Mines
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- ItemA review of mine closure and rehabilitation plans during the operations of large-scale mines in Zambia: a case study of Nchanga open pit mine.(The University of Zambia, 2022) Syafunko, Mutinta EstherThe world population continues to grow, with Africa projected to reach 2.4 billion people by the year 2050. This increase in population has resulted in a high demand for goods and services, which has subsequently triggered an increase in demand for mineral resources. Zambia, being a mineral rich country has seen an increase in exploration and exploitation of its mineral resources with some of the largest open pit mines in Africa being host to Zambia. Despite the positive economic impacts that come with mining, open pit mines have an adverse environmental impact, vis a viz, loss of biodiversity, land degradation, loss of ecosystems, etc. The country does not have any large-scale open pit mines that have closed which gives an opportunity for the mines to operate and close sustainably. The aim of this study was to review the incorporation of mine closure plans and progressive rehabilitation activities into the life cycle of large scale open pit mines in Zambia. This was done by an assessment of the current mine closure plans and a review of the benefits of incorporating these closure plans and progressive rehabilitation activities into the life cycle of large-scale open pit mines. The study focused on the Nchanga open pit mine, which is, a large-scale open pit mine in Zambia. The laws and regulations of Zambia were also examined in order to identify gaps and provide recommendations for improvement. The recommendations were drawn from an assessment of the current best practices and regulations and a review of international practices in Chile, South Africa and Western Australia. The methodology involved the use of survey questionnaires that were distributed to the local community, interviews that were conducted with key stakeholders, a site visit that was conducted at Nchanga Open Pit mine and the desktop review of the current laws and regulations on mine closure in Zambia. The results of the research revealed that the Environmental Protection Fund is the main framework used to deal with the issues of mine closure in the country. However, due to various factors including inability of local banks to provide bank bonds or guarantees to the mines and limited resources to carry out site inspections, the framework is not implemented effectively. There is therefore the need to review the effectiveness of this framework and revise it to be an effective tool for continuous rehabilitation and mine closure.
- ItemGeochemical assessment of an old Uchi tailing dump in Kitwe, Zambia.(The University of Zambia, 2024) Muma, StephenThis study investigates the characteristics of soil from an old Uchi Tailing Dump in Kitwe, Zambia, through field sampling and analysis. Soil samples were systematically collected using a grid sampling techniques to inform future environmentally responsible restoration strategies. Particle size distribution was assessed through sieve analysis while X-ray diffraction (XRD) provided insights into the soil's crystalline structure. Results from these techniques, along with elemental quantification using flame atomic absorption spectrometry, revealed a hierarchy of element concentrations in the Uchi Tailing Dump samples: Fe>Cu>Ca>Mn>Co>Zn, with pH ranging from 5.5 to 7.5. Notably, copper (0.56%) and cobalt (0.15%) levels were particularly high. Cuprite was identified as a significant source of copper while iron oxide contributed to elevated iron levels. XRD analysis highlighted quartz, kaolinite and dolomite as the predominant phases, with montmorillonite aiding in pH stability. The study also attributed high calcium content to calcite. Spatial distribution analysis revealed distinct patterns, with elevated copper in the northwest and increased cobalt in the northeast. Both topsoil and subsurface samples exhibited contamination, likely due to anthropogenic influences. The soil was predominantly fine sand (86% sand, 13% clay and 1.4% silt) with a gap-graded particle size distribution. The simulation results from PHREEQC revealed distinct saturation levels for various mineral phases within the tailings, with cupric ferrite (CuFe2O4) at 10.72, cuprite (Cu2O) at 3.08, zincate (ZnSO4: H2O) at -9.54, gypsum (CaSO4: 2H2O) at -4.85 and hematite (Fe2O3) at 13.10. The Geo-Accumulation Index (Igeo) confirmed contamination, particularly in copper (Igeo=5), cobalt (Igeo=2.5), iron (Igeo=0.5) and zinc (Igeo<0). Dust emissions, acid mine drainage, soil degradation and a reduction in biodiversity in the Uchi Stream are significant hazards associated with the Uchi Tailing Dump. In summary, the study underscores the significant pollution and environmental risks associated with the Uchi Tailing Dump, emphasizing the need for ongoing monitoring and remediation efforts to protect the ecosystem and community health in the area. In conclusion, this study highlights significant pollution and environmental risks at the Uchi Tailing Dump, emphasizing the necessity for continued monitoring and remediation efforts to safeguard the ecosystem and community health in the area.
- ItemExploring forest-water nexus in a changing environment of Kafue river basin, Zambia.(The University of Zambia, 2025) Kamamba, MuyakaWater insecurity in Zambia's Kafue River Basin (KRB) is rising due to climate change, land-use change and increased water abstraction. The role of forests in the hydrological cycle, particularly through evapotranspiration (ET) has not been adequately explored. This study addressed this gap. The main objective was to explore the forest-water nexus in the Upper Kafue River Sub-Basin (UKRSB), its implications for sustainable river basin management and Inter-Basin Water Transfer (IBWT) from Luapula River Basin to KRB, Zambia. A systematic literature review using PRISMA guidelines was conducted through Google Scholar (1970 to 2023). Remote sensing datasets: Actual ET (AET), NDVI, Total Canopy Cover and Tree Density were acquired and processed. In combination with forest inventory procedures. Data was analysed using QGIS for spatial analysis and Microsoft Excel version 2108 for statistical analysis. Twenty-five relevant papers on the forest-water nexus were identified, indicating limited research on this topic. A bibliometric analysis highlighted small co-author clusters with prominent figures like Paletto and Springgay suggesting limited collaboration. Indirect field observations emphasised the significance of riparian forests and Nymphaeaceae (water lilies) in stabilising riverbanks and reducing stream turbidity respectively. AET in 2022 ranged from 268 mm year־¹ to 1505 mm year־¹, with an annual average of 985 mm year־¹. Correlation between AET and NDVI varies with season, moderate during the dry season (r² = 0.48) and weaker in the wet season (r² = 0.32). Long-term trends (2009 2022) showed a decline in AET with a slope of -12.14, suggesting climatic changes or deforestation. A threshold AET rate of 80 mm month⁻¹ was observed from 2013 to 2022. To offset water loss seasonal variations, an annual requirement of 4.36 billion m³ is needed. The Kalahari Woodland land cover (1177 mm year־¹) had the highest AET rate, whereas Miombo/Chipya (1082 mm year־¹), Parinari (1005 mm year־¹) and Munga (1005 mm year־¹) woodlands showed lower rates. Species-wise, Julbernardia globiflora (1444.6 mm year־¹) exhibited the highest AET rate in the Kalahari Woodland. Pinus kesiya and Eucalyptus grandis plantations also demonstrated elevated AET rates both at 1280 mm year־¹. For these reasons, there is need for considering land cover types and species-specific ET rates in IBWT planning to mitigate water loss. Necessitating integrated river basin and forest management strategies aimed at water conservation in the KRB. Future research should determine tree age effects on ET and employ sap flow meters for species specific ET estimation. Collaboration among forestry and water institutions is necessary to enhance policy and management strategies.
- ItemAssessment of geotechnical considerations for ground control and stability at Nkana Synclinorium copper mine Mopani Plc, Zambia.(The University of Zambia, 2024) Mpaka, BarnabasNkana Synclinorium Mine is in the Southern part of the Nkana mining license area in Kitwe. The mine has been an underground operation since 1930 when the first shaft was sunk at Central Shaft. Vertical Crater Retreat (CVR) and Sub-Level Curving (SLC) are the main copper ore mining methods used at the mine. Due to increase in mine depth by 137m, from 3510ft to 3960ft (1.070 to 1.207km), mining operations have been encountering geotechnical challenges related to ground control and ground stability. This study applied Empirical methods (Barton’s Q system, 1974, Bieniawski (1973) classification and Hoek, 1994) for rock mass classification. Scanline mapping of geological structures was done to identify joints, bedding planes, schistosity and folds. The mapping was carried out along the crosscuts or tunnel walls at a 1.50m grade line elevation with geological features being picked along a stretched 100m tape. Borehole cores were examined for geological formations, grain size, colour, joints, and RQD. The assessment of rock reinforcement and surface support elements like cable bolts and shotcreting were done by using pull tests and uniaxial compressive strength (UCS) tests. Pull Testing was done in selected mine excavations to provide a quantitative measure of the relative performance of different anchor systems and compressive strength tests on concrete cubes were used to assess the quality and strength of the material used in shotcreting underground. Collection of survey data for over-break and under-break in tunnels mined underground was done by the author with the assistance of mine surveyors. The Theodolite was the major instrument used. Numerical modelling using MAP3D and Finite Element Analysis (FEA) softwares was used to assess ground stability around underground excavations. Evaluation of design systems for ground support and pillars was carried out with the reviewing of current design flow charts in comparison with design charts from literature for other mines around the world. Results of study indicate that the rock mass ratings (RMRs) for the samples of Basal Quartzite (BQ), Foot Wall Conglomerate (FCON), South Orebody Shale (SOBS) and Hanging Wall Argillite (HWA) rock formations compared well with Barton’s Q system RMR ranges except for Foot Wall Sandstone (FSAN) which was out of range. All pull tests conducted at 3 sites had an average failure rate of 22.3% while compressive tests gave a high failure rate of 83.3%. Numerical analysis using Finite Element Analysis (FEA) software indicate more stresses and displacement around the excavation before rock bolt support, and less stresses and displacement after rock bolts are installed around the same excavation. Over-break and under-break data did not show any correlation with mined linear meters of the tunnels. Geological factors like jointing, weathering and shearing as well as drill-and-blast challenges were attributed to over-break and under-break. In conclusion, folds and joints are major factors affecting ground and stability at Synclinorium mine, and the geotechnical database has insufficient data. The confidence of the current geotechnical database at Synclinorium mine needs to be improved through more data collection. Design excavation and ground support designs need to be improved and matched with the real situation underground. The key issues affecting drill-and-blast like varying powder factors in the shots, lack of pragmatic consideration of geological and geotechnical information in the design, and diligent adherence to the blast designs need to be addressed.
- ItemAssessment of sunflower (helianthus annuus l) for phytoremediation of heavy metal polluted mine tailings: a case study of Nampundwe mines tailings dam.(The University of Zambia, 2023) Chileshe, Kaela BeverlyMining is the main source of export income and contributes significantly to the Zambian gross domestic product. Besides its contributions to exports, the mining industry plays a pivot role in the economic and socio-political development of Zambia. It also provides essential mineral based raw materials to the local industry. However, mining activities have led to a generation of heavy metals laden wastes which are released into the environment in an unsustainable way causing the contamination of the ecosystems and posing a risk to human health. Most mining companies have not employed any rehabilitation or remediation program for the heavy metal laden wastes. For this purpose, this study was conducted to assess the potential of sunflower for phytoremediation of heavy metal polluted Pyritic mine tailings. Phytoremediation is an emerging technology in the remediation of mine tailings that uses tolerant plants species to clean up contaminated sites. It uses plants with high biomass and sunflower has been identified as such. These plants can extract, transfer, sequester and stabilize a variety of metals through mechanisms such as phytoextraction, phytostabilization, phytoaccumulation and phytovolatilization. In this study, pot experiment was conducted by growing sunflower (Helianthus annuus L) in pyrite mine tailings and in agricultural soil as a control. The study showed that the concentration of Cu reduced from 40.76mg/kg to 36.59mg/kg, Zn reduced from 3.58mg/kg to 3.49mg/kg andFe reduced 23.70mg/kg to 10mg/kg respectively in the mine tailings after six (6) weeks. Analysis of harvested sunflower (roots, stems, leaves) showed that sunflower could remove heavy metals from the tailings and the highest removal efficiency was 56.16% and the highest translocation factor was 0.25. Based on the results obtained it can be concluded that sunflowers have the potential to remediate contaminated pyritic mine tailings and phytoremediation is a viable and efficient technology to treat soils contaminated with heavy metals.