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By Steven J. Van Kauwenbergh, Talaat A. B. Lawendy

Batch laboratory-scale beneficiation tests were conducted on four high-iron phosphate samples. These samples included sedimentary ores (Tilemsi Valley, Mali and Tahoua, Niger), a sample from an igneous phosphate deposit (Matongo, Burundi), and a fine-grained phosphatic iron ore processing residue from Chile. The Matongo phosphate deposit occurs as a thick (up to 80 m) residual blanket of P205-enriched soil over solid parent rock (carbonatite and associated rock types). Although the Matongo deposit is an igneous deposit, ore from the deposit can be subjected to beneficiation treatments commonly used to treat sedimentary rocks. The beneficiation flowsheets designed to process these diverse ore types involve attrition scrubbing, size classification, and flotation. At the best flotation conditions tested, phosphate concentrates assaying 32.0%-39.0% P205 and 1.0%-1.5% Fe2O3, were obtained at 64.2%-82.2% overall P2O5 recoveries from run-of-mine (ROM) ores containing 9.2%-28.6% P205 and 5.9%-16.1% F,20,. A cleaner phosphate concentrate assaying 33.1% P205, 1.8% A1203, and 3.3% Fe2O3 at 53.4% overall P205 recovery was obtained from the phosphatic iron ore residue that originally contained 4.5% P205, 8.0% A1203, and 17.6% Fe2O3.

Jan 1, 1993

Along with kyanite and sillimanite, andalusite forms part of the sillimanite industrial minerals trimorphous alumina-silicate group. Theoretically, andalusite contains about 60% A1203 and 40% Si02, with a Mohs hardness of 7 to 7.5 and a specific gravity of 3.0-3.2. Andalusite generally occurs in the contact metamorphic zones of schists and shales, constituting about 10% of the ground mass ore body. The 5- to 20mm- (0.2- to 0.8-in.-) long crystals are usually liberated through crushing and magnetic/heavy-media separation. Relatively minor occurrences of andalusite are found in Andalusia, Spain (where it was first identified), Portugal, the former Soviet Union, Ghana, South Korea, California and North Carolina. It also occurs in China, France and South Africa. The latter two represent nearly all the andalusite that is exported. Andalusite is an inert refractory raw material that does not require calcining before use. It involves an internal conversion to mullite after heating to 1400° to 1600° C (2552° to 2912° F). At higher temperatures of about 1800° C (3272° F), the mullite converts to corundum and liquid silica.

Jan 1, 1995

By Archie W. Fletcher, R. J. Wesely, Nathaniel Arbiter, A. D. Zunkel

In contrast to pyrometallurgy's six thousand year history in the production of metals, that of hydrometallurgy is of relatively recent origin. The earliest reference to it at all was in the 16th century, with the first applications to copper in the 17th and 18th. In the 19th century, increased demands for pure metal resulted in development of electrolytic refining, and early in this century electrowinning. The rapid growth in wpper production in the present century, paricularly in the United States and Chile, stimulated the development of new technology for leaching, and for the recovery of copper from leach solutions. Solvent extraction has become a major factor during the past quarter century by permitting novel leaching technology which produces dilute or complex solutions. In addition, solvents other than sulphuric acid, and chemical methods for precipitating copper metal are now of increasing interest. These are trends which should grow in importance in the future with the need to process lower grade and more complex materials. The evolution of copper hydrometallurgy is reviewed briefly and key factors in recent major developments are presented with details of specific operations and with trends for the future indicated. The relative importance of copper hydrometallurgy is compared to that of pyrometallurgy in the light of probable changes in ore supplies and character.

Jan 1, 1993

By Andrzej Wala

Constantly increasing demand for energy materials and metal ores brought about tremendous progress in mining techniques which are characterised by a high degree of mechanization and concentration of works. One of the recent trends in underground mining mechanization is connected with an application of heavy machines with diesel engines [l],[2]. The introduction of diesel engines in mining all over world caused not only improvement in economic conditions but also the necessity to prevent contamination of air in the mine by toxic agents in diesel exhaust emissions. A generally used way of eliminating exhaust gases is proper ventilation of the cross cut by means of providing permanent exchange of air that would guarantee in every point of the cross cut and in every moment the decay in concentration of exhaust gases beyond threshold limit [3][4][5][6][7][8][9][10]. The present paper is an attempt to define a mathematical model describing the changes of concentration in cross cut face to which fresh air is distributed by ventilators and tubes in a forcing way. Obtained model should offer its practical adaptability to engineering calculation of the amount of fresh air needed for diluting and eliminating exhaust gases beyond threshold limit. Justness of these models has been confirmed by investigation of the growth of nitrogen dioxide concentration in air environment in some cross cut faces of Kiirunavaara iron ore mine in Kiruna (Sweden).

Jan 1, 1980

By G. Gaidajis

For the environmentally safe management of the sulphidic waste rock produced from the Stratoni mining facilities, TVX Hellas has examined, within the frame of the funded European research program ROLCOSMOS, the effectiveness of an alternative rehabilitation scheme involving the segregation of the sulphide rich components of waste rock and the engineered application of alkaline additives. The examined waste rock management scheme was evaluated with laboratory test work followed by pilot-scale field applications. In this paper, the results from the two-year monitoring period of the pilot scale application are presented.

Jan 1, 2002

By Frank F. Aplan

Froth flotation has been used to improve the recovery of fine coal, for minimizing the sulfur and ash content of clean coal and for the removal of fine coal from recycled or discharged backwater from coal preparation plants. Though froth flotation and allied processes for ores date from the turn of the century, with the first U.S. commercial application in 1911, coal flotation has been introduced into U.S. practice much more slowly. The first European coal flotation plant was started in 1920, and by 1933 Europe had 60 operating plants while the United States had only one plant, newly commissioned. Over the years there has been a steady increase in coal flotation so that today one-third of the 345 U.S. plants employ the process. This report traces U.S. coal flotation practice and technological improvements from early laboratory experiments in 1915 up to today's extensive use of the process.

Jan 1, 1999

By Kent S. Roessler

The Bureau of Mines is currently investigating the geophysical application of Tomography to monitor leachate during in-situ mining. Determining the location of the leachate is important for both economic and environmental reasons. By analyzing a sequence of tomographic images, we can determine where highly permeable/fractured regions are located and hence, major flow paths. Since BOMTOM (Bureau Of Mines TOMography - Tomographic Reconstruction Program), and BOMCRATR (Bureau Of Mines Curved RAy Tomography - Tomographic Reconstruction Program) are sensitive to user-selected ray path arrival times, we are also investigating the use of neural networks to automate the process of recognizing this feature. This paper presents a technique for detecting fracture zones and their orientations in a region between two boreholes, by using a motion analysis study of a sequence of tomographic images. It also addresses the need for an automated/unbiased method to pick crosshole seismic arrival times using a trained neural network. In exploration geophysics, the picking of first break arrivals represents a pattern recognition task. The neural net paradigm has proved to be a good method of solving this type of task. To pick the first arrival peak of a trace, the network is trained with a set of known (user selected) first arrival peaks by creating a binary image of a set of traces. Once trained, the neural net correctly picked first arrivals of the remaining traces in the set.

Jan 1, 1992

By E. Ozberk, J. B. Hiskey, M. J. Collins, B. J. Scheiner, M. E. Chalkley, I. M. Masters

Conventional zinc concentrates generally contain 5 to 10% Fe, while bulk concentrates can contain up to 20% Fe. As a result, the disposal of iron bearing residues is an integral part of zinc refining operations. The quality of iron residues must comply with ever changing and increasingly stringent environmental legislation. Zinc has been recovered from sulphide concentrates by a hydrometallurgical route for almost one hundred years. The disposal of iron was a major difficulty for the industry for many decades and was directly responsible for low overall zinc recoveries. The introduction of the jarosite process in the mid 1960's allowed for the treatment of neutral leach residues and the precipitation of iron in an easily filterable form. Subsequently, three additional iron precipitation processes have found commercial application in the zinc industry: the goethite process; the paragoethite process; and the hematite process. The Sherritt Zinc Pressure Leach Process has been developed for integration with existing roast leach electrowin zinc plants, or as a stand alone facility for the treatment of a wide variety of zinc bearing feed materials. It is essential that these processes allow for the disposal of iron residues in an environmentally acceptable form. This paper describes the integration of the Sherritt Zinc Pressure Leach Process with commercially proven iron precipitation processes. The results of laboratory testwork and data from operating plants are presented.

Jan 1, 1993

By W. Blake, J. K. Whyatt, B. G. White

In situ stress on the scale of a tunnel or mine may be distorted by geologic structures. The resulting variations in in situ stress have a direct bearing on the potential for mining-induced seismicity. New evidence collected from the Lucky Friday mine by US Bureau of Mines researchers, as well as a review of previous case studies, demonstrated that in situ stress variations affect the [spatial] distribution of mining-induced seismicity. Although overcore stress measurements have been useful in these studies. they are too expensive and, depending, on conditions, may be too difficult to collect. However, information on borehole and raise breakouts: deformation of mine openings: and patterns of seismicity, ground-control problems and rock-burst damage can be used to build a stress database. In conjunction with maps of mine structure and geology and models of rockmass behavior, this database can then be used to build a map of in situ stress variations. Such a map could provide a means of anticipating patterns of mining-induced seismicity and. Thus, could be the basis for planning appropriate measures to ameliorate rock-burst hazards.

Jan 1, 1997

By Brian W. Hester

Ore was first discovered at the Kidd Creek mine site during the first few days of December 1963 when a diamond drill hole there cut sulfide mineralization. This event marked the end of the search started 11 years earlier with the conception of a geological idea. Economic forces provided the stimulus needed for the application of this idea but other-events, and legal considerations, also played arole in delaying the ultimate discovery. The location of Kidd Creek is shown in Fig. 1. Management of the then Texas Gulf Sulphur Co. had become concerned in 1951 at the company's declining reserves of native sulfur in Texas. This problem was to be alleviated by new discoveries and development of methods to recover sulfur from sour gas. At the time, however, the solution appeared to lie in the recovery of sulfur from pyritic ores. Canada was chosen as the best country in which to find these ores. Walter Holyk was hired in 1951 to conduct the search. By 1952, he was working in the area near Sherbrooke, Quebec, known as the "Eastern Townships" where mineralization consisting of base metal sulfides in volcanic rocks has long been known. His observations here led him to the then revolutionary conclusion that such mineralization could have formed as part of the volcanic process and not, as was generally supposed at the time, by replacement. On learning of the discovery of similar mineralization near Bathurst, NB, he moved there in the spring of 1953. He was able to utilize his new concept and found the Half-Mile Lake sulfide deposit.

Jan 1, 1991

A linear programming model with integer sequencing variables is developed to schedule limestone production for a quarry in Central Japan. The model is used to optimize raw material production from the quarry supplying limestone to cement, quick lime and aggregate plants. Typically, the mining in the quarry takes place in four to six different areas each area having 3 or 4 mining increments. Each mining increment contains different quality of limestone. The limestone production from the quarry is transported to the plants byway of 3 ore passes. Each plant requires a given quantity of limestone per period meeting certain quality constraints. This paper will describe development of the scheduling optimization model and how it is used to schedule production by period within the quarry to meet the capacity and blending requirements of the plants.

Jan 1, 2003

By F. F. Peng, Z. Lu

Employing a combination of two types of polyelcctrolyte might become necessary to enhance both the settling rate of the flocs and the water clarity of a fine-particle suspension in a high-capacity thickening process. The sequence of addition, mixing, type and dosage of polymer all affect the overall performance and capacity of a thickening process. For the sedimentation of copper flotation tailings, the cylinder test results showed that two different techniques may be used to achieve the required performance, i.e., a high settling rate of the flocs and the deisired underflow density and overflow water clarity. The required performance can be achieved by either adjusting the pH prior to anionic polyelectrolvte flocculation or using a combination of polymer flocculant and coagulant (dual-polymer system). The dynamic thickening test results showed that only the approach using a dualpolymer system is capable of meeting the required performance. The effects of polvelectrolvte dosage, the sequence and numbers of polyelectrolyte addition, the feed concentration, the bed level and the rake speed on the settling rate, underflow percent solids and water clarity were studied in cylinder tests and in a laboratory dynamic thickening unit. The dynamic test is especially valuable in evaluating the addition and mixing of polymers. The results were evaluated quantitatively using total suspended solids in supernatant, underflow density and capacity per unit of settling area per unit of time. The objective of this study was to quantify and explain some of the parameters involved in the sedimentation of copper flotation tailings.

Jan 1, 1999

By Fathi Habashi

A LARGE number of metals are found in nature, in rich deposits, in the form of sulfides as shown in Table 4.1. Treatment of sulfide ores is done mostly by pyrometallurgical operations; it is only recently that hydrometallurgical processing started to compete with pyrometallurgical methods.

Jan 1, 1970

By Michael E. Salovich

The U. S. Department of Interior, Bureau of Mines (Bureau) has developed a prototype version of a computer application that combines hydrologic analysis with object-oriented graphics. This software is unique in that it presents analytic element analysis within an object-oriented CAD environment. Its user interface employs mouse handling, scrolling windows, dialog boxes, palettes, and pulldown menus. It can import scanned images of maps and overlay these images within the same window. This application was developed using object-oriented programming techniques. Several programming issues concerning graphics had to be resolved during development of this system. These include (1) how to represent hydrologic elements as graphical objects, (2) how to translate screen coordinates to map coordinates, (3) how to implement ?zooming? (changing the magnification level of a window), (4) how to overlay layers of images, and (5) how to import scanned images of maps. An object library was used to implement graphical user interface features such as scrolling windows and pull-down menus. Algorithms for CAD features such as map coordinate translation, zooming, and the layering of images were developed by Bureau researchers. The application has a modular source code structure and can be modified for use in other research applications.

Jan 1, 1992

By J. Loredo

Wastes related to abandoned mine sites can constitute important potential pollution sources, depending on their mineralogical and geochemical characteristics and volume. Mine waste disposal sites contain a diverse variety of wastes including overburden material and waste rocks, the ore which cannot be economically removed and wastes from the smelting processes when they are accomplished at the mine site. These materials are usually heterogeneous in size, mineralogy and metal concentrations. Asturias, in northern Spain, has an extensive mining history and, in consequence, there are abundant unreclaimed and derelict mine sites with abandoned mines and spoil heaps of different age, morphology, content and dimensions. In these spoil heaps, waste materials are subjected to the intense action of a humid environment, so the instability of sulphides and sulpharsenides results in the production of acid and metal-rich leachates, which are incorporated to surface water or infiltrated through the land reaching groundwater bodies. The mineralogical and geochemical characteristics of the stored materials are key data to evaluate if they represent an environmental risk. Mineralogy and geochemistry of wastes and the particular specific environmental conditions of each site affect the rate of weathering and therefore the metal release. The characterisation of mine wastes is a necessary step in order to establish suitable assessment strategies with the aim of reducing the leaching, transport and widespread of ecotoxic elements from mining wastes to the environment (surface water, sediments, soils and air). As a consequence of the weathering of As-rich mineral phases, high arsenic contents are commonly detected in effluents from mine voids and spoil heap leachates.

Jan 1, 2006

By Liguang Wang, Roe-Hoan Yoon

The thin film balance (TFB) technique was used to measure the equilibrium film thicknesses (H3 between two air bubbles in sodium dodecyl sulfate (SDS) and electrolyte (NaCl) solutions. The results were used to determine the magnitudes of the hydrophobic forces (K232) using the extended DLVO theory. The Km values determined from He measurement allowed us to predict disjoining pressure isotherms, which were found to be in excellent agreement with those obtained experimentally using a bike-wheel film holder. The rate of film thinning was measured at low SDS concentrations with varying amounts of electrolyte (NaCl) added. In general film thinning was controlled by the capillary pressure during the initial stages, while it was controlled by the surfaces forces during the later stages. At low NaCl concentrations, it was possible to predict the rate of film thinning using the Reynolds equation, provided that the driving force was corrected for the contributions from the hydrophobic force, which in turn were determined from the KZ32 values obtained from the He values measured experimentally. At high NaCl concentrations, where it was difficult to measure the equilibrium film thicknesses, the contributions from the hydrophobic forces were determined by fitting the film thinning data to the Reynolds equation. The K232 values obtained using both the equilibrium film thickness and the film thinning measurements showed that hydrophobic force deceased with increasing surfactant and salt concentrations. It was found that the hydrophobic force in foam films was very sensitive to the added electrolyte concentration.

Jan 1, 2005

By Richard Keith Corbin

Canadian junior mining companies whose gold exploration and exploitation programs take them across the border into the western United States should be prepared to deal with the myriad of title issues involved in acquiring unpatented gold mining claims. The purpose of this paper is to serve as an introductory outline for Canadian junior mining companies to mining laws of the United States, as well as to relevant laws of some of the western gold mining states. Topics will include the five w's (who, where, what, why and when) of Canadian junior mining companies1 rights and responsibilities in acquiring interests in U.S. gold mining properties by claim staking, lease or purchase. Historic terms of common parlance among U.S. miners, such as "claimjumping" are defined and discussed. Various legal doctrines, such as "pedis possessio" and "good faith" in the location of claims are covered as well. Controversial subjects of contemporary interest are addressed in some detail, such as whether to locate a bulk-mineable disseminated gold deposit with placer claims or lode claims, and whether lodes may be staked over placers. By thus heightening the awareness of Canadian junior mining companies, it is hoped that they can be properly prepared to avoid title disputes, and to win lawsuits when they are unavoidable.

Jan 1, 1988

By R. M. Clowes

LITHOPROBE is a collaborative, multidisciplinary research project that is providing new insights into the tectonic evolution of the North American continent through its work within 10 study areas across Canada. For the mining industry, such results provide a well-constrained regional framework and better understanding of the tectonic processes that lead to the development of ore deposits. In mining camps, seismic-reflection methods have proven effective in imaging shallow to moderately dipping lithologic contacts as well as structural features and, in some cases, have been used for the direct detection of orebodies. Here, short case histories are provided for the Abitibi greenstone belt (VMS deposits) in Quebec and the Thompson nickel belt in Manitoba.

Jan 1, 2002

The 70th Annual Meeting of the Minnesota Section of SME and the 58th Annual University of Minnesota Mining Symposium were held April 22-24, 1997, in Duluth, MN. About 450 attended both. The Fifth Annual Trade Expo, held during the meeting, was attended by a record 80 exhibitors. An SME short course on materials handling preceded the meeting. Iron-mining and the steel industries highlighted the meetings. Specific topics in the keynote addresses and technical sessions primarily concerned iron mining, iron- ore processing, product (taconite pellet) transportation and the steel market. Although the iron mining industry held center stage, several papers outside of iron mining were also presented. Iron mining in Minnesota contributes $1 billion to Minnesota's economy. According to the Iron Mining Association of Minnesota, more than 20,000 state jobs rely on the industry. Minnesota's iron mining industry came through tough times in the early 1980s, mostly because of worldwide competition. However, the industry has shown significant improvement in the last 15 years. A large share of the steel industry's competitiveness in the late 1990s is due to cost and quality improvements in the taconite mines. The taconite industry has become more productive, largely through the application of new technology. Since the early 1980s, Minnesota's taconite mines have nearly doubled the number of tons per worker-hour. Most of the taconite reserves in the United States are located in Minnesota's Mesabi, Vermilion and Cuyuna iron ranges. The Mesabi range alone contains an estimated 24. Gt (23.6 billion long tons) of mag- netic taconite. Since the 1950s, when taconite production first began, 1 Gt

Jan 1, 1997

By Terry Ramsey, N. Finkelstein

INTRODUCTION The Cyprus Pima Mine is located 20 miles southwest of Tucson, Arizona and about fifty miles north of the Mexican border. The Cyprus Pima orebody was discovered in 1950. Feasibility studies were begun in 1952 employing underground development. Economic studies showed open pit operations to be feasible and stripping of overburden was begun in late 1955. The first ore was reached in October of 1956. A 3,000 tpd (tons per day) concentrator was completed and began operation January 1, 1957. From these beginnings, Cyprus Pima Mining Company has expanded into a plant processing approximately 54,000 to 56,000 tpd. Four expansions were required to bring the plant up to its present capacity. Each expansion incorporated what had been learned in previous operation of the plant. The first expansion was completed in August of 1963 doubling design capacity to 6,000 tpd. In reality, because of softer than average ore, capacity was closer to 8,000 tpd. Expansion I1 was completed in July 1966 bringing design capacity to 18,000 tpd. Expansion I11 followed immediately. Completed in the summer of 1967, this expansion increased the design capacity to 30,000 tpd. The actual dry tonnage of this portion of the operation in 1974 averaged 38,400 tpd, again, primarily as the result of treating softer than average ore. The latest expansion (Expansion IV), completed in December 1971 and utilizing a semi-autogenous grinding circuit, is located in a separate building (Mill 11) approximately 200 yards southeast of the original mill (Mill I). Expansion IV was designed for 14,000 tpd, but after circuit modifications, averaged 16,500 tpd in 1974.

Jan 1, 1976