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By A. W. Randall

Geological Aspects of Ore Reserve Estimates of Pine Point District Zinc- Lead Deposits, N.W.T. Zinc-lead ores of the Pine Point District, Northwest Territories, Canada are hosted in paleokarst cavities within a Middle Devonian carbonate barrier complex. Of the nearly 100 deposits found, most are irregularly distributed along two main regional stratigraphically controlled trends. The ores, which occur predominantly as open space filling, form deposits most of which average one million tonnes in size with an average grade of 10% combined zinc plus lead. Geological features related to karsting control not only distribution of deposits but also their shape, size and grade. The higher grade ore in these deposits generally occurs in a relatively small core area. Consequently, accuracy of reserve estimation is dependent on drill hole density and understanding of karst geometry. Several case examples will be reviewed to demonstrate the relationship between shape, size and grade of deposit, geological reserves and drill hole density, along with a discussion of geological ore reserve estimation methods.

Jan 1, 1985

By D. R. Spears

The Bureau of Mines has investigated the fundamental aspects of shear-flocculation using a rapid, in-situ particle size analyzer. Silica was stirred in the presence of an aliphatic amine to determine the effects of collector coverage, stirring speed, and solids concentration on the kinetics of shear-flocculation. The results showed that shear-flocculation is a two-stage process. In the first stage, mean particle size increased rapidly in the first 1-2 min of reaction; in the second stage, an equilibrium was set up between the rate of floc growth and floc decay. Collector dosage affected the position of the equilibrium by altering the number of surface sites for particle-particle attachment. A minimum stirring speed was necessary for shear-flocculation to occur and was dependent on solids concentration and collector dosage. This speed was the minimum necessary for particles to overcome the electrostatic energy barrier which kept conditioned particles dispersed. Larger particles flocculated more rapidly. At very high stirring speeds, large flocs became unstable, resulting in a narrowed particle size distribution in the slurry.

Jan 1, 1993

By M. R. Carter

The Rochester Mining District is located some twenty-five miles NE of Lovelock, Nevada. The District was discovered and named in the 1860's by prospectors from Rochester, New York. For a number of years, they worked Rochester Canyon, sinking shafts and inclines and making open cuts. After reaching a depth of approximately eighty feet, the miners tapped an underground channel and were driven from these workings by a strong flow of water leaving pumps in the shaft and barely escaping with their lives. With the Rochester workings no longer accessible, the miners went to the southeast and established the Relief Mining District. About 1881, gold was found in the gravel at the mouth of American Canyon, to the east of Rochester. These placers were worked until 1895, first by the Americans who reportedly took out $1 000 000, and later by the Chinese who mined the gravel with great skill. It was estimated that the Chinese took out as much as $10 000 000.

Jan 1, 1987

By A. H. Balch

A physical elastic seismic model, based on the Peoria oil field was constructed and used to produce multi mode cross-borehole seismic data. Because this was a physical model, it was necessary to deal with a complex wave field consisting of compressional waves, shear waves, and converted waves. The recorded raw data were complex, have no resemblance to the inter-well geology, and were difficult or impossible to interpret. These unintelligible data sets were extensively computer processed. Detailed, accurate, images of the inter-well structure, and reflecting horizons were obtained as a result of this processing. This investigation demonstrates that excellent, accurate images of the inter-well geology can be obtained by skilled seismic cross-well data acquisition and extensive careful computer processing.

Jan 1, 1993

By W. N. Hamilton

British Columbia is geologically favourable for a rich variety of industrial mineral occurrences. Some have been produced for years, others overlooked until recently. Major production occurs for asbestos, gypsum, limestone, magnesite, silica and sulfur; lesser production for a dozen others. For several of the minerals, potential is much greater than existing production. New production opportunities exist also for diamonds, niobium and REE minerals, fluorspar, kyanite, nepheline syenite, talc, and several others. Alberta, though geologically less diverse, also has many industrial minerals. Limestone, salt and sulfur have the major production; clay and shale, silica, sodium sulfate and a few others lesser production. Opportunities exist for expanded production, and for new production in heavy (Ti -Zr) minerals, formation brines (Ca-Mg-I-Li), and gypsum.

Jan 1, 1987

By Stephen F. Munsell

The development of transportation systems for mined materials has historically been characterized by steadily increasing sizes in basic hauling units. This is especially true for open pit mines for which success is dependent upon the economical transportation of vast quantities of material. The depletion of high grade ore reserves has mandated a tremendous increase in the size and complexity of the ore haulage systems necessary for open pit mines, These increased demands were served by rail haulage systems in the early large open pit copper mines while later developed properties opted for the flexibility and lower initial costs of truck haulage. Now, we find the trucks being displaced as large overland belt conveyors tackle the problem of handling these ever larger quantities of low-grade ores with accompanying overburden ratios that can run as high as 10:1 or even 15:1. The basic development of large conveyors with shiftable sections and modular belts has generally taken place overseas, during the last few decades. The coal fields of central Europe proved an ideal testing ground for conveyor innovation because the low density and natural friability of the material created an ideal medium for transporting by belt conveyor. Now these proven ideas are being considered for and implemented into both the soft and hard rock mining industries of the United States.

Jan 1, 1978

By R. Mittler

Over 100 saprolite samples from Turkey Hill Gold Mine, Lumpkin County, Georgia, were analyzed (-80 mesh) for As, Au, and Sb. Maximum values are 16.2 ppm As, 7.9 ppm Au, and 29.1 ppm Sb. Results show trace element content of saprolite varies with topography: ridge top samples show a pronounced decrease in Au and Sb, and to a lesser degree in As, whereas, slope and valley samples have anomalous Au and Sb concentrations, with no discernable pattern for As. Statistical analysis shows strong correlation between Au and Sb and none between Au and As. This study will serve as a model for gold exploration in deeply weathered terrains with variable relief.

Jan 1, 1987

By F. Calizaya

A booster fan is an underground ventilation device installed in the main airstream to handle the total quantity of air circulated to one or more working districts. It is installed in a permanent stopping and equipped with airlock doors, a monitoring system and interlocking devices between the main fan and the booster fan. When adequately installed, a booster fan can be used to reduce the main fan pressure, reduce leakage and decrease the power consumption. However, an inadequate installation can increase the likelihood of mine fies and recirculation of air contaminants. This study identifies hazards associated with the operation and maintenance of booster fans. It analyzes the accompanying risks and recommends control measures to reduce those risks to acceptable levels. The ventilation network of an existing coal mine was updated to include a booster fan. The hazards associated with the operation of this fan were identified, the risks analyzed and the esponse to each failure mode established.

Mar 1, 2014

By David D. Eyer

In today's world coal market, coal quality is becoming increasingly important. Often the coal quality parameters are one of the crucial considerations in the development of a coal mine. Because of the user's tighter specifications and because of strict environmental regulations, coal producers are being called on to predict with increasing accuracy, not only the quality of their product but also the variability of that quality. This area of reserve evaluation is naturally receiving a great deal of scrutiny. Consolidation Coal Company has developed reliable and sophisticated methods for predicting coal quality, but the company's efforts continue to search for even better techniques. The following is a step-wise summary of The methods currently used by consolidation coal company, with A recent project used as an example. Two of the newer, and as yet experimental techniques will be briefly discussed.

Jan 1, 1980

By J. D. Miller

The fossil resins of certain western coals are of significance and of sufficient value as a chemical commodity to justify a fossil resin industry. At the present time these valuable fossil resin resources, worth more than $0.50/lb as a chemical commodity, are being burned as fuel for electric power generation. This waste of our fossil resin resources corresponds to a loss in revenue of $200 million per year -equivalent to the value of the coal itself! Improved process technology for the recovery of fossil resin is under development and includes selective flotation of fossil resin from fine coal streams and solvent refining of the fossil resin flotation concentrate to produce a premium resin product. The most recent developments in process technologies are discussed with respect to separation efficiency and product quality. It is clear that the development of a fossil resin industry should not be limited by process technology.

Jan 1, 1994

By Todd Burchett

Mining engineers spend countless hours and resources when designing a new underground coal mine. Their primary objective is to design the safest and most efficient operating mine with regards to coal production. A key variable often overlooked in this design stage is the slope conveyor. Typically, a slope conveyor is expected to operate with a 98-percent or higher availability. However, too often little effort is put forth by the mining engineer to optimize its design. Coal companies will rely on engineering, procurement, construction and management (EPCM) companies for the preliminary design, because the slope conveyor will be considered part of the surface material handling processes. This preliminary design will be used when soliciting quotations for the slope conveyor. Unfortunately, EPCMs may not have enough expertise with conveyors to optimize the design. This expertise is available with an original equipment manufacture (OEM) of conveyors, which ultimately may be responsible for supplying the slope conveyor. Each OEM will provide a bid package that represents what it considers to be the optimal design.

Jan 1, 2013

By Andrew W. Jenike

There used to be a time when bins were designed for total volume and placed in any available place of the plant. Poke holes were provided and feed was maintained by manual prodding, lancing, hammering, and by various mechanical flow-profiting devices. Little thought was given to what occurred inside the bins and why materials did not flow. Indeed, such mental effort was hard to justify while low-cost manual labor was plentiful, quality standards low, and rates of feed moderate. The past fifteen years have seen a drastic change in these conditions. We all know that labor for hard manual work is becoming unavailable at any wage, level. Standards of product uniformity are continuously rising. This uniformity is just as important in a fine ore feed to ball mills as it is in a cattle feed or in a flour mix. Rates of feed now frequently exceed 2,000 tons per hour per feeder. At that rate there is no time for, lancing or prodding. An efficient storage, plant contains a known available volume of bulk solid, and feeds it at the required time, at the prescribed rate, and without degradation of the product. A storage bin may also perform other functions such as blending of different grades, degasification of aerated, powders, isolation of different gaseous media. A contact bed of particles flowing by gravity in counter-current with a gas or liquid may be used as a continuous reactor. Gas or liquid pressures can be simply contained by, a sufficient head of flowing solid.

Jan 1, 1968

By Paul C. Lingo

Two recent antitrust cases, coming from widely separated areas, different industries and involving wholly different facts were decided by the Supreme Court on June 7, 1965. The decisions in there two cases may well prove to be the most important and far-reaching decisions in the field of labor law that have been handed down in the last 24 years. These cases, although quite dissimilar factually, had one common element. In both, the gravamen of the antitrust violation was bottomed on the terms of labor agreements negotiated by a multiemployer group. These cases are usually referred to as Pennington1 and Jewel Teat. Since a number of references will be made to the antitrust laws, it may be well to state briefly the applicable portions. Section 1 of the Sherman Antitrust Act makes "every contract, combination in the form of trust or otherwise, or conspiracy, in restraint of trade or commerce among the several states, or with foreign nations, is declared to be illegal...". Section 2 imposes criminal sanctions against "Every person who shall monopolize, or attempt to monopolize, or combine or conspire with any other person or persons, to monopolize any part of the trade or commerce among the several states...". Under Section 4 of the Clayton Act a person who sustains damages as a result of a violation of the anti¬trust laws is entitled to recover treble damages plus costs.

Jan 1, 1966

By A. M. Marabini, G. Belardi, V. Alesse, M. Acosta

Sotiel mine is situated in the Iberian Pyrite Belt in southern Spain, some 40 km north of the port of Huelva. Although mining operations at the site date back to Roman times, the present mine came into production in 1983 and 5.6 million tonnes of ore had been extracted by 1993. The orebody is volcano-sedimentary and consists of fine grained copper, lead and zinc minerals in massive pyrite surrounded by slates and volcanics. Prior laboratory research had resulted in the synthesis of a new collector, belonging to the MercaptoBenzoOxazole (MBO) class that acts selectively towards Cu and Zn minerals after activation with CuS04. The MethylMercaptoBenzoOxazole (MMBO) version of this collector had been used for the laboratory flotation of Cu minerals and sphalerite activated by CuS04. This resulted in identification of the optimal physicochemical conditions for laboratory-cell flotation of the two minerals from samples of complex sulphide ores, and subsequently the reagent has been tested in the Sotiel plant (Spain). The plant has three flotation sections. With conventional re-agents, the first section yields a Cu concentrate grading 21% with a total recovery of 29%, and the second one yields a 40% Pb concentrate with total recovery of 34% and a 47% Zn concentrate with total recovery of 78%. Application of the new synthetic reagent in the copper and zinc circuits produces a more selective process with a decrease in re- agent concentration grade and recovery are increased by 2 and 9 points respectively in the case of Cu and by 1 and 3 points where Zn is concerned. Moreover, the penalty elements in the Cu concentrate are halved.

Jan 1, 1995

By J. B. Hiskey

Thiourea is a reagent capable of complexing gold and silver. With the proper oxidant, thiourea can effectively dissolve metallic gold and silver. A thiourea leaching system possesses potential advantages over conventional cyanidation including acidic solutions instead of alkaline, cationic complexes in contrast to metal-cyanide anionic complexes, and faster leaching rates with acidic solution of thiourea. Generally, the rate of metal dissolution in thiourea solutions is fastest when ferric ion is employed as an oxidant. Acidic thiourea solutions for certain applications could offer a nontoxic and noncorrosive option for processing gold and silver. This paper provides information regarding the fundamental chemistry of the acidic thiourea system, and reviews the dissolution of both silver and gold in acidic solutions of thiourea. The recovery of gold and silver from acidic thiourea solution is discussed.

Jan 1, 1981

By Shangyong Lin, Wei Sun, Weiping Liu, Muhammad Azam, Junfeng Cheng, Yujie Zhao, David Asubonteng, Michael Ngoie

Copper concentrates have wide application in global smelting operations, comprising primarily of chalcopyrite (CuFeS2) as the principal mineral, accompanied by chalcocite (Cu2S) and bornite (Cu5FeS4) as secondary copper-bearing minerals. However, these concentrates frequently harbor detrimental impurities, notably fluorine ions, which can cause various complications during the smelting process. Moreover, an elevated fluorine content in copper concentrates may entail financial penalties and sales constraints. This review conducts a comprehensive analysis of existing methods for the removal of fluorine, presenting a nuanced assessment of their merits and demerits. It also provides valuable insights into the current landscape of fluorine elimination from copper concentrates and pinpoints pivotal areas warranting future investigation. This review endeavors to serve as a pragmatic resource for researchers and industry professionals operating within this domain.

Jan 1, 2024

By Fabio Mielli

Encompassing between 20 and 40 percent of the typical mining operational costs, energy in mining operations is a growing concern for the industry. However, this concern is a complex, multi-faceted variable that involves government regulations, societal pressures, cost and competitiveness. Managing energy efficiency is becoming a keystone of successful companies. The suggested energy strategy in mining and mineral processing operations must follow a well-structured approach to include the following: ? Understanding where energy is being used and why. ? Recommending and implementing energy conservation measures. ? Driving visibility to targets and results. ? Leveraging the energy spent across the enterprise. ? Developing a robust energy and sustainability strategy. Additionally, it must ensure that all decisions support the financial and operational integrity of the business.

Jan 1, 2012

By M. E. Grimes

Rio Algom Mines Ltd. owns eight uranium mines and mills in the Elliot Lake district of Ontario, seven of which were producing before 1960. At present only one mine is operating meeting current contract requirements. Under present economic conditions, it is not feasible to mine ore of less than 2.0 lbs./ton U308, although there are very large reserves below this grade. We are interested in preconcentration for three possible applications: to extend ore reserves by permitting use of lower grade ore, to reduce costs on processing of present grade ore, and to reduce capital investment in expanding production to meet future production goals.

Jan 1, 1973

By A. Yehia

Fluoride activation has been evaluated by Hallimond-tube flotation of collophanite in terms of fluoride concentration, conditioning time, pH, and temperature. The results reveal that efficient oleate flotation of collophanite can be achieved by fluoride activation. Fluoride adsorption by collophanite as a function of fluoride concentration, temperature, pH, and crystal structure suggests that, at low fluoride concentration, a fluoroapatite-type compound may form on the collophanite surface by chemisorption of fluoride ions at calcium sites; at high fluoride concentration, calcium fluoride ap¬pears to form at the collophanite surface invovling a surface-precipitation phenomenon. The formation of CaF2 on the surface of fluoride-treated collophanite is further substantiated by the FTIR spectroscopic measurements, which clearly shows a metathetic exchange with phosphate from the collophanite lattice during surface precipitation process.

Jan 1, 1986

By Peter C. Finlayson

Rapidly rising gas and oil prices and the falling quality of coal is forcing energy users in many parts of the world to consider the application of low grade fuel, particularly coal, for steam raising and power generation. However, the use of such low grade coal is normally resisted by the consumer because of operational problems associated with high ash content, sulfur emission and, in some instances, slagging problems caused by low melting temperature constituents in the ash. Recently developed technology involving 'fluidized bed combustion' offers a potential solution to these operational problems. Much of the early work was conducted in Britain, where rig tests were commenced during the early 1960's. This has led on to the successful conversion and operation of a fluidized bed fired industrial boiler at the Renfrew works of Babcock & Wilcox Ltd. Orders for the first commercial boilers incorporating this technology have recently been announced. Significant development work on fluidized combustion is now being undertaken in various parts of the world, in particular North America, Germany and Japan, and the first large scale units are under construction or being commissioned. This paper concentrates on the development of the technology in Britain, outlines the reasons for applying fluidized bed combustion and de-scribes its application at atmospheric pressure for steam raising and at elevated pressure for power generation . Coal Processing Consultants is a Partnership between the National Coal Board and Babcock & Wilcox Ltd. of Britain and has been established in order to provide technical advice and economic evaluations on all aspects of coal processing and utilization. In view of the involvement of its Parents in the development and exploitation of fluidized bed combustion technology, Coal Processing Consultants has been retained by clients in various parts of the world to provide expert advice on the application of fluidized combustion for particular coals and project situations.

Jan 1, 1978