Evaluation of two different mechanized earth moving technologies truck and shovel and IPCC for handling material from a large open pit mine using requesite design and operational conditions, efficiency, cost , skills and safety as criteria using sishen iron ore mine as a case study

An advanced coursework and a project submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements of MSc. Engineering (Mining), November 2015General For mining operations, both underground and open cast, there are generally accepted criteria used to arrive at the optimum mining method with which to exploit the ore body economically. Having selected the optimum mining method, mining companies should then make the decision to also select the optimum technology to apply given the various options that are now available. In the case of a shallow massive ore body where open-pit mining has been selected as the optimum mining method, the use of conventional trucks and shovels has been the popular choice but over the years, as pit become deeper, and stripping ratios increase, growing interest and adoption of in-pit crushing and conveying for both ore and waste has been gaining ground with several mining sites currently now operating, testing the systems or conducting studies at various stages for In-pit Crushing and Conveying (IPCC) in its different configurations (Chadwick, 2010). Open pit mining general involves the movement of pre-blasted or loose waste ahead of underlying ore out of the pit or to a previously mined part of the pit. This is then followed by the drilling and blasting or loosening of the ore and transportation to the processing plant or stockpiles. The conventional Truck and Shovel open pit operation involves the use of shovels – electric rope shovels, diesel or electric hydraulic shovels or excavators or front-end loaders to load the blasted, or loose waste and ore material in the pit onto mining trucks which haul the material to crushers or stockpiles if it is ore or to waste dumps in the case of waste. In a Fully Mobile IPCC (FMIPCC) system, the broken or loose material in the pit is loaded into a crusher or sizer by a shovel, continuous miner or dozer, crushed to a manageable size and transported by conveyor belts to the waste dump where it is deposited in place using spreaders if it is waste or onto stockpiles if it is ore. A combination of the two systems is where trucks dump material loaded at the face into a semi mobile crusher or sizer located in the pit close to the loading points N BANDA 392438 before conveying to destination thereby reducing truck haulage distance. In the semi-mobile configuration, the crusher is relocated closer to the loading points to minimise the hauling distance. Other various configurations are also employed depending on the various considerations. Although the Truck and Shovel system is considered as the convention in open pit mining, the IPCC system is not a new concept and has been operational on a number of mines worldwide for quite a number of years (Szalanski, 2010). Loading and hauling receive great attention especially in a high volume open pit mines due to the high cost contribution to the overall operation and therefore, if optimised, good cost savings can be realised (Lamb, 2010). Figure 1: Sishen Mining Cost Breakdown In the case of Sishen Loading and Hauling costs constituted 67% of the mining costs including labour mining support services in 2013 (Kumba Iron Ore, 2013). This picture remains unchanged to a large extent. In some cases the hauling cost alone can make up as much as 60% of the mining operating cost (Meredith May, 2012) Selection of a materials handling system between Truck and Shovel (T/S) and In-pit Crushing and Conveying (IPCC) has proven to be difficult due to limited understanding of the IPCC system especially its advantages and disadvantages relative to the Truck and Shovel system. The aim of this research was to unpack these two systems in terms of their applicability using studies conducted at Sishen 6,5% 8,8% 29,1% 22,7% 9,7% 0,6% 1,3% 0,4% 7,0% 4,2% 3,7% 5,9% Sishen Mining Cost 2013 Blasting Drilling Hauling L&H Contractors Loading Maintenance Other Mining Manangement Mining Engineering Mining Other Resource Management SHEQ Mining Support N BANDA 392438 Mine as well as develop some scorecard that could be used to select one over the other one. Sishen Case Study Sishen Mine is an iron ore open pit mine located in the Northern Cape province of South Africa and is part of Kumba Iron Ore Company which is Anglo American PLC. The mine has been in operation since 1953 with the current life of mine going up to 2030. It produces 44Mt tonnes of product from a 56Mt mine ore at a life of mine strip ratio of 4. One of the planned expansion the north part of the mine known as the GR80 and GR50 areas. Mining in these areas will require pre-stripping of 290Mt of clay material over the life of mine to expose the ore in pre volume phases. Figure2: Sishen Pit –Sishen Mine 2014. Sishen mine is constantly evaluating various technologies in its mining operations aimed at improving its bottom line by way of increasing productivity and efficiency, reducing costs and improving safety, however, the last time that the mine considered evaluating a technology that significantly could have resulted in a totally different operational philosophy was i contracted to institute a study to evaluate technology options for mining and moving majority owned by a minimum of 437Mt of calcrete and the underlying pre- g in 2007 when Snowden Mining Consultants run-ofmine areas is in -planned time and were N BANDA 392438 55 Mt of the calcrete/clay material per year from the waste pushback area in the GR80/GR50 area of the mine from 2009 till 2030. Snowden completed the Prefeasibility study in early 2008 in which they evaluated a conventional Truck and Shovel operation as well as IPCC. Economic viability of both systems in various configurations was demonstrated with the use of larger trucks and shovels ranked as the most economic option in terms of Net Present Cost (NPC), unit owning and operating cost per mined tonne and, to a less extent, in terms of risk and other considerations. In this case, the Truck and Shovel option was more economic than both IPCC configurations. However the small difference in the cost figures gave rise to interest in further evaluations. Following the Snowden study, Sishen engaged Sandvik Mining and Construction in 2008, to review the work done by Snowden and provide more detail and practical input to the IPCC system at scoping level. In the review, the IPCC system was shown to be the economic approach for the waste removal from the target area in terms of owning and operating cost. Practicality was also demonstrated and the case for the consideration of the IPCC system was put forward to Sishen. A further consultant, Sinclair Knight Merz (SKM) of Australia, was engaged, in the later part of 2008, to further evaluate and optimise the IPCC option to further demonstrate practically in detail at a feasible study level and strengthen its case by mitigating perceived risk. This included equipment specifications, mine and equipment layout per period per bench and risk assessment on the IPCC options. The mine, however, implemented the conventional truck and shovel option using larger equipment. The final decision was to stick with the current set up of Truck and Shovel system and gradually replace the current fleet of 730E Komatsu (190 tonne payload) trucks with the 930E or equivalent ( 320 tonne payload) and the current XPB 2300 P& H electric rope shovels and CAT 994/Komatsu WA1200 front end loaders with XPC 4100 P&H electric rope shovels, Komatsu PC8000/Liebherr 996 diesel hydraulic shovels and LeTournea L-2350 front end loaders to reduce the number of equipment and manage the operational cost. This decision was based on issues around initial capital investment, flexibility of the system to suit changing mining plans, ability of current personnel to run the system and general low risk appetite for change. The adopted option has its own challenges N BANDA 392438 such as supporting infrastructure requirements, labour intensity and associated low productivity and high cost, fleet management challenges to achieve required productivity constantly, supplies such as fuel and tyres and safety issues due to traffic density. A high level recalculation of the costs using current information was done as part of this research. For simplicity, no escalations or discounting were applied on future expenditure. The estimated unit owning and operating costs in 2014 terms for the study area were as follows:- Fully Mobile IPCC (FMIPCC) option ZAR 10.38/t, Semi Mobile IPCC (SMIPCC) option ZAR 13.12/t, Truck and Shovel option ZAR 15.80/t. The objective of this research is to use lessons from the Sishen case as well as other operations and gather expert views with the aim of establishing criteria that could be applied in a preliminary evaluation that would determine the suitability of either of the materials handling options. General Approach The costs were recalculated using as much current information as possible. Other considerations including advantages and disadvantages of either of the systems were examined in more detail, with real life examples examined where possible. This resulted in the establishment of generalized criteria for the selection of mining and transport technology for a large open pit mine with focus on conventional Truck and Shovel systems on one hand and IPCC systems, in their various formats, on the other. These criteria which identify conditions necessary for the successful adoption and implementation of either of the systems could then be used as input into the decision to carry out any further detailed studies of the options. The previous study reports on the Sishen mine case were examined, input parameters to the calculations checked and the general approached analyzed for practicality. The relative costs were also viewed for comparative purposes. Literature on these two main systems was reviewed including that from conferences. Other large operations running either one or both systems were looked at to gain N BANDA 392438 further insight. Original Equipment suppliers’ views on these systems were also looked at through many articles in the public domain. Sishen mine has previously had the IPCC system running in the same part of the mine in a semi mobile configuration, crushing and conveying waste. It was then changed to become a supplementary system for the ore handling system and the in pit crusher has never been relocated. The Truck and Shovel system took over the movement of all the waste and most of the ore at the mine. Lessons from these experiences were incorporated in this study

“Gamificación e innovación pedagógica”

Education has been immersed in a globalized world, where innovation is a fundamental requirement for teaching – learning of the students, also, with the term innovation are born several teaching techniques such as gamification, which its main characteristic the use of the game within the pedagogical process. However, most educational institutions do not know the benefits when use gamifying and innovating within education, this implies that there is no progress in the educational process, staying with traditional methodologies and techniques that do not achieve what was expected in terms of the learning of the student. Also, the student feels unmotivated when receiving classes in areas such as mathematics, so they do not feel interest when learning. That is why, the objective of the research focuses on implementing an innovative technological tool that allows gamifying the pedagogical process and thereby improve student learning in the area of mathematics. The methodology used in the research project is the qualitative research, likewise, bibliographic research was used, which allows to deepen the topic to be investigated based on different sources of information. The technique used in the research project is the interview, which was conducted to obtain information from the teacher and students. Accordingly, the interview guide was used as an instrument. As for the result obtained, it was possible to determine that there are teachers who do not know the term gamification in the teaching-learning, as well, students have no motivation when it comes to receive new topics in the area of mathematics. Finally, the research will contribute to the use of a technological tool called GeoGebra in the area of mathematics, and the use of the following ones in the development of new strategies and skills in the teaching-learning process of the students, so that the students are able to concentrate, be motivated and have interest in learning when receiving a subject.En la actualidad la educación se ha visto inmersa en un mundo globalizado, donde la innovación es un requisito fundamental para la enseñanza – aprendizaje de los estudiantes, asimismo, con el termino innovación nacen varias técnicas de enseñanzas como la gamificación, la cual tiene como principal característica el uso del juego dentro del proceso pedagógico. Sin embargo, las instituciones educativas en su mayoría desconocen los beneficios que se obtienen a la hora de gamificar e innovar dentro de la educación, esto conlleva que no exista avance alguno dentro del proceso educativo, quedándose con metodologías y técnicas tradicionales que no logran lo esperado en cuanto al aprendizaje del dicente. Asimismo, el estudiante se siente desmotivado a la hora de recibir clases en áreas como la matemática, por lo que no siente interés a la hora de aprender. Es por ello que, el objetivo de la investigación se centra en implementar una herramienta tecnológica innovadora que permita gamificar el proceso pedagógico y con ello mejorar el aprendizaje de los estudiantes en el área de matemática. La metodología utilizada dentro del proyecto de investigación se enmarca en la investigación cualitativa, del mismo modo se utilizó la investigación bibliográfica la cual permite llegar a profundizar el tema a investigar basándose en diferentes fuentes de información confiables. La técnica utilizada dentro del proyecto de investigación es la entrevista, la cual se realizó para obtener información de la docente y estudiantes. Acorde a esto, se utilizó como instrumento la guía de entrevista. En cuanto a los resultados obtenidos permitieron determinar que existen docentes que desconocen el término gamificación dentro del proceso pedagógico, así también, los estudiantes no tienen motivación a la hora de recibir nuevos temas dentro del área de matemática. Finalmente, la investigación aportara en la utilización de una herramienta tecnológica llamada GeoGebra en el área de matemáticas que contribuye en el desarrollo de nuevas estrategias y habilidades dentro del proceso de enseñanza-aprendizaje de los estudiantes, de modo, que los estudiantes logran concentrarse, motivarse y tener interés por aprender a la hora de recibir un tema tratado

Sistema Automatizado para el Control de Facturación y Existencias de Artículos y Servicios para la Construcción de la ferretería “Él Construye” de la República del Ecuador (SACFE).

El presente trabajo de investigación denominado Sistema Automatizado para el Control de Facturación y Existencias de Artículos y Servicios para la Construcción de la ferretería “Él Construye” de la República del Ecuador (SACFE) está contemplado en tres capítulos: Estudio Preliminar, Diseño e Implementación de SACFE. Se abordan temas inherentes: al objeto de estudio (Ferretería “Él Construye”), al análisis del costo realizado a través del modelo de diseño temprano de COCOMO II, a la herramienta y conceptos utilizados en el diseño de SACFE donde se realiza los diagramas de casos de uso tomando en cuenta los requerimientos funcionales del negocio a implementar en el sistema, al desarrollo de SACFE utilizando para su implementación el gestor de base de datos MSAccess y el entorno de desarrollo rápido de aplicaciones Borland Delphi de los cuales se hizo uso de los conceptos y características que presentan, a la ayuda en línea bajo la herramienta RoboHELP elaborada con el fin de estimular la explotación del sistema así como a las pruebas realizadas a SACFE permitiendo determinar el desempeño del software

The effect of acetaminophen (four grams a day for three consecutive days) on hepatic tests in alcoholic patients – a multicenter randomized study

Background: Hepatic failure has been associated with reported therapeutic use of acetaminophen by alcoholic patients. The highest risk period for alcoholic patients is immediately after discontinuation of alcohol intake. This period exhibits the largest increase in CYP2E1 induction and lowest glutathione levels. Our hypothesis was that common liver tests would be unaffected by administration of the maximum recommended daily dosage of acetaminophen for 3 consecutive days to newly-abstinent alcoholic subjects. Methods: Adult alcoholic subjects entering two alcohol detoxification centers were enrolled in a prospective double-blind, randomized, placebo-controlled trial. Subjects were randomized to acetaminophen, 4 g/day, or placebo for 3 consecutive days. The study had 95% probability of detecting a 15 IU/L difference in serum ALT. Results: A total of 443 subjects were enrolled: 308 (258 completed) received acetaminophen and 135 subjects (114 completed) received placebo. Study groups did not differ in demographics, alcohol consumption, nutritional status or baseline laboratory assessments. The peak mean ALT activity was 57 [plus or minus] 45 IU/L and 55 [plus or minus] 48 IU/L in the acetaminophen and placebo groups, respectively. Subgroup analyses for subjects presenting with an elevated ALT, subjects fulfilling a diagnosis of alcoholic hepatitis and subjects attaining a peak ALT greater than 200 IU/L showed no statistical difference between the acetaminophen and control groups. The one participant developing an increased international normalized ratio was in the placebo group. Conclusion: Alcoholic patients treated with the maximum recommended daily dose of acetaminophen for 3 consecutive days did not develop increases in serum transaminase or other measures of liver injury. Treatment of pain or fever for 3 days with acetaminophen appears safe in newly-abstinent alcoholic patients, such as those presenting for acute medical care.Funding for this study was provided by McNeil Consumer Healthcare to the Denver Health Authority, Denver, Colorado

The Role of Cytokines which Signal through the Common γ Chain Cytokine Receptor in the Reversal of HIV Specific CD4(+) and CD8(+) T Cell Anergy

BACKGROUND: HIV specific T cells are putatively anergic in vivo. IL-2, a member of a class of cytokines that binds to receptors containing the common gamma chain (γc) has been shown to reverse anergy. We examined the role of γc cytokines in reversing HIV specific T cell anergy. METHODS: PBMC from untreated HIV-infected individuals were briefly exposed to a panel of γc cytokines, and frequencies of gag specific T cells were enumerated by intracellular IFN-γ flow cytometry. RESULTS: Of the γc cytokines, brief exposure to IL-2, IL-15, or combined IL-15/IL-7 significantly enhanced (range 2–7 fold) the CD4(+) and CD8(+) T cell IFN-γ responses to HIV gag, with IL-15 giving the greatest enhancement. The effects of cytokines were not due to enhanced proliferation of pre-existing antigen specific cells, but were due to a combination of enhanced cytokine production from antigen specific T cells plus activation of non-epitope specific T cells. CONCLUSIONS: These observations support the notion that a significant number of HIV specific T cells are circulating in an anergic state. IL-2, IL-7 and particularly IL-15 as an immune modulator to reverse HIV-1 specific T cell anergy should be investigated, with the caveat that non-specific activation of T cells may also be induced

Addition of 7 Days of Zidovudine Plus Lamivudine to Peripartum Single-Dose Nevirapine Effectively Reduces Nevirapine Resistance Postpartum in HIV-Infected Mothers in Malawi

We assessed whether 7 days of zidovudine+lamivudine postpartum with single-dose nevirapine at labor decreases nevirapine resistance in HIV-infected women in Malawi

A call to action for climate change research on Caribbean dry forests

The final publication is available at Springer via https://doi.org/10.1007/s10113-018-1334-6Tropical dry forest (TDF) is globally one of the most threatened forest types. In the insular Caribbean, limited land area and high population pressure have resulted in the loss of over 60% of TDF, yet local people’s reliance on these systems for ecosystem services is high. Given the sensitivity of TDF to shifts in precipitation regimes and the vulnerability of the Caribbean to climate change, this study examined what is currently known about the impacts of climate change on TDF in the region. A systematic review (n = 89) revealed that only two studies addressed the ecological response of TDF to climate change. Compared to the rapidly increasing knowledge of the effects of climate change on other Caribbean systems and on TDF in the wider neotropics, this paucity is alarming given the value of these forests. We stress the need for long-term monitoring of climate change responses of these critical ecosystems, including phenological and hotspot analyses as priorities

Bryostatin Modulates Latent HIV-1 Infection via PKC and AMPK Signaling but Inhibits Acute Infection in a Receptor Independent Manner

HIV's ability to establish long-lived latent infection is mainly due to transcriptional silencing in resting memory T lymphocytes and other non dividing cells including monocytes. Despite an undetectable viral load in patients treated with potent antiretrovirals, current therapy is unable to purge the virus from these latent reservoirs. In order to broaden the inhibitory range and effectiveness of current antiretrovirals, the potential of bryostatin was investigated as an HIV inhibitor and latent activator. Bryostatin revealed antiviral activity against R5- and X4-tropic viruses in receptor independent and partly via transient decrease in CD4/CXCR4 expression. Further, bryostatin at low nanomolar concentrations robustly reactivated latent viral infection in monocytic and lymphocytic cells via activation of Protein Kinase C (PKC) -α and -δ, because PKC inhibitors rottlerin and GF109203X abrogated the bryostatin effect. Bryostatin specifically modulated novel PKC (nPKC) involving stress induced AMP Kinase (AMPK) inasmuch as an inhibitor of AMPK, compound C partially ablated the viral reactivation effect. Above all, bryostatin was non-toxic in vitro and was unable to provoke T-cell activation. The dual role of bryostatin on HIV life cycle may be a beneficial adjunct to the treatment of HIV especially by purging latent virus from different cellular reservoirs such as brain and lymphoid organs

Omicron B.1.1.529 variant infections associated with severe disease are uncommon in a COVID-19 under-vaccinated, high SARS-CoV-2 seroprevalence population in Malawi.

BACKGROUND: The B.1.1.529 (Omicron) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in the fourth COVID-19 pandemic wave across the southern African region, including Malawi. The seroprevalence of SARS-CoV-2 antibodies and their association with epidemiological trends of hospitalisations and deaths are needed to aid locally relevant public health policy decisions. METHODS: We conducted a population-based serosurvey from December 27, 2021 to January 17, 2022, in 7 districts across Malawi to determine the seroprevalence of SARS-CoV-2 antibodies. Serum samples were tested for antibodies against SARS-CoV-2 receptor binding domain using WANTAI SARS-CoV-2 Receptor Binding Domain total antibody commercial enzyme-linked immunosorbent assay (ELISA). We also evaluated COVID-19 epidemiologic trends in Malawi, including cases, hospitalisations and deaths from April 1, 2021 through April 30, 2022, collected using the routine national COVID-19 reporting system. A multivariable logistic regression model was developed to investigate the factors associated with SARS-CoV-2 seropositivity. FINDINGS: Serum samples were analysed from 4619 participants (57% female; 60% aged 18-50 years), of whom 878/3794 (23%) of vaccine eligible adults had received a single dose of any COVID-19 vaccine. The overall assay-adjusted seroprevalence was 83.7% (95% confidence interval (CI), 79.3%-93.4%). Seroprevalence was lowest among children <13 years of age (66%) and highest among adults 18-50 years of age (82%). Seroprevalence was higher among vaccinated compared to unvaccinated participants (1 dose, 94% vs. 77%, adjusted odds ratio 4.89 [95% CI, 3.43-7.22]; 2 doses, 97% vs. 77%, aOR 6.62 [95% CI, 4.14-11.3]). Urban residents were more likely to be seropositive than those from rural settings (91% vs. 78%, aOR 2.76 [95% CI, 2.16-3.55]). There was at least a two-fold reduction in the proportion of hospitalisations and deaths among the reported cases in the fourth wave compared to the third wave (hospitalisations, 10.7% (95% CI, 10.2-11.3) vs. 4.86% (95% CI, 4.52-5.23), p < 0.0001; deaths, 3.48% (95% CI, 3.18-3.81) vs. 1.15% (95% CI, 1.00-1.34), p < 0.0001). INTERPRETATION: We report reduction in proportion of hospitalisations and deaths from SARS-CoV-2 infections during the Omicron variant dominated wave in Malawi, in the context of high SARS-CoV-2 seroprevalence and low COVID-19 vaccination coverage. These findings suggest that COVID-19 vaccination policy in high seroprevalence settings may need to be amended from mass campaigns to targeted vaccination of reported at-risk populations. FUNDING: Supported by the Bill and Melinda Gates Foundation (INV-039481)