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By C. L. Jiang

The role of iron ions (Fe2+ and Fe3+) in the flotation of both ore-and coal-pyrite with ethyl xanthate was comparatively investigated. The complete/partial depression of ore-and coal-pyrite in neutral to weakly alkaline solution is due to the formation of ferric dihydroxy ethyl xanthate between xanthate and the oxidation products of pyrite, ferric and ferrous ions. With xanthate as collector, coal-pyrite was found to be nonfloatable above pH6. In the presence of iron ions and between pH6-9.5, the flotation of ore-pyrite was significantly depressed. Ferrous ions have a stronger effect on pyrite flotation than ferric ions in neutral to weakly alkaline solutions.

Jan 1, 1996

By M.P. ROY, ASHISH K. VISHWAKARMA, A.K. MISHRA, P.K. SINGH, VIVEK K. HIMANSHU

Principal component analysis (PCA) is one of the dimension reduction techniques widely used to classify data based on features. Ground vibration is a major hazard arising from rock blasting operations, and accurate prediction of the vibration is necessary for designing controlled blasting parameters. Most of the widely accepted predictors of ground vibration consider the maximum explosive charge weight per delay (MCPD) and distance as the parameters responsible for ground vibration, but mining sites with bigger production targets have varying geometrical parameters to suit the excavator utility. Accordingly, other blast design parameters will also have impacts on ground-vibration intensity. A blast vibration predictor considering all the blast design parameters would be complicated, and some of the parameters will have overlapping contributions to ground-vibration intensity. Data classification using PCA is a feasible solution, and regression analysis may be performed to develop predictors using the classified input data. In this study, PCA was used along with multivariate logarithmic regression to predict ground vibration, and the performance of this technique to predict ground vibration was compared with the performances of various existing empirical predictors. The evaluation suggests that the predictor with logarithmic regression followed by PCA performs better than the existing empirical predictors.

Nov 1, 2022

By M. A. Bouchat

The Kipushi deposit, where the Prince Leopold Mine has been installed, belongs to Union Miniere du Haut-Katanga and is located in the Belgian Congo, 20 miles SW of Elisabethville, at the vicinity of the Northern Rodhesian Border. The deposit is of the hydrothermal metasomatic vein-type; mineralisation took place, through the limestone of the, lower Kundelungu. This is a special fea¬ture of the deposit, compared to the other copper deposits of the neighbourhood, both in the. Belgian Congo and in Rhodesia. Actually, the primary mineralisation of these other deposits; is directly related to the stratigraphic systems: schistous dolomitic in the Belgian Congo and Roan in Rhodesia. Both facies are older than the Kundelungu and separated from this formation by a tectonic cataclysm. The valuable elements occuring at Kipushi are principally copper; and zinc. The deposit also contains smaller quantities of lead, precious metals and other elements including germanium.

Jan 1, 1960

By Lit-Mian Chan, David H. Carlson, John H. Johnson

This paper presents an apparatus and procedures to implement a methodology for controlling ambient air quality in a confined working environment, such as an underground mine, an underground storage area, or a tunnel. The air quality control methodology is directed at limiting the quantities of exhaust pollutants emitted by diesel-powered vehicles into the confined space by identifying vehicles that are excessive polluters. The methodology is based on tailpipe and ambient air measurements in the confined space, and the ambient air threshold limit values (TLVs) for the various diesel exhaust pollutants. The methodology consists of two computational methods; a deterioration criteria computational method to identify excessive polluting vehicles, and an engine performance computational method to determine engine performance and to provide information needed to diagnose engine faults. The methodology is designed for implementation in conjunction with a preventive maintenance program. The first part of the paper describes the mine air and tailpipe emissions measurement apparatus and techniques used to obtain data. This is followed by sections discussing the deterioration criteria and the engine performance computational methods. A section discussing some common engine emissions-related faults is also presented. Lastly, a proposed procedure to implement the methodology including a possible hierarchical structure for mine personnel involved to implement the procedures is presented.

Jan 1, 1993

By Gordon M. Elliott

Health risk underlies all of today's environmental regulations. Mine Manager's are no strangers to risk, but risk in the context of mine management is not the same as risk in the context of environmental regulation. One of the risks facing the mine manager is whether the mining operations meet environmental compliance standards. These standards are defined in terms of the frequency of occurrence of adverse health effects in an exposed population (i.e., health risk). Demonstration of compliance necessarily involves mathematical modelling and selection of values for input variables. What is not immediately apparent is that the method of estimating the human health risk has a significant influence on remedy selection and the amount of money spent at suspected contaminated sites. Using a hypothetical, mining-related example, this paper illustrates the disassociation between the current deterministic approach to health risk assessment and cost-effective decision making. This paper also illustrates how the probabilistic approach to health risk assessment provides a more realistic characterization of health risk and enables mine managers to identify cost-effective remedial strategies for the site.

Jan 1, 1992

By Terry W. Mellors, Robert J. F. Goodfellow

The underground industry has been forced to reconsider risk management sincethe introduction and implementation of the “Joint Code of Practice for Risk Management of Underground Works in the UK” published in 2003 and the subsequent international version published by the ‘International Tunneling Insurance Group’ (ITIG) in January 2006.What does this mean for major tunnel projects in the US and elsewhere? The discussion will highlight the implementation of the Codes to date, risk management principles embodied in the Codes and the use of risk registers as a projectmanagement tool and the management of risk.

Jan 1, 2007

By M. P. McArthur

General mining practices at W. R. Grace's Bonny Lake mine are much the same as those used in open pit phosphate mines in Central Florida, except for the difference in the depth of the overburden which introduces many variations, From 1945 to 1961 the mining at Bonny Lake has been from an area in which the overburden averages from 55 to 60 feet and in several locations exceeded 65 feet. The matrix thickness will average 15 to 18 feet for the areas mined. As you can see from the above depths a total hole depth will average from 70 to 75 feet.

Jan 1, 1962

By J. Abbott

This paper gives a brief description of the Compania Ninera del Pacifico (CNP) a subsidiary of the Campania Acero del Pacifico (CAP), its participation in the Chilean Iron Ore mining and the gradual development of its activities. mainly in this paper, it is explained the CNP experience in the production of 34 million tons of self-fluxing pellets for Blast Furnace in a period of ten years in its Huasco Pellets Plant.

Jan 1, 1989

By Chris C. Sundberg, Ronald E. Heuer, Stanley L. Paul, Peter M. Douglass

Use of prestressed concrete cylinder pipe (PCCP) for pressure tunnel liners is gaining popularity with contractors, engineers, and owners. This paper presents loading considerations and a beam-spring computer model approach to tunnel liner analysis, together with ultimate strength (US) and service load (SL) procedures for liner design. The US procedure is best suited to check for adequate liner strength under extreme loading conditions. The SL procedure, based on conventional pipeline design practice, is considered more appropriate when addressing crack control and serviceability under normal working load conditions. Other design and construction considerations are discussed and a design example is presented.

Jan 1, 1987

By H. A. DeMirjian

Oil production rate and ultimate primary recovery from a heavy or viscous oil reservoir is usually limited to a very small fraction of the original oil in place. Typically, normal production rate is in the range of up to 10 barrels per day and expected ultimate cumulative production is up to 10% of in place values. Heavy oil reserves are not all alike. The physical properties of the rock, the liquid hydrocarbons, and depths of the deposits are so different that each reservoir poses a unique enhanced oil recovery problem. In some reservoirs thermal recovery by internal heat generation or external heat injection has been successfully exploited. In other reservoirs, mining the oil bearing formation for oil recovery by surface processing has been practiced. This paper will present an overview of the heavy oil recovery state of the art and discuss the critical factors leading to the decision for selection of a conventional hydrocarbon recovery or mining and extraction processes.

Jan 1, 1978

By Pablo Hadzeriga

There are two places in the world where potash, trade name for potassium chloride, is economically recovered from naturally occuring brines by solar evaporation. One is at the Dead Sea and the other at Wendover, Utah. American Potash and Chemical at Trona, California recovers potash from natural brines, but uses fuel to accomplish evaporation. Under proper meteorological conditions the use of solar evaporation might be desirable from the economical standpoint. Of course, this may not be true when, if by artificial evaporation, a group of very valuable salts are recovered. This is the case of the American Potash operation at Trona. Solar evaporation has its limits. The working temperature is low. We may say, just to cover most areas of the world where solar evaporation may be practical, that it will take place between 18°C and perhaps around 45°C. In most cases the average working temperature expected will be around 25°C.

Jan 1, 1963

By T. K. McCranie, A. H. Tousley, A. H. Kackman, L. R. Gregory, A. Jr. McElrath, R. J. Krekel

In Roman and earlier civilizations the term cement was applied only to mixtures of lime, pozzolana, sand, water, etc., used as a mortar to bind larger stones. Today, portland cement, the subject of this section, can be briefly defined as follows: The product obtained by finely grinding clinker produced by calcining to incipient fusion (i.e., sintering) an intimate and properly proportioned mixture of argillaceous and calcareous materials. History The Egyptians were probably the first to join building stones with a mixture of sand and a cementitious material (i.e., having the property of or acting like cement). It is generally accepted that the cement used by the Egyptians on such structures as the Great Pyramid was calcined gypsum, Later the Greeks began to calcine limestone for use as a mortar with sand and water. Still later, broken brick and tile were added to the mortar to make the first concrete. The Greeks and Romans found that some sands produced mortars that were especially resistant to the action of water. Hydraulic (i.e., underwater-hardening) cements formed by combining slaked lime, water, and finely divided siliceous materials (e.g., pozzolana) possess superior strength and are capable of resisting the destructive action of water. They were used on the Pantheon, Colosseum, and other structures, some of which are still standing. In 1756 an English engineer, John Smeaton, found that an argillaceous limestone (i.e., containing an appreciable amount of clay as an impurity) produced a cement with greater resistance to the action of water. Despite Smeaton's findings, the use of the old mixture of lime and pozzolana long retained its popularity. Significant contributions in cement technology from England, Swe¬den, France, and Holland were made in the next 68 years. However, the invention of portland cement is generally credited to Joseph Aspdin, an Englishman, who in 1824 patented "portland cement." The name was selected because, on hardening, it resembled the natural building stone from the Isle of Portland, England. The patent features mixing ground limestone and argillaceous materials in appropriate proportions and calcining (i.e., expelling CO2 by roasting) the mixture. This superseded the existing practice of calcining naturally occurring argillaceous limestone. In about 1845 Isaac Johnson, also English, conducted experiments on proportioning the components and calcining them at higher tem¬peratures. His accomplishments are accepted as the beginning of the present-day portland cement industry. The U.S. cement industry originated with the demand for good hydraulic cement for building structures such as the Erie Canal, which was started in 1817. The first discovery of cement rock (i.e., naturally occurring argillaceous limestone with near-optimum ratios of calcium carbonate, alumina, and silica) near Fayetteville, N.Y., was made by C. White. In 1818, White secured a patent for the manufacture of natural cement from that deposit. Subsequently, several natural cement plants were built in 1830-1840 at Rosendale, N.Y., and in the Lehigh Valley of Pennsylvania. David Saylor, who participated in establishing a natural cement plant at Coplay, Pa., in 1850 discovered that a superior cement could be produced by calcining the rock at higher temperatures than hith¬erto. In 1871, Saylor obtained a patent and commenced the manufac¬ture of portland cement. By 1890, there were 17 portland cement plants in the United States with a combined annual output of 62,300 tons. At the end of 1970, the number of plants producing portland cement in the United States (including Puerto Rico) was 169, down from a maximum of 185 in 1967, with total annual shipments of 73.4 million tons valued at $1,298 million. (Fig. 1). In 1970, annual world production of hydraulic cement (which includes pozzolanic materials, hydraulic limes, natural cement, alumina cement, and portland cement, all of which are in current use in various parts of the world) reached 630 million tons (Table 1). Flowsheets of typical U.S. cement plants are shown in Chapter 13. Chemical Composition and Physical Properties It is generally accepted that portland cement clinker consists of a mixture of compounds or synthetic minerals. The four principal compounds are:

Jan 1, 1985

By Dennis Arthur Fenton

The hydrodynamic bearing was first described by, Reynolds in 1886, and has since been widely applied in motors, engines, compressors, hydroelectric turbines, and other machinery. For various reasons, the hydrostatic bearing currently predominates in the large, horizontal rotating machinery field (e.g. grinding mills). However, the current industry trend towards increasing size and energy efficiency has resulted in renewed interest in the advantages of hydrodynamic bearings. These advantages include structural improvements, reduced bearing friction, improved bearing life, improved transient characteristics, and reduced lubricant pump size and power requirements. In particular, the higher energy efficiency results in substantial savings on large machines. This paper describes some aspects of the design of large hydrodynamic bearings based on thirty years, of experience in the design of such bearings on grinding mills ranging in journal size from 2.1 m to 6.4 m, see Table 1.

Jan 1, 1985

By J. D. Miller

The processing of residues derived from various operations in the mining and metallurgical industry for by-product recovery is becoming more prevalent. A principal target for by-product recovery is flue dust produced by conventional smelting operations. Flue dust from zinc smelters has been processed for many years for the recovery of cadmium (1,2). The cadmium recovery technique which consists of a selective sulfation roast, followed by a water leach and zinc dust cementation, produces a lead cake residue (see chemical analysis in Table I), which consists primarily of lead sulfate.

Jan 1, 1975

By Marie-Josée Banwell, Cyriac Sebastian, Giacomo Falorni, Sara Del Conte

Interferometric Synthetic Aperture Radar (InSAR) is a satellite-based monitoring technique that complements other in-situ methods for detecting and measuring surface displacement. Recent advances in data processing algorithms, coupled with the use of high-resolution satellite systems, make it possible to now provide high-frequency InSAR monitoring services, with updated results delivered every time a new satellite image is acquired. The advent of large, continuously updated data sets, however, brings new challenges, including the need to rapidly sift through the data to identify only those points showing relevant ground displacement information. This has been achieved by using trend variation analysis tools, that quickly isolate and highlight only areas of anomalous behavior. The paper focuses on project case studies where continuous InSAR monitoring has proven to be key in identifying displacement trend changes near tunnel alignments.

Jun 13, 2021

By G. L. Alston

The mine disaster last November in northern West Virginia has compelled the coal mining industry to take a closer look at the methods of transporting and applying rockdust. The USBM has indicated they would like to see a minimum of 80% incombustble in the back entries and want rockdust to be maintained to within 40 feet of the face at all times. With today's high rate of advance of mining machines it will be necessary to apply dust in the immediate returns continuously and the working places mutt have dust applied during the operating shift. The inspectors have become more demanding in requiring clean-up of coal and coal dust in the working place before rockdust is applied and are insisting on better clean-up and better rockdust applications along belt conveyors. Maintaining a constant application of rockdust in the back entries can be done with a Trickle-Duster. The machine is designed with hopper capacities of either 400 or 1,000 pounds of dust. The discharge rate of dust being fed through 1-1/2 inch diameter hose can be adjusted from 1/2 to 5 pounds per minute. The hose is extended into the return through the last open breakthrough and the return air carries the rockdust along w th the coal dust, depositing them uniformly on rib, roof and bottom.

Jan 1, 1969

By C. E. Jordan

Abstract. The U.S. Department of the Interior, Bureau of Mines, as part of its effort to maintain an adequate supply of minerals and metals to meet national economic and strategic needs, is conducting research on the pneumatic recovery of coarse mica. A system of crushers, screens, and zigzag air classifiers is used to concentrate coarse liberated mica particles from mica ore and from the waste tailings of abandoned mica operations. The plus 0.21-millimeter-size mica is effectively recovered by this method. The mica concentrates produced contain over 90 percent mica. The method recovered up to 78 percent of the mica in the samples. As a dry concentration method, the pneumatic-beneficiation technique may be advantageous in areas of limited water resource.

Jan 1, 1980

By R. Froidevaux

Geostatistical estimation techniques were customized to enable forecast of production figures at the Silver Bell uranium mine (Uravan District). Surface drill hole data were used to provide a block model of kriged estimators of average uranium grades. The recoverable figures, such as ore-waste ratio and ore grade, are then deduced from regressive curves previously obtained from underground information and production data. Cross-validations of the entire model were performed and were found positive.

Jan 1, 1981

By N. Loganathan, Tan Boon Tee, Joe O’Carroll, Richard Flanagan

In recent years, tunnelling activities in Singapore have increased considerably with the construction of extensions to the existing sub-surface transport system, a deep tunnel sewerage disposal system, and tunnels for the laying power cables and other utilities. These tunnels are excavated through urban areas, adjacent to high-rise buildings, depressed road structures, beneath other tunnels, and buried services. Earth pressure balance (EPB) tunnel boring machines (TBM) have been used extensively in Singapore with great success. The risk associated with soft ground tunnelling, including tunnelling through Old Alluvium, can be minimized with an understanding of the geology, geotechnical parameters, and the tunnelling-induced behaviour of Old Alluvium (OA The purpose of this paper is to present some design and construction aspects of EPB TBM tunnelling through Old Alluvium.

Jan 1, 2005

By C. J. Pritchard, R. E. Gundersen

I commend the authors on examining an interesting method of shaft lining and attempting to improve safety in a dangerous environment by remotely installing the shaft lining. It is important, though, to not trade off shaft lining safety for long-term mine safety by lining an intake shaft with combustible material. In many operations, the mine utilities are installed next to the lining of the intake shaft, supplying a possible ignition source if damaged or overloaded. Although the polyurethane studied in the paper is of relatively high density, no mention is made of the flame retardency of the samples. When exposed to heat, small amounts of polyurethane will melt and bum but are extinguished when the heat source is removed. If large surface areas of combustible polyurethane - a tunnel or mine shaft- are exposed to ignition heat sources that are not removed or extinguished early, an uncontrollable, fuel rich fire may result with high carbon monoxide levels, low oxygen concentrations, and greatly increased burning rates that can have devastating effects on the ventilation system and miners' safety. Although these heavy polyurethanes lend themselves to a "pouring" application around the annulus of the shaft liners and is a continuous process, past experience with atomizing and frothing polyurethane spray systems indicates a high degree of maintenance and operator attention to the nozzle1 delivery system. This may require more miner's time to be spent in the shaft maintaining the foam system, negating some of the safety advantages of the system. If polyurethane foams are to be used in mines, they must be of the highest quality available in terms of flame spread, heat emitted while curing, and contaminants emitted while curing and spraying. In addition, employees must be given adequate training and be thoroughly informed in all aspects of polyurethane foam safety procedures. As witnessed by our fellow miners in South Africa, we can accept no less.

Jan 1, 1991