Assessment of the Potential of Reclaimed Mined Land for Agricultural Production

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One of the major negative impacts of mining is the damage caused to soil and surface vegetation. This includes loss of vegetation cover, fauna and their habitats, water bodies, landscape, disturbance to the existing soil structure, soil erosion, depletion of forest resources and threat to the rich biodiversity. This destruction culminates into reduced productive potential of the affected mined sites for both flora and fauna. To mitigate the impacts of environmental degradation, mining companies in Ghana are enjoined to reclaim their operational sites so that the ultimate land-use and morphology of these sites are compatible with either the current land-use in the surrounding area or with the pre-mining environment. This responsibility led to Newmont Ghana Gold Limited (NGGL), Ahafo to initiate an experimental concurrent reclamation exercise which commenced in 2009 at the Apensu South waste rock dump site. An area of 5.6 hectares was covered and divided into four treatment plots with different top and subsoil thickness at overall soil depth of one (1) meter. An un-mined farmland adjacent to the reclaimed area was used as control for the study. The study sought to assess the effectiveness of the reclamation exercise based on the various treatments and make appropriate recommendations for the best treatment in relation to soil physico-chemical parameters, in order to determine whether soil conditions meet the agricultural expectations of the inhabitants and its conformance to the predominant land-use within the area. The test of hypothesis was Ho:All treatment means would be equal whilst HA: Some treatment means would be unequal. Composite soil samples from the four treatments and control were analyzed for chemical properties (N, P, K, Ca, Mg, Na, Cu, Zn, Fe, pH) and physical properties (bulk density, water holding capacity). Notwithstanding the exertions made by the company to embark on this reclamation exercises, there is no base line data on the nutrients status of the reclaimed soils which will go a long way to determine their suitability or otherwise for Agriculture. It is for this reason that this research was carried out. The results of the analyses showed a highly significant difference (P<0.001) in the concentration of all the parameters for the various treatments except bulk density which showed significant difference (P<0.05). In this respect, the HO is rejected and HA accepted. It is recommended that about 0.3m of well-maintained topsoil is used to top-dress all future reclamation plots to promote effective plant growth.
A Thesis Submitted to the Department of Environmental Science, Kwame Nkrumah University Of Science And Technology, Kumasi, Ghana, in partial fulfilment of the requirements for the award of Master Of Science Degree in Environmental Science,