphur content was probably increased with pyrite inclusion as the most abundant mineral. Vitrinite is the most dominant maceral group constituting nearly 98% of all the macerals while liptinite and inertinite occur in very low concentration. Facies-critical models used to decipher the paleodepositional environment suggest that these coals evolved under wet moor with moderately high flooding in the paleomire which allowed the sulphate reducing bacteria to thrive.

Section: Introductionmentioning

confidence: 99%

Petrographic and Geochemical Characterization of Coals from Tiru Valley, Nagaland, NE India

Energy Exploration & Exploitation

et al. 2012

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“…3). Moreover, these coals show a close similarity in petrographic composition to the coals formed in Stable Shelf areas like the coal deposits of Meghalaya, Northeastern India (Singh and Singh, 2000).…”

Section: Evolution Of Coals 421 Formation Of Foredeepmentioning

confidence: 71%

“…6). The view is supported by another facies model which is based on the quantitative occurrence of liptinite macerals (Singh and Singh, 2000) and indicates the water depth condition. This model delineates the following three facies environment: A-Area for the development of algal bloom and the zone of anaerobic bacterial activity.…”

Section: Paleodepositional Environmentmentioning

confidence: 80%

Petrological Investigations of Oligocene Coals from Foreland Basin of Northeast India

Energy Exploration & Exploitation

2013

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The results of the petrological investigations carried out on coal samples from the Oligocene deposits of Northeastern India (Assam, Arunachal Pradesh and Nagaland) have been discussed. These deposits occur in the Tikak Parbat Formation (Barail Group) and were probably deposited in the foreland basin. Petrographically, these coals are enriched in vitrinite macerals (65.8-96.6 vol %, mean 87.2 vol %) with variable concentrations of liptinite macerals (2.7-35.4 vol %, mean 11.9 vol %). They contain low concentration of inertinite (nil-3.3 vol %, mean 0.9 vol %) macerals. The microlithotype is dominated by vitrite (61.5-100 vol %, mean 90.8 vol %). An elevated volatile matter (44.15 -60.20 wt %, mean 52.90 wt %, d.a.f. basis) and reflectance values (VRr 0.39-0.61%) put their rank as sub-bituminous type 'C' to high volatile bituminous type 'C'. The GI and TPI values favour telmatic conditions of origin with high tree density and prolonged wet conditions. This is in agreement with the paleoenvironment interpreted from the vitrinite and liptinite-rich microlithotypes, which suggested a forest and reed facies. However, the presence of inertinite in some coal seams indicates tectonic upheavals / regression of the sea resulting to periodic and short span dryness of the basin.

“…Sub-bituminous tertiary coal of northeast India was deposited under the influence of marine environment (Rajarathnam et al 1996). These coals have high sulfur and low ash content, with high organic sulfur, due to the influence of marine sources during diagenesis (Chandra et al 1983;Singh and Singh 2000;Ward et al 2007;Widodo et al 2010). Coal can be termed as low sulfur (\1 % sulfur content), medium sulfur (1 %-\3 % sulfur content) and high sulfur coals ([3 % sulfur content) based on their sulfur contents (Chou 2012).…”

Section: Coal Distribution and Its Characteristics In Northeast Indiamentioning

confidence: 99%

Coal mining in northeast India: an overview of environmental issues and treatment approaches

Chabukdhara

2016

Int J Coal Sci Technol

Northeast India has a good deposit of sub-bituminous tertiary coal. The northeast Indian coals have unusual physico-chemical characteristics such as high sulfur, volatile matter and vitrinite content, and low ash content. In addition, many environmental sensitive organic and mineral bound elements such as Fe, Mg, Bi, Al, V, Cu, Cd, Ni, Pb, and Mn etc. remain enriched in these coals. Such characteristics are associated with more severe environmental impacts due to mining and its utilization in coal based industries. Environmental challenges include large scale landscape damage, soil erosion, loss of forest ecosystem and wildlife habitat, air, water and soil pollution. Several physical and chemical methods are reported in literature for the removal of mineral matter, total sulfur and different forms of sulfur from high sulfur coal in northeast India. This paper may help different researchers and stakeholders to understand current state of research in the field. Initiatives may be taken towards sustainable use of coal resources by adopting innovative clean technologies and by implementing effective control measures and regulatory policies.