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By Paul Sainato

Recruiting and retaining students in the explosives industry is becoming increasingly important each year. With no undergraduate degree in explosives engineering currently available in the United States, it is from other industries and degree disciplines we must recruit. The 2014 annual ISEE conference saw the first anonymous online survey distributed to members of SEE student chapters of the International Society of Explosives Engineers. The survey contained questions about future job and career plans, ideal job placement, expectations of salary and current academic degrees. The purpose of the survey was to determine what these students expect or require from a career in the explosives industry, and their current path to pursue this. This information can help steer recruitment activities and job offers for graduating students. The success for both student response rates and interest from the industry has allowed space for a yearly update of this survey. A second survey was distributed in 2015 and included international students. This paper provides the data from a third online survey distributed to all student members of the International Society of Explosives Engineers, globally. Understanding the main incentives for a student to accept a graduate position as an explosives engineer can help us, as an industry; position ourselves to remain competitive in recruiting against other major degree disciplines.

Jan 1, 2016

By Delahant A. B, Dworski M

From the Saranac Laboratory for the Study of Tuberculosis of the Edward L., Trudeau Foundation, Saranac Lake, New York:We are assembled to honor the memory of our friend and colleague, Donald Cummings, one of the founders and a past president of the American Industrial Hygiene Association. I deem it an Unusual privilege to have been asked to give this first memorial lecture and hope that what shall have to say may be worthy of the occasion. It is fitting that we should discuss here the subject of Silicosis to which he devoted such a large part of his life and it is doubly fitting, I think, that I should report to you an extended series of investigations carried on by his associates at the Saranac Laboratory.The subject of silicosis may seem hackneyed to this audience which is so familiar with the tried and accepted methods of prevention and control.But in spite of our efforts, the condition is still with us and unfortunately is still being produced in many places. In industries that now maintain good control of dust, fresh cases are appearing on annual re-examination, whose major exposure date back to the days before the hazard was recognized.A few new employees, with apparently ineffective upper respiratory protection against inhaled dust, develop silicosis precociously in environments that are comparatively harmless to their fellows. In plants that have relaxed their vigilance under the urgency of war production schedules, conditions again prevail that will produce, disease in the future.Silicosis acquired new interest with the announcement by Denny, Robson and Irwin(1) in 1937 that it could be prevented by the inhalation of powdered metallic aluminium. It so happened that without knowledge of their work, we at the Saranac Laboratory had for some months been conducting similar experiments with one of the hydroxides of aluminium.Quite independently we discovered that hydrated alumina would also protect animals against quartz. Our approach to the problem had been empirical; we were trying to neutralize quartz particles by coating their surfaces with an insoluble material following the lead of Kettle who in 1932 had shown that this could be accomplished with iron. He neglected to describe his method and the chemist who prepared his coated...

Jan 1, 1945

By S. Prasad

The effectiveness of ultrasonic velocity measurements and attenuation of the propagating pulse was evaluated as a means of Non-Destructive characterization of cold worked and annealed copper. Commercial copper is subjected to mechanical working such as forging, rolling and thermal treatment to induce re-crystallization. The microstructural changes that occur in copper and a variation in its mechanical properties are subjected to analysis using the ultrasonic technique. The signal processing is carried out using the wavelet analysis technique. The features of wavelet analysis namely, localization in space and the presence of an infinite set of basis functions allows removing noise from the time series and components of a non-stationary signal to be analyzed. This is seen to improve the accuracy of the results obtained from the ultrasonic technique in the case of copper, which has distinct coarse grains that are difficult to inspect due to backscattering from the grain boundaries.

Jan 1, 2010

By E. P. Klier, S. M. Grymko

The transformations in eutectoidal systems have been extensively studied as they occur in steels.&apos; As a consequence of these studies the martensite, bainite and pearlite reactions found for most steels are widely recognized. Further, because of the work of Smith and Lindlief2 and of Greninger and Troiano3 these reactions, except for the bainite reaction, are considered as typical for all eutectoidal systems. The primary alloy studied by Smith and Lindlief2 was a CuAl alloy of near eutectoid composition as was the alloy more recently studied by Mack.4 The transformations in these alloys were, for the most part, studied metallo-graphically, while an X ray analysis of structures was essentially wanting. It has appeared desirable, therefore, to investigate selected CuAl alloys at and slightly away from eutectoid composition. For this purpose three alloys were prepared containing 10.5,11.9 and 13.5 pct A1 respectively. The results of a metallographic and X ray analysis of structures obtained for isothermal transformation of the ß-phase are reported here for the 11.9 and 13.5 pct A1 alloys. Introduction The phase equilibria in the CuAl alloys of immediate concern are indicated in the equilibrium diagram section presented in Fig 1.5 The equilibrium and transition structures which have been reported in this system are as follows: a = copper rich terminal phase (f.c.c.) ß = high temperature eutectoidal phase (b.c.c.) r2 = aluminum-rich intermediate phase (r-brass structure) a&apos; = modified a-phase postulated by Bollenrath and Bungnrdt.26 ß1 = ordered ß (b.c.c.) ß&apos; = martensite structure: A1 < 13 pct (near h.c.p.) ß" = ß&apos; of Smith and Lindlief2 7&apos; = martensite structure: A1 > 13.5 pct (h.c.p.); ß2 of Bollenrath and Bungardt.26 The eutectoid transformation can be suppressed at sufficiently high cooling velocities. The ß-phase is then retained to about 500°C where ordering sets in. The ordering interval is not satisfactorily known but indirectly appears to be non-suppressible. Subsequent to the ordering reaction and consequently at lower temperatures, the ordered ß1 decomposes to a marten-sitic structure. The kinetics of these reactions and in particular those of the martensite reaction have an important bearing on the results obtained in this investigation. Since some confusion exists concerning certain reported aspects of these reactions, they will be considered in some detail. THE MARTENSITE REACTION The martensitic structure is formed on cooling through a critical range6

Jan 1, 1950

Human-caused global warming has become the environmental cause celebre of the early 21st century. The strong warming alarmist camp currently includes the United Nations, most Western governments, most of the free press, many large corporations (including Enron, before it failed), the major churches, most scientific organisations and a large portion of general public opinion. This phalanx of support notwithstanding there is no scientific consensus as to the danger of human-induced climate change. There is, therefore, a strong conflict between the level of public alarm and its scientific justification. How can this be? In a democracy, the media serve to convey to the public the facts and hypotheses of climate change as provided by individual scientists, governmental and international research agencies, and NGO and other lobby groups. In general, the media have promulgated an alarmist cause for climate change; they have certainly failed to convey the degree of uncertainty that is characteristic of climate science, or a balanced summary of the many essential facts that are relevant to human causation. Climate change is as much a geological as it is a meteorological issue. Natural climate changes, both warmings and coolings, are indeed a societal hazard. We usually deal with geological hazards by providing civil defence authorities and the public with accurate, evidence-based, general information about events like earthquakes, volcanic eruptions, tsunamis and floods, and then by adapting to the effects when a damaging event occurs. As for other major natural disasters, the appropriate preparation for extreme climate events is to mitigate and manage the negative effects when they occur, and especially so for dangerous coolings. Attempting instead to æstop climate changeÆ by reducing human carbon dioxide emissions is a costly exercise of utter futility. Rational climate policies must be based on adaptation to dangerous change as and when it occurs, and irrespective of its sign or causation. The issue now is no longer climate change as such, the reality of which will always be with us. Rather, the issues are, first, the failure of the free press to inform the public about the true facts of human-caused climate change and of the dangers posed by natural climate change. And, second, the vested interests held by many of the groups of warming alarmists. These interests include not only the obvious commercial ones, but also the many scientists and science managers who have discounted or remained silent about the huge uncertainties of the human-caused global warming hypothesis because it suited them to do so. Public opinion will soon demand an explanation as to why experienced editors and hardened investigative journalists, worldwide, have melted before the blowtorch of self-induced guilt, political correctness and special interest expediency that marks the sophisms of global warming alarmists.

Jan 1, 2007

By Alfred Weiss

These volumes report on the study initiated by the U. S. Bureau of Mines to develop and apply a methodology to quantitatively assess the probability and potential benefits of technological innovation over the next twenty-five years. The potential was recognized for new technology to solve copper industry problems in the United States. Objectives of the study were to: (1) Develop a methodology to obtain the opinions of mineral experts about future events -their likelihood of occurrence, and, conditional on occurrence, when and to what extent they are likely to occur; (2) Identify, select, and describe potential technological innovations which would have significant impact on copper production; (3) Implement the methodology and obtain the opinions of the mineral experts regarding selected copper technologies; and (4) Analyze the expected future benefits of successful technological innovations :n the copper industry. Although individual technologies are continuously examined throughout the copper &apos;community&apos;, this study is the first known comprehensive forecast of future copper technology. This study is also believed to be unique 1n that it represents the consensus opinion of over sixty expert copper technologists on the expected use of innovative technology in the industry over the next 25 years. The report is contained in three volumes.

Jan 1, 1983

By J. F. T. Agapito, R. R. Goodrich

Yield pillars have been used for many years to help reduce stresses near mine openings and improve roof and floor stability. A yield pillar is often defined as a pillar that fails but retains residual strength. Stress transfer occurs through the roof and floor after the peak strength of the pillar is reached. High stresses are transferred from around the openings onto abutments that can be barrier pillars or unmined ground. This mechanism, often referred to as pressure arching, is possible as long as the width of yield pillars is less than the critical width above which stresses cannot be carried by the overburden. Significant stress transfer also can occur due to small amounts of pillar and/or floor yielding before the peak strength is reached. This is accomplished in a quasi-elastic manner with little or no visible roof and pillar fracturing or floor heave. Long-term stability may be achieved when stresses and mechanical properties are favorable to pre-failure yielding. This paper gives practical examples where improvements in stability and resource recovery were achieved with this mechanism. Yielding was assessed by comparing measured and calculated vertical pillar stresses. Results indicated that calculated stresses in the pillars were 25 to 40 percent higher than the measured stresses, demonstrating significant arching load transfer to the abutments. Pre-failure yielding is probably often present but unintentional in both development and production areas. Better recognition and use of this mechanism should lead to improved designs as mines become deeper.

Jan 1, 2001

By Dennis R. Dolinar, John L. Ellenberger, Gabriel S. Esterhuizen, Anthony T. Iannacchione

A survey of pillar conditions was carried out at 21 operating limestone mines that use the room-and-pillar method. The surveyed pillars were all located in rock that was classified as “Good” to “Very Good” using the RMR rock mass classification system. The average pillar width was 14.5m and the width to height ratio varied between 0.53 and 3.52. Pillar conditions were rated using a visual rating system that accounts for the effect of geological structures as well as stress related fracturing. Nine cases of pillar instability were recorded. Pillar instabilities were typically limited to individual pillars or small groups of pillars within an otherwise stable layout. Local geological structures such as inclined discontinuities or weak bedding planes contributed to instability in seven of nine cases that were observed. Elevated pillar stresses contributed to instability in the two remaining cases. All the unstable pillars observed had width-to-height ratios of less than 1.5. It is concluded that pillar instability is most likely to be caused by unfavorable geological structures in pillars with width to height ratios of less than 1.5. Stress related instability such as rib spalling becomes more prevalent when the average pillar stress approaches approximately 20 MPa.

By L. B. Pankratz

Thermodynamic data on the elements and oxides were reviewed, evaluated, and compiled at the Bureau of Mines Albany Research Center. Values for Cp°, S°, H° - H°298, - (G° - H°298)/T, ?HP, ?Gf°, and log K are given in tabular form. Cp°, H° - H°298, ?Hf°, and ?Gf° are also expressed algebraically. Examples of calculations using these data are given.

Jan 1, 1982

By G. Thom, A. Kay, J. B. Hyde

"This paper will initially outline the specific types of copper castings used in blast furnace iron production. Tuyeres, tuyere coolers and stack cooling plates will be discussed in some depth, with particular reference to their dimensional configuration and purpose.Following this, the failure of such cooling members will be discussed, with special focus on tuyeres. Tuyeres are the most common casting which often requires replacement. Reasons for failure and its effect on operations will also be included.The latter sections of the paper will deal with the strict specifications demanded by ironmakers regarding copper castings. The justification for such rigid demands will be explained through the material presented earlier in the paper.IntroductionThe modern 5000-tpd blast furnace, worth millions, is a large capital investment to be sitting idle. Consequently, ironmakers strive to minimize the loss in iron production and revenue from furnace downtime. Two major causes of downtime are furnace relines and shutdowns to replace damaged tuyeresor tuyere coolers. Copper ancillaries are important items in the production of iron. They are consumable items, therefore they contribute to the campaign life or to the downtime in blast furnace production.Several combinations of lining and cooling systems have been used with varying degrees of success. Blast furnace refractories have evolved from ceramic to carbonaceous linings. The Russians and Japanese have successfully introduced stave-cooled furnaces that may have several forms, such as evaporative cooling. Stelco has two furnaces which use the Russian-designed cast iron system. However, this paper will be confined to the use of copper cast cooling members in a conventional internally cooled furnace.Figure 1 is a schematic cross section of the E blast furnace. The three major sections of a blast furnace-the stack, bosh and hearth-are identified. Further, the locations of the various copper members are indicated. This furnace produces an average of 5300 tons of hot metal per day."

Jan 1, 1982

The ultraviolet spectrum of isopropyl ethylthionocarbamate (the principal constituent of Dow flotation collector Z-200) in water and of Z-200 itself in water was found to have an absorption peak at 242 nanometers(nm). The height of this peak was found to be directly proportional to isopropyl ethylthionocarbamate concentrations up to 15 p.p.m. Z-200 contains about 90 per cent isopropyl ethylthionocarbamate and the heightof the peak was proportionately lower, but obeyed the straight line relationship up to 15 p.p.m. This showed the potential value of spectrophotometric measurements for the determination of Z-200 residuals in flotation liquors.Methyl ethyldithiocarbamate (an impurity in Z-200) increased the peak height slightly, but other impurities in Z-200, xanthates, and most inorganic salts present in flotation liquors do not interfere. However nitrate ion and thiosulphate ion have absorption peaks which overlap the isopropyl ethylthionocarbamate peak.The simplest general method to overcome this effect is to extract the isopropyl ethylthionocarbamate into cyclohexane and to measure the absorbance of the extract.The maximum absorbance of the cydohexane extract was at 247 nm and the peak height at this wavelength was found to be directly proportional to the isopropyl ethylthionocarbamate or Z-200 concentration in the original aqueous solution. An alternative method is to measure the spectrum of the original aqueous solution using the aqueous raffinate from extraction as a reference solution. This gives the spectrum due to isopropyl ethylthionocarbamate alone and measurement of the absorbance at 242 nm gives the concentration in the original aqueous solution. Both methods give the same value for the concentration of isopropyl ethylthionocarbamate in the original solution.

Jan 1, 1969

By Jean Rosaire

?GWIOP Location ?Climate and Physiography ?History ?Geology ?Deposit Types ?Mineralization ?Historical Mineral Resources ?Conclusions and Work Program

May 1, 2007

For small particles of niekel flotation eoncentrate (av. size 50 pm) the predominant heat transfer mechanism under suspension smelting conditions, prior to ignition, is conduction from the gas and not radiation from nearby hot bodies. Results of laboratory tests using gas temperatures 380-700&#176;C and furnace wall temperatures 380-1100&#176;C were in accord with heat transfer theory. In practieal flash smelters earlier ignition, and hence better utilization of the space in the shaft, would result from introduetion at the top of the shaft of gases hotter than the ignition temperature of 500-600&#176;C.

Jan 1, 1979

By Hernán Parra

El presente trabajo señala la fase de tratamiento metalúrgico de pirrotitas que contienen oro, donde en la concentración por flotación se encontró un esquema adecuado para tratar pirrotitas auríferas considerando las restricciones ambientales que no permitieron incorporar técnicas de cianuración directa, que es como suelen tratarse es-tos minerales en el mundo. Asimismo, se propuso el uso de concentradores centrífugos para recuperar el oro libre fino en una primera etapa gravimé-trica, y concentradores de mesa Gemeni para obtener concentrados de alta cali-dad disponibles para fundición.

Sep 9, 2007

By H. Lyn Bourne

This is the fifth annual tabulation of mineral royalty information. This tabulation, like the previous editions, includes all of the earlier data. There are also 60 new entries. In addition to royalty information, some entries show the cost of purchased reserves. Two articles relative to the evaluation of minerals reserves appeared in December, 1986. R.H. Paschall (In the Aggregate, ME, p 1139) wrote a good article, although it lacked specific royalty data. However, this author takes exception to two ideas in Paschall&apos;s column. Paschall contends that the royalty rate does not affect the mineral appraisal. This present author could not disagree more. Paschall also claims the location of an industrial mineral deposit is the only serious or practical caveat in comparing royalties. Comments received here from readers helped make the list of caveats that are cited each year. The readers will decide which factors influence the mineral value for their commodities of interest. Paschall&apos;s point about the relationship of the parties who are negotiating a royalty agreement is important and very well taken. The other article, written by William Vernon (Pit and Quarry, December 1986), gives a step-by-step process on how to conduct a mineral appraisal. The article cites three reasons for an appraisal: transfer rights; collateral for a loan; and taxation. A fourth reason is to establish adequate compensation for reserves lost through condemnation. This author has appeared in several court cases where compensation for loss of mineral reserves through condemnation required a mineral appraisal. Royalty rate becomes an important factor in the appraisal process, although the Pit and Quarry article refers to that part of the valuation equation as "profitability." Both articles were well written and are recommended reading for those interested in mineral valuations. The same caveats that have appeared in previous columns relative to factors that influence the value of reserves are restated. The data in the table serve as a general reference and are not intended to present an absolute scale of reserves costs. Several factors influence the value of any mineral commodity. The factors include: • location/transportation - especially significant for most industrial minerals; • market conditions both for the commodity and the company acquiring the right to mine; • quality or grade of the deposit as it reflects the amount of processing/beneficiation necessary to produce the finished product; and • legislative restrictions and conditions for mining a given material at a given site. These and other factors will significantly influence the cost of reserves. The table shows the range of royalties and the variations in the basis of computing the fees. In a few instances, it gives the cost of acquired reserves based on purchase price and quantitative estimates of the material in place. The table lists the commodity in column 1, and the subsequent columns give: • the location by state, US geographic area, or Canadian province ; • the cost - R for royalty and P for purchased cost; • the year in which the lease or purchase agreement occurred; and • comments or footnotes for more information. The cost column requires more explanation. The units may refer to cubic yards (/cu yd), cubic feet (/cu ft), short tons (/T), or acres (/A). 1 cu yd = 0.76 M2 1cuft = 0.28m3 1 st = 0.9072 t 1 acre - 0.4047 ha or m2

Jan 7, 1987

By Stavros H. Constantopoulos

Mediterranean regions such as Greece, Turkey, Cyprus, Corsica and New Caledonia have experienced epidemics of malignant mesothelioma as a result of non-occupational, ??domestic?? exposure to tremolite asbestos and fibrous erionite. This exposure to tremolite asbestos and fibrous erionite is typified ??domestic?? due to its prevalence in regions with natural deposits of tremolite asbestos (or fibrous erionite) where the material from tremolite asbestos or fibrous erionite is used for domestic applications such as whitewashing. However, these exposures may be useful in examining the potential consequences of even small amounts of amphibole asbestos fibers in the ambient air. It can also elucidate the effects of fibers that behave like amphibole asbestos. However, this type of exposure is not useful for studying the potential effects of small amounts of asbestos in the ambient air of big cities due to the differing nature of the fiber types and modes of exposure between the regions. © 2008 Published by Elsevier Inc. Keywords: Tremolite asbestos; Erionite; Domestic; Environmental; Exposure

Jan 1, 2007

By R. C. Burtan

Long before recorded history, man began to dig into the earth&apos;s crust in a never ending search for useful materials. It is well known that more than half of the earth&apos;s crust is composed of silicon dioxide (SiO2), also known as silica. Silica and silica-containing material have a great many uses in modern society. This material, however, is potentially an extreme health hazard. Silicosis: Not a New Disease Centuries before the Christian Era, Hippocrates wrote of a lung disease common to those who mined in hard rock. He was obviously describing silicosis. It is also apparent from ancient writings that the Egyptians were aware of this malady. Dioscorides also wrote on this subject in the fifth century B.C. It is undoubtedly the oldest and best studied of the occupational lung diseases. Silicosis was certainly described by Agricola in his De Re Metallica published in 1556. Here he described lung disease among hard-rock miners. The original document was written in Latin and then translated in 1912 by Hoover and Hoover. One of these translators was Herbert L. Hoover, a former US president who once made his living as a mining engineer. More recently, there are numerous references in medical literature in the 19th and 20th centuries relating silica exposure to silicosis. There are specific references to mining in hard rock, as well as to sandblasting and a host of other industrial exposures. In 1919, Winslow described standards for measuring the efficiency of exhaust systems in polishing shops using sandblasting. These standards were equally applicable in the mining industry. As early as 1920, Winslow explored the efficiency of certain devices used to protect sand-blasters against the dust hazard. These devices were equally applicable in the hard-rock mining industry. The medical community recognized the silica health hazard in the early 1900s. Middleton described the illness in the British Medical Journal in 1929. He noted the danger to health at that time. D. Hunter mentions in his book, The Diseases of Occupations (1969), the monumental work of Merryweather in 1936, in which he surveyed the silicosis risk in Great Britain. He showed statistically that the average employment length of sandblasters who ultimately died of silicosis was 10.3 years, compared to 40.1 years for all fatal cases, irrespective of occupation. Sandblasting and hard-rock mining and drilling, obviously, are very hazardous occupations. Weil and Zisking of Tulane University wrote in 1975 that "it was known as early as 1935 that the course of silicosis is much more rapid in sandblasters than in miners or foundry workers. This can be explained by the fact that sandblasters are exposed to an almost pure siliceous dust containing high concentrations of respirable particles within the range of 1 to 3 micron size." Protecting the Worker The medical community recognized in the early 1900s the need for proper protective equipment for all of those who worked with siliceous materials. Middleton, writing in 1929, said: "The worker is then protected by a close fitting helmet with an air feed, much as in the case of an underwater diver. In spite of these precautions, cases of silicosis among sandblasters are being met with today. It is a matter for serious consideration whether a substitute, such as steel or iron grit, could not be used to replace the siliceous grit as the abrading material." C. E. A. Winslow, a professor of public health at Yale School of Medicine, and others wrote of the need to protect sandblasters by

Jan 7, 1984

During the drilling campaign conducted between October, 1942; and May, 1943, to prove the extent of the scheelite deposit worked by King Island Scheelite N.L. at Grassy, King Island, Tasmania, 35 holes were drilled and 606 samples recovered and assayed for their content. Of these, 238 came from outside the limits of the orebody and were for the most part barren, although a few contained some scheelite. The present statistical analysis is made only of the 368 samples taken from diamond-drill cores of the orebody itself.Drilling Pattern and Sampling MethodsFrom the purely statistical viewpoint, it is realised that methods employed in selecting sites for diamong.-drilling, and of collecting samples from drill cores, do not give a completely unbiassed set of data for analysis. Fig. 1 is a sketch plan showing the relativepositions of the drillholes, which were inclined at an angle of depression of 50 deg. The pattern does not conform to a properly randomized and&apos; regularly-spaced grid, the positions of the later holes being determined by the results obtained from previous holes.Statistically, the bias is, therefore, favourable. The unequal spacing of the drill holes and the lack of uniformity in direction of the lines along which the holes were drilled are unsatisfactory from the mathematical viewpoint; but it is realised that these irregularitiesare difficult to avoid in determining by the most economical methods the extent of such an orebody, and are dictated by geological rather than mathematical necessity.Sampling, also, is lacking in complete uniformity. Each sample is approximately 10ft. in length. However, owing to the fact that 100% recovery of core is rarely achieved, and actual lengths of samples taken are ,primarily governed by the length of the drill runs,and secondarily by lithological changes, there is a considerable amount of variation in the sample length.AssayingWith the exception of 28 samples from three drill holes all samples dealt with in this paper were assayed in the Melbourne University Ore-Dressing Laboratory of the Commonwealth Scientific and Industrial Research Organisation. These assays were given to the nearest 0.05% WOg as it was considered that more accurate determination was not possible. This fact has been taken into consideration in the frequency analysis below. The 28 assays determined by the Tasmanian Mines Department were given to the nearest 0.01%.

Jan 1, 1950

By G. Danha, D. Glasser, D. Hildebrandt, N. Hlabangana

"In this work, we apply a method known as the attainable region (AR) technique in order to optimize the milling and leaching process of a low grade gold ore. No work on the application of the AR optimization technique has been done yet on a joint milling and leaching process. The advantage of the AR approach lies in its ability to simplify the optimization problem, as searching over a defined set for the maximum of an objective function is a fairly standard procedure. The objective function we selected was that of optimizing a linear function of the value of the recovered material minus the cost of both milling and leaching. Using the three variables (milling time, leaching time and recovery), we constructed a 3D plot and used it to obtain all the possible recoveries from the different milling and leaching times. The optimum for our chosen objective was then found by overlaying a contour plot of the objective function on the 3D plot. Our results show that the optimum was obtained at 90 % recovery with a profit value of 600, milling time of 30 minutes and leaching time of 1750 minutes.INTRODUCTIONAfrican countries are facing a general increase in demand for electrical power. In South Africa, the demand is now surpassing the supply from ESKOM, the main electric power provider of the country. This has resulted in load shedding strategies being implemented in many local communities in an attempt by ESKOM to cope with the high demand. A potentially better approach is to propose use of energy efficient technologies in the country’s largest power consuming industry; the mineral processing sector.In mineral processing, milling is the highest consumer of energy. The objective of carrying out milling is not merely to reduce the particle size of the feed material, but also to liberate the constituent minerals that make up an ore. This is done so that valuable minerals can be separated from the gangue, in downstream processes, such as leaching. However, the milling process is generally performed relatively poorly, and at a considerable expense in terms of electrical power utilization. Tomanec and Milovanovic (1994) estimated that milling accounts for more than 50 % of the total power used in the concentration process, but this can rise to as high as 70 % for hard or finely dispersed and inter-grown ores. Apart from being relatively wasteful of energy, the milling process is also inefficient with regard to mineral liberation because of the indiscriminate nature of the grinding force."

Jan 1, 2016

By G. L. Smith

This paper consolidates the key elements of seven contributions, on strategic long-term planning, to two of the three international conferences on Strategic versus Tactical approaches in Mining held over the period 2005?2008. The holistic concept of strategic long-term planning as developed and implemented at Anglo Platinum is described. Consideration is given to the planning cycle, principles supporting the construction of the long-term plan, and aspects of unique best practice as developed in Anglo Platinum. Further description of Anglo Platinum?s approach to corporate governance, including the processes, methodology, systems, unique tools and techniques that are applied to value and select capital investment options is also given.

Jan 1, 2009