Abstract Mining in Brazil is one of the pillars that support its GDP (gross domestic product). Its execution requires technique and expertise. In a mining venture, the value chain drives the business to achieve its goals. Mine planning has a great influence on its performance, as it is through it that the organization is based to offer its products to the market and, consequently, the low compliance with the established premises will bring undesirable inconveniences. Within the planning, the short term is dedicated to operationalize the plans made possible by the long and medium term teams, in addition to attending to market variations. The indicators that control this process are of great importance, as an incorrect identification inserted in the various criteria that compose it can guide managers towards inefficient decision making. The objective of this study was, through lean methodology, to identify the main performance indicators that impact on the non-exception of the mining plan measured by the adherence and compliance indicators. In this method, the main causes of non-adherence and compliance with the mining plan were identified, enabling short and medium-term actions that leveraged the indicators. This study leveraged the average adherence and compliance by 17% and 54.9%, respectively, exceeding the target set for 6.5% and 49.2% respectively.

Resumo Introdução Tontura e desequilíbrio são disfunções comuns em idosos. A terapia de reabilitação vestibular é um método eficaz para o alívio da tontura crônica em pacientes com disfunção vestibular. A estimulação transcraniana por corrente contínua tem melhorado a função de equilíbrio em pacientes com disfunção vestibular. Objetivo Investigar a eficácia terapêutica da reabilitação vestibular combinada com a estimulação transcraniana por corrente contínua em pacientes idosos com disfunção vestibular. Método Em um estudo duplo‐cego randomizado e controlado, 36 idosos com disfunção vestibular crônica foram aleatoriamente designados para o grupo reabilitação vestibular e estimulação transcraniana por corrente contínua (n = 18) ou reabilitação vestibular isolada (n = 18). O protocolo de estimulação transcraniana consistiu em estimulação elétrica bifrontal multissessão do córtex pré‐frontal dorsolateral (intensidade de 2 mA e duração de 20 minutos), seguida de exercícios de reabilitação. O protocolo de reabilitação vestibular consistiu em exercícios de habituação e adaptação combinados com exercícios de marcha por um período de três semanas. O desfecho primário deste estudo foi o escore do dizziness handicap inventory e os desfechos secundários foram os escores da escala activities‐specific balance confidence e Beck anxiety inventory. Resultados Em relação ao escore do dizziness handicap inventory, a análise de variância de medidas repetidas mostrou um efeito principal significativo do efeito de interação do “tempo”, “estimulação”’ e estimulação x tempo. Houve redução significativa do escore geral do dizziness handicap com o “tempo” em ambos os grupos, foi mais pronunciada no grupo reabilitação vestibular e estimulação elétrica. Em relação à mudança nos escores do activities‐specific balance confidence, encontramos um efeito principal significativo dos fatores principais de “tempo” e “estimulação”, mas esse efeito não foi significativo para a interação estimulação × tempo. Para o escore do Beck anxiety inventory, observamos um efeito principal significativo do “tempo”, mas nenhuma evidência do efeito principal do fator “estimulação”. Conclusão A estimulação transcraniana por corrente contínua bifrontal em combinação com a terapia de reabilitação vestibular é uma abordagem promissora para melhorar os sintomas vestibulares crônicos em idosos.

Abstract Introduction Dizziness and imbalance are common dysfunctions in the elderly. Vestibular rehabilitation therapy is an effective method to alleviate chronic dizziness in patients with vestibular dysfunction. Transcranial direct current stimulation has reportedly improved balance function in patients with vestibular dysfunction. Objective This study was conducted to investigate the therapeutic efficacy of vestibular rehabilitation combined with transcranial direct current stimulation in elderly patients with vestibular dysfunction. Methods In a double-blinded randomized controlled trial, 36 elderly patients with chronic vestibular dysfunction were randomly assigned to either vestibular rehabilitation and transcranial direct current stimulation (n = 18) or vestibular rehabilitation alone (n = 18) group. The transcranial stimulation protocol consisted of multisession bifrontal electrical stimulation of the dorsolateral prefrontal cortex (2 mA intensity and 20 min duration), followed by rehabilitation exercises. The vestibular rehabilitation protocol consisted of habituation and adaptation exercises combined with gait exercises during a three week period. The primary outcome of this study was the dizziness handicap inventory score, and the secondary outcomes were activities-specific balance confidence and Beck anxiety inventory scores. Results For the dizziness handicap score, the repeated-measures analysis of variance showed a significant main effect of “time”, “stimulation” and stimulation × time interaction effect. There was a significant reduction in the overall dizziness handicap score with “time” for both the groups, which was more pronounced in the vestibular rehabilitation and electrical stimulation group. In terms of activities-specific balance confidence change scores, we found a significant main effect of “time” and “stimulation” main factors, but this effect for stimulation × time interaction was not significant. For the Beck anxiety score, we observed a significant main effect of “time”, but no evidence for the main effect of the “stimulation” factor. Conclusion Bifrontal transcranial direct current stimulation in combination with vestibular rehabilitation therapy is a promising approach to improve chronic vestibular symptoms in the elderly.

Abstract Objective Childbirth is a biological, psychological, and sociological event that can be a positive or negative experience, and, without support, this period may be potentially damaging. Parturition may distort maternal emotions and lead to short- or long-term disorders such as postpartum depression and anxiety. The present research aims to study the effects of dialectic behavioral therapy-based counseling on depression, anxiety symptoms, and postpartum hematocrit level. Methods The current research is a clinical trial study, and the sample was selected using parturients who were referred to the Health General Center with a diagnosis of postpartum depression and anxiety. The sample size consisted of 116 subjects who agreed to participate in the study. The patients in intervention group underwent group dialectic behavioral counseling (10 sessions/one session per week) and the control group did not receive any type of intervention. The patients were assessed in the first and last sessions as well as 2 months after the end of the sessions, using the Beck depression scale and Spielberg anxiety scale as well as the results of hematocrit tests. Data were analyzed using the IBMSPSS Statistics for Windows, Version 21.0 (IBMCorp., Armonk, NY, USA) Results The results implied the effectiveness of dialectic behavioral therapy on reduction of the depression score, anxiety symptoms (p-value ≤ 0.0001), and hematocrit level (p-value=0.04). The participants’ depression, anxiety, and hematocrit levels decreased in the experiment group compared to the control group, and this decrease has remained until the 2-month follow-up. Conclusion It seems that dialectic behavioral counseling reduces the levels of postpartum depression, anxiety, and hematocrits.

Abstract The traditionally and widely used Lerchs-Grossmann algorithm presents well-known limitations that newer propositions attempt to overcome. The direct block schedule (DBS) methodology, which has gained relevance with computational advances, obtains the final pit as a natural result of production sequencing, different from Lerchs-Grossmann-based algorithms. This process flow applies constraints in the final pit definition stage attempting to provide a more realistic result and to minimize risks. Slope instability is a common and inherent risk to open pit mining and may affect the project's net present value (NPV). A study of the impacts of slope angle variations on safety indexes and final pit NPV provides an auxiliary tool for the overall slope angle definition process. This article presents a case study in which the effects of variations of the overall slope angle on the safety factor (SF) and project NPV were analyzed. A total of 25 pits were generated by each studied final pit definition methodology, and each pit had the sections with the varied slope angles analyzed in the stability assessment, resulting in a total of 150 slopes analyzed. A comparison between the results obtained by the two different methodologies implemented in commercial software is presented. The results show no relationship between the NPV and the overall slope angle using the DBS methodology. An analysis of the results for each geotechnical sector obtained by the traditional methodology was conducted and may contribute to the trade-off analysis between the best slope angle to achieve a reasonable SF and the maximum NPV.

Abstract Mining Scheduling is the one that maximizes profit from mining over time. By means of computational methods, the deposit is discretized in blocks and algorithms are used to consummate this objective. The methods that are widely known nowadays for mining scheduling optimization of a discrete block model were based on graph theory, and among those most used by the mining industry is a solution found by Lerchs and Grossmann (1965) which, together with other methods, was consolidated as the process of traditional mining planning. For both supply and multi-destination models, there is a limitation of the current methodology, since it consists of the optimization of each mine separately which may not be a global optimization solution. This article proposes an optimization of the benefit in a stochastic model through the DBS (Direct Block Scheduling) for a copper mining complex with two mines, a pre-existing copper stockpile and two treatment streams, comparing several scenarios and analyzing the best alternative for the proposed problem.

Abstract The production rate of a mining operation has an important effect on the operational cycle and gross profit, which are often evaluated based on engineering practices. Assessment of the economic performance of mine operations in mining engineering is of great importance because an incorrect production rate can result in significant financial losses. The production rate is composed of two bases: the cost estimation and the price scenario. Bureau of Mines studies performed on American mines indicated that processing costs can be estimated through the production rate. This article proposes to connect the model presented by the Bureau of Mines and queuing theory to describe the operational costs, which are used to develop a production optimization methodology. The proposed cost composition describes a production system to verify the law of diminishing returns and the economy of scale. Between these regions of the production curve, the optimum point was determined with mathematical precision.

Abstract The transport distance in a mining operation strongly influences a mine operation revenue and its operational cycle because it is a fundamental part of the total mining costs. Generally, the transport route is determined based on an engineer's practical knowledge, which does not consider any mechanism to optimize the possible routes to be taken. In an attempt to establish a methodology for calculating the path that results in minimum costs to transport the mined block to its destination, the Dijkstra methodology is applied to a tree graph analysis, where the mining blocks are analysed as nodes of the tree. The transport cost is reflected as the arc of the graphs, which can use the Euclidean distance or the transport time for the calculation of the minimum path. The result obtained from the Dijkstra algorithm provided a non-operational route; to overcome this problem, an adjustment was performed through non-parametric equations. In this manner, it was possible to determine the transport costs for each block of the model. The paths based on Euclidean distance and transport time showed a tendency to increase for deeper mining regions. Identifying areas of largest growth and correctly quantifying their values increase the efficiency of mining planning.

Abstract Geologic modeling is an important step in determining the benefits and final pit dimensions for mining operations. Geostatistical models and distance-based functions are the main methods used to estimate the grade behavior. However, these two methods, despite their similar mean values, differ in spatial variability. The objective of this article is to prove, by comparing the two methodologies, that models with different spatial variability using the Lerchs-Grossmann algorithm will output subtly different final pit dimensions and scheduling. Furthermore, with the direct block schedule (DBS), these differences can be considerable. The tests compared the methodologies using the following three models: inverse distance (ID), ordinary kriging (OK) and turning bands simulation (TBS). The results demonstrate that the Lerchs-Grossmann algorithm is only slightly sensitive to the spatial variability of the grade; however, DBS requires the model populations to be better defined because of its greater sensitivity to spatial variability.

Abstract Determination of the best possible ultimate pit for an open pit mine is a fundamental subject that has undergone a highly evolutionary process, reviewed in this study, since the correct choice carries substantial economic impact for the industry. The correct choice can be very beneficial for project analysis, whereas an incorrect choice has the potential to mask huge financial and economic future losses that could render a project unfeasible. The advent of computers in the 1960s allowed sophisticated analysis for the selection of the best ultimate pit determination, under specific modifying factors such as economic, social, environmental, and political, but only in deterministic situations, i.e., when the problem and variables for the ultimate pit determinations were considered deterministically and almost always based on average values. Techniques such as the Lerchs-Grossman algorithm and mixed-integer programming are among many standard tools now used by the mineral industry. Geological uncertainty and the associated risks as well as the need to consider the appropriate time to mine a block during a mine operation have a significant impact on the net present value of the resulting ultimate pits. Stochastic aspects embed a probabilistic component that varies in time and are now under intense investigation by researchers, who are creating algorithms that can be experimented with and tested in real mine situations. One can expect that once these algorithms demonstrate their efficiency and superior results, they will readily dominate the industry.

O rápido avanço da tecnologia da informação e da aplicação de computadores ao setor mineral permitiu a automatização de vários processos da cadeia de valor mineral. Os sistemas ERP (Enterprise Resource Planning) forneceram a plataforma para a integração eficiente de todas as atividades de suporte da mineração. Apesar do avanço obtido com a aplicação dos computadores, não se conseguiu, até o presente momento, integrar, efetivamente, as atividades primárias da cadeia de valor mineral. A principal razão, para isso, são as incertezas existentes no processo produtivo, que são intrínsecas ao negócio, e a dificuldade de se quantificarem e qualificarem os benefícios advindos de tal integração, isto por não existir uma definição clara dos indicadores-chave de desempenho (KPIs). Esse trabalho apresenta uma análise da aplicação de sistemas ERP, na mineração do Brasil, identifica os KPIs mais importantes utilizados em empresas de mineração e discute a importância de seu mapeamento e medição para a gestão efetiva do negócio "Mineração".

The exceptional advance of information technology and computer application to the mineral sector has allowed the automation of several processes of the mineral value chain. ERP systems (Enterprise Resource Planning) provided the platform for the efficient integration of all support activities of the mineral value chain. Despite all advances gathered with the application of computers, it was not possible to date, to effectively integrate the primary activities of the mineral value chain. The main reason for that are the uncertainties present in the productive process, which are intrinsic to the business, and the difficulty to quantify and qualify the benefits obtained with this integration due to the lack of a clear definition of the key performance indicators (KPIs). This work presents an analysis of the ERP systems application in Brazilian mining, identifies the KPIs of some of the most important Brazilian mining companies, and discusses the importance of mapping and measuring these indicators for the effective management of the mining business.