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By J. N. Van der Merwe

"Platinum is a highly valuable resource, its safe and economic extraction is paramount. The success of platinum mining by the bord and pillar method depends heavily on a comprehensive and dependable pillar design method. Pillars need to be large enough to safely support the load and small enough to avoid loss of resources. A critical evaluation of current pillar design systems used in narrow-reef platinum mining was undertaken using practical experience from a large feasibility-stage platinum exploration project, supplemented by observations from several platinum mines in Zimbabwe. An extensive literature survey was undertaken in order to determine the current status of design systems. Through this approach, the shortcomings of current pillar design systems are highlighted. Areas are proposed for further research to obtain a better understanding on how additional factors influence pillar system stability. The exploration work highlighted how rock mass classification methods can be utilized in determining the overall strength of pillars. Current pillar design systems for narrow-reef platinum mining consider width-to-heightratio (usually with different exponents for width and height) and the strength of the pillar material. However, there are many more important factors that are not considered and which have a bearing on pillar system stability. An in-depth study of these parameters with a view to establish effective narrow- reef platinum mining pillar design systems needs to be undertaken. IntroductionPillars have been used as a means of support since the early days of mining. Pillarsupported mining methods such as bord and pillar require a reliable design system for them to be successful. This paper presents an evaluation of the current hard-rock mining pillar design systems as applied to a practical large-scale narrow-reef platinum mining feasibility study. It is vital to have a dependable pillar design system for economic and sustainable mining. Using an extensive database collected from the project, the pillar strength formulae were tested and several discrepancies noted. This necessitates the establishment of more reliable pillar design systems. In narrow-reef platinum mining, large compressive stresses accompanied by geological and geotechnical factors contribute to pillar instability. A well-formulated pillar design system is required that accounts for such factors so as to minimize pillar failures."

Jan 1, 2017

By Arturo Ressi di Cervia

From the times when men in lacustrine environments drove wooden piles into the mud to elevate their dwellings, until the beginning of the twentieth century builders reacted to the conditions found in the location of their proposed structures by attempting to distribute their loads in ways that could be supported by the foundation's soils; or, if those were unsuitable, by moving the structure, whenever possible. While many major structures were built on stable ground (the pyramids were founded on rock), others were built on [ ]

Jan 1, 2000

By Ofra Damm, v du Preez, D. van Vuuren, L. Simpson, H. Chikwanda

"South Africa is the world?s second largest producer of titanium bearing minerals, but apart from producing titanium mineral concentrate to form TiO2 slag, little further value is added in South Africa to mined minerals. Various studies were undertaken by both government and the private sector in an un-coordinated manner until 2007 when the South African Department of Science and Technology (DST) planned and adopted a national strategy to establish a local titanium metal industry through the research and development of key technologies that would provide a competitive advantage to such a local industry. The strategy entailed a two-pronged approach in the development of this capability, viz. simultaneous investments in the development of high-level human capital and technology in the fields of titanium metal powder production and downstream titanium metal powder processing technologies. To date significant progress has been made to establish research and/or pilot scale facilities in the following technical areas: TiCl4 production technology, titanium powder production technology, high energy milling of titanium powder, metal injection moulding facilities, rapid production of large components using laser additive manufacturing technology, investment casting of titanium, resource efficient machining of titanium and friction stir welding of titanium. Supporting technologies are also at an advanced stage through investments in titanium powder spheroidization and direct rolling of titanium powder. The intent with investment in some of these areas is not to develop new technology per se, but rather to establish local capability that will position South Africa to collaborate with other organisations in the world so that technologies can be acquired and transferred when needed in the future."

Jan 1, 2014

Those involved in managing risk today are asking various questions: why is it so frustrating to discuss æriskÆ with communities? why do consultative processes around æriskÆ get more and more complex? where is all this going to end? These questions will be addressed by examining how our understanding of risk has changed from one based on biophysical hazard to a broader view that includes social and cultural factors. There is evidence to suggest that we are living in a ærisk societyÆ, where the goal of æsafetyÆ has replaced that of equality in a class based society. The global mining industry operates within this complex and politicised environment. The very meaning of ædevelopmentÆ has broadened from the narrow economic vision to include the social and environmental factors which make up æSustainable DevelopmentÆ. Corporate accountability now extends beyond traditional shareholders to wide groups of stakeholders. The mining industry is developing responses which look beyond traditional technocratic methods. At the industry level these responses have included the recent Mining Minerals and Sustainable Development global and regional reports It has proven challenging and difficult to operationalise these new understandings at the company level and it is time to look at the bigger picture.

Jan 1, 2003

By Peter Hatherly

As a discipline, geophysics covers an enormous range of scales and applications - from planetary geophysics through to the monitoring of acoustic emissions of rock samples. Although it is not a core discipline within the mining industry, geophysics has a useful role in providing information on the nature of the rock mass and the way it is responding to the mining process. For coal mining purposes, geophysical studies mainly seek to - delineate boundaries between the coal and the various layers within the surrounding strata - determine the physical properties of the rocks in-si tu, and - monitor the response of the rocks to the mining process Some of these applications may be associated primarily with mine planning, but once a mine is underway, most geophysical results can be used for the purposes of ground control. For example, insights into the nature of a geological fault mapped by a 3D seismic reflection survey will be relevant to determining support requirements while mining through it. In some instances there are parallels in the use of geophysics by the petroleum industry. Seismic reflection and wireline logging techniques have mainly been developed for petroleum exploration where their on-going development continues to provide spin-offs for the coal industry. The 3D seismic survey techniques that we now routinely employ were in their infancy 25 years ago and, almost certainly, the high quality borehole scanning tools that are now available would not have been developed without the need for petroleum well evaluation. Mining has also led to the development of specific techniques. An example is microseismic monitoring for the management of roof conditions during longwalling, and also the prediction of rock and coal bursts. The use and success of this technique have grown greatly over recent years. Another example lies with the use of geophysical wireline logs to predict rock strength and in rock mass classification. Coal seams also provide an unusual geophysical situation in that they form seismic and electromagnetic waveguides. The in-seam seismic and radio imaging methods have been developed to exploit these geological properties. In this paper I address the development and application of geophysical methods such as these with a particular emphasis on their role in ground control. We will see that there have been many developments over the past 25 years but we should also think about the future and how geophysics needs to be developed. From a miner?s perspective, one obvious area of need is in the detection of voids in the vicinity of current mine workings, be they old workings or karsts within nearby carbonate beds.

Jan 1, 2006

By L. A. Sandham

Environmental impact assessment (EIA) in South Africa is administered by the Department of Minerals and Energy (DME) for the mining industry, and the Department of Environmental Affairs and Tourism (DEAT) for all other sectors. Thus far, EIA research has focused on the process under the auspices of DEAT but none has focused on the EIA process that has been mandatory in the South African mining industry since 2004. Using the Lee and Colley(Lee et al.13) review package as a basis, a review model specifically tailored to the needs of the mining industry was applied to review the quality of a sample of 20 environmental impact reports (EIRs)approved by the DME. Results reveal that 85% of the EIRs are of a satisfactory quality. Presentational and descriptive components generally achieved higher quality grades than the analytical components such as impact magnitude and alternatives. The results show that in spite of some areas of weakness, and in spite of being conducted in terms of different legislation, EIR quality in the mining sectors appears to conform to the overall standard of quality of EIRs in other sectors in South Africa, and is also on a par with quality abroad. Hence, despite the criticism that DME is usurping the role of DEAT, it is concluded that EIRs of comparable standard are being produced, and that the quality of EIRs in the mining sector do not provide supporting evidence for this criticism. However, EIR quality is only a single aspect of EIA effectiveness, others including action and implementation of EIA proposals and mitigation measures.

Jan 1, 2008

By Gilbert R. Tallard

"Pouring deep foundations by the tremie pipe method is nowadays such a common process that it has becomes an unspecified practice. Means and methods are almost entirely at the contactor’s discretion. A variety of practices are permitted and seldom associated with the discovery of abnormalities and areas of random defects in concrete. This writer wishes to call the attention of stakeholders to the initiation details of the tremie pour operation.KEYWORDSINTRODUCTIONThe advent of slurry as a means of shoring an excavation of relatively small cross section but of possibly great depth has become part of state of the art in foundations construction, with the substitution of said slurry by concrete to provide the structural end product element through the use of tremie pipes. In appearance, there is nothing more simple than pouring concrete into a tremie pipe through a hopper after the basic work has been done i.e. the excavation or drilling, the cleaning of the slurry, the placement of the reinforcing cage, then the tremie concrete pour is almost a reward for a successful achievement. Force of habit has removed the awareness on the process fundamentals for initiating the pour; a variety of practices used call for a review and a reassessment as a means of reducing construction defects that may result from flawed practices, and and especially we are pouring deeper holes. This writer intends to address this issue focusing both on the drilled shaft and the diaphragm wall industries.TREMIE PIPES AND HOPPERSA tremie pipe diameter needs to be sufficiently large to allow the rapid descent of concrete with a minimum of friction loss and avoiding possible bridging in relation to aggregate size. Impervious joints between pipe sections are essential to prevent slurry “raining” over the concrete which can cause concrete segregation pockets and possibly plug the pipe with damaging consequences. That tremie pipes be long enough to reach the bottom may be self-evident but poorly written specifications can be erratic on that subject and seldom specific in terms of inches. A standard pipe of 10 inches is well accepted throughout the foundations industry; double O rings and spline joints are common and function well if properly maintained. However the practice to cover the joint with the ineffable duct tape indicates that all is not always well with this detail. Also, spline cables may shear in case of very long tremie pipes causing the separation of the tremie pipe requiring a restart in midstream with another probable source of inter mixing of concrete and slurry with subsequent defects."

Jan 1, 2017

By P wade

This is the first Presidential Address given to the Nottinghamshire Branch of The Institution following the merger of the Nottinghamshire and North Derbyshire Branch of The Institution of Mining Engineers (IMinE) and the Midland Branch of The Institution of Mining Electrical and Mining Mechanical Engineers (IMEMME). I intend to review the formation of the individual institutions as well as what has been achieved by mining related institutions over the years and finally I intend to look to our future.

Jan 11, 1996

By Stephen H. Stow

A relationship exists between the color and the chemical composition of the pebbles from the Bone Valley Phosphate Formation. Darker-colored pebbles are relatively high in iron oxide and relatively low in calcium phosphate when compared to lighter-colored samples; the brown color of the phosphate pebbles can be correlated with their iron content and the black and gray colors with their organic carbon content.1,3 It was anticipated that the darkness of a phosphate sample might be quantitatively measured by a simple reflectivity test and that the amount of reflected light could be correlated with the chemical composition of the rock, especially with the elements which cause the color and darkness of the Florida phosphates. Twenty-one samples of production grade phosphate rock from Hillsboro County, Fla., were studied. All samples were ground to -200 mesh for reflectivity tests and analyses. All analyses are accurate to well within ±2% of the reported value, except for aluminum and organic carbon, which are accurate to only ±15% of the reported amount. Reflectivity measurements were taken with a model 610 Photovoltmeter for tri-stimulus amber, blue and green, and white lights. Experimental procedures and data are available upon request. Results Table 1 contains linear correlation coefficients (LCC) for the element-reflectance relationships for the samples. The top portion of the table refers to the LCC between the percent of light reflected off the samples and the percent of a given element (or its oxide) as analyzed. In the lower portion of the table the LCC refers to the relationship between the same reflectance data and the chemical analyses which have been corrected on the basis of 0% acid insoluble material (chiefly quartz) in the phosphate rock. Each LCC presented in Table I is computed for the 14 coarser samples exclusive of the seven concentrates since the concentrate samples appear to have anomalous reflectivities upon comparison with the coarser grades. Only the most significant LCC for each element is presented in graphical form. Discussion of Data Iron: [Fig. 1] is a graph of the relationship between iron and reflectivity (LCC = - 0.98). A good correlation with Fe2O3, is expected due to the relationship between the tan (or brown) color and the abundance of iron oxide, the principal mode of occurrence of iron in Florida phosphates.8 Note the location of the seven triangles which repre-

Jan 1, 1972

By R. K. Logric

Bor flotation tailings are very interesting from two reasons: first, is having due value presently, and second represent serious pollutant into this region of Balkan. This paper is only one small part of investigation about processing of valuable minerals from tailings, and desulphurization of this biggest pollutant in the same time, by refloating. The main objective of this work is to pay attention on this problem for resolve greatest environ-mental problem of Serbia and Balkan in the nearly future. Bor is potential regional risk spot, since that failure of its tailings dams would release high amounts of toxic materials that would reach the Danube River. The basic goal of this experimental investigation was finding some possibility for flotation tailings treatment by classical froth flotation. In order was obtained material effect through copper recovery, and environmental protection by moving the rest of reprocessing into the safe place. The work present obtained results of laboratory tests in two laboratories: laboratory of mineral and recycling technology at the faculty in Bor, and laboratory of department of mineral processing of ITNMS in Belgrade.

Jan 1, 2014

By B. Tora

Coal mining activity is inextricably connected to waste production. These include coal slurries deposited in environment. Current knowledge in the field of mining and especially mineral processing allows extracting valuable fuel from deposit coal slurries. The article discusses of previous works devoted to coal slurries inventory in Jankowice Mine in Poland (Upper Silesia) and quality assessment of coal slurries. 12 samples of coal slurries deposited in waste pond of Jankowice Mine was taken for the investigation. Total amount of wastes deposited is more than 100 thousands tones. Keywords: re-flotation, coal wastes, waste storage, industrial verification

Sep 1, 2012

By XING Xiangdong, Zhang Jianliang, MA Jinfang, WANG Zhenyang

The non-equilibrium reflux reaction behavior of phosphorus was studied with synthetic slags formed by using the AR chemical reagents and changing the initial condition of basicity, FeO, MgO and Al2O3. Due to increase of viscosity, the dephosphorization slag with high basicity inhibits the full contact of slag with iron, which leads to the low reaction rate in the early stage. However, since the high basicity improves the activity coefficient of CaO, the dephosphorization rate and phosphorus capacity goes up in late reaction stage. FeO promotes the increase of reaction rate in early dephosphorization stage. But the polarization force of Fe2+ is stronger than Ca2+, which hinders the reaction between phosphate ion and CaO and reduces the stability of PO4 3-. Thus, high content of FeO will adversely impact on dephosphorization reaction. In addition, MgO has a promoting effect to the dephosphorization, whereas Al2O3 has a negative influence.

Jan 1, 2016

By E Bouchard March, F Lavoie, B Legare, K Bourassa

Quebec Iron Ore (QIO), a subsidiary of Champion Iron Limited (Champion), completed the restart of the Bloom Lake iron ore mine located in the heart of the Labrador Trough region of Northern Quebec, Canada in February 2018. Prior to its restart, the concentrator flow sheet underwent major upgrades which brought the iron recovery to the highest of all Labrador Trough operations. After two profitable years of production, QIO, supported by Soutex, started to look at technologies to improve its current performance and integrate into its expansion project flow sheet. From the lessons learned while optimising Phase 1, the addition of a scavenger-cleaner processing stage was identified as an improvement opportunity to increase recovery, produce a higher-grade product, and further improve the stability of concentrate quality. In 2019, the NI-43101 feasibility study for the Phase 2 expansion, aiming to double the production of high-grade iron ore concentrate, was published. Based on the metallurgical test work, the hydraulic classifier was selected to perform the scavenger-cleaning duty for its well-established performance and known behaviour at the cleaning step in the Phase 1 plant. To validate laboratory results, a pilot scavenger-cleaning hydraulic classifier was installed in Phase 1. Although the hydraulic classifier was selected for the feasibility study, metallurgical test work performed with the REFLUX® classifier showed interesting potential. It was thus decided to also install a pilot RC300 Reflux classifier at the scavenger-cleaning stage in Phase 1. Despite their apparent great similarities, the metallurgical performance was significantly different, and many dozens of sampling campaigns highlighted the different performance of both pieces of equipment considering the feed material particle size. This article presents the pilot plant results in terms of recovery, selectivity and stability for both the Reflux classifier and the hydraulic classifier operated in a scavenger-cleaner stage at the Bloom Lake iron ore concentrator.

Nov 8, 2021

By J. A. Burger

Research in the eastern U.S. has shown that productive mine soils and forests can be restored using the following guidelines: (1) cooperation among the mine operator, landowner, and regulatory authority in developing the mining permit; (2) replacing topsoil or creating a desirable medium in which trees are planted; (3) loosely grading non-compacted topsoil; (4) using native and non-competitive domestic ground covers that quickly protect the site; and (5) planting a proper silvicultural mix of crop trees for their commercial value along with nurse trees for wildlife and soil improvement.

Jan 1, 2002

The purpose of this paper is to provide a ælook behindÆ the Coal Mine Health and Safety Act 2002. The more important policy considerations in the development of the Act are described along with a summary of the main provisions of the Act. The Act, together with supporting regulations and other instruments will formalise the use of risk management as a necessary discipline in the systematic management of occupational health and safety. It must be recognised that the purpose of this paper is not to provide a legal interpretation of the legislation nor is it to provide legal advice. Rather, the main purpose is to provide some indication of the underlying intent behind the Act.

Jan 1, 2003

By Tiago Ramos Ribeiro

Os processos de redução direta utilizam-se de gases redutores (CO e H2) para redução do ferro e produção do DRI. A geração deste gás se dá através de reforma de metano que pode ser feita em um reformador, ou dentro do reator de redução com o DRI como catalizador. O último caso ocorre nos processos auto reformadores. A cinética da reforma de metano com H2O catalisada por DRI foi estudada em temperaturas entre 875°C e 1050°C. Os resultados mostraram que até conversão de metano de 0,50, a reforma é controlada por reação química catalítica conforme mecanismo proposto por Münster e Grabke(3,4). Acima desta conversão, o mecanismo não foi determinado. O uso de gás com potencial abaixo do limite para carburação (CH4/H2O < 1) resultou em DRI sem carbono. Com gás de potencial igual ou acima do limite, a carburação do DRI ocorreu e no caso do gás similar ao do processo industrial a carburação impediu a reação catalítica de reforma.

Oct 30, 2017

By Altemar Dettogne do Nascimento

A Máquina de Lingotamento Contínuo nº 1 da ArcelorMittal Tubarão (AMT), com capacidade nominal de 1,8 milhões de toneladas/ano, teve seu start up em 1995. A máquina é curva com raio de 10,5 m. São produzidas placas de 200, 225 e 250 mm, largura de 800 a 1650 mm e velocidade até 1,7 m/min. Em Abril de 2012, a Máquina parou para uma reforma geral. A empresa Italiana Danieli Davy Distington foi contratada para fornecer a engenharia, fabricação e entrega dos equipamentos no período de 12 meses. No ano anterior à parada da máquina, foi realizado um site survey, o que possibilitou a elaboração de um planejamento detalhado de todas as atividades. A reforma da máquina teve como objetivos principais: correção do alinhamento da máquina, substituição de estruturas oxidadas, implantação de novas tecnologias e redução do tempo de exposição dos operadores a ambientes agressivos (alta temperatura, projeção de aço, queda de cascão da panela e material particulado) através da implantação da sala remota de controle dos veios. A máquina foi colocada em operação em 10 de agosto 2012 após ter completado, sem desvios, as fases de instalação e testes. Este trabalho mostra as fases de desenvolvimento deste projeto, os resultados das tecnologias implantadas e os testes de performance para diferentes famílias de aço.

Jul 29, 2018

By Everton Azola de Mattos

A Retomadora de Minério 342-RE-001 da Anglo American é um equipamento fundamental para a homogeneização do minério, porém este equipamento apresentava problemas de performance operacional desde início da operação da Planta Industrial de Barro Alto. Em agosto de 2015, as equipes de Engenharia e Manutenção realizaram um levantamento de todas as intervenções feitas no equipamento desde o início da operação em 2012, classificando estas intervenções em seis grupos, utilizando as ferramentas da metodologia Lean Six Sigma. Desta forma, foi possível realizar o Retrofit da roda de caçambas, manutenção geral nos rastelos, trucks e na lógica de automação que eram os sistemas que mais impactavam na estabilidade e disponibilidade física do equipamento.

Aug 17, 2017

By Bingwen Z, Fengyi K

The hydraulic-stowing mining method is most effective for mining thick coal seams. It is superior to the sliced cover- caving and artificial mining method and the fully mechanized sublevel-caving mining method for the following reasons - a much higher recovery rate is achieved, there is much less surface subsidence and roof pressure, there is no hidden danger of gob fire, and much less methane emission and coal dust problems, etc.. However, its superiority is overshadowed by its backward stowing technique which makes mechanisation of mining and stowing difficult, causes bleed water interference to production and to the environment and is uneconomic because of the high cost of stowing material. These disadvantages limited its application to coal seams that are difficult and not suitable to be mined by other mining methods. The remedy is in reforming it thoroughly to permit mining of otherwise unminable seams and this paper presents the reformation.

Jan 1, 1992

By Liang Yinhuai

The hydraulic-stowing mining method is most effective for mining thick coal seams. It is superior to the sliced cover-caving and artificial mining method and the fully mechanized sublevel-caving mining method for the following reasons - a much higher recovery rate is achieved, there is much less surface subsidence and roof pressure, there is no hidden danger of gob fire, and much less methane emission and coal dust problems, etc.. However, its superiority is overshadowed by its backward stowing technique which makes mechanisation of mining and stowing difficult, causes bleed water interference to production and to the environment and is uneconomic because of the high cost of stowing material. These disadvantages limited its application to coal seams that are difficult and not suitable to be mined by other mining methods. The remedy is in reforming it thoroughly to permit mining of otherwise unminable seams and this paper presents the reformation.

Jan 1, 1992