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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/8193

Title: Evaluation of land reclamation with MPTS at AngloGold Ashanti: a chronosequence approach.
Authors: Yawlui, Ignatius Senyo Yao
Issue Date: 15-Nov-2015
Abstract: Mining generally destabilizes environments and the entire ecosystem. To ensure that mining activities co-exist harmoniously with the human and physical environment, guidelines have been developed which all mining companies are obliged to comply. Reclamation is a desirable and necessary remedy to return the mined areas to an acceptable environmental condition whether for resumption of the former land use or for a new use. The research was carried out at Anglogold Ashanti, Obuasi Mines Ltd to evaluate land reclamation with MPTs. The study was in two parts: a sociological survey and a field evaluation. The survey was conducted in 3 communities namely: Binsere, Sansu and Kunka using semi-structured questionnaires, focus group discussions and personal observations. Eighty – one respondents were interviewed comprising of environmental experts of the mining company, the Community Relation Officer, Chiefs/Opinion leaders and selected households. The field experiment was carried out on four reclaimed sites of the ages of 3, 6, 9 and 12 years and a cocoa farm which has never been mined as the control. Soil samples were taken at three depths of 0 – 20, 20 - 40 and 40 – 60 cm from the four reclaimed sites and the control with a hand held auger and analysed for soil fertility parameters and selected heavy metal contaminants. The study revealed high community participation in the land reclamation exercise ranging from weed and fire control, supply of local seeds, seedling establishment and maintenance of reclaimed sites. Multipurpose trees: Gmelina spp, Cedrella odorata, Cassia siamea, Cassia mangium, Anegreila robusta, Daniella ogea, Mansonia and Terminalia superba, Terminalia ivorensis, Khaya ivorensis, Triplochitin scleroxylon and Entandrophragma utile were used in reclaiming mined out sites. The company uses the following reclamation processes and procedures to rehabilitate the disturbed sites: earthworks/slope battering, spreading of oxide material, spreading of top soil, construction of crest drains and broadcasting of cover crops to control run-off and erosion, tree planting and II field maintenance. It was observed that land reclamation had significant effect on the pH of the soil. The 12 year old reclaimed site recorded the highest percentage base saturation of 87.9% with the lowest of 61.8% recorded on the 9 year reclaimed site. Soil total nitrogen and SOC content were higher in the top 0 – 20 cm depth than the 20 – 40 and 40 – 60 cm depth. Exchangeable acidity ranged from 0.71 to 1.08. Soil Arsenic content was highest in the 3 year old site (9.44 mgkg -1 ) and least in the control site (0.48 mgkg -1 ). Highest lead concentration of 1.45 mgkg -1 was recorded on the 3 year old site and the lowest of 0.67 mgkg -1 on the control site. Copper was highest in the 3 year reclaimed site and the depth of 0 – 20 cm also recorded the highest value. The highest micronutrients were recorded on the 3 year old reclaimed site thus there was drop in the soil micronutrients with increase in years of reclamation.
Description: A thesis submitted to the Department of Materials Engineering of the College of Engineering, in partial fulfilment of the requirements for the award of the degree of Master of Science, in Environmental Resources Management, 2015
URI: http://hdl.handle.net/123456789/8193
Appears in Collections:College of Engineering

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