NewAge, Dhaka, Bangladesh. September 13, 2007
Bangladesh is undoubtedly heading towards a major energy crisis in the days to come. But with the reserve of coal, even if recovered even by open pit mining, will at best contribute a pond, if not a drop, in an ocean. So we must explore multiple options like undertaking massive search for oil, gas and coal, tapping wind energy in the coastal belt, generating small-scale hydro-electricity in the hilly terrains, solar energy, and coal extraction by underground mining only from the known deposits, writes Dr Aftab Alam Khan, Professor Aftab Alam Khan, Department of Geology, Dhaka University.
An open pit coal mine may contribute four, five, even ten times greater than an underground coal mine does in energy production, an example cited from Germany. However, the controversy lies with a different scenario that might have been overlooked by some who are advocating for open pit coal mining in Bangladesh. The first line of comparison between the two should be drawn based on the principal condition lies with the same level and standard. If the level and standard between the two are different than those of the comparisons, it is not likely to sustain. Bangladesh and Germany are two countries with marked differences in culture, socio-economy, physiography, geomorphic, hydrogeologic and overall geologic point of views.
The North Rhine Westfalia (NRW) coal mine areas in Germany do not possess any catchment area like Teesta fan in Bangladesh. Neither does it possess such thick groundwater bearing formation like Dupitila in Bangladesh overlying directly coal beds. Sand, clay and gravel layers overlying the coal bearing formation in NWR converge towards a valley not even 10km wide and eventually is directed along the valley gradient towards The Netherlands occupying very negligible land in NWR, Germany. The NE-SW geological cross section of NWR coal mine area clearly exhibits its subsurface geological condition which is markedly different from Bangladesh coal field region. While the coal field regions in Bangladesh are characterised by more porous and permeable thick groundwater bearing layer directly overlying coal bearing formation and diverge radially along multiple river valley systems occupying around 50 per cent of the valley covered region. In addition, around 30 per cent and more area of the Teesta fan will be affected by massive groundwater depletion. Both surface and subsurface gradients in the North Rhine Westfalia (NRW) coal zone are directed to only narrow linear zone along Rhine river valley. While, both the surface and subsurface gradients of Bangladesh coal field areas are directed radially along Sib-Barnai, Atrai and Little Jamuna river valley systems.
It is reported that the NRW mining area is pumping out 550 million cubic metres of groundwater annually where open pit mining is likely to start and very interestingly this mining area is not characterised by or linked to any such region like Teesta fan and thick Dupitila formation. Hence, it is apprehended that if an open pit mine is started in Bangladesh it would require dewatering few times higher than that of NWR open pit mine area. Barapukuria underground coal mine is pumping out around 15 million cubic meter of water annually from a water bearing formation at around 300m depth which is markedly sealed at the top by an impermeable shale/clay layer separating overlying highly porous and permeable Teesta fan sediments and Dupitila formation. Thus, the present dewatering at Barapukuria underground mine is being managed for the water discharging only from the coal bearing formation alone. An obvious question arises as to how much water shall be required to be pumped out when an open pit mine face along with the entire Teesta fan and Dupitila in coal field areas will be open?
An article/company brochure published by RWE Power AG (www.mining-technology.com) states quote ‘Rheinbraun has developed sophisticated dewatering programmes that can handle up to 1,200Mmm³/y of groundwater without affecting neighboring communities’ water supplies’. However, it did not mention actually how much of water is being managed by dewatering and from flooding in actual field development. The article has projected very successfully the positive sides of an open-pit coal mining in NRW, Germany but it has very candidly overlooked the article published in Natural Resources on March 21, 2007 by Steffen Winter (http://www.spiegel.de/international/germany) where it was written ‘Germany has little oil or natural gas, but it does have large reserves of another resource: lignite. However its extraction through open cast mining is highly controversial — and can lead to the disappearance of entire villages’. It further states that ‘the excavators used at the mining facilities have devastated an area equal to 182,000 soccer fields, wiping at least 244 villages and neighbourhoods off the map’. More interestingly it states that ‘Central German Brown Coal Mining Company (Mibrag) has been owned by US investors — Washington Group International and NRG Energy — since 1994 –– there’s no shortage of money, and the firm is used to dealing with public resistance. The company has been trying to access the coal beneath the town of Heuersdorf in Saxony since 1994, the citizens protested, but then the so-called “Heuersdorf Law” was passed by Saxony’s state parliament, stating that the village — which is 709 years old — has to be vacated by 2008, the dead buried in the cemetery will be moved to new graves and the church will be rebuilt elsewhere’.
Germany is a net energy importer, with its total energy consumption exceeding its production by a very large margin. Germany presently ranks as the world’s 5th greatest energy consumer, accounting for about 3.4% of the world’s annual energy consumption. Germany has consumed about 4 million gigawatt-hours of electricity in the year 2003 against only one third of its own production in comparison to Bangladesh’s approximately 50 thousand megawatt-hours of electricity. A comparison on other components is listed in the table. With such differences, how could an example of benefit out of open pit mining be brought to justify the same for Bangladesh?
Bangladesh is undoubtedly heading towards a major energy crisis in the days to come. But with the reserve of coal, even if recovered even by open pit mining, will at best contribute a pond, if not a drop, in an ocean. So we must explore multiple options like undertaking massive search for oil, gas and coal, tapping wind energy in the coastal belt, generating small-scale hydro-electricity in the hilly terrains, solar energy, and coal extraction by underground mining only from the known deposits. Import of gas from Shwe Gas Field on the Arakan coast in Myanmar might be another option to minimise immediate crisis.