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By Brian W. Mackenzie

The paper addresses five questions concerning the economic of gold exploration in the western Canadian shield. Can historical footprints be used to project future gold prices for exploration planning? Experience suggests that gold price forecast are too clo ely tied to current market events to provide meaningful guidelines. What range of breakeven gold price will typically be required to ju tify gold exploration in Canada? Minimum price requirements. initially asses ed at $540 to $1080 per ounce, probably lie in the range of $480 to $760 per ounce (expressed in 1985 Canadian dollar). Within Canada, what role do regional conditions and taxation policies play in determining the viability of prospective gold exploration targets? Striking interprovincial differences are found to exist, given the same geological circum tance -Nova Scotia, ew Brunswick, and Quebec rank towards the top in term of motivating exploration, Briti h Columbia provides the least investment incentive, while Saskatchewan and Manitoba place around the middle of the Canadian league. How can minimum acceptable tonnage-grade conditions for gold targets in the western shield be established and, then, constructively applied to provide exploration planning guidelines? Minimum target conditions, realis tically defined in terms of a broad band of doubt, can be used judiciously to help balance the direct costs of uneconomic exploration with the opportunity costs associated with rejecting economic deposits. How does the average cost per ounce of gold discovered in the western shield compare with the overall Canadian experience? Average discovery costs for the we tern shield, apprai ed at $100 per ounce, are shown to compare favourably with the Canada-wide record.

Jan 1, 1986

By Carlos Gualdron, Elizabeth Gomez, Rafael Bolivar

The productivity index of the Coopracarcegua Ltda., a mid-size coal mining company of Norte de Santander, Colombia, was related absenteeism using accident, productivity and profit data four years. The analysis was based on type, severity and frequency of accidents, number of absentee days; price per metric ton, and other relevant parameters. The enterprise is formed by 5 different mines of thermic coal, each one with different exploitation technologies and different productivity. Each mine was analysed separately and the loss of profit due to absenteeism was calculate for each one. The study showed that the foregone earnings due to absenteeism in terms of the whole productivity of the enterprise was about of 6.6% of the total profit average the 4 years, with calculated values of 14.7%, 3.5%, 8.4% and 4% per year in the evaluated period. The study identified that the most important cause of absenteeism was "General Disease". The foregone earnings in 2009, the highest loss for the analysed period, was about US$ 0.937 million and during the whole evaluated period was US$ 2.46 million.

Jan 1, 2014

By W C. Burton, J S. Kuszma, T O. Aspinall

The environmental impact of mining and evolving environmentallegislation has received increased attention worldwide in the last two decades (Bradfield, Shultz and Stone, 1996). The potential impacts associated with unstable spoil dumps from mine operations is the focus of concern both by the mining industry, environmental regulatory agencies and members of the public. Engineered slopes of mine spoils may be stable at the end of construction, but they can deteriorate over time. There is thus the need to increase the base of knowledge on the existing practices of spoil dump design and rehabilitation. Efficient engineering design and systematic economic evaluation of spoil dump reshaping techniques for mine rehabilitation assists in maintaining the expected standards of environmental compliance. As part of the overall approach for effective engineering design ofspoil dumps, a comprehensive, computational and efficient tool isrequired for assessing the economics and productivity of existing spoil dump reshaping practices for efficient mine rehabilitation. Such a design tool is useful in linking current spoil dump environmental management practices with engineering design planning and economic impact evaluation. This paper identifies the processes for the economic impact evaluation for existing spoil dump reshaping practices and proposed final site dump designs. Selection of an efficient spoil dump design at optimum costs will ensure operational efficiency. A case study is presented identifying economic impact evaluation in earthmoving equipment selection and the costs involved for the reshaping of spoil dumps to that of varying final site designs.

Jan 1, 2000

By Axel Preusse

Due to a political decision, German hard coal mining will come to an end in the year 2018. By then, there will have been more than 150 years of industrial grade mining activities. Located in the western part of Germany is one of the most densely populated areas of Europe. Multiple coal seams have embossed the earth?s surface up to 20 meters (21.87 yards), as mining has subsided. The aftercare of hard coal mining will consist of three tasks: groundwater management, polder management, and groundwater treatment. The Ewigkeitslasten (cost in perpetuity) at the current groundwater level has been determined in the past. The actual cash value is calculated to be about 12.4 billion euros (approximately 16.5 billion dollars). The cost of groundwater management is directly related to the groundwater level. Rising groundwater levels will reduce the cost of pumping water. Known effects of rising groundwater are uplift of the surface, emission of methane gas at the surface, higher risk of cave-ins, and contamination of drinking water horizons. Each of those processes produces cost in order to prevent negative consequences (e.g., uncontrolled methane emissions) or to handle reparations (e.g., damages caused by surface uplifts). In the long run, it is the goal to minimize the Ewigkeitslast. As a first step, all cost-generating processes are specified, and a cost type based characterization is performed. The objective of this case study is to identify key parameters to determine the quality of a cost-generating process (proportional cost, fixed amount cost). Afterwards, it is intended to specify the quantitative impacts of each parameter and to set up an optimization model to minimize the overall cost. The quantitatively specified parameters will form the base out of which the optimization model is created.

Jan 1, 2013

By Stanley G. Butcher

"The methods generally applied to predict performance and financially evaluate beneficiation options are reviewed.Typical costs f or a western Canadian thermal coal operation are examined. Preparation-from truck dump to loadout-frequently amounts 10 over a quarter of total minesite costs. Failure to achieve projected yield-whether caused by mine or plant problems-s-substantially increases production costs because more coal has 10 he mined to meet a specific market demand. Problem identification by mass/ash balances is recommended.Thorough characterization of the coal and associated waste materials and more reliable prediction of beneficiation process performance are therefore essential to determine a project 's financial viability.IntroductionWestern Canadian coal prep a ration plant capacity is partway through a massive expansion program . In 198 1 potential product ion was 14 million tonnes, by 1985 it will be 26 million tonnes per year. Only two years ago the industry was concerned whether it could sustain this rate of growth to meet market demands : now with diminished market demand and lower coal prices being offered by our international competitors there are doubts whether t his potential will be fully employed , even by 1990.One direct consequence o f the occurrence of a variety of coals in a stunningly beautiful but complex geo logical setting such as the Rocky Mountains and their Foothills is that each project is unique. Coal is a low value per tonne product. To supply distant markets from geographically isolated deposit s necessitates expensive , dedicated , infrastructure . T o be profitable these operations must achieve eve ry advantage of the economy of scale.Each of the mi ne complexes commissioned in the 1970s experienced severe problems in the area o f co a l preparation . Most bought their way out , paying for major plant modifications by increasing the scale of their total operation . The current market recession may not allow new operations this route to profitability.The objective of this paper is to illustrate the economic impact of coal preparation problems on the profitability o f the total minesite operation and thus provide a sound basis for decision making process."

Jan 1, 1985

By Wayne Hilgedick

Peabody Coal Company is the nation's largest producer of coal and is headquartered in St. Louis, Missouri. In 1978 Peabody divisionalized its operations to establish more responsive and effective mine management. Peabody Coal Company's Arizona Division operates two large surface mines, the Black Mesa and Kayenta Mines. Both are located in northeastern Arizona, approximately 30 miles from Kayenta, Arizona, on the Navajo and Hopi Indian Reservations. The Black Mesa Mine produces 4 to 5 million tons of coal per year and the Kayenta Mine produces 7 to 8 million tons per year. Coal from the Black Mesa Mine is transported 274 miles by coal slurry pipeline to the Mohave Generating Plant located on the Nevada/Arizona border at Bullhead City, Arizona. This plant is jointly owned by Southern California Edison, the Los Angeles Department of Water and Power, Nevada Power Company and Salt River Project Agriculture Improvement and Power District.

Jan 1, 1983

By J. C. Agarwal

Most metals are produced from minerals containing one or more of the desired metals, some contaminating metals, silicate, oxides, carbonates, and sulfides. Therefore, in the production of metals, there is generally a gaseous effluent in pyrometallurgical processes and a liquid effluent in hydrometallurgical processes. There are also solid residues such as waste ore, tailings, dust, and slag, created by the metal recovery processes. There are two important distinctions between the effluents and the residues: I. Effluents ? gases and liquids ? affect the neighboring environment for miles from the point of emission, while residues affect only the soil on which they are stored or dumped. 2. The environmental and economic effects of effluents are known and felt essentially immediately. By contrast, the environmental effects of the residues may not be known for a long time. For these reasons, the economic impact and the potential corrective actions required are very different for effluents and residues.

Jan 1, 1992

By G. Richard Dreese, Harold L. Bryant

The coal mining industry has had a long history of successfully externalizing part of its costs. Thus the private or internal costs of coal mining have been minimized and the social or external costs have been ignored. The externalized costs have largely taken the form of water pollution from acid mine drainage and sedimentation of stream channels from eroding spoil banks and gob piles. The environmental problems created by strip mining are very conspicuous, so the public demand for legisla-

Jan 1, 1975

By G. Richard Dreese

Most coal mining states have passed or amended laws restricting strip ruining in the past two years. In light of this and in anticipation of further restrictions by the states and the federal government on strip mining this paper attempts to show the Impact of these new laws on the structure of the coal mining industry in Ohio and specifically on one small stripping firm in Ohio. The implications of the study are applicable to other states under similar circumstances and to other industries which are being caught up in the ecological-economic struggle.

Jan 1, 1973

By H. L. Bourne

The sand dunes which line the east shore of Lake Michigan resulted after the last, or Wisconsin, glacial period in Michigan. Melt-water streams carried vast quantities of glacial debris to the near shore areas of predecessors to Lake Michigan. As the lake levels receded, these vast quantities of sand were exposed to the prevailing westerly winds, which was the last major process that acted upon the sand and resulted in the formation of the dunes. 1 These dunes are one of the significant natural resources within the state. Michigan dune sands supply about 90% of the foundry sand used in the automotive industry, and 40% of the foundry sand used 2 for all purposes within the United States. The deposits owe their importance to the following factors: grain size distribution, grain shape, mineral composition and location with respect to the foundry sand market. In spite of their economic significance these I deposits are in jeopardy through legislative preemption.

Jan 1, 1975

By Cooper P. G

I he Electrolytic Refining and Smelting Company (ER&S) has oper- ated a copper smelter at Port Kembla, NSW since 1908. The feasibility of modernising the smelter was recently studied and external influences were shown to have a substantial impact on the project economics. Profita- bility is determined by the relative magnitudes of treatment charge income earned from processing raw materials and the operating costs incurred. Treatment charges are usually denominated in U.S. dollars and are deter- mined by market forces in the world copper industry. ER&S is no different from other Australian manufacturing industries in that it must maintain its competitive position by controlling costs. The modernisation project seeks to achieve this through new technology and improved labour Productivity.

Jan 1, 1988

By Heidecks C

Sub-level stoping with consolidated rockfill is the main method for mining steep dipping baryte and fluorite veins in Germany. Drifting is fully mechanised using drill jumbos, LHD units and shotcrete support. Stopes have heights up to 50 m with sub-level distances up to 15 m. Winning of the pillars between sub-levels is done by longhole blasting in slices of 3-5 m length on strike. Mucking is done on the lowermost level by LHD units. After each blast rockfill with binder (cement and/or fly ash) is dumped into the scope from the uppermost level. Economic success depends on both geological and technical parameters and factors, eg vein thickness and dip, ore grade, size and distance of sub-level drifts. Of particular influence are ore loss in pillar winning and dilution both in drifting on vein and in pillar mining. A comprehensive computer program has been developed for calculating the total cost per tonne run-of-mine ore respectively per tonne of concentrate for a single stope. The cost model includes development, longhole blasting, mucking and haulage to the mill, milling and ventilation. All costs (labour, energy, supplies, maintenance, depreciation and capital cost) are taken into account. Dilution and recovery are both considered. The program can be used to estimate the cost of mining a particular stope. It can also be used to investigate the influence of relevant parameters and factors on the economic result. By this way it should be possible to optimise the technical design of a stope.

Jan 1, 1995

By Koppe J. C, Dimitrakopoulos R, Costa J. F

Grade control and the delineation of ore/waste in open pit operations is traditionally based on the comparison of estimated grades with an economic cut-off. This paper deals with an alternative approach to grade control based on estimating gra

Jan 1, 1998

Mining executives often have a difficult task determining what the strategic objective of the business should be as this can be impacted by the prevailing market conditions. In addition, they have no mechanism to quantitatively 'test' the impact of this strategic decision on the business and understand the underlying dynamics. During the commodities bull run of 2003 to 2008 the strategic objective may have been to grow the long term value of the business (NPV) through increased tonnage, acquisition and finding new reserves, which all came with an increasing fixed cost base. Now with the financial crisis upon us and the collapse of commodity prices and demand, executives have adjusted their strategies as 'cash is king' and short-term cash flow, in some instances at the expense of long terms value, is the order of the day. For many mining companies, mine closures, reductions in production and cost cutting exercisers are now the focus. In many instances, management do not have an ability to rapidly test different strategic alternatives to 'test' the impact on value, unit costs, reserves and profitability at the operational level and optimize the underlying trade-off variables. Economic modelling of the complete business value chain is a means of linking the operational 'reality' and strategic choices, so that the full impact can be assessed. This paper describes some of the challenges facing mining executives and how economic modelling can be applied to make decision making more rigorous.

Jan 1, 2010

By N. Sasto, E. Bondi, G. R. Lane

Cyest Corporation has been involved in economic modelling and optimisation with various mining clients within South Africa, and internationally, for the past 5 years. In the mining industry in particular, the relationships between variables that are controllable, and those that are not, and the physical and economic outcomes are complex and often non-linear. These relationships constitute an economic system. In the mining context, although many of the relationships can be accurately quantified on a ?single variable to single variable? basis, such simplistic relationships will not suffice in order to understand the dynamics of an entire mine. One has to specify and quantify the relationships between hundreds, if not thousands, of variables. Furthermore, in reality, these relationships change over time. This is the role of an economic model where all the relevant cause-effect relationships, within pertinent constraints, are accurately represented. Models that are used for optimisation must therefore capture the dynamics of the economic system in question as well as anticipate changes to the relationships between these variables. An accurate economic model is a prerequisite for successful optimisation. Optimisation entails the allocation or configuration of resources, within control of management, which will maximise (or minimise) a desired objective function. An optimal configuration (implying trade-off) of controllable variables therefore exists for a given set of assumptions that will yield a maximised objective function. Due to the multi-variant trade-offs required for optimisation, the concept of the ?Economic Surface? or ?Hill of Value? has been used to represent these optimisation outcomes and to discern the route to an optimal configuration. A good example of this is the volume versus cut-off grade trade-off that yields an optimal value for a particular shaft with its unique geological and economic assumptions. More recently, Cyest has extended these economic models to incorporate risk associated with variance in assumptions and inputs. This is termed DFA (dynamic financial analysis) and incorporates stochastic modelling and some of the latest actuarial techniques around modelling global assumptions (such as pricing and exchange rate). This paper will cover the theory around mine optimisation through some example case studies, and also explain the latest thinking regarding incorporating DFA.

Jan 1, 2007

By W. Biermann

All industrial processes are economically driven, resulting in the ever increasing need for process optimization in order to stay competitive and profitable. Numerous models has been published depicting the optimization of the raw material usage in an arc furnace, as well as the thermal and electrical efficiency; however, to obtain a holistic view of the cost-effectiveness of the process one needs to expand the model to include the cost of all the operational variables. This project therefore aimed to not only include the raw material feeds and power consumption as input variables, but also the labour, maintenance, and environmental costs to generate an all-inclusive financial balance. In the end, the model was able to mathematically optimize the ferrochrome (FeCr) production process through evaluating the effect of a specified combination of input parameters. It could therefore be used as a tool to aid in managerial decision-making; to appraise and correspondingly adjust certain operational variables in order to achieve a maximum return on investment. This paper fully describes the reasoning behind the choice of the essential model components, the assumptions made during the models development, the calculation approach, as well as the advantages, limitations, possible applications, and areas for expansion of the final model. Through running simulations with plant data, it was found that the accuracy of final model remained fairly constant when applied to stable furnace conditions, but was met with a number of limitations when applied to more complex situations. These limitations could, however, be overcome through further development and expansion of the existing model to include a larger number of process variables.

Jan 1, 2012

By Paul M. Tyler

OF THE 92 elements generally accepted by chemists as constituting the primary building blocks of matter, all but the very rarest have been investigated with a view to employing them in steel manufacture. The surprising thing is that so few have been found commercially acceptable. Despite the relatively small number of elements involved, the use of alloys in steel making is one of the most complicated and probably one of the least well understood of modern industrial enterprises. The action of individual elements in steel making has been described often and a profuse and somewhat acrimonious literature covers pretty much the whole field of ferroalloy ore supplies. In the middle ground between the miner and the -steel maker developments are less carefully watched by most observers and except for an occasional description of the technique of some conversion process or the tariff hearings in Congress, little is said about them. The present paper has been submitted in the hope that it will stimulate broader constructive economic thinking. It undertakes to describe in' relatively nontechnical terms this great and growing though highly complex industry and to study its relations to national progress.

Jan 1, 1932

By Paul Tyler

THE extensive employment of nonmetallic minerals antedates the use of metals, but only within the last two decades has the production of nonmetals begun actually to keep pace with the complicated activities which characterize the so-called Machine Age. The economic changes ushered in by the Industrial Revolution were reflected first in an increased demand for metals and for fuels. In the modern sense, therefore, the nonmetallic mineral industries are new and afford new opportunities for engineer and economist alike. A certain amount of caution is indicated, therefore, before attempting to apply ready-made formulas to the problems of these industries. Economics is not an exact science. In the field of production technology where the number of variables is fairly well known, the principles of economics are readily applicable, but as the student proceeds through the province of marketing into the unexplored regions of psychology and sociology he must distinguish carefully between scientific reasoning and purely metaphysical speculation, even when the latter masquerades as economics. The present paper attempts to prove no preconceived theorems and is designed primarily to stimulate careful thinking on sundry neglected phases of these industries. An attempt is made to differentiate the general problems into single aspects which afford promise of being comprehended separately; also, some fundamental statistical data are presented, but merely to indicate a method of scientific approach applicable to more intensive studies.

Jan 1, 1933

By Carlos Avalos Casillas, Saul Ortiz Landeros

The current work shows metallurgical results obtained at the Centro de Investigación y Desarrollo Tecnológico (Peñoles CIDT), as a continuation of the work first published in February 2012. With the aim of optimizing the economic values of the products, ores from San Julian (Fresnillo) were selectively floated to produce a lead concentrate and a zinc concentrate containing high silver values. In the laboratory, this included regrinding of the rougher and scavenger lead concentrate to increase the liberation of mineralogical species and thus lower zinc recovery. Cyanide leaching bottle tests were conducted to improve the value of the silver. It is proposed to leach the silver contained in the zinc concentrate and then recover the silver using the Merrill Crowe process. The results show a reduction of zinc recovery in the lead concentrate from 11.3% to 2.0% after regrinding to a P80 of 10 microns, improving the metallurgical quality and economic value of the lead and zinc concentrates. Also laboratory and pilot scale cyanidation tests showed that about 65 to 80% of silver will be leached from the zinc concentrate, after regrinding to a P80 of 10 microns. The proposed processing increases the economic recovery of silver from 72.7% to 78.8%.

Jan 1, 2014

By Kai Nielsen

The paper presents the results of several industrial and laboratory blasting, crushing and grinding tests and experiments investigating how blasting can influence the subsequent crushing and grinding operations. The paper also describes how these results can be used in order to optimize the entire comminution process from solid ore to a semifinished or marketable product. Two cases are presented, one looking at the processing of fine grained taconite ore, and the other discussing the processing of raw milling product for cement burning.

Jan 1, 1998