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By Shiou-Chuan Sun

THIS paper presents the design and operation of a frothmeter capable of measuring the frothing characteristics of pine oils and other frothing reagents. The experimental data show that the froth-ability of pine oil is governed by: 1—rate of aeration, 2—time of aeration, 3—height of liquid column, 4—chemical composition of pine oil, 5—pH value of solution, 6—temperature of solution, and 7—concentration of pine oil in solution. The effect of mineral particles on the behavior of froth also was studied, and the results can be found in a separate paper.' The results also show that the relative froth-abilities of pine oils in the frothmeter generally correlate with those in actual flotation, provided that other factors are kept constant. In addition to pine oils, the other well-established flotation frothers were tested, and the results are included. In this paper, compressed air frothing is the frothing process performed by means of purified compressed air, whereas sucked air frothing is the frothing process accomplished by purified air sucked into the glass cylinder by a vacuum system. The term vacuum frothing denotes that froth was formed by degassing of the air-saturated liquid under a closed vacuum system. Apparatus The frothmeter, shown in Fig. 1, is capable of re-producibly measuring the volume and persistence of froth as well as the volume of air bubbles entrapped in the liquid and is capable of being used for compressed air frothing, sucked air frothing, and vacuum frothing. Fig. la shows that for compressed air frothing, the apparatus consists of an airflow regulating system, 1-3; a purifying and drying system, 4-8; a standardized flowmeter to measure the rate of airflow from zero to 500 cc per sec, 9; and a graduated glass cylinder, 13; equipped with an air regulating stopcock, 10; an air chamber, 11; and a fritted glass disk to produce froth, 12. The fritted glass disk, 5 cm in diam and 0.3 cm thick, has an average pore diameter of 85 to 145 microns. The pyrex glass cylinder has a uniform ID of 5.588 cm and an effective height of 63 cm. The inside cross-sectional area of the glass cylinder was calculated to be 24.53 sq cm, or 3.8 sq in. For sucked air frothing, Fig. lb shows that the apparatus for compressed air frothing is used again, with the following modifications: 1—compressed air and its regulating system, 1-3, are eliminated; and 2—a vacuum system, 16, equipped with a vapor trap, 15, and a vacuum manometer, 17, is added. The vacuum system can be either a water aspirator or a laboratory vacuum pump. Any desired rate of airflow can be drawn into the glass cylinder, 13, by adjusting the opening of the air regulating stopcock, 10. The sucked air stream is cleaned by the purifying and drying system, 4-8, before entering the glass cylinder, 13. When this setup is used for vacuum frothing, the air regulating stopcock is closed. The frothmeter has been used for almost 3 years and has proved to give reproducible results, as illustrated in Table I. With a magnifying glass and suitable illumination, the frothmeter also can be used to study the attachment of air bubbles to coarse mineral particles.' Experimental Procedures Except where otherwise stated, the data presented were established by means of the compressed air method. The volume and persistence of froth were recorded respectively at the end of 4 and 6 min of aeration at a constant rate of airflow of 29.3 cc per sec, which is equivalent to 71.6 cc per sq cm per min, or 462.6 cc per sq in. per min. The aqueous solution for each test, containing 1000 cc of distilled water and 19.2 ± 0.5 mg frothing reagent, was adjusted to a pH of 6.9 0.2. The volume of froth is expressed as cubic centimeter per square centimeter and is equivalent to the height of the froth column (the distance between the bottom and the meniscus of the froth). The volume of froth was obtained by multiplying the height of froth by the cross-sectional area of the glass cylinder, 24.53 sq cm. Before each test, the glass cylinder, 13, was cleaned thoroughly with jets of tap water, ethyl alcohol, tap water, cleaning solution, tap water, and finally distilled water. The cylinder with stopcock,

Jan 1, 1953

By C. A. Hardie, G. F. Leichtle, J. A. Finch, J. A. Watson

"The recycling of wastepaper has become an important and common process worldwide. Techniques similar to those used in the mineral processing industry are used to produce high quality recycled fibres for use in newsprint. The mineral processing group at McGill University, in conjunction with the Pulp and Paper industry (Mechanical and Chemi-mechanical Wood Pulp Network), has adapted one of these techniques, column flotation, for the purpose of deinking wastepaper. This article describes the typical process of recycling wastepaper from a mineral processing point of view. It also presents results from McGill University’s flotation column test work at a Québec wastepaper recycling facility. IntroductionThe recycling of wastepaper has become an important and common process worldwide, including Canada which is now the world’s largest importer of wastepaper (CPPA, 1996). Much of the current drive to increase the utilization rate of recovered paper is a reaction to the solid-waste disposal problem that faces many Canadian and United States municipalities. The real problem in the disposal of solid waste is not the absolute amount of garbage that must be disposed of each year, but this amount in relation to available disposal capacity.Environmental restrictions on the creation of new landfill sites and incinerators (the two main options for disposal of municipal solid waste) have tightened the demand/supply balance in the solid waste disposal market. This shrinking availability of waste disposal sites in the face of increasing population with greater disposal requirements defines the Developed World’s solid waste crisis. Not only are there fewer disposal sites available, but the costs of using them is skyrocketing. These factors have increased government regulations mandating recycled paper content in newsprint. Conservation and environmental issues make the current drive for wastepaper recycling a real issue and business opportunity."

Jan 1, 1999

By Zhenbo Zhao

The processes and equipment for INLRFH (Isothermal Normalizing by Utilizing the Residual Forged Heat) of alloy carburizing steel products are presented. It is shown that four key parameters: namely (I) cooling rate before isothermal normalizing, (IT) the lowest cooling temperature before isothermal normalizing, (111) isothermal normalizing temperature and (IV) isothermal normalizing time, should be controlled. The prediction and calculation of these parameters can be achieved on the basis of components treated and the technical requirements of the steel parts by an on-line expert system. The cost-reductions due to the energy savings resulting from implementing this system for automotive parts heat-treatment are most promising.

Jan 1, 1999

By Enrique Levy

Central America is graduating this year into large scale mining with the start up of Inco's multi-million dollar nickel laterite processing plant in Guatemala. In the other extreme of the Isthmus in Panama Texas Gulf Sulphur is doing check diamond drilling and foundation test drilling at the Cerro Colorado copper porphyry. The higher price of gold and silver has spurred development and exploration of several small precious metal mines. The purpose of this presentation is to make a brief resumé of the most important mines operating in the area and a list of significant exploration projects. Also, tables will be shown to compare mining codes and taxes. Unfortunately these tables lack information on Panama. Before starting I like to express my appreciation to Kennecott Copper who permitted the use of some of the data compiled by the author on their behalf during the year 1975. Other persons which did not want to be named also have my gratitude.

Jan 1, 1977

By Dajian Wang

To obtain the thermodynamic properties of a multicomponent liquid alloy system over the whole range of concentration at an arbitrary temperature, the free volume cell theory has been applied to derive the formula of activity coefficients of liquid solutions based on the infinitely dilute solutions at some temperature. The linear logarithmic relationship between activity coefficients of binary dilute solutions and reciprocal of absolute temperature have been verified, and are in good agreement with the experimental values from the literature. The Monte-Carlo algorithm was used to calculate the nonlinear end value equations of binary systems, then the free volume parameters obtained were correlated with the activity coefficients of liquid binary, ternary, and quaternary systems at an arbitrary temperature. Three dimensional a-X-T diagrams of some binary systems representing the temperature and concentration dependence of activities were plotted. The calculated results regarding non-ferrous alloy systems have been statistically examined with the experimental values from the literature. Hence, this simple approach could be useful for analyzing thermodynamic properties of liquid alloy systems.

Jan 1, 2000

By F. X. Tartaron

Behavior of hard-burned quicklime was compared with that of soft-burned quicklime in an oxygen converter utilizing oxygen blowing in a rotating cylindrical vessel, set at a 30° to 60° angle to the horizontal and operated at a predetermined speed of rotation. Four pairs of tests were made) each comparing hard lime with soft lime. Three of the pairs differed from one another in the quantity of lime employed) and the fourth differed in blowing time, All four pairs showed an increase in yield when soft lime was used. Three of the pairs revealed that the ratio of the oxygen consumed with soft lime to the oxygen consumed with hard lime was the same as the ratio of metal yield with soft lime to the metal yield with hard lime. The fourth pair contained an error and could not be included. Finally, a close inverse relation was found between the combined iron in the slag and the combined lime in the slag, which can be expressed by the equation pct Fe = 52.67 -0,906 (pct CaO).

Jan 1, 1967

By Robert S. Shoemaker

The development of a metallurgical project is a business venture rather than a technical exercise, and its real objective is to obtain the maximum return on investment consistent with the limitations imposed by company policy and the requirements of society. Demand for profits is the driving force for technical advances and naturally leads to improvements in processes, equipment and plant designs. In the mineral dressing field there have been virtually no new processes developed since the introduction of flotation, and the steady erosion of profits by inflation has been offset only by increasing equipment size. Unfortunately, in recent years, plant designers have not always utilized the largest equipment or the opportunities for functional and economic design presented by the development of larger equipment. Lower cost plants can be developed providing that unrealistic restraints arising from the prejudice of past practices are avoided. As an illustration of this premise, three different approaches were taken toward the design of a clearly delineated but hypothetical copper concentrator of 20, 000 tons per day capacity. While the same flowsheet was used in each case, designs were produced for a conventional plant, an alternate using the largest available equipment, and a third scheme utilizing large equipment and the most functional design which could be developed, including features derived from many plants in many different industries. Capital costs were developed for the three separate designs based on a location in the southwestern United States. Ancillary facilities were identical in each case and included a mine truck shop, a maintenance shop, a general office, and a nominal starter dam for tailings disposal within 5000 feet of the plant. Water supply within 1000 feet of the plant, and power furnished to the property boundary has been assumed in each case. The flowsheet of the three plants is shown in Figure 1 and represents the treatment of a typical sulfide copper ore by three- stage crushing followed by single-stage ball milling. Concentration is by flotation roughing and scavenging followed by regrinding of the concentrates and two stages of cleaning.

Jan 1, 1971

By G. Roy, D. R. Lentz, A. O. Wills

"Abstract - Diamond-drill hole DDH-B357, located 1.5 km north of the Brunswick No. 6 Zn-Pb- Cu-Ag volcanic-sediment-hosted massive sulfide (VSHMS) deposit, intersects three exhalative horizons within variably altered felsic volcanic rocks of the Nepisiguit Falls and Flat Landing Brook formations. These three petrographically indistinguishable iron formation intervals (Fe2O3T = 21.4 wt.%) likely represent cogenetic hydrothermal sedimentary units because they display a common geochemical signature: Fe2O3T = 42.9 ± 10.5 wt.%, MnO = 5.4 ± 3.1 wt.%, elevated base metal values (Zn+Pb = 1999 ± 1091 ppm), strong enrichment in additional exhalative components (CaO = 5.3 ± 3.9 wt.%; P2O5 = 1.43 ± 1.00 wt.%), oxidized signature (Fe/Mn = 10 ± 6), as well as a common immobile element signature (Zr/TiO2 = 0.025 ± 0.007) representative of a pelagic source. The calc-alkaline to transitional host volcanic rocks can be discriminated by Zr/TiO2, and to a lesser extent by Th/Nb: Nepisiguit Falls Formation: Zr/TiO2 = 0.053 ± 0.004, Th/Nb = 1.08 ± 0.37; Flat Landing Brook Formation: Zr/TiO2 = 0.107 ± 0.043, Th/Nb = 0.86 ± 0.17. A symmetrical repetition of the footwall-iron formation-hanging wall stratigraphic sequence is observed in DDH-B357, with distinct felsic volcanic rock domains separated by the three iron formations. This is best explained by parasitic F2 folds on the west flank of the south-plunging Brunswick antiform, similar to the fold closures known to host massive sulfide accumulations in the Brunswick No. 6 and No. 12 mines. Iron formation geochemistry and felsic volcanic rock chemostratigraphy from drill core sampling can provide an effective mineral exploration tool for the structurally complex rocks of the Bathurst Mining Camp. Sommaire - Le forage au diamant DDH-B357, situé à 1.5 km au nord du gisement de Sulfures Massifs à Encaissant Volcanique et Sédimentaire (SMEVS) de Zn-Pb-Cu-Ag Brunswick No. 6 recoupe trois horizons exhalatifs au sein des roches volcaniques felsiques diversement altérées des formations de Nepisiguit Falls et de Flat Landing Brook. Ces trois intervalles de formation de fer, impossibles à distinguer pétrographiquement les uns des autres, représentent vraisemblablement des unités sédimentaires hydrothermales cogénétiques sur la base de leur signature géochimique commune: Fe2O3T = 42.9 ± 10.5 % poids, MnO = 5.4 ± 3.1 % poids, des teneurs élevées en métaux usuels (Zn+Pb = 1999 ± 1091 ppm), un fort enrichissement en composantes exhalatives additionnelles (CaO = 5.3 ± 3.9 % poids; P2O5 = 1.43 ± 1.00 % poids), une signature oxydée (Fe/ Mn = 10 ± 6), ainsi qu’une signature d’éléments immobiles communs (Zr/TiO2 = 0.025 ± 0.007) indicative d’une source pélagique. Les roches volcaniques encaissantes calco-alcalines à transitionnelles peuvent êtres reconnues par leur rapport Zr/TiO2, et à un moindre degré par leur rapport Th/Nb: Formation de Nepisiguit Falls: Zr/TiO2 = 0.053 ± 0.004, Th/Nb = 1.08 ± 0.37; Formation de Flat Landing Brook: Zr/TiO2 = 0.107 ± 0.043, Th/Nb = 0.86 ± 0.17. Une répétition symétrique de la séquence stratigraphique Mur-Formation de Fer-Toit a été observée dans le forage DDH-B357, avec des domaines distincts constitués de roches volcaniques felsiques séparés par les trois formations de fer. La meilleure explication est que le flanc ouest de l’anticlinal Brunswick à plongée sud est affecté par des plis parasites F2, similaires aux zones de charnière contenant les sulfures massifs des mines Brunswick No. 6 et No. 12. La géochimie des formations de fer et la chimiostratigraphie des roches volcaniques felsiques en forage peuvent fournir un outil d’exploration minérale efficace dans les roches structuralement complexes du Camp Minier de Bathurst."

Jan 1, 2006

By D. S. Brown

Few issues pose quite as profound consequences to the quality of life and the creation and distribution of wealth as how we protect the natural environment. No longer a peripheral but a global concern, the environment, once almost nobody's business, has now become everybody's business. It is also the single biggest issue facing mining and mineral activities. This heightened ecological awareness and sensitivity have spawned a new commitment to restore, protect, and preserve nature. But that very commitment poses difficult socio-economic trade-offs, such as: What and how many resources can be given up to prevent and reduce pollution? What are the opportunity costs associated with meeting higher environmental standards? What problems are more important or pressing than others and should be given priority? Choices have to be made that may entail unintended consequences for other societal goals.

Jan 1, 1994

By J. G. Cullain

Inco Limited is an integrated mining, smelting, refining and manufacturing company with operations located worldwide. The Ontario Division operations consist of 13 mines and 10 processing facilities located in Sudbury, Port Colborne and Shebandowan. The scope of our utilization of energy in the Ontario Division in 1976 included in excess of 2.2 billion kilowatt hours of electric power, 12 billion cubic feet of natural gas, 60 million Imperial gallons of residual oil and smaller quantities of other fuels. In addition to the primary energy consumption, waste-heat energy is recovered in various operations throughout the Division, thereby reducing our primary energy requirements. Total expenditures for primary energy alone in 1976 exceeded 60 million dollars. Energy management studies were initiated by Inco's Utilities Department in late 1972, and resulted initially in a program of electric power cost reduction. This program produced significant results by improving the use of the water available for our hydraulic generation facilities and by a comprehensive peak reduction program. Our experience showed that a program of peak power control creates an awareness of both peak and energy costs, and thereby encourages a general reduction in the electric energy consumption as well as lowering the peak demand. Energy management is a continuing program at Inco and, recently, a formal energy management policy and program was instituted. Energy management committees were formed in each plant or mine area to identify the major areas for energy; consumption, thereby isolating areas with large potential energy losses, and determining immediate action which will improve the energy efficiency or reduce the energy waste within their respective areas. A decentralized program with good cross-communication between all committees was felt to be the best method of providing an on-going effective energy management program. In the future, the projections of dwindling fossil-fuel supplies in Canada and the resultant spiralling energy costs will further emphasize the need of sound energy management practices for all Canadian industry.

Jan 1, 1977

By Connor Langford, Murray Gant, Ken Massé

For public organizations, preparing accurate project cost estimates is a critical component in capital project planning. Project delivery methods provide a structured approach to moving projects through the design and construction lifecycle, and typically use cost estimates as key inputs at each stage to determine if the project will advance. As design stages can occur years or even decades before construction contracts are awarded, estimates need to make reasonable assumptions about how the work may be executed (means and methods) as well as potential future market trends so that appropriate values for material pricing, labour costs, escalation, and owner’s costs can be included. This process is challenging enough during stable markets, as historic trends can often be misleading and require a suitable understanding of economic factors to use appropriately. When you mix in the market volatility that has been observed since 2020, developing accurate project cost estimates becomes even more challenging. In cases such as this, having a structured approach to cost estimating that includes an adequate risk-based reserves cannot be overstated as it provides the basis for ongoing project decisions. This paper explores some of the historic and more recent market trends that have impacted key aspects of project cost estimates for capital project planning. It also provides recommendations on how to develop cost estimates for infrastructure projects, with examples from Metro Vancouver, which plans for and delivers regional-scale services to 2.6 million residents. A brief commentary on the use of escalation clauses in contracts is also presented.

Jun 13, 2023

By J. S. Fox

It is generally recognized that the interpretation of bedrock geochemical data in volcanic terrains can be improved by adjusting for rock-type. Various chemical attributes of volcanic rocks have been put forward in the literature as rapid indicators of rock-type, but there is some question as to which of these is the most reliable . Only one such attribute, total iron, seems to have seen systematic use in geochemical mapping in the Flin Flon region. Discriminant analysis of 500 basalts, andesites, dacites and rhyolites suggests that SiO2 is the most important rock-discriminating variable and that MgO, CaO, TiD2, AI2O3 and FeOtot, are successively poorer discriminators. Lithological normalization in the subalkaline volcanic environment should therefore be made over ranges of this variable. Trace-metal data from drill core through the sulphide orebody at Hanson Lake, Saskatchewan are used to demonstrate various approaches to lithological correction, including silica normalization, factor analysis and trend analysis. All of these extract economically important information from the core that is not apparent in the raw data logs. However, silica normalization does not seem to be subject to as many serious limitations as factor and trend analysis in this case, and therefore seems to provide the most reliable basis for the interpretation of subsurface exploration geochemical data.

Jan 1, 1978

By L Dyer, A Keith, G D. Corder

As mining activity moves to remote and less developed locations globally, a holistic approach to mine development is fundamental for achieving a balance between strong financial returns and corporate social responsibility and transparency. Key inter-related fundamentals such as social licence to operate, life-of-mine operational planning, minimising environmental impacts and, most importantly, attractive investment returns for the mining company all contribute to the viability of any new mining project.However, the typical practice in the mining industry is often to treat environmental and social/community aspects as separate compliance issues that are dealt with at minimum cost and disruption to the project and resulting operation. This often results in less than optimum environmental and social outcomes, and presents considerable liabilities at the time of closure when rehabilitation programs continue to require funding when all revenue has ceased.The five capitals model seeks to identify each of the key contributors to sustainable development as financial, manufactured/physical, social, human and natural to formulate a type of triple bottom line approach balancing these often competing project factors. The SUSOP® sustainability risks and opportunities framework, developed by the mining industry, bases its approach on the five capitals model and proposes an approach that breaks down enterprise silos to identify innovative solutions for life-of-mine sustainability. This framework has been developed with the nature of mining projects in mind in order to produce approaches and outcomes relevant throughout the life cycle from the planning phases, through project design and construction into operation and closure.This paper argues the need for a more holistic approach to the development and operation of mining projects, and presents case studies where a holistic approach has been applied, in whole or part, and discusses the lessons learned from these case studies.CITATION:Corder, G D, Keith, A and Dyer, L, 2014. A capitals based approach – leading innovation in planning for life-of-mine sustainability, in Proceedings Life-of-Mine 2014, pp 499–512 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By Robert M. Grogan, James C. Bradbury

The Illinois-Kentucky mining district has, since 1880, accounted for 80 per cent of all U.S. production of fluorspar. The ore deposits are of two types: vein deposits formed by fissure fillings along faults and bedding-replacement deposits formed by the replacement of strata at certain favored stratigraphic positions along minor faults and fractures. Fluorite is the chief valuable mineral in the deposits. Sphalerite and galena commonly are present in small amounts but, in some ore bodies, may form a substantial part of the valuable constituents of the ore. Calcite is the chief gangue mineral; quartz and barite Exposed strata range from Devonian are present in various amounts. through Pennsylvanian in age. Igneous intrusive rocks occur as mafic dikes and sills and intrusive breccia dikes and plugs. Structurally, the district is situated on a generally northwest- trending arch that has been sliced into a series of long, narrow blocks by normal faults that trend northeastward. The structural The localization of the ore deposits by faults and fractures, the association of fluorite mineralization with intrusive breccias, and various lines of petrographic and geochemical evidence indicate that the fluorite-zinc-lead deposits were epigenetic and deposited by solutions emanating from a deep alkalic magma.

Jan 1, 1968

By Walter K. Utt

The vibration levels of the heavy machines used in surface mining are much greater than for vehicles used on highways. In order to assure the proper functioning of electronic equipment placed on the surface mining vehicles, the U.S. Bureau of Mines has conducted a program of field measurements to define their vibration environment. The information in this report is for a class of vehicle that has a blade for scraping and wheels with rubber tires. The statistical information derived from these measurements can be used as a basis for laboratory testing to qualify equipment for a surface mining vehicle of this class. The envelope that would encompass 99 pct of the vibrations encountered in normal operations is presented for each location on the vehicle. The five locations for which data were recorded are the floor of the cab, the engine, the frame, the drive train (gear, differential, and torque converter), and the axle. Tabulated data are provided for those who wish to use a different probability level. The appropriate test profile for the laboratory testing can be determined from the information presented in this report.

Jan 1, 1993

By Roberto Parreiras Tavares, Frederico da Costa Fernandes, Guilherme Antonio Defendi, Vangleik Ferreira da Cruz, Júlio César de Sousa Pena

"Near-net-shape casting is an important area of research in the iron and steel industry today. Among the near-net-shape casting processes, the single-belt caster seems to be the most promising, since it is the only one that can achieve levels of productivity similar to those obtained with conventional continuous casting machines. One of the most important aspects in the single-belt casting is the feeding system used to deliver liquid metal over the belt. This system determines the velocity distribution and the levels of turbulence of the liquid metal and affects the quality of the strips. In the present work, a metal delivery system having a simple geometry was proposed. Using the CFD code CFX 5.6, a mathematical model to simulate three-dimensional turbulent fluid flow and heat transfer in that system has been developed. This model was used to analyze different configurations of the metal delivery system and the free surface shape of the fluid was also determined. A physical model of the feeding system was built and used to validate the predictions of the mathematical model. The fluid flow calculations have been validated by dye injection experiments and laser doppler anemometry. Measurements of the free surface levels have also been performed. These experiments provided supporting evidence for the predictions of the mathematical model.IntroductionTo maintain its competitiveness in the present market, the metallurgical sector, particularly the steelmaking companies, are developing new techniques of production. Some of these new processes are focussed on the strip casting technologies. Among these technologies, the SingleBelt process is considered the most interesting option, reducing the number of rolling steps and, consequently, the final cost of the product, especially the part associated to the energy consumption (fuel and/or electric energy). This process can also reach levels of productivity that can not be matched by other strip casting methods(1). One of the most important aspects concerning these new processes is related to the liquid metal delivery system. This system can have a significant effect on the final quality of the strips, since it determines the velocity distribution and the levels of turbulence of the liquid metal."

Jan 1, 2004

By W. R. Reed, G. J. Joy, B. Kendall, A. Bailey

"Testing of the NIOSH-designed roof bolter canopy air curtain (CAC) has gone through many iterations demonstrating successful dust control performance under controlled conditions. J.H. Fletcher & Co. (Fletcher), an original equipment manufacturer of mining equipment, has further developed the CAC concept by incorporating it into the design of its roof bolting machines. A new CAC design has been developed incorporating the results of testing of the NIOSH design and the recent Fletcher design. Observations from smoke testing conducted on this new CAC design in a laboratory setting show promise for improved performance. INTRODUCTION Exposure to respirable coal mine dust can cause coal workers’ pneumoconiosis (CWP) otherwise known as black lung. If silica is present in the dust, the miner may develop silicosis in addition to CWP. CWP and silicosis are occupational respiratory diseases that are ultimately fatal and have no cure. The only method of prevention is through elimination of exposure to respirable coal mine dust and crystalline silica (quartz). The current occupational exposure limit (on an MRE basis) for respirable coal mine dust is 2.0 mg/m3 during each shift that a miner is exposed in the active workings of the mine or in mine facilities [30 CFR 70.100 2015]. Recently enacted legislation changes this standard beginning in August 2016 to 1.5 mg/m3 for a full working shift [Federal Register, 2014]. If the respirable coal mine dust contains more than 5% silica, the applicable respirable dust standard is reduced; calculated as 10 divided by the percent quartz present [30 CFR 70.101] so that the effective exposure limit for respirable quartz is 0.1 mg/m3 for a full working shift. Sources of exposure to respirable coal mine dust for the roof bolting occupations include infrequent maintenance and cleaning of the vacuum dust collection system and operating the bolter downwind (in the return air) of the continuous miner [Goodman and Organiscak, 2003]. Recent studies have demonstrated that vacuum dust collection systems are effective in capturing bolter-generated dust, if maintained and operated correctly and if proper face ventilation techniques are used. However, most exposure to respirable coal mine dust for the roof bolter occurs when the roof bolter machine is operated downwind of the continuous miner [Potts et al., 2011; Colinet et al., 2013]. Because of this higher exposure downwind of the continuous miner, the roof bolter is generally limited to working downwind of the miner only once during a production shift"

Jan 1, 2016

By R. F. Sharpe

THE Bullion mine, in the famous Cariboo district of British Columbia, is situated on the left bank of the South fork of the Quesnel river, approximately three miles below the outlet of Quesnel lake. A good road leads 63 miles northeast to the property from Williams lake, the railhead on the Pacific Great Eastern railway. The mine may also be reached over good roads from Vancouver via the Fraser canyon, Ashcroft, Clinton, and the 150-mile house, a total distance of 407 miles. In the early days of placer mining on the South fork of the Quesnel, several rich bars were found. The 'pay' on one of these at the mouth of Dancing Bill gulch was followed up the gulch by a Chinese company, who proved to be the discoverers of the present Bullion mine. This Chinese company commenced working in 1884, in what was then referred to as the China pit. Although working under very primitive conditions, it is reported that, during the ten years they operated the property, they recovered in excess of $900,000 in gold. This somewhat large recovery was due to a local concentration, the result of Dancing Bill creek having meandered down that portion of the channel and washed off the overburden. In 1894, a syndicate composed largely of the Canadian Pacific Railway directorate of that time, with J. B. Hobson as their field manager, acquired the property, as the apparent magnitude of the operation was too great for the resources of the Chinese company. Mr. Hobson, during the first ten years of his regime, developed the mine into a large-scale hydraulic operation, and during that period, from 1894 to 1905, recovered approximately $1,234,000 in gold. In 1906, the property was sold to the Guggenheim Exploration Company, who retained Mr. Hobson as Manager and embarked on an extensive programme to bring in additional water. This project was never completed, however, work being suddenly abandoned in 1907 and the mine closed down. Shortly afterwards, the property was purchased by a small operator on what is believed to have been largely borrowed capital. This venture resulted in no production, but in much litigation, which eventually reached the Privy Council in 1920.

Jan 1, 1939

By James Westfield

A brief résumé follows of activities of the Division of Coal-Mine Inspection that have had a favorable effect on health, safety, and the reduction of injuries at coal mines: 1. The Federal Mine Safety Code fur Bituminous Coal and Lignite Mines of the United States was issued originally by the Director of the Bureau of Mines on July 24, 1946, after consulting with management and labor representatives of the coal-mining industry. The code has been used by Federal coal-mine inspectors while inspecting bituminous-coal and lignite mines as a basis for determining the existence of unhealthful and unsafe conditions and practices in these mines. A revised code was issued by the Secretary of the Interior on October 8, 1953, after further consultations with representatives of management and mine workers and was incorporated by reference in the 1952 and subsequent bituminous -coal wage agreements. The agreement of May 29, 1946, between the Secretary of the Interior, acting as Coal Mines Administrator under authority of Executive Order 9728, and the United Mine Workers of America, covering bituminous-coal and lignite mines in Government possession, charged Federal coal-mine inspectors with the responsibility of making periodic investigations of the mines and reportin; to the Coal Mines Administrator any violations of the Federal Minis Safety Code. Federal coal-mine inspectors also had temporary authority to close mines found to be imminently dangerous, but such authority under Executive Order 9728 was removed on June 30, 1947, when Government control of the mines was terminated.

Jan 1, 1960

By M. Sunkpal, K. C. Kocsis

"An underground environment with high air temperature and humidity conditions generated from various heat and moisture sources can significantly affect the thermoregulation processes of the human body. This can lead to a series of heat-related illnesses such as heat exhaustion, heat cramps and heat stroke. The majority of the metabolic energy of a mine worker results in the production of heat. If the human body is to maintain thermal equilibrium, then this metabolic heat must be transferred to the ambient surroundings at the same rate. The heat loss from the human body occurs through a combination of heat transfer processes, such as respiratory heat exchange, convection, radiation and evaporation. If the heat loss from the human body to the ambient surroundings is less than the metabolic heat produced, the excess will be accumulated within the human body, which will result in a rise in the core and skin temperatures. This can ultimately lead to a heat-related illness or a combination of heat-related illnesses. This paper aims to discuss major heat-related issues and provide an overview of various mine ventilation and cooling systems, which can be employed to overcome high levels of heat and humidity in underground mines. In this paper, the effects of heat exposure on the health, safety and productivity of the mine workers are also highlighted. IntroductionMining in the United States remains one of the most hazardous industries, despite significant reductions in fatal injuries over the last century (Coleman and Kerkering, 2007; Saleh and Cummings 2011; Jacklitsch, Musolin and Kim, 2016). Occupational health hazards within the mining industry include hazards that are physical, such as traumatic injury or hearing loss; chemical, such as silica or diesel particulate matter; biological; ergonomic; and psychological (Donoghue, 2004; Saleh and Cummings, 2011). The effects of some of these hazards can be diagnosed immediately, while many, like black-lung and silicosis, will have long-term effects on the health, safety and life quality of mine workers (Donoghue, 2004; National Institute for Occupational Safety and Health, NIOSH, 2000). Among these hazards, exposure to heat and humidity can significantly affect the safety, health and productivity of mine workers, particularly in deep and hot underground mines (Roghanchi, Sunkpal and Kocsis, 2015). Short-term acute heat exposures can cause a rise in the core temperature of the human body, which can result in a heat-related illness or combination of heat-related illnesses. Adverse long-term chronic heat exposure can generate serious occupational heat-related illnesses, such as cardiovascular diseases, mental health problems and chronic kidney diseases. High core body temperatures coupled with dehydration can generate negative behavioral effects such as physical fatigue, irritability, lethargy, impaired judgment, loss of dexterity and loss of concentration (Xiang et al., 2014)"

Jan 9, 2017