Exploitation of Phulbari coal deposit is a must
AKM Sahmsuddin
The Financial Express, 18th. May 2010
Proposal of Asia Energy: Asia Energy proposed to extract about 10-15 million tons of coal from Phulbari Coal Field adopting open-pit mining method from a depth ranging from 250 to 300 meters by removing 4400 million tons of overburden (rock, sand, mud, soil) covering an area of about 5.2 sq. km. throughout the life of the mine. The life of the mine is estimated to be 36-38 years. Mining operations will mainly consists of dewatering of aquifer, cleaning and top soil stripping, overburden removal, rehabilitation of mined out areas and overburden dumps. Coal seams ranging in total thickness between 20 and 65 meters are planned to be extracted from the upper and main coal seams. Aquifer dewatering will be continuous throughout the operation life of the mine. Asia Energy assessed that a large quantity of groundwater ranging from 400 to 800 ML/day will need to be discharged throughout the operational life of the mine. Asia Energy plans to make discharged groundwater available to the tune of 100 to 230 ML/day for riparian use, river discharge purposes and water for coal fired power station. Out of removable 4400 million cubic meters of overburden, 30% overburden will be dumped ex-pit and the remainder will be deposited back into the pit. According to the Asia Energy mine would displace 40,000 people of some 100 villages and a portion of Phulbari town. To maintain dry working condition in open-pit mine, aquifers and aquitards need to be depressurized. Due to mine dewatering activities water level drawdown will form an irregular ellipsoidal shape with water level declines in excess of 10 km from the mine. This would reduce groundwater availability to Phulbari Township, surrounding villages and local farming communities within the given area of influence. Groundwater will also impact on bio-diversity, wetlands and rivers in the surrounding areas. All the above mentioned information is from Asia Energy.
Impact on geological, hydrogeological & social environment: Potential and major groundwater reservoir of Bangladesh lies in the north-western region of Bangladesh covering greater Dinajpur and Rangpur districts. The groundwater resource of this region is the main aquifer of Bangladesh which is about 80-120 meters thick in the DupiTila formation and situated at about 10-12 meters below surface. A study by School of Environmental Studies, Jadavpur University, Kolkata and Dhaka Community Hospital (DCH) on “Possible Arsenic Contamination Free Groundwater in Bangladesh” reveals that groundwater of north-western region of Bangladesh is almost arsenic-contamination free. Water level runs lower in the region during dry season and makes it difficult for the tubewells to draw water. The government and non-governmental organisations have been trying tree plantation for many years to prevent desertification in the north-western region of Bangladesh.
Groundwater level is falling alarmingly in the northern districts of Bangladesh. The underground water level in eight districts of the northern region including Dinajpur is falling gradually posing a threat to Irri-Boro farming. About 30% tubewells in the area have become inoperative for want of underground water. The water reserve in the upper part of underground water level has been exhausted and the next level has gone down by about five meters. The badly affected districts are Dinajpur, Thakurgaon, Kurigram, Rangpur, Lalmonirhat, Nilphamari and Gaibandha. According to a NGO consultancy firm, the northern region has the possibility of turning into a desert if water is lifted from underground level exceeding 15,000 cusecs a year. But at present about one lakh cusecs of water are being lifted for irrigation, which is alarmingly higher than the red signal. Most alarming is that the lifted water is not being balanced by regular seasonal rainfall. The maximum gap may cause natural disaster at any time if the situation continues as cautioned by the experts.
Extraction of Phulbari coal through open-pit mining method will be disastrous for the north-western region in particular and Bangladesh in general due to dewatering of underground from DupiTila formation to the tune of 800 million liters per day over a period of 38-years by Asia Energy. Dewatering in the Phulbari mining area will not only disturb the major aquifer, it will also damage the most potential and massive aquifer of north-western Bangladesh, making the area a desert like place. Re-injection of only 25% of extracted toxic and contaminated water, as proposed by Asia Energy, cannot improve the situation. If underground mining method is adopted there will be no such threat to environment.
Prof. Nazrul Islam of Department of Geography and Environment at Dhaka University says Dhaka WASA should avoid groundwater extraction and search for surface water sources in order to save groundwater environment. Relying on groundwater extraction alone poses a grave threat to land subsidence with a potentially negative impact like that experienced in countries like Thailand (Bangkok) and Mexico, he said. “Two decades ago land subsidence of few inches took place every year in those countries due to unbridled groundwater extraction”. While the benefits remain uncertain, the results to the environment could be seriously harmful, he explained. “The initiative to set up 1000-ft depth tubewells in Dhaka city is very destructive since existing 600-ft deep tubewells have already created a large vacuum within the underground level due to lack of water recharge, making the situation very vulnerable to earthquakes”, he asserted. Experience shows that over extraction of groundwater can cause land subsidence and lead to creation of underground vacuum which make us all the more vulnerable to earthquake. Extraction of huge quantity of groundwater at Phulbari coal basin will put the north-western region of Bangladesh to the threat of natural disaster, land subsidence, land sliding and earthquake. Adopting underground mining method will eliminate the region from those threats. Asia Energy has proposed to re-inject only 25% of water which is toxic and contaminated and will also affect the fertility of refilled agricultural land.
Access to safe water is a fundamental human need and therefore a basic human right. We need to supply healthy water and to ensure that everyone has excess to it. The right to water has been accepted as a natural, social fact. We have no right to deny Phulbari People’s right to access to water for coal. Water is no less important than oil, gas and coal. Under the above circumstances open-pit mining at Phulbari and extraction of pure and clean groundwater to the tune of 400-800 ML/day over the whole operational life of the mine cannot be justified. Underground mining method at Phulbari will not deny the people’s right to access of water.
According to Asia Energy the top-soil will be removed and preserved once mining operation begins in a particular block. This top-soil will be preserved before it is brought back and spread on the top of the area filled. The top-soil will be utilized after completion of mining one particular block which may take 3-5 years. It will be very difficult to preserve top-soil for such a long time. Top-soil may be washed away during monsoon. At least 3-5 monsoon will be there before top-soil is used at the top of the filled out mining block. And the fertility of the top-soil will be lost during these 3-5 rainy seasons. During monsoon, already mined out area will be filled up by rain water, which is required to be pumped out again. During rainy season mining will be difficult and may have to be postponed to facilitate pumping water out of the mine to make it dry for mining. Thus 2-3 months in a year may be lost due to above reasons. Thus uninterrupted supply of coal to the power station and other consumers may not be possible. The above situation may be avoided adopting underground mining method.
About 2, 00,000 people from 150 villages will have to be evacuated from the mine area. Within the coal mine vicinity or nearby area there is no such barren land to allocate the people. It will be very difficult to relocate those people in a thickly populated region like ours. Moreover, they will be deprived of their livelihood. These will be significantly minimised if underground mining method is adopted.
Asia Energy’s proposal to rehabilitate the people phase by phase and block by block in the refilled area cannot be materialized since coal mine regulations will prohibit affected people to live such close to an operative mine.
The coal seam lies below more than 200 meters from the surface. The overburden of Phulbari coal deposit is incompetent, unconsolidated and water logged. Technically open-pit coal mining should not be done below 150-200 meters. These are practiced in our neighboring countries India and China. The unconsolidated and water logged bed above the coal seam will disturb the stability of the working ‘bench’ and installation of heavy equipment will be very difficult in the loose soils at intermediate depth for extraction of coal. During the rainy season the situation will be much more complicated.
Existence of major faults in the Phulbari coal basin indicates presence of highly disturbed zone. This will facilitate rapid drawdown of water table. This will disturb the stability of major aquifer in the region. Since major, massive and most potential water reservoir lies above the coal seams, open-pit mining will therefore definitely damage the major aquifer. There are agricultural lands, villages, township, forests, etc. at the surface of the coal deposit. Rehabilitation, relocation and compensation by land in congested areas like Phulbari will be very difficult. All these factors make open-pit mining at Phulbari non-feasible and non-viable.
Phulbari (Bangladesh) open-pit mine is not comparable with RWE (German) open-pit mine: Germany is one of the most developed and industrialised nations in the world, while Bangladesh is one of the most thickly populated and least developed countries in the world. The density of population in RWE mining areas vary from 290-529 inhabitants per sq. km. area whereas the density of population in Phulbari area is about 916 per sq. km. area. The people of Phulbari area are dependent on their agricultural land while RWE people are not dependent on their land that has been under mining. RWE rehabilitated over 30,000 people in last 50 years in barren and unused land. Whereas about 2, 00,000 people from Phulbari area will have to be rehabilited during 30 years mostly in agricultural land or otherwise usable land. And those lands are not easily available. RWE installed 1400 wells for 100% reinjection of mine pumped out waters to different sources while Asia Energy proposed to install 80-100 dewatering tubewells for reinjection of 25% of the mine pumped out water. Phulbari coal basin lies beneath a massive and most potential aquifer of Bangladesh whereas RWE mine does not lie beneath such a most potential and major aquifer of Germany. RWE re-injects 100% displaced water whereas Asia Energy proposed to re-inject 25% of displaced water at Phulbari. Open pit mining operations involved lowering of the groundwater level which will ultimately generating acid mine drainage (AMD). Because of large discharge area, only an innovative in-situ technology can be used to reduce the AMD. Such a technology has been developed on a laboratory scale in Germany and is currently being tested in an aquifer already contaminated by AMD in a bid to assess and improve groundwater quality. We are not aware of such initiative by Asia Energy in Phulbari. The geological and hydrogeological settings of Phulbari deposit are completely different than that of RWE deposit. RWE mines have been developed by local experts while Phulbari mine has been proposed to be developed by foreign experts.
Under the above circumstances, Phulbari open pit mine cannot be compared with RWE open pit mines. Thus RWE experiences cannot be applied at Phulbari fully and perfectly.
Present low recovery of Barapukuria underground coal mine cannot be the basis of adopting open-pit mine at Phulbari: M/S Wardell Armstrong, a reputed mining exploration and consulting company of U.K., conducted techno-economic feasibility study of Barapukuria coal deposit during 1987-1991. Wardell Armstrong strongly rejected the idea of open-pit mining at Barapukuria. They have estimated removal of 8,000-10,000 liters of groundwater per second for the whole operational life of the mine (30-years) to dewater DupiTila aquifer for open-pit mining of Barapukuria coal deposit. M/S Wardell Armstrong realised that the huge extraction of groundwater for such a long time from DupiTila aquifer may damage the most potential and major aquifer in the whole region. This is one of the reasons that M/S Wardell Armstrong opted for underground mining at Barapukuria. Wardell Armstrong suggested about 35% – 40% coal recovery by adopting underground longwall mining method. This is being practiced all over the world.
Present recovery of 7% to 8% recovery of coal from Barapukuria coal mine cannot be the basis of adopting open-pit mining at Phulbari. Coal recovery from Barapukuria may be increased to 35% to 40% if “hydraulic stowing” is undertaken. Moreover if hydraulic stowing is conducted present subsidence that has occurred at Barapukuria could be minimised. Even if latest underground coal extraction technology is adopted coal recovery from Barapukuria may rise to 60% to 70%. Present low recovery is due to lacking of concerned authority. Therefore, present low recovery of Barapukuria coal cannot be cited as a supportive example for open-pit mining at Phulbari.
Why BHP Australia left Bangladesh after discovery of Phulbari deposit: Initially BHP Australia discovered Phulbari coal in 1997 after taking lease from the government. BHP is a world standard reputed mining company. They did extensive exploration work during 1995-1997 and discovered Phulbari coal deposit. But in 1998, BHP assigned the job to a lesser known company Asia Energy and left Bangladesh. Probably BHP realised that in a thickly populated country like Bangladesh where coal seam lies beneath three valuable resources – water reservoir, agricultural land, township and villages – open pit mining, damaging and destroying three important resources of Bangladesh, will be simply disastrous.
Underground coal gasification (UGC): Geological, hydrogeological and social environment of Bangladesh coal deposit in the north-western region have made open-pit coal mining very difficult and underground mining expensive. But we have got substantial reserve (about 3000 million tons) of high grade bituminous coal from so far explored areas. For the greater interest of the country these coals must be harnessed. Using Underground Coal Gasification (UGC) technology – these coals may be exploited. UGC technology is now widely used in many countries including USA, Australia, China, Japan, etc. and gaining popularity. Bangladesh may undertake a feasibility study on implementation of Underground Coal Gasification (UGC) technology in Jamalganj Coal Field where neither conventional underground mining method nor open-pit mining method can be applied.
It’s a must: Exploitation of Phulbari coal deposit is a must for Bangladesh. Specially to meet the power demand of the country, installation of coal-based power station using locally produced coal has become very urgent. Therefore development of Phulbari coal field, adopting underground mining method, should be immediately undertaken.
The government may undertake a detailed hydro-geological study on major and potential aquifer in the north-western region of Bangladesh in the light of Asia Energy’s proposal for open-pit coal mining at Phulbari as well as for underground coal mining option. At the same time Asia Energy may examine underground mining prospects at Phulbari and may submit underground mining proposal to the government as a second option. Adopting underground longwall mining method 35% to 40% coal recovery is very much possible at Phulbari which can easily meet AEC’s requirement to run 1000MW power station at Phulbari. Moreover, using present and latest underground mining technology, 60% to 70% recovery of coal can be made through underground mining method. We don’t need to recover 90% coal, by open pit mining for also export, as per AEC. We need to recover for our own consumption as per requirement. That is very much possible adopting underground mining method at Phulbari. Therefore having both the proposals from AEC, underground and open-pit, Govt. can take the decision.
A former managing director of Pashchimanchal Gas Co. Ltd. (PGCL), Petrobangla, Engr. AKM Sahmsuddin is a petroleum & mining consultant. He can be reached e-mail: [email protected]
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