Scielo RSS <![CDATA[Journal of the Southern African Institute of Mining and Metallurgy]]> http://www.scielo.org.za/rss.php?pid=0038-223X20110013&lang=pt vol. 111 num. 1 lang. pt <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>Fatigue knowledge - a new lever in safety management</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2011001300001&lng=pt&nrm=iso&tlng=pt The purpose of the paper is to give an introduction to the concept of fatigue and its causes in the mining industry. By knowing the fundamental role it plays, together with its dynamics, can positively contribute to a mine's safety management system. The difference between physical and psychological fatigue will be addressed with a possible range of causes that could trigger fatigue. There are two main sources of fatigue: firstly, work-related fatigue which is associated with activities at the workplace; and secondly non-workrelated fatigue. The shared responsibility between the employer and employee is also discussed as it involves factors that occur both in and outside the workplace. Employers have the responsibility to manage fatigue through using a risk management approach. Employees have the responsibility to ensure they get enough sleep, take sufficient and regular nutrition, are healthy and physically fit and come to work fresh and alert. The impact of the implementation of a fatigue management plan and procedures has the potential to eliminate employee fatigue or its causes, reduce the likelihood of fatigue occurring in the workplace, and counteract the effects of fatigue when it occurs. Factors considered when implementing a fatigue management system include: extended hours of work, shift work, time of day and work design. Fatigue is one of the major role players (either causal or contributory) when it comes to causes of fatalities in the mining industry. Our main challenge in identifying whether fatigue played a role is the fact that it cannot be tested in post-mortems like drug or alcohol abuse. It is an aspect worth understanding and getting an organization sensitive to managing it properly to benefit both organizational as well as employee needs. <![CDATA[<b>Controlled blasting for enhanced safety in the underground environment</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2011001300002&lng=pt&nrm=iso&tlng=pt Good blasting practices based on the careful application of explosive energy lead to significantly safer mining operations. Case studies demonstrate how the selection of the correct charge mass, explosive type and round design are vital for extracting the exact amount of rock required and preventing spurious damage to the remaining rock mass. In other cases the explosives are applied to precondition the rock mass, design rockburst resistant support, prevent damage to important excavations and reduce the exposure of miners to unsafe conditions. The Hybrid Stress Blasting Model is used to understand the explosive rock interaction and to illustrate and contrast good and bad blasting practices. In all cases, good supervision is required to continue safe mining according to the design. <![CDATA[<b>Mine safety net development and applications</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2011001300003&lng=pt&nrm=iso&tlng=pt Good blasting practices based on the careful application of explosive energy lead to significantly safer mining operations. Case studies demonstrate how the selection of the correct charge mass, explosive type and round design are vital for extracting the exact amount of rock required and preventing spurious damage to the remaining rock mass. In other cases the explosives are applied to precondition the rock mass, design rockburst resistant support, prevent damage to important excavations and reduce the exposure of miners to unsafe conditions. The Hybrid Stress Blasting Model is used to understand the explosive rock interaction and to illustrate and contrast good and bad blasting practices. In all cases, good supervision is required to continue safe mining according to the design. <![CDATA[<b>Changing minds -'a white flag'</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2011001300004&lng=pt&nrm=iso&tlng=pt Good blasting practices based on the careful application of explosive energy lead to significantly safer mining operations. Case studies demonstrate how the selection of the correct charge mass, explosive type and round design are vital for extracting the exact amount of rock required and preventing spurious damage to the remaining rock mass. In other cases the explosives are applied to precondition the rock mass, design rockburst resistant support, prevent damage to important excavations and reduce the exposure of miners to unsafe conditions. The Hybrid Stress Blasting Model is used to understand the explosive rock interaction and to illustrate and contrast good and bad blasting practices. In all cases, good supervision is required to continue safe mining according to the design. <![CDATA[<b>A safety plateau at Modikwa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2011001300005&lng=pt&nrm=iso&tlng=pt Good blasting practices based on the careful application of explosive energy lead to significantly safer mining operations. Case studies demonstrate how the selection of the correct charge mass, explosive type and round design are vital for extracting the exact amount of rock required and preventing spurious damage to the remaining rock mass. In other cases the explosives are applied to precondition the rock mass, design rockburst resistant support, prevent damage to important excavations and reduce the exposure of miners to unsafe conditions. The Hybrid Stress Blasting Model is used to understand the explosive rock interaction and to illustrate and contrast good and bad blasting practices. In all cases, good supervision is required to continue safe mining according to the design. <![CDATA[<b>Can buffer stores improve productivity?</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2011001300006&lng=pt&nrm=iso&tlng=pt The management of critical resource inventories is an important productivity lever and a significant risk factor-risk in the sense that poor resource availability lends itself to disempowerment of workers, unsafe work practices, wasted spending (high unit costs), and poor quality of work (including mining waste/rework). Most underground platinum mines experience lost blasts that directly lead to reduced productivity. In most surveyed shafts, 30% of lost blasts can be attributed to shortages of critical material and/or equipment. The problem is prevalent despite the existence of conventional transitory surface and underground stores. This paper discusses the introduction of buffer stores as a complementary materials storage system in order to improve health and safety in mines as well as reduce lost blasts. Both quantitative and qualitative results have shown that buffer stores result in dramatic improvements in productivity and are readily acceptable by stakeholders. <![CDATA[<b>Safety considerations in underground logistics - a look at vertical, horizontal and in-stope transportation systems</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2011001300007&lng=pt&nrm=iso&tlng=pt Transportation accounts for some 26% of all mine accidents in South Africa. Although this figure may not be as prolific as fall of grounds accidents or accidents caused by seismic events, the enormity of transportation accidents demands attention, especially as many of these accidents are avoidable. This paper investigates vertical (i.e. shaft), horizontal (i.e. haulages), and in-stope transportation systems and their function as it applies to safety. Recent transportation accidents are discussed looking at current trends within the three transportation areas. In the shaft area, discussions will focus on handling of material cars, loading and off-loading of the workforce and management of shaft orepass systems. The horizontal component will focus on personnel transportation, safety around trains and hoppers, and handling of material in the cross-cut. The discussion on in-stope transportation will focus on the general congestion of the stope environment and how it affects the overall movement of personnel, material, and rock. Of concern are the large numbers of material handling and scraper winch accidents that occur and which will be discussed in some detail. The paper will conclude with a section on proposed guidelines within the three above-mentioned systems for mine engineers to consider in mine design and life of mine planning and scheduling. <![CDATA[<b>The ongoing evolution of stope panel support at Impala Platinum Limited</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0038-223X2011001300008&lng=pt&nrm=iso&tlng=pt Transportation accounts for some 26% of all mine accidents in South Africa. Although this figure may not be as prolific as fall of grounds accidents or accidents caused by seismic events, the enormity of transportation accidents demands attention, especially as many of these accidents are avoidable. This paper investigates vertical (i.e. shaft), horizontal (i.e. haulages), and in-stope transportation systems and their function as it applies to safety. Recent transportation accidents are discussed looking at current trends within the three transportation areas. In the shaft area, discussions will focus on handling of material cars, loading and off-loading of the workforce and management of shaft orepass systems. The horizontal component will focus on personnel transportation, safety around trains and hoppers, and handling of material in the cross-cut. The discussion on in-stope transportation will focus on the general congestion of the stope environment and how it affects the overall movement of personnel, material, and rock. Of concern are the large numbers of material handling and scraper winch accidents that occur and which will be discussed in some detail. The paper will conclude with a section on proposed guidelines within the three above-mentioned systems for mine engineers to consider in mine design and life of mine planning and scheduling.