Assessment of Rehabilitated Surface Mine Lands in Anglogold Ashanti, Obuasi
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Date
2013-08-09
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Abstract
The burgeoning impact of mining on the environment has created a lot of public concern in recent years. During surface mining the vegetation and the soil are removed causing disturbances to the entire ecosystem. These ecosystems are required to be rehabilitated through a variety of treatments in accordance with the Legislative Instrument 1652 and Act 490. The main objective of this study was to investigate the processes involved in ecological rehabilitation of land affected by surface mining and how successful these schemes have been in reducing the negative impacts and ensuring the sustainable use of the land at AngloGold Ashanti, Obuasi. Persons involved with rehabilitation were interviewed to solicit information on the rehabilitation processes of the monitoring sites. The Landscape Function Analysis developed by the CSIRO was used as a monitoring tool to assess two surface mine sites T3 and Justice which were 1 and 20 year/s old respectively and compared with their natural ecotypes to determine their extent of success. On the rehabilitated sites the landscape organisation index, the infiltration, stability and nutrient cycling indices were generally lower than that of the undisturbed ecotypes. The stability, infiltration and nutrient cycling indices of T3 which were 20.6%, 16.7% and 16.2% were lower than their critical threshold values of 39.4%, 24.1%and 16.7% rendering T3 not self - sustainable. Justice was partially self - sustaining because its stability and nutrient cycling indices which were 64.6% and 26.8% exceeded their critical threshold values of 51.5% and 13.8% respectively except for its infiltration of 36.9% which was lower than that of the critical threshold of 40%. The standard errors of the various indices were calculated for statistical reliability. The results obtained suggested that within-site patchiness is more influential and it affects the stability, nutrient cycling and infiltration indices. It was recommended that more engineering features that serve as patches should be encouraged when rehabilitating surface mine sites.
Description
A thesis Submitted to
the Department of Materials Engineering
Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
in Partial Fulfilment of the Requirements for the
Degree of MASTER OF SCIENCE IN ENVIRONMENTAL RESOURCES MANAGEMENT
Department of Materials Engineering
College of Engineering.
August, 2013