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By Kegomoditswe Koitsiwe, Tsuyoshi Adachi

"This paper characterizes quarterly LME copper price fundamentals from 1995 to 2011 by analyzing the transformation of the market mechanism based on structural change perspective. Using chow test for structural change based on the least square multiple regression, we divide the price fluctuation into: Stable price period (1995Q3-1999Q2), Low stable price period (1999Q3 – 2003Q3) and Price fluctuation period (2003Q4 – 2011Q2). The results show the existence of structural breaks disproves the investigation of the full sample period as a whole. In different structural breakpoints the main drivers of copper prices changes and their impact are significantly different. Moreover, the paper examines the role of speculation in copper price fluctuations.Introduction The rise in commodities price volatility and financial and economic crisis have led to questions over the organisation of futures and physical commodities markets. Spikes in commodity prices and volatility have coincided with a surge in financial speculators in the commodity markets inspiring a polarised and hotly debate among academics and practitioners about the role of investors in the development of physical markets. In his seminal work Kaldor (1939) focused primarily on whether speculative activity in the futures markets reduces the variance of commodity spot prices. Yet, part of the literature finds that the introduction of futures contracts destabilizes the spot market. IMF (2006) studied commodities boom and its causes concluding that there is little support for the hypothesis that speculative activity affects either price levels over the long run or price swings in the short-run. The impact of speculative activity on commodity prices remains a highly contentious topic. Other market analysts take the view that the supply and demand for physical commodities remain the major determinants of market trends (Krugman 2008). It is the aim of this study to contribute to the literature by examining the drivers of copper price changes from a structural change perspective. In this context we are attempting to answer to: What are the main drivers leading to copper price fluctuations? Are these factors having the same effect in different periods or not? It is meaningful to understand drivers of copper prices and thereby, their fluctuations because it will help developing countries depending on copper export to anticipate market situation and avoid bad economic development challenges that can result from price fluctuations. Moreover, this can ensure sustainable mineral supply."

Jan 1, 2017

By Duane A. Smith

Horace Tabor. No 19th century Colorado mining man is better known but, unfortunately, probably less understood. He is little appreciated for his significant contributions to the industry and the state. A century ago, Tabor was headline news. The legend today, however, has become so all pervasive and so interwoven with fact that the two are hard to separate. For example, he never told Baby Doe on his death bed to hang on to the Matchless mine. Yet this has emerged as staple Tabor fare. So much attention has been focused on his matrimonial triangle that it overshadows the man. Symbol of mining's reward Tabor traveled west in the 1859 Pike's Peak gold rush. In the next generation, he came to symbolize the rewards mining might lavish on an individual. The Leadville Daily Herald (Sept. 10, 1882) could write, without exaggeration, that "the extent which the mining industry of Colorado is under obligation to Tabor cannot be easily estimated - what he has done for Leadville and Denver is patent to all." It had not come easily, nor had Tabor started out a success. His early placer mining at Payne's Bar, near present-day Idaho Springs, CO, had turned no fortune. So in 1860, he, his wife Augusta, and son went south to Colorado City, then over Ute Pass and up the Arkansas Valley to Oro City. Arriving soon after the initial discovery, Tabor staked a good claim. With a sharp eye, he and Augusta broadened their base by establishing a store. Both mining and business would pay dividends in the following years. By the season's end, though, Oro City was already declining. Always on the lookout for a richer district, Tabor and his family moved the next year across the mountains to promising Buckskin Joe. The familiar pattern followed, with the store and post office being the center of their attention. Mining investment and management now replaced the earlier physical panning and sluice operating. Seven years later, the Tabors abandoned Buckskin Joe and returned to Oro City. It had moved up California Gulch to be near the district's best mine, the Printer Boy. Middle class was not enough Middle class respectability, plus a steady income, was the Tabor's by the 1870s; fine as far as it went. But it proved far from the fortune Horace had always been seeking. Oro City languished in the backwash of Colorado mining and Tabor seemed like many men who had drifted around the Territory following the ebb and flow of mining. His faithful wife Augusta had been a steady factor in the success the family achieved. She helped year after year to operate the store and post office. Not simply the happy-go-lucky individual he has often been portrayed, Tabor was a hard working businessman/mine owner. An R. G. Dun and Company agent evaluated him in 1876 "Net worth $23,200. Is a very shrewd businessman and not liable to lose money, has a good chance to make money as he had no competition." Leadville: Tabor's silverlined-fortune After all those years on the Colorado mining frontier, in 1877, Lake County's wealthiest and most respected merchant made another move. It was short in distance, only 4 km (2.5 miles) down California Gulch, then a little north to a new mining camp. This new camp, soon named Leadville, gave birth to the Tabor fortune and legend. Middle-aged (Horace was 47), the Tabors once more set up their general store and found themselves in the midst of the open¬ing of a new district. This time silver beckoned and not the gold that had brought them West 18 years before.

Jan 1, 1989

By Quan Li, Xiang Ren, De Lui, Yumin Zhang

SL-type continuous centrifugal separator with injection flow (Injection Flowing Film Centrifugation, IFFC) for separating fine and ultra-fine minerals has been developed recently in China and it is capable of recovering particles down to one micron in size. In this paper, the principle of its separation is discussed. IFFC is a special transient pulsating film which combines both thin film jigging and thin film concentration functions. It not only can intensify the looseness and stratification of the settled particles, but also create a hydraulic weir effect to improve recovery of fines and ultra- fines and significantly improve the performance of thin film separation. In a Chinese tin gravity concentrator, SL devices, SL-1200s (capacity 1.5-2.0 ton/hr) and SL-600s (capacity 0.5 ton/hr) were applied to treat -1 0 micron cassiterite slime(removed as tailings at the past) and to replace the old tin flotation system(-74+10 micron slime). The plant results show that 50-60% of the cassiterite can be recovered from -10 micron slime with an enrichment ratio of 10-12. Particle down to one micron were recovered. Under optimal conditions, the recovery from -74+10 micron slime can reach more than 85%. The recoverable size range can be determined by calculation.

Jan 1, 1995

The objective of this study is to classify ore and waste in a selected mine. The support vector machine, was used for the classification purpose, is applied to a zinc ore body in a skarn deposit located in the central region of the Peruvian Andes. The input parameters used for the model are spatial coordinates and the lithological information of the ore body. The input data was divided into training and testing data sets and the performance of the model was tested using the testing data set. The results show that more than 76% of the data could be properly classified by this method. The ore waste maps of the deposit was then developed using SVM model. From the result it was observed that a comparatively very few number of cells classified as ore. The ore is concentrated in small lodes at the middle of the volume of study, and not uniformly distributed throughout the study area. The lithological map of the deposit was also constructed as it was used as an input parameter for the SVM model. The indicator kriging was used for generation of lithological map of the ore body. Key word: Ore waste classification, Support vector machine, Indicator kriging, Confusion matrix.

Jan 1, 2008

By H. Köse, C. Tatar, C. Helvaci, F. Simsir

The Çayirhan coal basin is located 124 km (77 miles) west of Ankara,Turkey. With approximately 520 Mt (570 million st) of lignite reserves, the Neogene Çayirhan basin is one of the important coal districts of the central Anatolia region. The Çoraklar formation consists of crossbedded sandstone, channel fill conglomerates, mudstones, carbonaceous shales and volcanoclastic pebblestones, which are fluvial in origin. The lower and upper lignite seams occur, respectively, in the lower and the uppermost parts of the Çoraklar formation. The lignite deposits are in the Çayirhan and Koyunagili portions of the Beypazari Neogene basin. The Çayirhan coalfield consists of lower and upper lignite seams. The lower lignite seam does not outcrop at the surface. Its lateral discontinuity and relatively low sulfur content, plus sedimentologic and stratigraphic features of the associated sediments, indicate a fluvial origin. Thus, the lateral spreading and geometry of the lower lignite deposits were controlled by the channel, flood plain and well drained marshes of a fluvial system. The mining method employed at Çayirhan is the fullymechanized, retreat, working longwall with caving system. Due to ventilation, haulage and tectonic conditions, panel lengths from 0.6 to 1.7km (0.4 to 1.1 miles) are chosen, and 220-m (720ft) face lengths are used. The annual coal production is 2.2 Mt (2.4 million st).

Jan 1, 1994

By Gary F. Rajala, Bruce R. Greenwood

INTRODUCTION The Empire Mine is an iron ore mining, concentrating and pelletizing facility operated by The Cleveland-Cliffs Iron Company in the Upper Peninsula of Michigan. Owners of the mine are Inland Steel, LTV Steel, Wheeling-Pittsburgh Steel and Cleveland-Cliff s. The orebody is a fine-grained, low grade iron formation with magnetite as the primary constituent. Also present are iron carbonates, iron silicates, chert, hematite, goethite and quartz. The original six concentrating lines were started in late 1963. Successive expansions of ten lines in 1967, five lines in 1974 and 3 lines in 1979 have resulted in Empire reaching a present annual capacity of 8.0 million long tons of pellets. The Empire flowsheet was developed over several years of laboratory bench testing, pilot plant testing and testing of a full-scale primary autogenous grinding circuit. Since the original flowsheet was established, modifications have been made based on pilot plant and full-scale plant tests. The present flowsheet for three sections of the concentrator consists of one stage of crushing, two stages of closed circuit autogenous grinding, two stages of magnetic separation, one stage of hydraulic concentration and two stages of flotation (rougher and scavenger). The flowsheet for the fourth section of the concentrator (Empire 4) is the same as the first three sections, except a crusher has been added to crush excess pebbles. The Empire 4 flowsheet appears in the at- tached figure. PRIMARY GRINDING CIRCUIT FLOWSHEET Empire has a total of 24 individual grinding lines. However, at the present time, Line 1 is not being used for processing crude ore. The primary mill on Line 1 is now grinding flux stone for fluxed pellet production and the secondary mill is being used as a ball mill to grind rougher flotation tailings prior to a scavenger flotation circuit.

Jan 1, 1992

By K. C. Vories, C. D. Elifrits, F. F. Haston

The required reclamation of land disturbed by surface coal mining often results in the creation of some oversteepened slopes that are prone to rapid erosion and sediment production. This natural activity on such slopes is not desirable nor allowed under current regulations. Experience has shown that novel approaches must be devised to address the problem. Research conducted on field sites in Missouri has indicated that construction, during the reclamation and grading processes, of a man-made drainage system will control the erosion. The drainage system must replicate or exceed the natural system in terms of drainage density and channel frequency. Basic design considerations are summarized in this paper, and field results are shown.

Jan 1, 1987

By T. T. Gronfors

The excavation process and equipment used for excavation join firmly each other. By changing the process or method, the construction of equipment may be altered essentially. It has been possible to develop a wholy new type of hydraulic boom for tunnelling, when only parallel drilling instead of V-cut is used. The utilization of controlled blasting has made small holes more desirable. So the controlled blasting has had an influence on the selection of drill steel equipment and in this way also influenced the construction of the equipment.

Jan 1, 1970

By Y. C. Kim

This paper describes the implementational aspects of a blast hole kriging system that has been developedfor the purpose of daily ore/waste control in an open pit mine. The primary goal of blast hole kriging is to improve the ore/waste delineation procedure. A complete computer program package called Blast Hole Kriging (BHK) System was developed for IBMIPC AT or XT computers, using the Fortran language and supplemented by a few assembly language routines for the bit- map manipulation. This paper emphasizes the practical implementation requirements of the system and discusses system design considerations.

Jan 1, 1991

A Mineração da Trindade (Samitri) is a major Brazilian iron ore producer. Founded in 1939, privately owned Samitri operates six mines with a total production capacity of 14.5 Mt/a (16 million stpy). The mines are located in southeastern Brazil in the state of Minas Gerais. They are operating in the iron ore quadrangle, Brazil's primary iron ore-producing region. In addition to iron ore production, Samitri has the capability to produce 350 kt/a (386,000 stpy) of ferruginous manganese ore from two mines, also located in the iron ore quadrangle. Historically, about 70% of Samitri's production of lump ore, sinter feed and pellet feed is exported. Destinations include Belgium, Luxembourg, France, Germany, Trinidad and Tobago, China, Turkey and the United States. Alegria Mine In September 1989, Samitri started a new processing plant to treat itabirite, a low-grade iron ore. The goal of the plant was to produce sinter feed (coarse fraction) and pellet feed (fine fraction). Primary separation of sinter feed from pellet feed was accomplished with conventional vibrating screens making a 0.4-mm (40-mesh) cut. The screen oversize was stockpiled as sinter feed. The undersize was deslimed with hydrocyclones and upgraded by conventional froth flotation. Resulting pellet feed grades ranged from 3% to 3.5% Si02. A change in pellet feed requirements by Samarco Mineração SA, a Samitri subsidiary, called for Si02 levels below 1 % and increased production levels. Moreover, market demands called for a change in sinter feed size distributions. Unfortunately, lower pellet feed Si02 levels could not be achieved with the existing process. This was because of the presence of 35% +0.15 mm (+100 mesh) in flotation feed. Flowsheet development. Laboratory and pilot-plant studies conducted at Samitri's research facility found that to achieve lower Si02 levels, the +0.15 mm (+100 mesh) in flotation feed must be kept below 5% to 10%.

Jan 1, 1997

By Thomas W. Camm

The U.S. Bureau of Mines has extensive experience estimating the cost of mining and mineral processing operations as an ongoing part of its information and analysis studies. With the increased interest in remediation of mine wastes, the USBM is developing a methodology to expand its cost estimating expertise to include costs of various remediation techniques applicable to mineral processing and mining wastes. By integrating waste remediation costs with existing USBM cost estimating systems for mine and mill operations, a comprehensive system for cost engineering studies will be developed.

Jan 1, 1995

By C. W. Benjamin

The paper covers the development of an efficient, "state-of-the-art" design approach encapsulating extensive research and development by Gulf on soft loading, low impact, zero spillage transfer chutes. The development, which interacts and interfaces the comprehensive methodologies for transfer chute design, allows Gulf to deliver detailed designs within 8-24 hours rather than the norm which is weeks or months. Outputs include 3D models of completed transfers and support structures along with rendered 3D representations of the design which can be fully manipulated around all axis in 3D.

Jan 1, 2000

By Richard R. Klimpel

This paper will summarize the trends resulting from the data generated in a large number of laboratory and industrial studies con- ducted by this author where various slurry rheology factors have been carefully changed and controlled. Factors such as percent sol- ids, addition and/or removal of fines, slurry mill filling level, specific material oriented breakage properties, chemical additions, etc. are discussed with a number of illustrating examples. This paper is specifically aimed at developing rheologically related operating guide- lines for plant engineers so that improved operating conditions can be selected.

Jan 1, 1997

By H. A. von Schonfeldt, H. Douglas Dahl

INTRODUCTION During the past decade, significant pro¬gress has been made in applying rock mechanics principles to mine design problems by a great number of researchers. Some of these new techniques have found their way into the engineering and planning offices of the operating mine. In spite of these advances, however, the application of rock mechanics in the day-to-day mine planning and design of our domestic coal mines is rela¬tively rare. There are a number of reasons responsi¬ble for this relatively slow progress, not the least of which is the question of how to measure the success or cost effectiveness of a sizable rock mechanics effort in an opera¬ting mine. Firstly, the properties of geologic materials generally vary over a wide range and it is, therefore, difficult to assess whether an improvement in the mining conditions is due to a design change or due to a change in the geologic conditions. A second reason for the slow acceptance of rock mechanics in engineering thinking is the fact that some of the concepts are quite difficult and that physical evidence of their validity to mine design is still rare. Thirdly, com¬munication between research, engineering and applications oriented people appears to function only intermittently. In our view, however, the most important impediment lies in the "state-of-the-art." Exactly how much can rock mechanics help the mine operator? The best that rock mechanics can do at present is determine whether one approach is better than another when weighed against some design objective (stress, strain, deformation). We cannot determine the abso¬lute best ground control design -- only what is better. If ground control is lost, the statement that "it's the best one we looked at" means very little to the harried operator. While the "state-of-the art" has advanced a great deal, it has certainly not been reduced to an engineering matter in that design hand¬books are available -- they are not. The success of a rock mechanics program, there¬fore, can be determined only over a long period of time of continuous effort.

Jan 1, 1977

By Boyd Eisenbraun, Dennis Murr, Milton Rojas

Approximately since 1925, the phenomena of grinding and classification of minerals with screens have been studied. In the U.S. iron ore mining operations located in the so-called “Mesabi Iron range,” magnetite processing plants have made progress in the application of high-frequency screens that have allowed them to process low-grade Taconite ores and successfully achieve the economic benefit of these minerals. In the particular case of magnetite minerals disseminated in the siliceous matrix, the main objective is to reduce the generation of particles called “middlings” with high silica contents. Commonly the primary challenge of the metallurgical task is to achieve high recoveries and iron concentrates with low impurities. To achieve this, several studies and industrial applications have shown success in this regard and not only in iron ores, but also in other minerals around the world. The study described in this paper attempts to describe some key aspects that helped develop an effective solution and list the benefits associated with this modern process design by using industry-proven technologies for minerals in Chile that have similar characteristics to the minerals of the iron belt in the United States.

Feb 1, 2025

By Joseph M. Chelini

Today, the two major operating costs of rubber tired off-road equipment are diesel fuel and tires. Mine Management has minimal control over the ever accelerating diesel fuel costs. However, they can exercise control over abnormal tire costs. Fortunately, with available technology and cost analysis methods, experience shows us the outlook for controlling tire costs is encouraging. Most earthmoving operations using off-road, rubber tired haulage and support equipment have abnormally high total tire costs. These costs, utilizing Tire Information Management, have been reduced more than 30%; 20% can often be guaranteed. Management Apathy on the subject of tires in a complex mining operation perhaps can be understood, but management apathy applied to an abnormally high operating cost, of which tires are, begs for a solution.' Tires have been professionally neglected for many years in most mine operations. This is exemplified in the January, 1982 issue of Mining Engineering by Charlie Son in his article Reducing Earthmoving Tire Costs. He compared the efforts to improve diesel engine costs to the same efforts given to earthmover tires.

Jan 1, 1983

By David J. Gurtler

In early 1988, Chino Mines Co. began using a system of economic splits for all materials encountered in mining. All mined material is evaluated as mill ore, solvent extraction electrowinning plant feed, and non-ore material, to determine its disposition. Results thus far indicate a significant increase in financial returns on material mined compared with the copper cutoff grade previously in use. Chino Mines is a partnership between Phelps Dodge Corp. (two-thirds ownership) and Mitsubishi Corp. (one-third ownership). The company produces copper and byproduct metals from the historic Santa Rita del Cobre mining district in southwestern New Mexico. The history of copper production in the district began with the use of surface native copper by native Americans before 1800. Spanish soldiers from Mexico later became aware of this district and mining began in 1801. The district was worked intermittently until 1909 when the Chino Copper Co. was formed, with Daniel C. Jackling as vice president and managing director. Concentrator operations were started in 1911. Kennecott purchased the company in 1933 and built a smelter in 1939. Chino Mines Co. was formed in 1980 when Mitsubishi purchased one-third of Kennecott's holding at the property.

Jan 1, 1990

By M. Wason

An Ore bed magnetic liner element is made of permanent ceramic magnets embedded in a rubber molding. (See figure 1) They are difficult and expensive to manufacture correctly. Therefore, the lining for a complete mill is expensive, as high as 400% more than conventional rubber liners. The magnets are not very resistant to impact as they are very brittle. Mills of 12 feet or more can use only I inch balls; mills under 12 feet can use balls of 1-1/2 inches. These liners are therefore used in regrind applications with small balls or in secondary pebble mills. Rubber liners for these applications last a long time, so if life was the only consideration, the pay back for these liners would be longer than the life of the mine. The Ore bed liner and its bed of ball chips or magnetic ore is relatively thin and the surface of this bed has a high coefficient of friction. The liners are made so that opposing poles are situated next to each other and that the mill shell and the bed of ore or ball chips completes the magnetic circuit. (See figure 2) The combinations of these properties results in a very efficient liner. Due to the low profile of this bed, there is no material that is lifted too high, so we have a very compact charge with very high attrition, good for fine grinding. These liners have shown a 10% ball consumption reduction and a 10% lower power draw for the same capacity. Due to the magnetic orientation, the bed is formed in a wave shape along the lines of magnetic force. Tests conducted at a copper mine in the southwest United States have confirmed these findings. The mills where the liners were tested are 10.5 feet by 16 feet Hardinge regrind mills operating as overflow ball mills.

Jan 1, 1999

By Mark William Johns

Carbon-in-pulp (CIP) is the preferred method of gold recovery om cyanided plp. However, other gold adsorbents (namely, ton-exchange resms) are being introduced to the industry as they are considered to have several advantages over carbon for the recoery of gold. A set of test methods have been developed by the industry to evaluate the quality of different carbons. owever, many ?f these tests are not applicable to evaluating ton-exchange resms. Hence, a need has arisen for a method to evaluate the different adsorbents. This paper introduces a philosophy to evaluate an adsorbent that results in an estimation of the capital cost and the operating cost associated with the adsorbent. Tests that have been devel­ oped to evaluate the ability of an adsorbent to adsorb gold (in­solutton . counter-current) and to evaluate the optimum adsorbent for a specific pulp (in-pulp batch) are introduced. A method of converting the test data into an economic dimension is present­ed. Case studies are presented to highlight the discussion.

Jan 1, 1996

By R. Sivamohan, F. Huang

A mineral processing strategy developed for the finely and complexly interlayered calcite rich wollastonite, microcline, and iron-garnet ore of Jokkmokk, northern Sweden, gives an overall calcite recovery of 89.4% at a grade of 90.7% CaCO3. The wollastonite product assays 53.0% Ca- SiO3 at a recovery of 92.2%. The significant elements of the developed strategy are stepwise grinding, wet high intensity magnetic separation (WHIMS), reverse flotation and starvation flotation. Stepwise grinding avoids the overgrinding of soft calcite. WHIMS removes the colored iron-garnet impurity and thereby increases the whiteness of the product. Reverse flotation enables a simple flotation circuit and starvation `flotation helps to optimize the physicochemical conditions in cleaner flotation by giving rougher products of narrow particle size distributions. Moreover, with the reagent scheme developed in this work only one cleaner stage is necessary for the various rougher flotation products to be upgraded to give the foregoing results. In this paper, the strategy is presented in detail along with appropriate results.

Jan 1, 1990