Search Documents

By B. C. Alberts

Planning the use of South Africa's energy resources, especially coal, is of the utmost importance. The State and the mining industry require reliable official estimates of the economically mineable coal reserves for planning purposes. An overview of al the previous reserve estimates is given, with specific attention to the two most recent estimates-those of Petrick and De Jager. The differences between these two estimates are highlighted. The following important aspects are discussed: . the need to update the information regarding South Africa's mineable coal reserves, . the necessity of understanding and agreement between the coal-mining industry and the State department responsible for updating the coal-reserve data, and . the importance of the specific assumptions used in the updating of the data. A downward adjustment of mineable reserve figures is proposed, and the factors that influence the meaningful exploitation of the coal reserves are discussed. A recommendation is made as to how the Waterberg coal reserve should be exploited, and it is concluded that the Soutpansberg Coalfield cannot be exploited economically in the foreseeable future. An evaluation of the status of the coal-export trade is made and compared with the assumptions and targets set at the start of the coal-exportation scheme. The comparison shows the extent to which the exploitation of the coal reserves is being negatively influenced by the current market situation. Recommendations are made regarding planning for the coal-export market, and the aspects that have to be taken into account to keep South Africa in the export market are identified. Reference is made to the fact that the present unrestrained wage and salary adjustments, which show a total disregard of South Africa's poor productivity record, require serious thought and speedy rectification if the country is to survive in the export market. A salary and wage strategy must be developed to suit the specific needs of the Republic of South Africa.

Jan 1, 1987

By I. J. Geldenhuys

South Africa’s mining and metals industries have an illustrious history dating back to the Late Iron Age. We live in a complex and data-intensive world that has already fundamentally changed how we work and live. The outbreak of the global COVID-19 pandemic in 2020 resulted in immeasurable suffering worldwide, but the crisis also accelerated many technological developments and altered the way we think about, and experience, technology and work. Problem-solving requires new and rapidly changing skills to manage the data tsunami. Whether at the rock face or on the processing plant, the fundamentals have not changed, although how we interact with minerals and their properties has changed dramatically. Sustainable processing and design are non-negotiable if we genuinely want to achieve the aim of the cradle-to-cradle principle. As we venture forth, what can scientists, engineers, technologists, and mathematicians learn from history? History is data presented in a context; sometimes, the context is also important. We exist in an age of data, with most of the world’s data created in only the past two years. History can enhance our understanding of the present and enhance our future outcomes. Lessons from history can help provide insights into making ethical and sustainable choices related to technology or engineering in the mining and metallurgical industry. Shifting the perspective of mining and metallurgy professionals from a narrow focus on complex technical solutions towards a broader context for problem-solving and designs that includes the entire ecosystem is crucial. In other words, using or reflecting on historical process development is, at its core, systems thinking.

Sep 1, 2021

By R. T. Jones

"SynopsisScientific progress relies on the publication of ideas and experimental results that can be replicated, tested, and improved over time. The first printed book on metallurgy to have been published in Europe is considered to be De la Pirotechnia, written in Italian by Vannoccio Biringuccio, and published in Venice in 1540. Together with De Re Metallica, written by Georgius Agricola and published in Latin in 1556, this can be considered to mark the start of scientific and technical literature in this field. Scientific publishing of journal papers has been in existence for 350 years, since the world's oldest and longest-running scientific journal, the Philosophical Transactions of the Royal Society, was first published in London in 1665.The nature of scientific societies has changed significantly since the early days when regular meetings were held to discuss science and conduct experiments, and the reading of scientific papers took place, and publication of papers was undertaken to record the proceedings of meetings, often including rather robust debate. In today’s world, there is a plethora of publications, and it is close to impossible for anyone to keep up with the vast flow of information. International conferences with hundreds of presentations have taken the place of the local meetings that used to discuss a single paper or experiment. In this frenetic environment, it is essential that researchers are able to trust the material they read.The system of peer review is used to maintain standards and to improve the quality of papers. This vital system is, however, significantly flawed. There is little incentive for reviewers to invest sufficient time in picking up all errors in publications, and any ineptitude on their part is usually protected by anonymity. It has reached the point where some reviewers have mistakenly permitted the publication of hoax papers deliberately presented with a complicated scientific facade. In light of such astounding inadequacies, perhaps a more open review process would be an improvement. Electronic publishing allows errata to be linked to the original papers.There is an increasing trend towards open access for papers in scientific journals and conference proceedings, which helps to reach as wide an audience as possible. This also supports the statement in the Universal Declaration of Human Rights, which says ‘everyone has the right freely to … share in scientific advancement and its benefits’."

Jan 1, 2015

By Dr. Calvin J. Konya, Anthony Konya

Beginning on the Niagara Power Project, presplitting became a widely used blasting technique to obtain smooth walls in mining and construction projects reducing scaling, creating more stable pits, allowing the application of slope steepening to reduce waste removal and increase mining depths, and increasing the safety of mine and construction workers. This technique has been minimally studied in comparison to production blasting and currently two separate theories are present on the mechanics behind the presplit. The first is that shockwave collisions between boreholes cause a tension zone to develop causing the split formation. The second is that gas pressures build in the boreholes causing hoop stresses between holes leading to a presplit formation. Practical blasting methods in presplitting such as propellant presplitting and precision presplitting would not be applicable based on the shockwave theory yet are widely used and documented in the industry. Along with this, modern research using a borehole simulation device and advanced pressure gauges have allowed the authors to obtain true borehole pressures in decoupled blastholes. This paper will present this research which correlates the borehole pressure to variables such as the Young's Modulus and Tensile Strength of various rock types giving blast designers the ability to design a presplit to function in many rock conditions, including weak rocks such as siltstones and mudstones.

By Anthony Konya, Calvin J. Konya

This paper will present this research which correlates the borehole pressure to variables such as the Young's Modulus and Tensile Strength of various rock types giving blast designers the ability to design a presplit to function in many rock conditions, including weak rocks such as siltstones and mudstones.

Feb 1, 2020

By William Gleason

During the past five years, mining operations have had access to press technology for piping and joint fittings that can save owners a significant amount of time when installing or replacing pipes by eliminating the need for welding or threading. Viega, with North American headquarters in Wichita, KA, entered the mining sector in 2009, adding to its already expanding industrial sector. Since then, the company?s global engineering department has paid considerable attention to its industrial division, bringing its expertise in plumbing solutions for residential and commercial buildings to the mining and mineral extraction industry. ?We have a lot of applications in the mining industry.?We have a lot of applications in the mining industry throughout the United States, Canada and Mexico and continue to expand in the mining industry,? Tom Shields, Viega?s director for industrial accounts explained. ?Since we made the decision to increase our presence in the industrial markets, we have been aggressive and more than 240 applications have been approved by our engineering department in Germany.? Getting approval from Viega?s engineering department is no small feat. During a tour of the manufacturing facilities in Ennest and Großheringen, Germany, Mining Engineering, as well as a select few other publications and clients, were shown Viega?s manufacturing process. At the Ennest facility, hundreds of millions of fittings are produced, and each one is inspected mechanically and with a laser at the end of the production line. With four production facilities in Germany and one in the United States, Viega is able to ship to anywhere in the world. The company distributes everything from fittings to stainless steel pipe.

By W. Curlook, V. G. Papangelakis, M. Baghalha

A pressure acid leaching process has been developed for the extraction of metal values, nickel, copper, cobalt and zinc, from base metal smelter slags. The basic concept contemplates cooling the smelter slags through solidification sufficiently slowly to induce a good measure of crystallization; and subsequently, after fine grinding, to pressure leach such slags at around 250°C while applying oxygen overpressure, utilizing smelter byproduct sulphuric acid. High levels of extraction of the slags' metal values are thereby achieved. It has been shown that if the same slags are quenched thereby producing an amorphous structure, the resulting metal extractions are very low. The process is applicable to smelting furnace throwaway/discard/dump slags, as well as to in-process converter slags. By extracting the bulk of the residual base metal values in the throwaway/discard/dump slags, the resulting leached residues are rendered virtually benign vis-à-vis the external environment.

Jan 1, 2004

By Tassos Grammatikopoulos, Mike Johnson, Niels Verbaan

Seabed polymetallic nodules, which contain significant quantities of metals key to electrification such as nickel (Ni), cobalt (Co), copper (Cu) and manganese (Mn) can be processed using several different metallurgical processing options, including direct smelting and subsequent hydrometallurgical refining of the copper/nickel matte; ammoniacal leaching (gas reduction or Cuprion); and acid leaching (often reductive). Many of these approaches suffer from reduced cobalt extraction, difficult physical performance, or overall circuit complexity in general, leading to increased risk to the overall project. SGS has considered the pressure acid leaching of nodules for further investigation, as publicly shared data on this processing route stem from the 1970s and 1980s, and are not always easily accessible. This article details the series of tests conducted and provides updated results obtained — high Ni/Co/Cu recovery with limited manganese/iron (Mn/Fe) — as well as comments on the potential treatment options on the product solution and residue.

Sep 1, 2025

By Tassos Grammatikopoulos, Mike Johnson, Niels Verbaan

Seabed polymetallic nodules, which contain significant quantities of metals key to electrification (nickel, cobalt, copper, and manganese) can be processed using several different metallurgical processing options, including direct smelting and subsequent hydrometallurgical refining of the copper/nickel matte, ammoniacal leaching (gas reduction or Cuprion), and acid leaching (often reductive). Many of these approaches suffer from reduced cobalt extraction, difficult physical performance, or overall circuit complexity in general, leading to increased risk to the overall project. SGS has considered pressure acid leaching of nodules for further investigation, as publicly shared data on this processing route stems from the 1970s and 1980s and is not always easily accessible. This paper will detail the series of tests conducted and provide updated results obtained (high Ni/Co/Cu recovery with limited Mn/Fe), as well as comment on the potential treatment options on the product solution and residue.

Feb 1, 2025

By R Williams, P Godwin

In a time of changing rainfall patterns and in the light of recent tailings dam failures, there is closer environmental scrutiny for proposed tailings dam construction or expansion. Therefore the elimination of the traditional tailings dam could provide both environmental and cost benefits to an operation. One method to dewater tails is using pressure filtration to achieve lower moistures than what is currently available using other dewatering technologies. Further benefits include a higher rate of filtrate recovery, reuse of waste material and the potential for dry stacking of the filtered tailings cake, thereby minimising both risk and cost. This paper chronicles the replacement of two existing belt filter presses with a single McLanahan recessed plate filter press to dewater a tailings stream at a Bacchus Marsh site. It covers the slurry testing, equipment selection, installation, commissioning and operation of the filter press to achieve the following objectives:• removing the current tailings dam and slimes cells from the existing process to minimise failure risk and reduce the cost of a dam upgrade, as well as operational and maintenance costs• free up the surface area which was previously occupied by tailings dams and slimes cells• recover additional water to be returned to the process• reduce flocculent usage• reduce truck movements and handling.The project’s owner also expects to reduce carbon emissions by over 3000 t over the lifetime of operation as well as substantially reducing operating expenditure. By recognising the carbon reduction benefits, the project owner was able to successfully achieve partial funding through the Voluntary Waste Industry Protocol.An unanticipated, but as yet unquantifiable, bonus for the project was to seek an offtake agreement for the tailings thereby allowing the tailings to be considered a valuable source of beneficiated clay suitable for the construction industry.CITATION:Godwin, P and Williams, R, 2017. Pressure filtered tailings – environmental and cost benefits, in Proceedings MetPlant 2017, pp 324–334 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By Bradford C. Wesstrom

The extraction of metals from Copper Refinery Slimes may involve many different processes. This paper describes the use of pressure leaching for decopperizing of copper refinery slimes at the El Paso Refinery. Process equipment will be described, along with the process chemistry, unit operations and unit processes associated with the decopperizing process. Copper contained in the raw slimes ranges from 15-35%. After autoclaving less than 1 % copper remains.

Jan 1, 2000

The primary (sulphide) resources at Aphrodite are refractory in nature, requiring an oxidation process stage to be introduced to facilitate extraction of the gold. The company is investigating the use of pressure oxidation (POX) as the oxidation method for processing of high grade gold bearing concentrate it plans to produce at Aphrodite. POX has been used extensively around the world for the past 30 years and continues to be the favoured option for a number of refractory gold plants currently in the design and construction stages. Initial pressure oxidisation testing investigated the effect of temperature, pressure and grind size on a bulk flotation concentrate prepared from Alpha lode material. The concentrate averaged 47.3 g/t gold and was prepared from a composite of core samples averaging 1.49 g/t gold. Sub-samples of the concentrate were subjected to POX for 1 hour resulting in rapid oxidation during this very short period. Testing undertaken showed that there was a significant increase in sulphide oxidisation at higher temperature (220°C) and pressure (2,500 k/Pa) for the two grind sizes (75 and 20 microns) evaluated. The proposed flowsheet, OPEX and CAPEX are critical aspects for project development.

Jan 1, 2014

By Walter S. Weeks

CONFUSION appears to exist in the discussions of fan testing because engineers do not agree on what energy should be credited to the fan in certain cases, and because certain terms that are used in the discussions seem to have double meanings. The purpose of this paper, therefore, is to discuss the useful energy that should be credited to the fan and the methods of determining this energy, and to suggest changes in nomenclature for the sake of clearness. The instruments commonly used in the measurement of fan pressures are the manometer, the static tube, and the impact tube. The static tube is a tube with small pinholes in it. When connected to one leg of the manometer and placed in the air current with the holes facing at right angles to the direction of the current, this tube causes the manometer to register the static pressure, unaffected by the impact of the air. The impact tube is a tube with an opening that faces the air current. When connected to one leg of the manometer, this tube causes the manometer to register a pressure which is the static pressure modified by the impact of the flowing' air on the end of the tube. If the static tube is connected to one leg of the manometer and the impact tube to the other leg, and both instruments are inserted close together in the air current, the static pressure is eliminated and the manometer registers the impact pressure. The efficiency of a fan is the percentage of the expended power utilized in useful work. The items to be included as useful work are a matter of convention, and as the conventions are not universal I feel that the matter is open to discussion.

Jan 1, 1929

By Dale C. Matthews

Pressure oxidation of refractory gold ores is becoming more popular in what has become an environmentally sensitive society. This article discusses some specific process problems and solutions involved with starting up and operating an autoclave circuit. The Getchell gold deposit is located about 72 km (45 miles) northeast of Winnemucca, NV. The deposit was discovered in 1934 and first production came about in 1938. The oxide portion of the ore body was mined and milled from about 1936 through 1950. Refractory arsenic-bearing sulfide ores had long been known to exist in the Getchell deposit. These ores had been mined concurrently with the oxides since 1938.

Jan 1, 1991

Conventional wisdom in the mineral processing industry leads one to believe that pressure oxidation of refractory carbonaceous (preg-robbing) ores is not a practical approach to process development. Initial acid pressure oxidation testing on carbonaceous sulfide ores at the Twin Creeks Mine supported this conventional wisdom. After testing other refractory process options, including air and oxygen enriched roasting, Santa Fe Pacific Gold decided to take a second look at pressure oxidation, using conditions outside the normal range of conventional practice. A combination of very fine grinding and high operating temperature and pressure resulted in significant increases in gold extraction. This paper details the effect of operating parameters developed for Twin Creeks on gold recovery, sulfur oxidation, carbon oxidation/passivation and preg-robb through the laboratory and pilot plant investigations.

Jan 1, 1995

By AUDLEY H. STOW

I. INTRODUCTION. THE general drift of the discussion as to the relative merits of pressure- and exhaust-fans has resulted, if we may judge from the prevailing practice, largely in favor of the latter. The subject has been hitherto treated, however, with special reference to highly gaseous mines, the effect of the form of ventilation upon dust-explosions having been too little considered. Even in mines containing practically no gas, dust-explosions may occur; and if, as I believe, pressure-fans are to be preferred for their effect upon dust, it may be worth while to reopen the debate, and to challenge the advisability of exhaust-ventilation under certain conditions. There are several forms of colliery-ventilation, which may be described as follows: Plain or simple pressure-ventilation, in which the fan acts as a pressure-fan, and the movement of coal is unobstructed at the surface by doors or equivalent devices in drifts or shafts, the traveling and haulage thus being in the return-current. Plain exhaust-ventilation, in which the fan acts as an exhaust-fan, the movement of coal being likewise unobstructed at the surface, and the traveling and haulage being in the intake. Obstructed pressure-ventilation, in which the movement of coal is obstructed at the surface, in order that the traveling and haulage may be in the intake. Obstructed exhaust-ventilation, in which the movement of coal is obstructed at the surface, in order that the traveling and haulage may be in the return. The apparent advantages in running a fan "pressure" during working-hours, and " exhaust" between shifts, seem to justify the recognition of this combination as a standard form of ven-

Feb 1, 1909

By Takashi Miyamoto, Hideo Nakae, Hideki Yamaura, Takeshi Yanagihara

"For the production of partially composed metal matrix composites, namely discontinuous MMCs, using a casting· process, the interpenetrated phase composites with SiC particles were fabricated by pressureless iDfiltration using molten Al-Si alloys. This process is based on a wetting phenomenon, therefore, we discussed the technique based on the reactive wetting. The SiC particles coated by diluted water glass were sintered in a mullite Tammann tube and simultaneously infiltrated with molten Al-Si alloys in air at 1173~1573K. As for the improvement of the wettability between the SiC and the liquid aluminum alloy, Fe3O 4 powder was mixed with the water glass due to the thermit reaction between Fe3O4 and molten aluminum alloy. In some experiments, pure aluminum powder was placed on the sintered SiC to increase the interfacial area and the chemical reaction between the sintered Sic. and the melt. By combining these conditions, we succeeded in the complete infiltration without pressure at 1173K.IntroductionAs is well known, the mechanical properties of metal matrix composites (abbreviated MMCs) are superior than that of ordinary metals. However, their use has not been widely accepted because the production cost is very high due to their poor machinability. Therefore, the production of partially composed, namely discontinuous MMCs, by as the Lanxide process [l,2] has been investigated for many years. The Lanxide process, it takes a long time, sometimes up to 10h, in a nitrogen atmosphere for the infiltration. Therefore, the cost will be higher for common use. On the other hand, a high 'pressure process has been adopted for the production of discontinuous MMCs by the Toyota Motor Corp.[3]."

Jan 1, 2000

By J. E. Hawley, R. C. Hart

"The Preston East Dome gold mine is in the southeastern part of Porcupine district, Ontario, 5 miles southeast of Timmins, and immediately south of the property of Dome Mines, Limited.The claims now owned by this Company were originally staked in 1909. After the property had remained dormant for many years, the present Company was organized in 1936 to resume development operations. Two shafts had been sunk: at the time of the early work on the claims, but lateral work from these failed to reach the ore deposits. A successful diamond drilling campaign undertaken under the direction of D. G. H. Wright, however, was followed by the sinking of a five-compartment shaft arid the erection of a mill. From the start of operations to the end of 1944, 1,292,000 tons of ore averaging $11.60 in gold a ton have been mined.An outstanding feature in this mine is the occurrence of the major gold deposits in quartz porphyry intrusives, though minor deposits are also found in the adjacent Keewatin volcanics. Most of the ore occurs in fractures, but the filling was accompanied by varying degrees of replacement of schistose wall-rocks. The ore deposits may be classified as:"

Jan 1, 1954

By C. L. Emery, A. V. Corlett

"The stress equilibrium is disturbed in a body of rock by a mine opening and is restored by a redistribution of the stresses around the opening. The pattern of the redistribution of unilateral stress around an opening has been established by mathematical analysis and photoelastic measurements. The pattern for multilateral stress is found by superimposition of unilateral fields. The mathematical analysts do not use the elastic moduli as parameters and they are not significant in photoelastic work. The medium is isotropic. The concept of unilateral stress from vertical loading and the classical pattern of its stress distribution around openings does not explain commonly observed failures around the perimeters of mine openings. They show evidence of compression where tension is postulated.When it is recognized that few minerals and perhaps no rocks are Hooke Solids, most rocks must be St. Venant Solids. The components have varying degrees of elasticity and viscosity. The assembly will be-have elastically to rupture under shock loading, but when loaded short of rupture will adjust viscously to equilibrium. Similarly, the highly elastic components may initiate rupture before equilibrium can be established when stress is instantaneously relieved. Polycrystalline adjustments may produce permanent deformation. The mechanics of consolidation, especially in sedimentary deposits, ac-quire a stress component normal to the direction of compaction which can exceed that of the loading. It is one source of prestress. There are others. The principles of prestress design are based on the normal beam reactions, modified by a built-in compression in the lower chord. When the beam is loaded to design limits, the lower chord retains some compression and the whole beam depth is effective in compression. Some of the . common evidences of failure in compression over a mine opening can be duplicated in a prestressed experimental model.When the triaxial stress pattern is recognized and suitable measuring techniques are devised, mine design can be done on a rational basis."

Jan 1, 1959

By W. Burr Bennett

The prestressed concrete industry in particular, and the precast concrete industry to some extent, are rank newcomers to the concrete construction field compared to the cement, ready-mixed or concrete masonry industries. This young industry reflects its youth and vigor in its enthusiasm, optimism and the belief that it can reach any goal it chooses to set -- and it is setting its sights high. The prestressed and precast concrete industry fully expects to become the major structural and architectural material by the 1980's. Before exploring how the industry expects to reach this goal, a brief look at the origins and the growth of the industry may be useful in an evaluation of the feasibility of this goal. It was always recognized that concrete, strong and efficient for supporting loads which cause compression, was weak and inefficient when used to carry loads which induce tension. Thus the reason for reinforced concrete in which the concrete efficiently carries the compression in a flexural member while low grade steel bars reinforce the concrete in the areas 'of tensile stress. (Fig. 1). The steel being relatively inexpensive, can passively, but quite effectively carry tensile force while the concrete carries compression. The concrete in contact with the reinforcing also protects the steel from corrosion and acts as insulation to provide a superior "built-in" fire resistance. The major disadvantage of reinforced concrete relative to its main competitor, steel, is its weight in relation to its load-carrying capacity. Reinforced concrete systems, such as waffle slabs, I-beams, thin shells, etc. ,

Jan 1, 1971