Browsing by Author "Pitawala, HMTGA"

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    Stability of mica, k-feldspar and apatite in water, organic matters and citric acid
    (Department of Earth Resources Engineering, 2007-11) Amaraweera, THNG; Pitawala, HMTGA; Fernando, GWAR; Karunaratne, S
    The short term stability of mica, feldspar and apatite in different geochemical conditions were tested in the laboratory. Different proportions of powdered minerals (<125 pm) were mixed with organic matter with water, water and 2% citric acid. The mixtures were kept under room conditions, using controlled moisture content. The water soluble ionic concentrations of each mixture were measured and their variations with the time were studied. The study revealed that the dissolution of minerals is controlled by mineralogical characteristics of them and the chemical nature of solutions. Both mica and feldspar release higher amounts of potassium compared to other ions when they are in water or in moist organic matter. Feldspar is stable whereas mica and apatite are significantly unstable in the citric acid. However, mica released considerably higher amount of iron in the acidic media (pH-2-3). The dissolution of apatite and K-feldspar is low when mineral mixtures contain biotite. Biotite mica and apatite have high potential to use as fertilizers for crops growing in acidic soils.
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    A study on environmental issues due to the development of nuwaraeliya baduua road
    (Department of Earth Resources Engineering, 2018-08) Adikarii, AMHV; Pitawala, HMTGA; Abeysinghe, AMKB; Samaradivakara, GVI
    Special emphasis has been given on road construction by the National Highways Sector Project (NHSP) of Sri Lanka i n order to bring socio-economic upliftment. However, construction and developments of roads of the country create many environment issues. Rehabilitation and improvement of the NuwaraEliya - Badulla road which r un through the hilly area were established in 2010. Construction length of the road was considered to identify the environmental impacts. Slope instability, hydrological conditions, soil erosion and blasting effects were studied. Disturbance of the natural drainage systems and making deep cuts and fills across already fragile slopes were identified as the main causes. Highly unstable slopes are identified in the Dabalawelahinna area. Dougolla Oya and Gregory Lake are the hilly affected water bodies of the area. Area around the rock quarry has been affected due to blasting vibration and high air blast over pressure. Since the vibration of back side of the quarry is high, landslides can be occurred in future. The life style of species live in Hakgala strict nature reserve has been disturbed due to noise and vibration. Prior to the construction of roads in hilly areas, special attention should be paid, specially on the morphological and geological conditions