Annual Conference on Mining for Sustainable Development

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Browsing Annual Conference on Mining for Sustainable Development by Subject "Abandoned mines"

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    Nutrients, Fe and bacterial removal in sub surface flow constructed wetlands treating polluted mine water
    (Department of Earth Resources Engineering, 2007-11) Dharmasiri, KLGNC; Yalini, A; Jeewantha, DLC; Karunarathne, S; Karunaratne, S
    A study was carried out to compare the performance of a pilot scale subsurface flow constructed wetland system to treat polluted water in Ragama prison quarry, an abandoned mine pit Two cement sand tanks with the dimensions of 7.5 m * 0.75 m x 0.75 m were constructed. Both the tanks used a mixture of aggregates as the substrate, where 40-60 mm was used in the treatment zone and both 20-30 mm and 40- 60 mm was mixed in the ratio of 1:1 in the inlet and outlet zones. Typha Latifolia (T.Latifolia) was planted in one tank, while the other was kept unplanted as the control. The initial plant biomass density was 1.7 kg/m2. Each horizontal subsurface flow bed is fed continously with polluted water at 173 litres per day and the retention time was maintained as 8 days. Concentration of nitrate, nitrite, ammonia, total and ortho phosphate, Fe and faecal coliform in the influent and effluent of the wetland system were monitored daily and their removal rates were determined. Nitrites, nitrates, phosphorus and Fe removal.in planted tank varied between 45%-80% whereas it was between 40%-70% in the unplanted tank. Removal efficiency of free ammonia in planted system was 6 % less than that of unplanted tank .However, bacterial removal in both planted and unplanted tanks were similar being 51%.
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    Problems of ground water in connection with abandoned open pit mines
    (Department of Earth Resources Engineering, 2006-10) Amarasooriya, AMSB; De Silva, MR; Suraweera, PSTK; Wedage, WN; Karunarathne, S; Disanayake, DMDOK; Karunaratne, S; Dissanayake, DMDOK; Ratnayake, N.; Chaminda, SP
    Mining is an essential activity upon which many other industries rely on immensely. The magnitude of the problem caused by abandoned mines in the time to come can be understood from the topographic maps prepared using remote sensing applications and field studies in Athurugiriya, Gonapola and Kaduwela areas of the Colombo district. Mahara harbour quarry and the Ragama prison quarry, two abandoned metal quarries were studied with reference to the prevailing conditions of the water quality and the ground water regime. Geological investigations were conducted at the site to identify possible linkages of the pit with the surrounding ground water regime. By analysing the water samples for physical, chemical and biological parameters, the quality of the water was studied .Results show severe pollution in pit water as well as in surrounding round water. The harbour quarry has maintained it's purity due to the efforts and care taken by its stakeholders and neighbours, The continuously degrading quality of the environment at the prison quarry site makes its neighbours affected as well as accused for the problem. The study further shows that in addition to the water quality studies, socio environmental factors should be further studied in order to provide a sustainable solution to the prevailing environmental pollution problems related to abandoned open pit mines in and around Colombo district.