Journal of natural sciences, life and applied sciences最新文献

{"title":"Rock failure criteria and mechanisms of failure for excavation stability design: a chronological evolution","authors":"Musa Gama, P. Chileshe","doi":"10.53974/unza.jonas.3.1.459","DOIUrl":"https://doi.org/10.53974/unza.jonas.3.1.459","url":null,"abstract":"Failure of rock, when it does occur, follows definite mechanical laws and that its probability, can, at least in some instances, be predicted sufficiently in advance of actual occurrence so as to prevent any great danger to the miner. The article chronologically describes rock failure criteria of some practical and most frequently featured strength criteria for predicting failure mechanism of rocks from rock sample or models (lab scale) to total structure or rock mass breakdown (field scale). A cross section range of criteria, from the typical and indispensable to state of the art ones, categorised under isotropic or anisotropic, stress, strain and energy related failure criteria that are predominantly derived on the basis of Coulomb, von Mises and Griffith theories of failure are reviewed. More attention and discussion has been given to most practical criteria like the Mohr-Coulomb and Hoek-Brown. Evolution of mechanisms of rock failure over time by various authors. The paper demonstrates progression of rock failure criteria, and that current theories hinge on classical ones.","PeriodicalId":16473,"journal":{"name":"Journal of natural sciences, life and applied sciences","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77383810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of laboratory automation and informatics at Mufulira analytical laboratories","authors":"C. Mulenga, K. Nyirenda, M. Songolo, Y. Hara, J. Banda","doi":"10.53974/unza.jonas.3.1.461","DOIUrl":"https://doi.org/10.53974/unza.jonas.3.1.461","url":null,"abstract":"Mopani Copper Mines has been experiencing late process of result reporting at its Analytical Laboratory. The delay in reporting results has been attributed to increased number of samples and analyses that are required within standard laboratory practices. Because Analytical Laboratories desire to enhance their performance as a way of increasing operational capacity, reduce operational costs, and improve cash flow, technological trends which elevate experimental data quality and reduce laboratory turnaround times were adapted at Mufulira Analytical Services Department. The study was undertaken to assess the impact of laboratory automation and informatics on the cost of operations, production output and quality of operations. Primary and secondary data was collected and analysed on a sample population size that included employees from the Analytical Services Department and client departments. The research study made the following conclusions: (i) Automation and Informatics has resulted in improvement on the performance of operations of analytical laboratory, with the increase of 5.03 per cent on the number of samples analysed, cumulating to 1,344 number of samples in reference to the months of July and August in the base year of 2013. (ii) There was a reduction in costs as a result of automation and informatics as evidenced on savings of 32.83 per cent on overtime hours, which cumulated to 1,331.34 hours saved, with reference to the base year 2013. (iii) Automation and informatics has resulted in reduction of errors and an improvement in the performance quality of the analytical laboratory. (iv) Post-automation and informatics was better than pre-automation and informatics. In order to reduce costs, increase cash flow and improve performance, the study recommended that Mufulira Analytical Services Department should scale up automation of its laboratory processes.","PeriodicalId":16473,"journal":{"name":"Journal of natural sciences, life and applied sciences","volume":"58 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84561634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation and design of a mine ventilation system for Mindola deep mine :(5220 L - 6365 L ore zone) Zambia: Determination of significant contributors and factors","authors":"P. Lukonde, P. Chileshe","doi":"10.53974/unza.jonas.3.1.466","DOIUrl":"https://doi.org/10.53974/unza.jonas.3.1.466","url":null,"abstract":"The paper reports research findings on the evaluation and design of the end of mine life ventilation system for the 5220L – 6365L ore zone of the Mopani Mindola Copper Mine in Kitwe, Zambia. The purpose of mine ventilation is to provide suitable environmental conditions in working places. The objectives of the research were: firstly, the evaluation of the current mine ventilation system for the 4440L – 5220L ore zone, taking into account the aged ventilation system infrastructure and, secondly, building of a ventilation baseline database for design of the end of mine life ventilation system taking into account the planned increase in production, and subsequent increase in depth of mining from 1586m (current depth) to about 1930m (5220L – 6365L ore zone). In evaluating the current ventilation system and designing the end of mine life ventilation system the methodology involved, firstly, collection of the mine and equipment physical details as well as primary and secondary data of the current ventilation system by means of ventilation surveys, analyses, and computations as well as processing of obtained data so as to use it in the design of the end of mine life ventilation system. Findings were: High wet-bulb temperatures (in excess of or close to 31.0 o C) were recorded in several mining areas below 4440L; Low air volumes of 1.5 – 4.5m3/s and velocities of 0.6 – 1.5m/s (lower than legal/scientific baselines of 30.0m3/s and 4.0m/s respectively) were evident in a number of mining areas between 4370L and 4440L; Dust concentrations of ventilation air in almost all mining areas were compliant with the established legal and or scientific baselines of 100 ppm; Obnoxious gas concentrations both in the general body of ventilation air and diesel unit exhaust emissions were well below Zambian legal/global scientific baselines of 1000 ppm CO2 and 100ppm CO . The total quantity of air leakage was in excess of 224 m3/s (35 % of total downcast air). In summary, the computed heat loads in the current mining zone (4440L – 5220L) recorded that diesel engine equipment with a total heat load of 1,792.5 kW (49% of the total heat generated) was the highest contributor, indicating it to be the 127 most important variable. Secondly, electrical equipment (fans), exposed rock (strata), metabolism, and others accounted for 1,861.5 kW (51% of the total heat generated). In conclusion, reduction and or replacement of diesel equipment electrical equipment would bring about significant reduction in mine heat load, and reduce or eliminate the need for refrigeration of the Mindola mine workings at depth.","PeriodicalId":16473,"journal":{"name":"Journal of natural sciences, life and applied sciences","volume":"68 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73719719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of impurities removal process for low-grade Sanje iron ore using mineral processing technologies","authors":"M. Siame, J. Kaoma, A. Shibayama","doi":"10.53974/unza.jonas.3.1.460","DOIUrl":"https://doi.org/10.53974/unza.jonas.3.1.460","url":null,"abstract":"In this study, the impurities removal process for low-grade Sanje iron ore was developed using Wet High-intensity magnetic separation (WHIMS) and Reverse flotation (RF). Sanje Iron Ore is the low-grade hematite ores found in Nampundwe area of Zambia from which Iron is to be extracted and used as the feed in the steelmaking process. The ore contains 34.18 mass per cent Iron grade, 31.10 mass% of Silica (SiO2) and 7.65 mass per cent Alumina (Al2O3). Magnetic Separation experiments were done using Series L Model 4 laboratory magnetic Separator (L-4 Machine) as the first stage impurity removal process and the effect of various magnetic separation parameters such as magnetic flux density, particle size density and pulp density of the feed were studied. The results showed that 10 T was optimal magnetic flux density which enhanced the recovery of 93 per cent of iron with 53.22 mass per cent grade. The iron concentrate produced from magnetic separation contained 12.04 massper cent Silica and 3.94 massper cent Alumna and therefore, it was further treated using Reverse flotation. In reverse flotation, various parameters such as pH, collector dosage, Iron depressant dosage and quartz activator dosage were investigated. The results showed that 81.94 per cent was recovered at the concentrate’s pH of 6.8 using 200 g/T of 0.1 per cent calcium oxide (CaO) as silica activator and one kg/T of 0.1 per cent causticised starch as Iron depressant. Sodium Oleate (NaOL) and Dodceylamine Acetate (DAA) each with discrete dosage, were used as Anionic and Cationic collectors respectively. Alumina was consequently reduced to 1.04 mass per cent and Silica to 2.04 mass per cent at optimum respective collector’s dosage of 0.250 kg/T using 0.02 kg/T of Methyl Isobutyl Carbinol (MIBC) frother. Additionally, phosphorous was also observed to be reduced from 0.05 mass per cent to 0.01 mass per cent. The designed multi-stage process involving feeding the concentrate from WHIMS into RF process therefore produced a high-grade iron concentrate iron with 67.27 mass per cent grade, 2.04 mass per cent silica, 1.04 mass per cent alumina.","PeriodicalId":16473,"journal":{"name":"Journal of natural sciences, life and applied sciences","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78939778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mining induced displacement and resettlement (MIDR): a case of Muzabula compound in Solwezi mining district Zambia","authors":"M. Kumwenda, P. Chileshe","doi":"10.53974/unza.jonas.3.1.464","DOIUrl":"https://doi.org/10.53974/unza.jonas.3.1.464","url":null,"abstract":"Liberalisation of the economy in the early 2000s by the Zambian government led to the privatisation of the State owned mining assets. Kansanshi Mine in Solwezi, North-western province of Zambia was sold to First Quantum. When the company started mining in 2004, some families in Muzabula compound that where in proposed mining area were displaced. Mining induced displacement and resettlement (MIDR) led to loss of socio-cultural, economic and environmental aspects of the displaced families thereby affecting their livelihood. Included was loss of land, common property resources, and disruption of social networks, loss of traditional authority and identity and destruction of forests and loss of access to the river. The objective of the research was to evaluate the impact of MIDR on the livelihood of the displaced community of Muzabula Compound. The conceptual and theoretical framework was based on the ‘Impoverishment Risks and Reconstruction model’ that looks at impoverishment risk assessment of socio-cultural, economic and environmental aspect in its analysis that arise from displacement. Qualitative research methods were used to collect data through semi structured interviews with the community, mine representative and government officials. A total number of forty-seven participants took part in the interviews. Grounded theory was used for data analysis and interpretation. Displacement took place in two phases, in 2004 at the beginning of mining and in 2015 during the construction of the smelter road. During the first phase, people were compensated in form of money at $3190 (US Dollars) per 50 x 50 metres of land. The amount included houses, fruit trees, fields and whatever was on the land. The second phase, compensation was in form of good concrete houses better than the mad houses demolished and help in farming inputs and skills. The displaced families who were subsistence farmers improved their produce. The first displacement resulted in increased risks of impoverishment for the displaced due to loss of livelihood as the displaced families were not involved in the planning. The second displacement was properly planned and improved the displaced families’ livelihood. Planning must include all stakeholders who are the community, the government, Civil Society like the Church, Non-Governmental Organisations working in the community and the Mining Company officials. The 96 interests of the community to be displaced must be considered as a first priority. The paper concludes that Government must adhere to policies that govern mining displacement and resettlement to reduce on loss of livelihood for the displaced. In the first displacement this was not considered as the displaced families were not engaged in any planning meetings and were just informed by the government officials and traditional leadership that they will be displaced and compensated.","PeriodicalId":16473,"journal":{"name":"Journal of natural sciences, life and applied sciences","volume":"110 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89530196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kitwe black mountain - Is Zambia realising the true value from it?","authors":"Jackson Kapobe, Charles Mazala, Richard Phiri","doi":"10.53974/unza.jonas.3.1.462","DOIUrl":"https://doi.org/10.53974/unza.jonas.3.1.462","url":null,"abstract":"Nkana slag dump (The Black Mountain) in Kitwe, Zambia, has existed since 1931 when the copper smelter was commissioned. This 20 million tonnes of smelter slag contains about 0.34 per cent - 4.5 per cent cobalt and average 1.2 per cent copper. When Zambia Consolidated Copper Mines Limited was privatised, the slag dump was purchased by Anglo Vaal Mining (90% shareholding) who built a smelter in Chambishi in 2000 to recover the cobalt and copper in the slag. The smelter operations closed in 2006 and the slag dump was later sold to Nkana Alloy and Smelting Company Limited. Various small scale illegal miners (locally called Jerabos) started illegally reclaiming the slag and selling to Chinese buyers operating small scale mineral processing plants. In the recent past, the government surrendered its 10 per cent shareholding of the slag dump to Chapamo Minerals Processing Company owned by the small scale local community (Jerabos). The substandard technologies being used by these small scale plants yield very low recoveries of about 50-60 per cent for both cobalt and copper, thus discarding huge quantities of valuable cobalt and copper which could be recovered if appropriate technologies were applied. This potential revenue to the nation in taxes is being lost. These small scale plants have not invested in appropriate advanced technology which can yield above 90 per cent recoveries because of their quest to make quick and easy money. The serious safety shortcomings at the slag dump have resulted in unnecessary loss of lives. The recent incident on 21 June, 2018 claimed 11 lives. There is need to study the physical structure of the slag dump to provide clear understanding of the safety precautions to be taken while reclaiming the material. There is, therefore, an opportunity to increase recoveries of the cobalt and copper by applying appropriate advanced technologies to process the slag. This will result in improved revenue, thus realizing the true value.","PeriodicalId":16473,"journal":{"name":"Journal of natural sciences, life and applied sciences","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80901095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Factors Affecting the Main Contractor-Subcontractor Relationship in the Zambian Construction Industry","authors":"Tafadzwa Mudzvokorwa, Balimu Mwiya, Erastus Mwanaumo","doi":"10.53974/unza.jonas.4.1.378","DOIUrl":"https://doi.org/10.53974/unza.jonas.4.1.378","url":null,"abstract":"Due to the magnitude and complexity of many of these projects, contractors have resorted to subcontracting to share responsibilities and mitigate project risks. The Zambian government has also invigorated the practice of subcontracting in the construction industry as it plays an imperative role in increasing economy viability and development of local contractors. Ministerial Statement on July 25, 2012 directed RDA to ensure minimum of 20 percent sub-contracting on all major road contracts to Zambian-Owned Companies. Instead of improving project success, subcontracting can act as a catalyst for poor project outcomes. Though there are many reasons that contribute to problems from subcontracting, a strained relationship between main contractors and subcontractors can be seen as a notorious contributor to poor project outcome. The study aimed at investigating the relationship between main contractors and subcontractors in Zambia, establish factors leading to interface problems and those factor that can help improve this relationship. Questionnaire survey was adopted in order to collect data and investigate the relationship. A total of 80 questionnaires were distributed. The questionnaires were distributed by hand and via email. Out of the targeted 80 respondents 56 responded, giving a response rate of 70 percent. The study established that the relationship between main contractors and subcontractors in Zambia needed to improve, as it was not in an effective state. Interface problems were caused by payment issues, poor communication, unexpected price escalations and poor construction work. In order to address interface problems, the study found that there was need for better communication between the parties, timely payments and subcontractors’ access to labour and machinery","PeriodicalId":16473,"journal":{"name":"Journal of natural sciences, life and applied sciences","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75825019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Operation Strategy for Water Supply Service Delivery in Lusaka’s Upcoming Residential Areas. A Case of Lusaka Water and Sewerage Company","authors":"Bweupe Lombanya, J. Chileshe","doi":"10.53974/unza.jonas.4.1.376","DOIUrl":"https://doi.org/10.53974/unza.jonas.4.1.376","url":null,"abstract":"Access to safe and affordable drinking water is a basic need for every human being. However, with Lusaka Province being the fastest province in Zambia, it is evident that the rapid development of upcoming residential areas as well as illegal settlements in the outskirts of the city has outplaced the installation of water supply system by the water utility company. Therefore, the main aim of this study was to assess Lusaka Water and Sewerage Company’s competitive priorities in its endeavor to provide safe and affordable water services in Lusaka’s upcoming residential areas. The research employed a non-intervention approach. Structured questionnaires and interviews were used for data collection. 30 household questionnaires were administered to households in Libala, Chalala and Obama residential areas respectively. Two water samples were collected randomly from each location and tested for quality. The findings showed that cost of drilling a residential borehole was K 17,351 with the reported minimum cost at K5000 and maximum at K75, 000. Borehole water from Chalala and Obama was found to be contaminated with total and feacal coliform bacteria. Nonetheless, piped water in Libala was found to be compliant with the World Health Organisation (WHO) standards. The residents in Libala were also generally satisfied with the water supply services, but had concerns over the high water tariffs, the late response to water problems and the elevated levels of chlorine in the water. Majority of the respondents also reported that a decentralized water supply system was an innovative idea. From the overall findings, the main operational core competency identified was the water quality. As a result, for LWSC to extend water supply to the upcoming residential areas in Lusaka, it was recommended that LWSC formulates a welldocumented operations strategy that will focus on the cost of the service and time of service delivery. These can be achieved through a well thought out and implementable capacity strategy and asset management. Capacity strategy will involve decisions on the sizing, timing, type and location of real assets or resources.","PeriodicalId":16473,"journal":{"name":"Journal of natural sciences, life and applied sciences","volume":"465 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83019065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predicting Global Solar Radiation on A Horizontal Surface A Case Study For Zambia","authors":"Chisala Kapumpu","doi":"10.53974/unza.jonas.4.1.374","DOIUrl":"https://doi.org/10.53974/unza.jonas.4.1.374","url":null,"abstract":"Insolation models have been recognized for many years in solar energy systems as important tools to determine radiations for locations lacking insolation data base. Unfortunately, for most geographical areas in Zambia, the insolation data is not available. Correlations between the daily measurements of global solar radiation and the meteorological parameters were presented in tabular form for the selected locations. A common relationship to estimate global solar radiation for the all Zambia is also established. The values of correlation coefficients established varied from 53% to 97% and the errors of estimation were between 0.24 and 0.0.84.","PeriodicalId":16473,"journal":{"name":"Journal of natural sciences, life and applied sciences","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85263453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Green's Function Method Solutions to Solve of nth-order Linear Differential Equations: طريقة حلول دالة جرين لحل المعادلات التفاضلية الخطية ذات من الرتبة النونية","authors":"Nedal Hassan Elbadowi Eljaneid, Abdelradi Abdelrah","doi":"10.26389/ajsrp.n140720","DOIUrl":"https://doi.org/10.26389/ajsrp.n140720","url":null,"abstract":"In this research article, we present the Green's function approach of ordinary differential equations with initial and boundary conditions, we represented the differential equation by an integral equation. The text provides a sufficient theoretical basis to understand Green’s function method, which is used to solve initial and boundary value problems involving linear ODEs and PDEs. The main result the construction of a Mathematica Package valid to calculate the explicit expression of the Green's function related to the two-point boundary value problem (2. 3), where the nth order linear operator Ln defined on (2. 1) has constant coefficients.","PeriodicalId":16473,"journal":{"name":"Journal of natural sciences, life and applied sciences","volume":"59 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74313029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}