DIMAPUR | Jan 06, 2016:
Coal mining in Nagaland, both open caste and rat-hole mining have been major contributors to global warming with the release of methane from the coal seam and mining sites during operations, according to a report of Nagaland Pollution Control Board (NPCB). Notably, Methane is a potent greenhouse gas with a global warming potential 23 times that of carbon dioxide. The discharge of carbon dioxide into the atmosphere associated with burning of coal is also a major contributor to global warming and its adverse effects on health and well beings such as heart stroke, malaria, declining food production scarce water supplies, social conflict and starvation.
A team of scientists and experts of NPCB conducted a survey on 48 mining sites in four districts of the state viz, Mokokchung, Mon, Longleng and Wokha from April to June 2014, where it was noticed that air pollution in each coal mines is due to fugitive emission of particulate matters and gases, including methane, sulphur dioxide and oxides of nitrogen. There are 12 mining sites in Mon, 2 in Longleng, 5 in Wokha and 29 in Mokokchung district.
Mon district is the worst sufferer of the situation. In Mon district, the survey showed that the Upper Tiru drains was found to be most acidic with pH 4.5Dissolve oxygen (DO showing the value of 1 mg/land Biological Oxygen Demand (BOD) as 11 mg/L. This signifies that unless and until the water is treated before discharging it may have a drastic impact on both aquatic organisms as well as to human beings.
Water samples were taken from 3 locations in Longleng district near Bur-Namsang 1, Bur Namsang 2, and Dikhu river, where it was found that Bur-Namsang 2 has the least value of 3.7 while DO and BOD value shows 0.6 mg/L and 16mg/l respectively.
The report read that the water samples from Morokjo village has the least pH value of 3.28 and samples from Tsopo village showed the lowest Dissolve Oxygen (DO) at 5 mg/l and biological oxygen demand (BOD) at 14 mg/l. A separate study was carried out in two subdivisions of Mangkolemba and Tuli in Mokokchung district, where it was found that water samples from Mongchen village has lowest pH and dissolved oxygen of 2.6 and 5.6 mg/l. For coal mining, mountain slopes in Khar and Mongchen villages were excavated to a large extent which resulted in subsidence of land and landslides during heavy rainfall making it risky for the villagers settled in surrounding areas.
It was revealed in the study that the mining operations like drilling, blasting, movement of the heavy earth moving machinery on haul roads collection, transportation and handling of coal, screening, sizing and segregation units are the major sources of such emissions. Dust at mining operations can be caused by tucks being driven on unscaled roads, coal crushing operations, wind blowing over areas disturbed my mining.
The study report further said that underground mine fire is also another source of air pollution in some of the coal fields. Spontaneous combustion is caused when coal oxidises and airflows is insufficient to dissipate heat, this more commonly occurs in stockpiles and waste piles, rarely imbedded coal underground. Where coal fires occur, there is attendant air pollution from emission of smoke and noxious fumes into the atmosphere. Coal seam fires may burn underground for decades threatening destruction of forests, homes, roadways and other valuable infrastructures.
According to the study, approximately 75 Tg/S per year of sulphur dioxide (SO) is released from burning coal. After release sulphur dioxide is oxidized to gaseous H2SO2 which scatters solar radiation and thereby exerting a cooling effect on climate that masks some of the warming caused by increased greenhouse gases. Release of SO2, also contributes to the widespread acidification of ecosystems.
People living in the vicinity of the mining sites complained about the never-ending bad road condition because of heavy vehicles plying through the areas thereby polluting the air resulting in asthma, sinuses etc. High level of suspended and reparable suspended particulate matters increase respiratory diseases such as chronic bronchitis and asthma cases while gaseous causing health hazard to the exposed population.
Unabated coal mining also releases mercury, particulate matter, nitrogen dioxide, sulphur dioxide and dozens of other substances known to be hazardous to human health.
(Source: http://www.nagalandpost.com/)