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By S. A. Abdel Sabour

Strategic decisions in the mining industry are made under multiple technical and market uncertainties. Therefore, to reach the best possible decision, based on information available, it is necessary to integrate uncertainty about the input variables and model financial risk of the project?s merit measures. However, this provides few useful insights to decision-makers unless accompanied by modelling management responses to uncertainty resolutions. It is widely acknowledged that conventional decision-support methods based on static, no-change, discounted cash flow (DCF) techniques such as net present value (NPV) and internal rate of return (IRR) tend to provide inaccurate value estimates. This could mislead the strategic decision-making process and result in significant value losses. This paper aims to model financial risk related to uncertainty about market variables such as metal prices and foreign exchange rates. Other sources of risk that are related, for example, to geology and production costs are not considered in this work. The article outlines a flexible financial model that integrates uncertainty about market variables and management flexibility to react to uncertainty resolutions into mine project valuation using a real-options valuation technique based on Monte Carlo simulation. Significance of information generated from this simulation-based flexible valuation model to the strategic decision-making process is tested using an illustrative case study of a Canadian mining project. The project is a typical multi-metal, open pit mine that produces copper and gold. In this case, there are three uncertain market variables, which are: copper and gold prices and US$/CAN$ exchange rate. Financial valuations are carried out using both the conventional static DCF method and a flexible real-options model. In the flexible model, management flexibility to decide whether to go ahead with the next expansion or terminate production operations is integrated. Results show how the flexible financial model can enhance the decision-making process.

Jan 1, 2009

By G. Laird, N. B. Gray, N. Lawson

"Photographic, video, laser, hot film and conductivity methods are used in the experimental study of gas-liquid flows. A discussion of their capabilities and limitations are given in this paper illustrating the wide range of phenomena that can be studied. Most of these methods are limited to physical models at room temperature with transparent fluids, although they can be extended for use with opaque and hot fluids. A number of these techniques have been used by the GKW CRC in studies on industrial plants and their usage is increasing although a number of technical difficulties still need to be overcome. An in-depth discussion of the laser doppler anemometry (LDA) and particle image velocimetry (PIV) methods is given with experimental results on the flow field of an air plume in water based on advanced development of the techniques and studies carried out at the GKW CRC. The LDA method provides high resolution data on the velocity profiles, while the PIV method provides an overall view of the complex flow structure occurring at the gas-liquid regions. These two methods complement each other in providing experimental data for validating numerical models and exploring the complexities of multi phase flows.IntroductionThe injection of gases into melts is an important operation in the metallurgical industry. It is used in converters, anode furnaces, blast furnaces, ladles, bath smelters, zinc fumers and many other smelting processes. In many of these processes, the gas is injected into a molten bath resulting in the formation of bubbles that promote reaction, mixing, alloying and heat transfer. The study of gas-liquid systems presents enormous challenges to the researcher due to the complexity of the mathematical and physical modelling which require innovative numerical and experimental skills."

Jan 1, 1996

By John T. Whetton

"FROM 1850 when the annual production was around 50 million tons, coal output in Great Britain expanded rapidly to 225 million tons in 1900 and 287 million tons in 1913. However, during the First World War, countries which had previously bought large quantities of coal from Britain sought other sources of sup-ply or developed their own coal re-sources. Thus from the record figure of 73 million tons exported in 1913, Britain's coal exports declined until in 1938 they stood at 39 mil-lion tons. An important reason for this was the development of oil engines for marine propulsion. Today, nearly all the navies and mercantile shipping in the world have turned to oil engines. Sometime in the future, however, it is reasonable to expect nuclear power to replace oil.During the Second World War, coal output in Great Britain and manpower at the mines were reduced considerably and in 1.945, 175 mil-lion tons were produced by 709,000 miners. Exports were meagre, only 8.""7 million tons went to foreign consumption. During the severe winter of 1947, inland demand for coal exceeded production and exports were prohibited. Even importation of coal was required to meet inland demand. These were years when the coal industry of Great Britain made immense efforts to secure maximum output irrespective of economy. The energy needs of Great Britain appeared insatiable; but had it been possible to export, the nationalised mining industry could have made huge profits as there was a world shortage of coal. However, home needs were considered to be the priority and many overseas markets were lost. Other producers moved in and secured long-term contracts. Not only was the British export market lost, but also the nationalised industry had to sell the imported coal at the same prices as home-produced coal and suffered losses up to of:3 per ton. Bence, at a time when the National Coal Board might have ac-cumulated a reserve fund to cope with less prosperons times, it was having to spend large sums of money securing sufficient coal for inland consumption. This was a time when intensive efforts in the mining industry, comparable with those of many industries and establishments inclusive of the armed services during the war, would have produced a greater amount of coal and have been of immense value to the country as a whole."

Jan 1, 1960

By W. E. Wrather

CURTAILMENT of production was a matter of far more serious concern to the oil industry through 1933 than the search for new supplies of oil. The huge reserves of crude, built up during past years, instead of inspiring a feeling of security, were viewed apprehensively. The status of past laws and court decisions seemed to guarantee to operators the right to produce oil at will, and this entrenched privilege was so widely adhered to that the market was-in a constant state of chaos. The more modern idea of the ownership of oil in place and correlative rights gained headway slowly, since usually there were enough belligerent producers, staunch believers in the old established order, to defeat the efforts of the majority who sought to' introduce order and restraint. State regulatory commissions were unable to cope, with the rebellion among producers with the result that those who abided by proration rulings were penalized, while those who flouted the rulings and produced unrestrainedly were able to make profits on large volumes of flush oil even at low prices. This situation, known in the vernacular as the "hot 'oil" problem, became so acute that the industry was threatened with ruin. The low price for 36c A.P.I. in the Mid-Continent came in April. at 25c per barrel 'but gradually moved upward to the long-hoped for price of $1.00 per barrel in October, after the Federal Government had taken a hand in the matter and effectively allocated production among the oil producing states and materially curbed the "hot oil" runs.

Jan 1, 1934

By Brian R. Green

Resin-in-pulp (RIP) technology has been developed for recovery of gold. It is now time to look forward to the potential for application of the technology to other situations. Some cases have been identified and have merited preliminary testwork. Four examples, which illustrate the potential of RIP, are dealt with in this paper. These include removal of metal-cyanides from pulps, recovery of manganese that is difficult to wash from filter cakes, recovery of nickel from low grade pulps, and recovery of zinc from process residues. The discussion includes descriptions of the problems, factors that affect the choice of resin, and factors that will affect the economics of the process.

Jan 1, 1998

Editor’s note: As usual, the June issue features an industrial minerals review. And some thanks are in order. Thank you to the industrial minerals annual-review editor, to the technical committees chair and vice chairs and to the authors of the individual commodity profiles. Jim Norman of GeoTrans Inc. is the industrial minerals annual-review editor. Gary Tomaino, Specialty Minerals Inc., is the chair of the SME industrial minerals technical committees. Technical committee vice chairs include: •Lucy McCartan, U.S. Geological Survey, agricultural minerals as well as sorbents, filter and process aids. •Steve Herron, Oglebay Norton Performance Minerals, ceramics and refractory materials. •Srinivas Veeramasuneni, U.S. Gypsum, chemical raw materials. •William Langer, U.S. Geological Survey, construction materials. •Vanessa Santos, Independent, fillers and pigments. •Richard Berg, Montana College of Mineral Science and Technology, specialty minerals. Their help makes possible this June industrial minerals issue. On behalf of the readers, the editors thank them.

Jan 1, 2003

By Ronald B. Stotelmeyer

This report summarizes the U.S. Bureau of Mines evaluation of the mineral resources of eight roadless areas in several National Forests in Montana. The areas are amoung those that have been proposed as additions to the National Wilderness Presevation System In various sessions of the U.S. Congress. Mineral Commodities present include gold (lode and placer), silver, copper, lead, zinc, molybdenum, tungsten, rare-earth elements, fluorite, and barite. Numerous mineral deposit types occur. Past production was from gold placers and vein-type deposits. There is potential for development of large volume porphyry copper-molybdenum, disseminated gold, stratabound copper-silver, and exhalative massive-sulfide metallic deposits. A substantial increase in metal prices is needed before any known vein-type deposits will be economic.

Jan 1, 1994

By Ingrid Hann

The Triple Bottom Line ? Economic Sustainability ? Creation of Joint Venture companies ? Planned evaluation of other kimberlites ? Social Sustainability ? Impact Benefit Agreement and Participation Agreements ? Education and training initiatives ? Environmental Sustainability ? Environmental management ? Mine closure planning

May 1, 2008

By R. L. Schmidt

The Methane Control and the Respirable Dust Groups at the Twin Cities Mining Research Center (TCMRC) cooperated recently in obtaining production samples of approximately 1 ton each, from the loading conveyors of a ripper, a borer, and a loading machine in conventional development headings. These samples were sized, in four stages, from plus 4 in to minus 10 µm. The conventional product had the least fines of the three production methods. The borer product had more fines than did the ripper product, but it also had a greater amount of large pieces. All three products, as sampled, had essentially the same amount of minus 10-µm particles. Photomicrographs and surface?-area comparisons were made. Gas -adsorption, surface-area determinations on particles under 37 µm give essentially the same value. Surface-area calculations, assuming spherical particles and no porosity, give a smaller area to the conventional product.

Jan 1, 1972

By Edwin S. Secor

The Federal Bureau of Mines conducted a field survey of 153 bituminous coal strip and auger mines to estimate coal recovery from surface mines in the Eastern United States. Recovery was calculated from field data by measuring coal losses resulting from mining coal and leaving barriers. Mean total recovery for strip mining in States east of the Mississippi River was 83.0 percent and ranged from 72.3 percent for Tennessee to 91.3 percent for Maryland. Mining losses and barrier losses were 10.1 and 7.7 percent, with standard deviations of 4.8 and 10.4 percent, respectively, indicating that barrier losses, although less than mining losses, were more variable. Mean total coal recovery varied only slightly for the two regions studied; 82.7 percent for Appalachia and 84.3 for the Midwest. Total recovery grouped by mining method--contour, area, and mountaintop removal--was 79.8,84.7, and 85.3 percent, respectively. Mean auger recovery was 35.9 percent; of the total average loss of 64.1 percent, over one-half resulted from design limitations while the remainder was attributed to operating losses. The wide recovery range at individual mines indicates the variability of the eastern surface coal mining industry. Because of this, care should be exercised in applying the results of this report to reserve estimates other than those of a general nature.

Jan 1, 1977

By Malcolm Black

Introduction The circumstances under which the gold mining industry was forced to curtail operations a few years ago are well known to all. The effect of those circumstances is particularly noticeable when one enters some of the larger mills that were designed, in better times, to treat relatively large tonnages. On their grinding floors one will observe that a number of grinding units are lying idle, and the ravages of rust are everywhere in evidence. The same applies to other equipment throughout these mills. In 1941, we found it necessary to reduce tonnage considerably in the Wright-Hargreaves mill. With the assumption that a lower tonnage would be of long duration, we began to focus our attention on some of the idle equipment with a view to re-arrangement of the flow-sheet for greater economy of operation. In an article by the writer published in the Engineering and Mining Journal (March, April, and May issues, 1939) , it was pointed out that in designing this mill there was a very limited floor space available. The choice of thickening equipment was imposed solely by the necessity for space: conservation. Thickening by gravity would have required 5,000 square feet of floor space, whereas Genter thickeners required only 1,200 square feet. As a consequence, the Genters were chosen. The decision to add flotation to the circuit was made primarily to save space. On a cost-plus-tail basis, 80 to 100 hours agitation on all pulp would produce similar overall results, but would require much more space.

Jan 1, 1948

By H Thanasekaran, J Kohmuench, B Seaman

To achieve an efficient separation in the flotation process, valuable particles need to be selectively segregated from the gangue while utilising a minimum number of flotation stages. TodayÆs existing flotation technologies are effective for fine particle size classes; however, limitations due to particle buoyancy and bubble-particle detachment restrict the effectiveness of traditional flotation approaches on coarser particles. As a result, flotation circuits are generally configured to process only fine particle size classes in order to maximise recovery in the primary stages. Eriez has invented a novel flotation technology, the HydroFloat, which overcomes these limitations by carrying-out flotation in a dense, fluidised-bed medium allowing for the recovery of coarse particles (>0.250 mm). Over the last 15 years, this technology has been successfully applied to industrial minerals with several full-scale units installed to recover particles up to and exceeding 3 mm diameter in primary flotation circuits. This paper includes discussions on the history of this technology, process theory, existing applications, and a review of recent sulphide-based laboratory test work conducted for Newcrest mining and others. Benefits of this approach, such as improved recovery, low energy consumption and reduced reagent addition will also be reviewed.CITATION:Kohmuench, J, Thanasekaran, H and Seaman, B, 2013. Advances in coarse particle flotation - Copper and gold, in Proceedings MetPlant 2013 , pp 378-386 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

At Namdeb, submerged beaches are earmarked for sampling and future mining and various sampling configurations are tested for optimality through the use of spatial simulations. For the creation of these virtual orebodies, basic statistics and variograms are needed, but in this specific instance no data exists from which the necessary parameters can be determined. The best that can be done is to use proxy data from onshore beaches, with adaptations where needed. The reworking of raised beaches during periods of rising and falling sea levels in some cases destroyed the internal beach structures, and it is very difficult to determine the variograms. A method is proposed whereby simulated annealing is used to adjust the sample locations to align the data pertaining to beach crests or cliff lines, thus improving the variogram structure along the shoreline in the direction of the highest geological continuity.

Jan 1, 2014

By Jack A. Caldwell

"This paper describes the nature of stage curves and the ways in which they have been used to study the construction sequencing of tailings impoundments. They provide a simple graphical method of representing the main aspects of an impoundment, studying the effects of different impoundment geometries, and predicting and controlling impoundment operations.IntroductionThe designer o f a tailings impoundment must, at all stages of design, examine the relations hip between the volume o r tones of tailings that will be deposited at the impoundment, the height to which the tailings will rise in a given time and that rate at which the various parts of an impoundment will be constructed. The operator, if he is to keep proper control of this impoundment, must be able to examine the effect of different deposit ion rates at the impoundment, and the consequences of placing more or less tailings at different parts of the impoundment. The operator must be able to see at a glance just how much higher an impoundment will be at the end o f the following yea r of deposition, and this he must be able to do in order to formulate his annual construction and operating plans.Stage curves are the best way o f modeling an impoundment. The simple impoundment model represented by the stage curves enables the designer and operator visually to examine the relationships between the various factors, such as impoundment volume, deposition rat e and construction rate, that dictate the essential features o f impoundment design and operation.A design model for a tailings impoundment may be formulated as in Figure 1. This involves the site selection process, the definition o f a geotechnical model, a water balance model and a height-capacity-production model."

Jan 1, 1983

By J. R. Bhamidipati, Nagy EI-Kaddah

"Over the years, mathematical modeling has been established as a viable tool for design and analysis of melting and solidification processes. Modeling of electromagnetic casting and melting systems involves three coupled problems -- determination of the containment field, the shape of the meniscus, and the temperature field -- which have to be solved simultaneously. One of the difficulties in numerical simulation of these systems is in defining and gridding the solution domain as the meniscus shape of the liquid region is not known a priori. This paper describes a methodology for solving these coupled problems in a two-dimensional electromagnetic containment field. This method is based on the solution of the electromagnetic, free surface dynamic, and heat transfer equations in a fixed domain in computational space by mapping the physical space into an invariant computational space during the search for the equilibrium shape using a variable non-orthogonal coordinate transformation. This approach, also, eliminates the need for regridding the liquid and solid regions during phase change. This methodology is demonstrated for two electromagnetic confinement systems -- the Magnetic Suspension Melting process and the electromagnetic casting of aluminum. The model predictions are in good agreement with available data for these systems. It is suggested that the methodology presented here is likely to provide a useful tool in the design, analysis, and optimization of electromagnetic confinement systems. IntroductionDuring the past decade, mathematical modeling has emerged as a viable tool for the design, analysis, and optimization of casting and melting processes /1-2/. It is generally recognized that the usefulness of modeling to study the interplay between the various process parameters without resorting to extensive experimentation relies heavily on accurate representation of the physical phenomena in these systems. In modeling electromagnetic confinement casting and melting systems, it is important that the model address all aspects of electromagnetic field interaction with the metal, if accurate predictions are to be obtained /3/. The electromagnetic field affects the heat transfer phenomena primarily through joule heating. In addition, the electromagnetic forces play a key role in heat redistribution in the molten pool via melt stirring, and, in confinement systems, support the molten metal pool."

Jan 1, 1994

By K. Bommer

"In today’s fast paced, globally competitive world, reliability and machine uptime are of the utmost importance to a successful operation. Along with these targets more emphasis is being put on cost reduction and decreasing the environmental impact of the overall system. To achieve these goals, automatic lubricators and lubrication systems have been used in many industries for years and are now becoming a common tool in the mining industry as well. These systems are able to provide proper lubrication amounts at the proper times autonomously, helping to keep the machines running smoothly while minimizing the physical support required. Copper mines in the southwest have begun utilizing auto lubrication to avoid mistakes and unplanned shut downs on critical equipment. This paper will describe the engineering behind these products and review case histories where these tools have been successfully utilized in the mining industry. INTRODUCTION In a dirty, dusty, wet environment, where machine uptime is imperative, proper lubrication of bearings is the only way to survive. With the push for cost reduction and mines striving to lower their environmental impact and increase worker safety according to MSHA guidelines, the old lubrication practices have come under scrutiny. It is no longer encouraged or cost effective to have maintenance personal walk from point to point throughout the entire mine pumping a shot of grease into each bearing once per shift. Automatic lubricators and lubrication systems have been on the market for years but recently, as the market focus has changed and technology has developed, the use of these systems has begun to rise in the mining industry. Automatic lubrication systems can be as simple as a single point lubricator lubricating one (1) bearing or a more complex system lubricating numerous bearings. With system design, the automatic lubricator provides a preset amount of grease to a bearing at regular, predetermined intervals. The systems designed to lubricate more than one bearing contain grease pumps of some design and possibly PLC controllers which can be used to remotely adjust and monitor the system. As can be seen in Figure 1, the right amount of lubrication can be achieved much more reliably with automatic lubricators. Depending on application needs, the market now has products to fit almost every wish list. This paper is going to focus on the single point systems that are lower in cost but are still being effective."

Jan 1, 2015

By Gwendolyn D. Hood

The U.S. Bureau of Mines developed a dewatering technique for treating wastewater that was tested on waste slurry from a commercial tile company in Alabama. Raw wastewater samples were pretreated with 10 Ib calcium chloride and 10 lb Wyoming bentonite per 1,000 gal of slurry. After pretreatment, polyethylene oxide (PEO) at dosages varying from 0.05 to 0.20 lb per 1,000 gal was mixed with the waste slurry, forming strong, tough floes that were separated from the clarified water using a trammel. The flocculated slurry was dewatered to a consistency that could be handled for subsequent disposal in a landfill. The clarified water quality was equivalent to that of the company's present treatment system.

Jan 1, 2010

By H. J. R. Way

The work to be described was undertaken at various periods from 1937 to 1939 on the Busia gold field, in the eastern province of Uganda. It was decided to examine the possibility of reef prospection by the resistivity method, for it was not known how far the usually disintegrated nature of most reefs in the ubiquitous laterite near the surface would obscure indications obtained by resistivity traverses. The work at the commencement was therefore largely experimental, but the results obtained thereby were satisfactory, and a survey was started at the Government closed area at Amonikakine. With the limited time and resources at the writer's disposal, it was not possible to complete the survey to his satisfaction or to follow up exhaustively all the geophysical indications, but some of the results of the experimental work and the survey were of sufficient interest to be worth recording; in particular the relation between the width of reef, electrode separation and shape of the curve, and the interference effect of constant separation curves over zones of float are significant and useful. Three new veins were located, but only one contained sufficient gold to warrant detailed prospection. This was called the Geophysical reef, and was uncovered over a strike distance of 1140 ft., and there are indications that it extends over a distance of 1990 ft. These results and the recom- mendations consequent therefrom were embodied in a special report to the Uganda Geological Survey. History OF the Field The Busia field is in the southeastern corner of Uganda near the Kenya-Uganda border, and is about 17 miles north of the northeastern corner of Lake Victoria. Gold was first discovered in the area in the stream beds by Davies1,2 in 1932. Subsequently numerous small alluvial claims were worked by prospectors and the area was prospected for reef by a company for periods varying from three to nine months, but was finally abandoned, as the results were considered unfavorable. Further prospecting by the Geological Survey in 1935-1936 under Davies8 and later under the writer4 uncovered three reefs with sufficient gold values to be of economic interest. These were finally taken over by a company known as Borderland Syndicate, which still owns the area, and from September 1937 to the end of 1941 about 13,000 oz. of gold was extracted from reefs of the area proved by the Geological Survey. Opencast mining operations are still proceeding (February 1943). The Amonikakine area lies to the immediate north of that of Borderland Syndicate. A certain amount of prospecting had been done when the writer started work there. As a result of his report, this area was taken over by another syndicate, but little further work was accomplished before it ceased operating because of difficulties of wartime working.

Jan 1, 1946

By H. J. R. Way

The work to be described was undertaken at various periods from 1937 to 1939 on the Busia gold field, in the eastern province of Uganda. It was decided to examine the possibility of reef prospection by the resistivity method, for it was not known how far the usually disintegrated nature of most reefs in the ubiquitous laterite near the surface would obscure indications obtained by resistivity traverses. The work at the commencement was therefore largely experimental, but the results obtained thereby were satisfactory, and a survey was started at the Government closed area at Amonikakine. With the limited time and resources at the writer's disposal, it was not possible to complete the survey to his satisfaction or to follow up exhaustively all the geophysical indications, but some of the results of the experimental work and the survey were of sufficient interest to be worth recording; in particular the relation between the width of reef, electrode separation and shape of the curve, and the interference effect of constant separation curves over zones of float are significant and useful. Three new veins were located, but only one contained sufficient gold to warrant detailed prospection. This was called the Geophysical reef, and was uncovered over a strike distance of 1140 ft., and there are indications that it extends over a distance of 1990 ft. These results and the recom- mendations consequent therefrom were embodied in a special report to the Uganda Geological Survey. History OF the Field The Busia field is in the southeastern corner of Uganda near the Kenya-Uganda border, and is about 17 miles north of the northeastern corner of Lake Victoria. Gold was first discovered in the area in the stream beds by Davies1,2 in 1932. Subsequently numerous small alluvial claims were worked by prospectors and the area was prospected for reef by a company for periods varying from three to nine months, but was finally abandoned, as the results were considered unfavorable. Further prospecting by the Geological Survey in 1935-1936 under Davies8 and later under the writer4 uncovered three reefs with sufficient gold values to be of economic interest. These were finally taken over by a company known as Borderland Syndicate, which still owns the area, and from September 1937 to the end of 1941 about 13,000 oz. of gold was extracted from reefs of the area proved by the Geological Survey. Opencast mining operations are still proceeding (February 1943). The Amonikakine area lies to the immediate north of that of Borderland Syndicate. A certain amount of prospecting had been done when the writer started work there. As a result of his report, this area was taken over by another syndicate, but little further work was accomplished before it ceased operating because of difficulties of wartime working.

Jan 1, 1946

By Richard W. Smith

Why are we losing our liberties? (1) . . . because our local chambers of commerce come to the National Chamber's annual meeting, vote for a policy on federal economy, and then go to Capitol Hill and ask for a federal project for their area. (2) ... because our mining men ask for a subsidy to mine submarginal deposits that can't be economically mined in a free economy. (3) . . . because 18,000 men and organizations all over the country recently wired or wrote a Congressional committee asking that the Army Engineers be exempt from the President's power to reorganize the Executive Branch of the government under the recommendations of the Hoover Commission.

Jan 1, 1949