Scielo RSS <![CDATA[Journal of the Southern African Institute of Mining and Metallurgy]]> http://www.scielo.org.za/rss.php?pid=0038-223X20130010&lang=es vol. 113 num. 10 lang. es <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>Mine optimization</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2013001000001&lng=es&nrm=iso&tlng=es <![CDATA[<b>Serious dialogue</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2013001000002&lng=es&nrm=iso&tlng=es <![CDATA[SAIMM Career Development Day - 13 August 2013]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2013001000003&lng=es&nrm=iso&tlng=es <![CDATA[<b>SAIMM Career Development Day<i>: Report back on Mentoring</i></b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2013001000004&lng=es&nrm=iso&tlng=es <![CDATA[<b>International Honours for two Wits Engineers</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2013001000005&lng=es&nrm=iso&tlng=es <![CDATA[<b>The use of change management and behaviour-based training in an improvement project aimed at creating organizational sustainability in a multicultural mining environment in Zambia</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2013001000006&lng=es&nrm=iso&tlng=es Change management and training initiatives in remote rural settings in Africa are generally difficult to implement successfully due to factors such as varying levels of education, multiple nationalities and languages as well as cultures in one workplace. The challenge has always been the ability to implement change management and training initiatives that will have an impact despite these differences. Essentially this requires that the change and training interventions employed are applicable and should work well with a wide range of individuals sitting in one room - in practice this can vary from semi-literate workers to engineers with PhDs. In this paper we will share the theory behind behaviour-based change management and training and present a case study that reviews an actual supply chain improvement and sustainability implementation at a Zambian copper mine. The case study explains the results achieved as well as the interventions employed to achieve these results in a multidimensional organizational environment. This paper is relevant to delegates who are faced with implementing changes or training in a similar mining environment. <![CDATA[<b>Yield improvement at a mid-sized coal mine in the Witbank coalfields</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2013001000007&lng=es&nrm=iso&tlng=es A study was initiated and solutions implemented to address the root causes of a 30°/o^J0°/o lower than predicted product yield achieved at a Mpumalanga coal mine. A holistic MRTM approach, which focused on improving exploration, geological sampling and analysis, geological modelling, planning, mining, and beneficiation practices, was used. The study indicated that deviations in the planned versus actual yields at the DMS plant were caused mainly by incorrect geological yield predictions, high and variable levels of dilution, and near-dense material, as well as the textural properties of the ore. <![CDATA[<b>A framework to simplify the management of throughput and constraints</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2013001000008&lng=es&nrm=iso&tlng=es We show that the prioritization of business improvement and performance management decisions may be significantly improved by taking into account the systemic effects of changes made in a single process area. To do so we build a model of a mining value chain, taking into account consequential downtime that arises from downstream and upstream starvation and choking effects of each activity. Introducing the concept of internal capacity, this approach yields insight into the relative importance of key metrics such as loading and hauling rates. We suggest that a holistic view of this type should be a core component of business improvement and performance management decisions. <![CDATA[<b>Integrated optimization of underground mine design and scheduling</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2013001000009&lng=es&nrm=iso&tlng=es It is common practice for underground mine plans to be created sequentially, where results from one planning process form the input data for another. While this is practical for manual methods, computerized optimization techniques should consider an integrated approach to creating the global mine plan. This is because optimizing an individual mine planning process, such as stope layouts, introduces a likelihood of increasing costs or decreasing revenues associated with other areas, such as production scheduling, as harmful decisions must be balanced. Considering the interaction and influence that individual underground mine planning processes have on each other during optimization will provide more profitable results than if these are ignored. Optimization techniques for stope layouts and production scheduling are reviewed. An integer programming model is proposed that allows for either integrated or isolated optimization. Both approaches are separately applied to a block model. The results demonstrate the model's ability to produce optimal long-term sublevel stoping mine plans and the benefits of using an integrated approach. <![CDATA[<b>Relating high-resolution tilt measurements to the source displacement of an M2.2 event located at Mponeng gold mine</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2013001000010&lng=es&nrm=iso&tlng=es As part of JAGUARS (JApanese-German Underground Acoustic emission Research in South Africa), high-resolution tiltmeters were installed during 2007 at Mponeng gold mine, South Africa, in an attempt to study and understand the risks posed by in-mine seismic events and to subsequently use the knowledge gained to mitigate these risks. In December 2007, an M2.2 event occurred at Mponeng and was detected by the tiltmeters installed. The tilt expected for the M2.2 event is modelled through the use of numerical and analytical tools and utilizing, as input parameters, characteristics of the event such as the rupture area, the amount of slip, elastic properties of the rock, the state of stress before the event occurred, and frictional parameters of the rupture. The calculated tilt values are correlated and compared with the recorded data, and are found to be of the same order. Certain input parameters, such as the initial rupture point, are further constrained by varying them, during modelling, until the calculated and observed tilt values are approximately equal. From modelling, it can be concluded that the rupture point had to be closer to the location of the tiltmeters. In addition, possible locations acting as source areas for the observed aftertilt are determined. Further modelling still needs to be done to quantify the effects of the tunnel close to the tiltmeters and plastic deformation of the rock <![CDATA[<b>The absence of strategy in orepass planning, design, and management</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2013001000011&lng=es&nrm=iso&tlng=es Material transfer in underground mines often relies on ore and waste pass systems. Over the years the authors have investigated the design and performance of orepass systems in several Canadian and South African mines. It has been recognized that while most mining operations have either implicitly or explicitly clearly defined objectives, in the design and successfully operate orepass systems there seems to be an absence of a strategy on how to best attain these goals. Consequently, it is not surprising that the majority of operations reviewed by the authors experience a number of problems of varying degrees of severity and economic consequences. This is illustrated by reference to both South African and Canadian operations. The second part of this paper focuses on a review of tactical interventions to rectify orepass problems or mitigate their impact. The paper closes with a framework for a flexible strategy for the design and operation of orepass systems.. <![CDATA[<b>Erratum</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2013001000012&lng=es&nrm=iso&tlng=es Material transfer in underground mines often relies on ore and waste pass systems. Over the years the authors have investigated the design and performance of orepass systems in several Canadian and South African mines. It has been recognized that while most mining operations have either implicitly or explicitly clearly defined objectives, in the design and successfully operate orepass systems there seems to be an absence of a strategy on how to best attain these goals. Consequently, it is not surprising that the majority of operations reviewed by the authors experience a number of problems of varying degrees of severity and economic consequences. This is illustrated by reference to both South African and Canadian operations. The second part of this paper focuses on a review of tactical interventions to rectify orepass problems or mitigate their impact. The paper closes with a framework for a flexible strategy for the design and operation of orepass systems..