Engineering
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- ItemDevelopment of an early warning system for predicting rock bursts and rock induced displacements in seismically active mining blocks at Mufulira underground mine (deeps section).(The University of Zambia, 2024) Mukuka, MosesMufulira Mine has been in operation since 1933. The Mine is situated on the Copperbelt region of Zambia. It is predominantly rich in copper mineralization. Due to increase in mine depth which currently stands at 1,557 m, the mine has been experiencing geomechanical challenges such as rock failures due to excessive stress changes around some mining blocks. This has necessitated changes in mining sequences to suit the present geomechanical conditions such as development of de-stressing cross-cuts between 62 and 64 blocks. Additionally, blocks have been subjected to shotcrete support method to prevent possible rockbursts/rock falls which can endanger safety of men working in these areas. This study applied laboratory geotechnical investigations for intact rock mass to determine unconfined compressive strength (UCS), secant and tangent Young’s Modulus (E Sec and E Tan), and secant and tangent Poisson's Ratio (ν Sec and ν Tan), Brazilian and Triaxial Compressive Strength tests as well as geological field mapping methods to understand the Geomechanics mechanisms controlling rock burst prone mining blocks at Mufulira mine. Laboratory findings indicated high values of Brazilian (Tensile strength) ranging from 7 MPa to 12.1 MPa, Uniaxial Compressive Strength (UCS) ranging from 126 MPa to 226 MPa and Triaxial Compressive Strength ranging from 124 MPa to 466 MPa were obtained. Damage mapping conducted in the footwall drives, cross-cuts and mining drives excavations indicate that there is a changing stress as one moves away from the retreating stope face to the east. An early warning monitoring system at Mufulira mine has been developed through modification of the existing micro-seismic monitoring system to allow the quantification of exposure to seismicity and provide a logistical tool to guide the effort into the prevention and control of, and alerts to, potential rock mass instabilities that could result in rock bursts. Two geophones have been interconnected in series and connected to the network system via the optical fibre junction box within the seismically active mining blocks to enhance accuracy in picking up rockbursts and rockfalls. Geomechanics properties of rocks determined in the laboratory experiments, geotechnical and geological mapping results were used to suitably place the geophones in suitable proximities within the seismically affected mining blocks. This modified micro-seismic monitoring system is susceptible to change if mining locations change due to changes in geotechnical and geological parameters such as rock types, jointing and fracturing.
- ItemDevelopment of underground mine monitoring and communication system based on wireless sensor networks.(The University of Zambia, 2023) Mazimba, ClementHistorically, mining has been an enormous contributor to the development and sustainability of several societies. The industry despite being a source of wealth is not without risks and challenges, including environmental and operational hazards. These pose a huge challenge to the safety and health of the workers and equipment and result in huge losses in terms of human capital, machinery, operational time, and valuable infrastructure. Accidents that occur in mines can be minor or significant depending on the nature of operations, and safety measures that have been put in place. The underground environment is particularly more challenging than an open pit environment due to the need for a controlled environment for mining operations to occur. Controlling the environment requires constant monitoring of parameters that make it safe for humans and machinery to work effectively and safely. To enhance safety and mitigate risks in underground mining, this study proposes an integrated, real-time monitoring and communication system that utilizes advanced sensing technologies and robust communication networks based on reliable protocols. The system leverages a wireless sensor network (WSN) strategically deployed and placed across the mine to track and report key environmental parameters. These sensors continuously collect and transmit real-time data using a combination of Internet of Things(IoT) based sensing devices, a designed prediction algorithm for every sensing node detecting a designated anomaly, and secure communication protocols. The transmitted data is processed at the designed gateway, located at the central hub, and further sent to an IoT platform where deviations from optimal conditions are identified, triggering automated alerts and emergency response mechanisms. In this study, temperature and humidity were selected as two of the parameters to be used particularly to demonstrate the sensing and communication capabilities of the WSN. A DHT11 sensor was used and combined with an ESP32 microcontroller unit (MCU), which was programmed in C++, to form a single sensing node. This node was programmed to collect and transmit data to the transceiver that relayed it along with other transceivers at an interval of 10 seconds. The system used two communication protocols, ESPNow, and Long Range (LoRa), to transmit the data from the nodes to the transceiver, and from one transceiver to the next respectively. The combination proved effective in that ESPNow provided immediate and real-time updates in localized areas while LoRa transmitted the data reliably over considerable distances without dropping the data integrity. The results of preliminary simulations indicate that the proposed system significantly improves hazard detection accuracy and reduces response times to potential threats. Compared to traditional monitoring methods, the system enhances situational awareness, leading to a measurable reduction in mining-related accidents and improved operational efficiency. Additionally, real-time alerts— delivered via mobile applications, email notifications, and on-site alarms—enable rapid response, allowing for immediate evacuation and risk containment. The findings underscore the importance of integrating digital safety solutions in underground mining operations. This study contributes to broader efforts in improving mining safety standards, aligning with industry best practices and regulatory requirements. Future research should explore further optimization using artificial intelligence for predictive risk assessment, as well as the scalability of the system to incorporate various types of sensors to get a more holistic view of the operational environment
- ItemCharacterisation of surface water quality in the Luapula river basin and developing a WQImin model for potential inter-basin water transfer to the Kafue river basin.(The University of Zambia, 2025) Kazekula, JovitaThis study underscored the importance of water quality, providing insights for sustainable resource management in decision-making and development planning. The study focused on the Luapula River Basin (LRB) in Zambia, a potential donor for inter-basin water transfers to the Kafue River Basin (KRB). The research objectives included establishing baseline data on surface water quality and developing a cost-effective Water Quality Index model (WQImin) for regular monitoring. Data was collected during both the dry and wet seasons of 2022 and 2023, respectively. Two triplicate samples were collected from each sampling point using the grab sampling method from 57 sampling points in the dry season and 91 sampling points in the dry and wet seasons. The samples were analysed according to the standard methods for the examination of water and wastewater. In the dry season, Electrical conductivity (EC) ranged from 8 µs/cm to 225 µs/cm, Total dissolved solids (TDS) values ranged from 5 mg/L to 162 mg/L, pH values ranged from 6.19 to 8.4 and temperature ranged from 18.50C to 28.10C, potassium ranged from 1.7 mg/L to 12 mg/L, sodium ranged from 5.3 mg/L to 36.3 mg/L, chloride ranged from 8 mg/L to 55 mg/L, turbidity ranged from 1.39 NTU to 37.2 NTU, iron ranged from <0.002 mg/L to 2.234 mg/L, calcium hardness ranged from 6 mgCaCO3/l to 30 mgCaCO3/l and total hardness ranged from 20 mgCaCO3/l to 106 mgCaCO3/l. In the wet season, EC ranged from 6 µs/cm to 78 µs/cm, TDS ranged from 2 mg/L to 50 mg/L, pH ranged from 5.97 to 8.23 and temperature ranged from 20.80C to 28.80C, potassium ranged from < 0.01 mg/L to 2.4 mg/L, chloride ranged from 2 mg/L to 14 mg/L, turbidity ranged from 0.3 NTU to 24.9 NTU and iron ranged from <0.002 mg/L to 1.4 mg/L. Calcium and total hardness values were all below the detection limit of 1 mgCaCO3/l in the wet season. Total and faecal coliforms ranged from 0 CFU/100 ml to > 200 CFU/100 ml in both seasons. The concentrations of nitrate, phosphate and sulphate were below the detection limit of 0.01 mg/L. Similarly, the levels of manganese and lead were below the detection limits of <0.002 mg/L and <0.01 mg/L, respectively, in both seasons. The spatial-temporal variations were influenced by precipitation patterns, geological factors and anthropogenic activities, notably evidenced by elevated coliforms, iron, turbidity, sodium and chloride levels in specific areas. Hydro-chemical analysis characterised the surface water as a calcium–magnesium–bicarbonate type, indicating underlying geological geology rich in silicates. The WQI indicated that nine per cent of the sampling points in the LRB were unsafe, seven per cent were very poor, four per cent were poor, 2 per cent were good and 58 per cent were excellent for ambient purposes. The poor and unsafe WQIs in specific locations were mainly attributed to iron and turbidity. However, the overall WQI for the LRB was 38 per cent, indicating that the LRB has good-quality water making the implementation of inter-basin water transfer to the KRB feasible. A multi-linear regression model was developed for predicting the WQI value based on only five parameters (the WQImin value). The use of WQImin has the potential to save on the costs and time associated with water-quality monitoring. This model has the potential to aid in understanding challenges linked to inter-basin transfer and support the formulation of management strategies prioritizing water availability and ecosystem and livelihood sustainability.
- ItemEnhancing resilience in the distribution networks to wind storms causing power outages affecting essential loads.(The University of Zambia, 2023) Ndhlovu, LikongeThis study, which was conducted and analyzed, examined the causes of power outages affecting essential loads such as hospitals, fire stations and many others due to storms, which caused the power distribution network's wooden poles to fall to the ground. The storm had wind speeds ranging from 30 to 60 meters per second. Due to this, there was a need to enhance the resilience of the distribution network against wind storms. Therefore, two best options were implemented to solve this problem that was hardening the 33kV lines connecting essential loads and integrating PV plants with battery storage on their buses. In the first method, class 1–4 wooden poles were tested to see if they could withstand the storm. From 30 m/s to 40 m/s, all classes of pole passed the test, however, at 50 m/s, only class 1 wooden poles were successful. At 60 m/s, all classes of wooden poles failed the test, so PV plants with battery storage were integrated into the distribution network and during the storm, the network continued supplying the essential loads in island mode of operation. The Python programming language was used to create a program that determined the failed pole class during the storm based on the fragility curve's probability of failure. Therefore, after integrating PV plants with battery storage, a grid impact study was conducted to determine if they would operate in accordance with the Zambia grid code, which they did. To measure the resilience of the distribution network, resilience indices were calculated and analyzed. Therefore, the active power supplied to the distribution network was calculated before, during, and after the storm, keeping in mind that maybe the 33kV lines connecting essential loads fell on the ground, causing an outage. Hence, PowerFactory DIgSILENT 2018 was the computer software that was used to calculate the active power supplied. The test distribution network was the Kasama distribution network. In conclusion, after implementing the two best options, the distribution network's resilience against storms causing power outages affecting essential loads was enhanced
- ItemDesign of Yb3+ doped laser for industrial application.(The University of Zambia, 2021) Simpungwe, MosesThe design and development of ytterbium-doped fibre lasers (YDFLs) operating around 1018nm laser wavelength and pumped around 976nm has advanced in technology since the first ytterbium laser was tested in 1988. The fiber lasers are used in various sectors such as communications, material processing, medical to mention but a few. Laser designers have the great objective of ensuring that the parameters such as pump power, active fibre cable and ion concentration are optimized for better quality laser output power. Further, the right choice of the output coupling between the Dichroic mirror (DM) and Fibre Bragg Grating (FBG) help eradicate the challenges faced in laser device design in terms of power output. Previous studies have reported use of diode lasers operating around 976nm as pump sources and lasing around 1018nm. There are, however, few reports on pump source use of 980nm on ytterbium doped laser fibre in the literature. This study therefore sought to contribute to improving on the power output of the YDFLs operating in continuous wave (CW) mode. In this modeling, a 980nm wavelength pump source with a lasing value at 1018nm wavelength and Dichroic couplers are deployed. In modeling the Yb3+ doped Laser, a quantitative approach was used. Linear differential equations were solved in order to determine the optimized values for the variables. Simulations using Computer software simulation -MATLAB were conducted. Power output of 59.64W was achieved against pump power of 68W, giving a slope efficiency of 87.71%. The operational characteristics of this Yb3+ doped fiber laser device in bidirectional pumping promises significant applications in radar, laser machining, free space communication and medical treatment. The results, further, show that the fiber cable length, the ion concentration and the choice of reflectivity on the OC and HR are critical when designing a fiber laser. Based on the results from the model, this study recommends that a study of the model be conducted experimentally to ascertain if the theoretical results will match with the experimental results.