Abstract:
This research work was carried out to evaluate the potential hazards of coal mining and the effects of such hazards on the environment using the Okaba coal mine as a case study. Field activities were implemented to carry out physical and visual assessment in its surroundings. Soil and water samples were taken from marked locations in and around the mine and carefully analyzed for heavy metal contamination. A total of 10 representative water samples and 10 representative soil samples were collected and analyzed. The result of analysis of the water samples labeled shows the mean concentration of heavy metal increasing in the order of Fe>Mn>Zn>Cu>Cr>Pb with values of 139.97>34.49>4.10>0.644>0.11>0.08 in milligram per litres respectively; while that of soil samples increased in order of magnitude as Fe>Mn>Zn>Cu>Cr with values of 11205>44.94>5.22>4.281.73 in milligram per kilogram respectively. The heavy metal concentration values exceed the WHO standard by 138.97(mg/l) for Fe, 34.09(mg/l) for Mn, 1.1(mg/l) for Zn, 0.07(mg/l) for pb for soil samples and 11204(mg/l) for Fe, 44.54(mg/l) for Mn, 2.22(mg/l) for Zn, 2.2(mg/l) for Cu for water samples. The measured soil and water pH were 2.10 and 3.33 respectively. This is an indication that the soil and water samples are acidic. The yellow colouration of pond water is an indication of exposure to pyrite which has caused acid mine drainage. The water-filled mine pits are potential site of hazards to human life and live stocks. Failing land and slopes in the mine pit is another source of hazard to human life. It is recommended that leached elements from the waste dump be prevented from draining into the nearby water bodies and mine pit be barricaded to avoid serious contamination and physical harm to humans, plants and other animal species.
