AngloGold Ashanti (South Africa)

Abstract In Ghana, indoor residual spraying (IRS) has been a key intervention for malaria control since 2008. After seven years of IRS with an organophosphate insecticide, which substantially reduced malaria incidence, IRS programs transitioned to neonicotinoid-based products between 2018 and 2019 as part of an insecticide rotation plan. This change was informed largely by entomological data from limited pilot districts, with little evidence on epidemiological impact. We assessed the effect of this transition using monthly, district-level malaria incidence from 2015-2022 in 22 IRS districts across four northern regions. Incidence was calculated from routinely reported confirmed malaria cases in the Ghana Health Service District Health Information Management System, adjusted for testing rates, with population denominators from census-based estimates. An interrupted time series model with generalized estimating equations was fit to 2015-2019 data, when organophosphates were in use, to generate counterfactual trends through 2022, adjusting for rainfall, temperature, vegetation index, seasonality, and initiation of seasonal malaria chemoprevention. Observed incidence exceeded counterfactual estimates in the first transmission season after the switch and remained higher in subsequent campaigns. Across all districts, incidence was 26% higher under neonicotinoid IRS than expected under continued organophosphate use (IRR = 1.26, 95% CI 1.07-2.08). Regional differences were observed, with significant increases in the Northern (IRR = 1.76, 95% CI 1.04-2.74), North East (IRR = 1.83, 95% CI 1.08-3.40), and Upper East (IRR = 4.26, 95% CI 2.17-8.50) regions, but not in the Upper West (IRR = 1.25, 95% CI 0.90-1.70). These findings suggest that the transition to neonicotinoids may have reduced IRS effectiveness in northern Ghana. Future pilots of new IRS products should incorporate both entomological and epidemiological outcomes to guide region-specific selection before national scale-up.

<p><em>Students' learning outcomes, especially in mathematics, are still unsatisfactory because many of them have not reached the KKM. For this reason, it is necessary to improve the results and completeness of students' mathematics learning through the use of educational video media. Thus, the purpose of this study is to describe the improvement of the completeness of the mathematics learning outcomes of MI students in grade V on the material of addition and subtraction of fractions by using learning video media. This research is a classroom action research (PTK) conducted in two cycles. The PTK model used is Kemmis and Mc Taggart's model with four stages namely planning, implementation, observation and reflection. The research was conducted in MIN 2 Kulon Progo. The research instruments used were mathematics learning outcomes tests on addition and subtraction of fractions at the end of each cycle, observation sheets, and field notes. The research data were analyzed descriptively to obtain the mean or average and the percentage of completeness of student learning outcomes. While qualitative analysis was used to describe the results of the observations and field notes. The results showed an increase in the percentage of completeness of learning outcomes in each cycle. In the pre-cycle, the percentage of completeness of student learning outcomes was 20%, in cycle I it was 73%, and in cycle II it was 97%, so there was an increase in the percentage of completeness of learning outcomes by 23% from cycle I to cycle II.</em></p>

This study examines how local government spending affects public services provided to the public. The performance of public service delivery is measured by the achievement of the performance of local government operations which are the object of evaluation in the Evaluasi Kinerja Penyelenggaraan Pemerintahan Daerah (EKPPD) which is carried out annually by the Ministry of Home Affairs. Whereas government expenditure is regional government expenditure per function per capita. Using a sample of 94 local governments, this study took the period 2014 to 2018. The results showed that per capita expenditure function had a positive effect on the performance of local government administration for regional government authority in education, health and infrastructure (housing and public facilities). The capital expenditure ratio is also tested to see the effect of capital expenditure on the performance of public service delivery. In testing the performance of the health and infrastructure sectors, this ratio has a significant negative effect, but for the performance of the education sector this ratio has no significant effect. This means that capital expenditures incurred by local governments have not been effective in meeting the needs of public services for the community, especially in the field of education.

Drill-hole spacing analysis (DHSA) and optimization are becoming commonplace for uncertainty assessment and management in the mining industry. However, there is no standardized DHSA workflow, and the outputs of certain methodologies are not interchangeable. We group available simulation-based DHSA methods according to their accounted uncertainty into (i) raw uncertainty, assessed by drawing realizations from synthetic data-sets with the drilling spacings to be tested; and (ii) model uncertainty, in which these synthetic data-sets are used to assess the variation between the estimated model and the (unknown) actual value. DHSA workflows available in the literature ignore the differences between both types of uncertainty. Commonly, the DHSA algorithm is chosen without a detailed analysis of its uncertainty output, which may lead to misleading results and suboptimal decisions. While available solutions are based only on assessing raw or model uncertainty, the proposed approach simultaneously analyses both and their relationship for models at different stages of the mine. The integrated analysis results deliver more information to support decision-making than available methods. Principles, practical considerations, and discussions of the advantages of the proposed integrated analysis are presented. The approach is applied to a real gold deposit to illustrate its use.

This paper discusses the experimental qualification process of Fabric Reinforced Cementitious Matrix (FRCM) composites with Polyparaphenylene BenzobisOxazole (PBO) textiles. FRCMs consist of fiber textiles incorporated within inorganic cement or lime mortar matrices and have emerged as composite materials suitable for the retrofit of unreinforced masonry structures. The Italian Ministry of Infrastructures and Transportation and the European Organization for Technical Assessment have developed guidelines defining standard tests to certify the FRCM mechanical properties for qualification and acceptance purposes. This paper presents part of the experimental qualification results for PBO-FRCM composites with two PBO textiles (unidirectional and bidirectional) applied to two different masonry substrates (clay bricks and tuff blocks), considering tensile, bond and durability behavior. Direct tension tests were carried out on PBO textiles and FRCM specimens, with or without textile lap splices. Single-lap tests allowed determining the bond properties of both FRCMs on clay-brick and tuff-block masonry substrates. The stability of the tensile properties with respect to degradation induced by environmental actions was evaluated by performing direct tensile tests also on FRCM specimens conditioned in humid, saline, and alkaline environments, or subjected to high-temperature stress.

Abstract Checking and treating extreme values is commonplace in modelling workflows. The main methods to manage outliers may be categorized into graphical, Kriging- and simulation-based approaches. While graphical methods usually classify outliers from a global perspective, geostatistical methods evaluate outliers in a local context. Ordinary-Kriging based approaches are affected by conditional bias associated with the distribution tail(s), impacting on the correct classification of extreme values; the simulation method is based on the fact that geostatistical simulation is robust for outlier values. However, this approach ignores the interaction among outliers in the same neighborhood. The proposed approach considers that there are two values available at every sampled position, the sampled value and the conditional probability estimated from nearby data through cross-validation; the sampled value. Each value outside the user-defined threshold is classified as an outlier and is edited by merging the sampled and kriged value through Bayesian Updating. The proposed method is performed in normal-score units using Simple Kriging to (i) correctly estimate conditional distributions in the cross-validation step; (ii) avoid conditional bias; and (iii) minimize the outlier influence on experimental-variogram modelling. The proposed method is compared to three other widely used methods in a case study of a gold deposit. The proposed method substantially improved the local accuracy and reduced the number of misclassified blocks of a reference model.

Abstract A comminution process is a material size reduction and separation process which is primarily used in the aggregates and the minerals processing industry. Knowledge related to equipment’s operation, raw material properties, operational strategies, control system, maintenance, etc. is needed to design a capable plant. New needs are arising from the industry for existing operational crushing plants such as investigation for improvements, upscaling, and downscaling of the capacity. The paper presents an application of simulation-driven development for a crushing plant in an existing gold processing plant. Due to the change in ore characteristics and the need for optimizing the cost of operation, it is required to investigate the opportunities for improvement and alternative options for downscaling the capacity of the plant. A systematic process for configuring, developing, and evaluating alternative concepts using a process simulation tool is presented. The results show the process of generating knowledge for alternative crushing plant operation settings and how the choices can be selected and eliminated using boundary conditions. The evaluation presents possible improvements and alternative concepts with their opportunities and pitfalls.

For more than 30 years, sulfide gold ores were treated in metallurgic plants located in Nova Lima, Minas Gerais, Brazil, and accumulated in the Cocoruto tailings dam. Both flotation and leaching tailings from a deactivated circuit, as well as roasted and leaching tailings from an ongoing plant, were studied for their acid mine drainage potential and elements’ mobility. Detailed characterization of both tailings types indicates the presence of fine-grain size material hosting substantial amounts of sulfides that exhibit distinct geochemical and mineralogical characteristics. The samples from the ongoing plant show high grades of Fe in the form of oxides, cyanide, and sulfates. Differently, samples from the old circuit shave higher average concentrations of Al (0.88%), Ca (2.4%), Mg (0.96%), and Mn (0.17%), present as silicates and carbonates. These samples also show relics of preserved sulfides, such as pyrite and pyrrhotite. Concentrations of Zn, Cu, Au, and As are higher in the tailings of the ongoing circuit, while Cr and Hg stand out in the tailings of the deactivated circuit. Although the obtained results show that the sulfide wastes do not tend to generate acid mine drainage, leaching tests indicate the possibility of mobilization of toxic elements, namely As and Mn in the old circuit, and Sb, As, Fe, Ni, and Se in the tailings of the plant that still works. This work highlights the need for proper management and control of tailing dams even in alkaline drainage environments such as the one of the Cocoruto dam. Furthermore, strong knowledge of the tailings’ dynamics in terms of geochemistry and mineralogy would be pivotal to support long-term decisions on wastes management and disposal.

2019 aura surtout été l’année du cinéma non anglophone, avec quelques très grands films dont Portrait de la jeune fille en feu (France), quatrième long métrage de Céline Sciamma qui mêle merveilleusement féminisme, poésie et réflexivité, Douleur et gloire/ Dolor y gloria (Espagne) le nouveau métafilm de Pedro Almodóvar, et surtout le triomphe de Parasite (Corée du Sud, Bong Joon Ho) à Cannes et – plus surprenant et sans doute politique – aux Oscars, avec ce premier Oscar du Meilleur Film attr...