Coal Coal is a readily combustible sedimentary rock composed essntially of lithified plant materials, with small amount of inorganic matter present in the form of mineral impurities. Wet, spongy and porous organic debris called peat is compressed, lithified and altered to coal by burial compaction and thermal alteration. As the coalification of peat proceeds with increasing burial, progressively higher ranking coal are generated. Accordingly coal has been classified into the following ranks:
1. lignite or brown coal
2. sub-bituminous coal
3. bituminous coal
4. anthracite coal.
The quality of coal is determined by the amount of moisture, fixed carbon, volatile matter, ash and total sulfur present. Coal was the principal commercial energy source of the world till the end of nineteenth century. With the advent of petroleum resources the share of coal in the world energy mix had reduced. Yet, it remains a leading fuel throughout the world.
Till date five major gondwana coalfields have been discovered in Bangladesh. In order of discovery year these are Jamalganj (1962), Barapukuria (1985), Khalashpir (1989), Dighipara(1995) and Phulbari (1998). It is more than hundred' and seventy years since geologists forecasted good possiblity of discovering large coal deposit beneath the alluvial plain of North Bengal. The hopes of the geologists were vindicated when in course of searching for oil in 1959 SVOC drilled a hole in Kuchma X-1 in Bogra district, where Gondwana coal was encountered at a depth of 2381m from surface. Consequently in 1961 under the UN-Pak Mineral Survey Project the Geological Survey of Pakistan (GSP) carried out detailed geological, geophysical and drilling operations in the districts of Bogra and Rajshahi and found coal resources of about 1,050 million tons in Jamalganj. Barapukuriua coalfield was discovered in 1985 by' GSB in Dinajpur district. Coal layers are encountered at a shallow depth of about 18-500 meter. In 1989 GSB discovered another coalfield at khalashpir in Rangpur district where coal layers are encountered at depths of about 257-450 meter below surface. In 1995 another major coalfield was discovered by GSB at Dighipara where coal was encountered at adepth of about 250 meter below the surface. An USA- Australian coal mining company BHP discovered a major coalfield named Phulbari in 1997. Here coal was encountered at depth of 130-260 meter below surface. The total coal reserve in the five discovered fields in the country is about 2000 million tons.
Besides the Permian Gondwana coal in the northern part of Bangladesh, GSP discovered two beds of ligno-bituminous Tertiary coal in Takerghat-Baglibazar area at a depth of 45m to 97m below the surface in the years 1960-62. The beds are 0.90m to 1.70m thick and reserves were estimated at 3.00 million tons.
At present coal is being produced commercially only from the Barapukuria underground coal mine in Dinajpur district that has gone through a period of 8 years of construction and one year of production. Current production rate is about 1500 tons per day. The plan to establish an open-pit mine in nearby Phulbari was aborted last year in the wake of mass protest by the local people. Coal in the Jamalganj-Paharpur area is too deep to mine. Extraction of coal bed methane from this field is under consideration.
Table below shows major coal fields and reserves in Bangladesh.
|Coal field (district)||Year of discovery||Discovered by||Depths of coal seam (in meter)||No. of coal seam||Reserve (million ton)||Status|
|Jamalganj (Joypurhat)||1962||SVOC||640-1158||7||1053||Minig not feasible economically|
|Barapukuria (Dinajpur)||1985||GSB||118-506||6||303||Underground mine started production|
|Phulbari (Dinajpur)||1997||BHP||152-246||1||380||Open pit mine feasibility study undertaken in 2004|
Source Petrobangla; Geological Survey of Bangladesh.
The facts that make coal mining difficult in Bangladesh is the greater depths of coal seams and more importantly because of the occurrence of a 100-200 meter thick loose water bearing sandy layer covering the coal deposits. In 2002, National Gas Utilization Committee forecasted that share of coal in energy mix of Bangladeh will not change very significantly in short to medium term future and its contribution will possibly remain in the range of 4-6% of the total commercial energy input of the country. Most of the energy experts believe that there is no option for Bangladesh other than mining its coal for power generation, because the future power demand cannot be met from gas-based power plants as the gas reserve is too limited to run for long. At present, the only coal-based power plant (250MW) in the country is in operation near Barapukuria coalmine, which feeds the plant. If the Barapukuria mine runs efficiently for its expected lifespan and if feasibility studies conducted at other fields conclude positively only then we can expect that the contribution of coal in the total energy mix in the country will increase in future. [QM Arifur Rahman and Sanzida Murshed]
See map in mineral resources.