Search Documents

By Hillary W. St. Clair

Mining activity began in colonial times with ironmaking operations scattered along the eastern seaboard. Iron furnaces and forges manufactured iron implements from bog iron ores using charcoal from the extensive forests as a fuel. Lead ores were mined in the Mississippi Valley and copper ores in the Lake Superior region. However, the real beginning of the American mining industry did not occur until the 19th century. The history of American mining is organized around three epochal events. The first was the discovery of gold in California in 1848, which marked the beginning of a period of apprenticeship in mining and metallurgical techniques. The second was the discovery of the fabulous Comstock Lode in western Nevada in 1859, which expanded mining throughout the Far West and led to large-scale underground mining and the development of smelting techniques for lead, silver, and copper ores. The third event was the building of a transcontinental rail-road system after the Civil War, which brought about the consolidation of the industry from a large number of independent mines, mills, and smelters into integrated operations run by large corporations. Thus developed the mining industry that today supplies the energy and critical materials for the great-est industrial complex the world has known.

Jan 1, 1977

By Christopher Mark

Sixty years ago, underground coal mining was the most hazardous job in the United States. Roof falls were a big part of the problem. They killed about 100 miners every year, more than all other causes put together. Fast forward half a century to 2016, which is the first year ever with zero roof fall fatalities. Just three miners were killed by roof falls during the following 6 years. How was this historic goal achieved? This paper starts with a modern analysis of the causes of the roof fall fatalities in 1968. Then it follows the reductions over time by category, using snapshots of the fatalities occurring in subsequent decades. Along the way, it evaluates the influence of the regulatory environment, changing mining methods, and better ground control technology. The paper shows that in 1968, more than half of roof fall fatalities at large mines were attributable to an inadequate safety culture. The immediate effect of the 1969 Coal Mine Health and Safety Act was to reduce the riskiest activities, like needlessly going under unsupported roof. Other hazards, like large roof falls, required technological developments before they were brought under control. Roof control plans, which the U.S. Bureau of Mines had been advocating since the 1920s, played a significant role throughout the process.

Jul 1, 2023

By Kaiwen Liu

Activated carbon is widely used in the removal of organic and/or inorganic contaminants from waste water due to its high surface area, porous structure, and specific surface reactivity. However, in practical applications, it is difficult to recover the activated carbon completely by screening or classification. In this project,we prepared a magnetic form of activated carbon (magnetic activated carbon or M-AC) by precipitation of iron oxides on the surface of activated carbon. The M-AC can be easily separated from effluents by applying an external magnetic field, thus it can be recycled and regenerated for reuse. M-AC was characterized by X-ray diffraction (XRD), specific surface area measurement, and scanning electron microscope (SEM).XRD results show that the major phase of coated iron oxides on activated carbon is magnetite (Fe3O4). The specific surface area of activated carbon was found to be reduced after the impregnation of magnetite particles on the surface. The SEM micrograph shows the aggregation of the iron oxides on the surface of activated carbon. M-ACwas found effective in removing DETA (diethylenetriamine) species and metal ions from solutions. Cu (II) with initial concentrations from 5 ppm to25 ppm in solution is removed by more than 99% with the addition of 0.1 wt.%ofM-AC. For the removal of 25 ppm DETA species from solution, an addition of 0.5 wt.% of M-AC is required due to the larger size of the DETA molecule. Moreover, M-AC showed a good loadingproperty for nickel and gold ions from solutions. M-ACshows a better adsorption capacityover activated carbon and its potential applications in carbon-in-pulp for gold leaching and waste water treatment. Keywords: magnetic activated carbon (M-AC),diethylenetriamine (DETA),metal ion,adsorption

Sep 1, 2012

By CHARLES R. KETES

I. INTRODUCTORY. INDUSTRIALLY, the most important service that geological science can now render to mining in the Upper Mississippi leadand zinc-fields is to devise some practical scheme whereby the productive ore-belts may be located with greater certainty than they have been in the past. Up to the present time there has been little service of this kind, and in spite of all that has been worked out concerning the geologic features of the region, and notwithstanding all that has been written about these ore-deposits, this particular phase of the subject has been, for some reason or other, the very one that has received the least consideration. The neglect by geologists in this respect has been all but complete. The following notes are suggestive of some practical solutions to the problems presented. As here suggested, the geologic relationships of the ore-bodies were surmised some years ago, though somewhat vaguely perhaps. No opportunity for securing critical data appeared until recent investigations of a private character were undertaken, which bad in view the extensive prospecting of undeveloped areas. Fresh from rather wide experiences of a decade in the principal mining-regions of four continents, and after a lenstrum's residence among the chief mining-camps of the West and of Mexico, under conditions which measured geologic hypotheses in meters and rigidly tested their values in, terms of dollars, the recent return to the Joplin field and a new survey of its ore-conditions were fraught with somewhat unexpected results. Aspects of the ore-deposition were presented of which previously there was no hint. Ten years' absence from the district had tended greatly to clarify former hazy impressions. It enabled many features, then only dimly outlined, to be considered more nearly in their true perspective and in their real relationships to their surroundings. It permitted a great mass of details collected a dozen years before in connection with the work of the Missouri Geological Survey to be viewed under new light and to

Feb 1, 1909

By O. C. Garst

"The lightness and relatively high strength per unit weight of certain magnesium alloys have interested designing engineers for many years. Ever since the noted investigator Bunsen3/ first produced the element by electrolysis of the fused chloride in 1852, utilization of this light metal has been considered. Magnesium is widely distributed over the earth's surface in high-grade as well as low-grade deposits; it occupies eighth place in the list of elements arranged in order of their decreasing abundance, as there is 2.24 percent magnesium in the earth's lithosphere. Even though the element is distributed widely in the form of relatively insoluble: minerals and also as soluble salts in sea water and spring water, as well as being an indispensable constituent of plants and animals, the technology of magnesium was slow development. This slowness of development was first caused by confusion or the part of the early investigators who thought that magnesia, magnesite, magnetite, and the pyrolusite-type manganese ores were compounds of the same metal. At one time the metal that we now know as manganese was called magnesium, and magnesium was called either magnium or talcium. In addition to this coon, the chemical activity of the metal, especially at high temperatures, created problems that are still difficult to solve.With the advance of science in all branches, .methods for -he production of magnesium were developed. The methods first used for producing the element were: (1) reduction of magnesium salts with alkali metals,4/ (2) electrolysis of aqueous solutions of magnesium salts, and (3) electrolysis of fused magnesiun salts.The first attempts to produce magnesium by the carbothermal reduction of magnesia were failures as sufficient thermodynamic knowledge concerning the reversibility of the reaction between magnesia and carbon was not at hand. As the igneous electrolytic Method for making the element was more easily controlled than the others and. yielded more metal per unit of energy, considerable work was expended on the improvement of this process. The work in this field paralled that on the electroreduction of aluminum and the alkali metals. For several years the entire magnesium industry was dependent on this igneous electrolysis process for its supply of the metal, but as demand for the metal increased and more scientific knowledge was available, other processes were developed. Today magnesium is produced by the electrolysis of molton magnesium chloride electrolytes, the carbothermal reduction of magnesia, in arc furnaces followed by shock cooling of the furnace gases by a coin inert atmosphere, and the silicothermal reduction of calcined dolomite in stainless steel retorts."

Mar 1, 1946

By Miao Tian

Large quantities of copper complex resources are produced globally and urgent to be cleanly processed. This article presents a thermodynamic analysis of mixed smelting process including low-grade polymetallic copper sulfide concentrates, high copper content sulfide concentrates, metallurgical by-products (copper removal slag from lead metallurgy), and copper powder from electronic waste. A top blown smelting reactor to simulate mixed smelting process is developed using a metallurgical process simulator, METSIM. Reactor parameters, heat loss and phase distributions are estimated from actual plant data. The proper proportion between complicated primary and secondary copper resources is determined by analyzing the influence of the feed rates of various resources, oxygen, silica flux and revert on the smelting performance. Autogenous smelting process is built by optimized matching materials of copper complex resources, in terms of the reactor temperature, copper content in matte and slag, and the percentage of magnetite in slag.

By F. Hassani

This Paper describes a sudden spill of rock waste used for backfilling from a waste pass at one of the underground mine in Canada thus causing a major failure/accident. The mine operator immediately launched a detailed investigation to understand the causes of this accident and develop procedures to prevent any recurrence of such events in future. The investigators from McGill University were invited to collaborate with the engineers at the mine to examine this accident. The events leading to the accident were studied and appropriate measurements were taken and samples of the waste material was collected for further test and analysis. The field visit and the interview of the witnesses allowed a detail documentation of the events. The sequences of events related to the incident together with the experimental results obtained in the course of the investigation is detailed. The waste material was characterised in the laboratory with regard to its behaviour in the presence of water. This information is then discussed and the failure mechanism involved in this accident is identified. The full recommendation as well as the immediate operational measures implemented by the mine to prevent future occurrence of such events are discussed and presented.

May 1, 2003

By Courtney A. Young

Cyanide is a critically important chemical to the mining and metallurgical industry. It has a strong affinity for metals making it favorable as an agent for metal finishing and treatment as well as a lixiviant for metal leaching, particularly gold. These technologies are environmentally sound but, because cyanide is very toxic, safeguards are required to prevent accidental spills and treat effluents before being discharged. Various methods of cyanide remediation by separation and destruction for cyanide management purposes are therefore reviewed. The methods have been broadly categorized as physical, -adsorption. complexation and oxidation methods including photolysis and other advanced-oxidation processes. Reaction mechanisms for these methods are presented throughout this paper, Finally, the methods are compared in regards to their effectiveness in treating various cyanide species: free cyanide, thiocyanate, weak-acid dissociables, and strong-acid dissociables.

Jan 1, 1998

By P. M. Swash

This paper reviews the application of some mineralogical techniques in the evaluation of the Uitkomst Ni-Cu deposit, South Africa. The low grade of the ore necessitates detailed and representative characterisation in order to establish the prospects viability. The relevant mineralogical information is generated by using optical microscopy, magnetic and heavy liquid . separations, XRD. SEM and EMPA. Methods used are briefly reviewed. The cost savings and metallurgical understanding that is provided by the mineralogical work is described especially with regard to milling, flotation and the presence of by-products (PGMs and chromite).

Jan 1, 1991

By A. G. Roach

HISTORY AND LOCATION SEAL HARBOR GOLD MINES, LIMITED, was incorporated in January, 1934, to take over 116 acres of mining lands in the Stormont gold district, Guysboro county, Nova Scotia. The nearby ten-stamp Mulgrave mill was also purchased, and since that time 974 acres of adjoining properties have been secured from the Government by direct lease. The property is served by a motor road and is about two miles from the village of Goldboro, situated on the shore of Isaac's harbour. The bulk of ?the supplies are brought in by coastal steamer from Halifax, a distance of about 100 miles, since the nearest railway connections are at Antigonish, some 40 miles distant. EARLYY WORK The Seal Harbor properties include the old Partington and Beaver Hat mines. A small tonnage of ore was mined from each and treated on the properties in stamp mills, which were later torn. down . A survey of old records shows that this ore averaged about $8.00 gold per ton. Development work by the present Company was confined to the 100-foot level until February, 1935, but after that rime the incline shaft was deepened to 425 feet and the 300-foot level was explored east and west of the shaft. Six belts of ore were intersected to the west of the shaft. The ore from these belts was hand sorted and the ore portion was put through the 10-stamp Mulgrave mill to defray operating expenses and to serve as a sample of the deposits. The average recovery per ton from this sorted ore was $6.10. Samples of the ore were sent to the testing laboratories of the Mines Branch, at Ottawa, and of Canadian Industries, Limited, at Toronto. Recommendations from both of these authorities were for removal of the coarse gold by concentration and barrel amalgamation, followed by cyanidation of the residue.

Jan 1, 1937

By A. C. Fieldner, W. A. Selvig

Information concerning the fusibility of coal ash has become of considerable value to the consumer of coal, mainly in connection with the troublesome formation of clinker resulting from the melting of the ash constituents of the burning coal. The growing interest in such data has led the Bureau of Mines to make a general survey of the "fusing" or "softening" temperatures of the ash from coals of the United States. It is hoped that this information when used together with the large number of coal analyses published 1 by the bureau will assist the consumer of coal in comparing different coals, and in selecting the coal best adapted for his purpose.

Jan 1, 1922

By E. P. Youngman

Titanium ranks as one of the more abundant elements, is widely distributed, and occurs in concentrated form in numerous deposits. This substance was discoveres 140 years ago; but despite the efforts of metallurgists and chemists to find a place for it in industry, only within the last 10 or 15 years has the increased use of titanium pigments provided any extensive outlet for titanium ores. Even to-day titanium is confined to a few highly specialized industrial applications. The metal itself is now quoted regularly in trade journale, but scarcely yet can it be said that the production or use of the metal. has progressed very far beyond the laboratory stage. Ferroalloys containing the element were largely used for a time, especially in connection with the manufacture of Bessemer steel rails; but as American rail- ways adopted open-hearth rails in preference to Bessemer rails, the demand for the alloys in the rail manufacture gradually dwindled into insignificance. New outlets for ferrotitanium have been found in the steel industry; and the production of titanium alloys, both in the United States and in Europe, has increased in recent years. By far the largest use of titanium at the present time, however, is in pigments. The manufacture of titanium white began in Norway, but at present the United States is the leading producer. One of the two companies now operating in the United States is also the leading factor in European production. Although titanium occurs, in many minerals, the principal commercial sources are rutile (the natural oxide, Ti02) and ilmenite (iron-titanium oxide, FeO. TiO2). The latter is a coal-black mineral, but it is the one used in the manufacture of the titanium white of commerce, as well as in the manufacture of ferroalloys and arc-lamp electrodes. Rutile, the natural oxide, is not pure white and, being less common in nature, costs more; it is, therefore, reserved for use in the manufacture of titanium chemicals employed in relatively small amounts in dye works and bleacheries and for sundry minor purposes. This paper summarizes the titanium industry, with special reference to its economic aspects. It is offered as a survey of current trade literature and as a digest of material in the files of the bureau and is presented in response to numerous inquiries from prospective producers as to ways and means of exploiting deposits. (At present, much of the ilmenite consumed in this country comes from overseas, principally from British India..). A forthcoming circular, devoted to deposits of titanium-bearing ores, deals with foreign and domestic sources of supply.

Oct 1, 1930

By William Gleason

"Speakers and attendees of the 2016 Cutting Edge Conference could not be faulted for keeping one eye on the presentations taking place at the Hyatt Regency at LAX in Los Angeles, CA on Nov. 7 and 8 and another on the results of the historic election in the United States that took place on Nov 8. While there was certainly interest in the presidential campaign, there was also a great deal of interest in Measure M on the California ballot. Measure M, which passed easily, is a half-cent sales tax increase that will fund the most ambitious transit expansion in Los Angeles County history.In the coming years, the ballot measure will transform a traffic-choked region by funding the construction of nearly a dozen new rail lines with an estimated $120 billion raised in four decades. Among the projects that could come to fruition are a twin-rail tunnels project through the Sepulveda Pass and new connections in the city.During the update on West Coast projects, Bill Hansmire summed things up with a slide asking “How much work is there on the West Coast,” and his answer was “Billions.”From Seattle, WA south to Los Angeles, there is already a lot of work for tunneling and underground construction experts, and Measure M ensures that there will be plenty of work for decades to come.Currently, The Los Angeles County Metropolitan Transportation Authority (Metro) has three rail projects underway that were funded by Measure R in 2008 — the Regional Connector, the Purple Line subway extension and the Crenshaw/LAX Line that are designed to alleviate the traffic pressure with an eye to more solutions.Measure M is the fourth sales tax increase to fund transportation in L.A. County, bringing the base sales tax rate to 9.25 percent. In some cities, which already levy their own sales tax, the rate would be higher, The Los Angeles Times reported.About 35 percent of the revenue will fund major new transit projects, such as the subway under the Sepulveda Pass, extension of the Gold Line to Claremont, extension of the Crenshaw Line to West Hollywood and acceleration of the Purple Line Subway construction along Wilshire Boulevard to finish in 2024, 10 years earlier than scheduled.About 17 percent would fund a dozen highway improvement projects, such as widening parts of I-5 in the Antelope Valley and southeastern county, adding bus lanes to the Sepulveda Pass section of the 405 freeway and adding truck-only lanes to a section of the 710 freeway."

Dec 1, 2016

By X. Li, J. C. Stankus, J. Ma, H. Chen

Accurate evaluation of stress and geological conditions is critical to ground control design in underground openings. For a slope entry, the problem is more difficult, because a slope will transverse through many types of strata. Over the last few years, Keystone Mining Services LLC, an affiliate company of the Jennmar Corporation, has developed a new methodology designated the “Stress, geologic and support design system (SGS).” The method analyzes the stress, geology and support design for a mine slope. The method has been successfully applied in various new slopes across the United States, and ground control plans developed using SGS methodology has helped coal companies successfully pass review and/or hearings by state and federal regulatory agencies. With a case application in the U.S. Midwest, this paper details and demonstrates the main concepts of the methodology, including (1) analysis of stress and geology and identification of strong, fair and weak zones along the slope; (2) primary and supplemental support design; (3) long-term support design in the form of steel square sets or arches and (4) validation of the support design utilizing advanced finite element computer modeling.

Jan 1, 2011

By Paul W. Cleary

"DEM application in mineral processing has for many years been heavily focused on simulating mills of various types. This method can be used to simulate many other aspects of mineral processing operations and can be used both to enhance understanding of the underlying flows and of issues such a breakage, wear, blockage, product degradation, segregation and mixing. The application of DEM to four important classes of non-comminution problems and equipment commonly found in or near mineral processing plants are described. These are:- Particle transport (examples include a conveyor belt and an inclined screw conveyor)- Sampling (assessment of sample bias for cross-stream samplers)- Separation (the efficiency of vibrating screens)- Storage and reclaim (discharge from a multi-port hopper and segregation in a splitter bin with asymmetric ingoing and outgoing conveyor belts, apron feeders and impact plate)."

Jan 1, 2003

By M. L. Harris

Explosions in underground mines and surface facilities such as processing plants are caused by confined accumulations of combustible dust and/or flammable gas mixed with air in the presence of an ignition source. Underground explosions can be prevented by minimizing methane concentrations through methane drainage and ventilation, by adding sufficient rock dust to inert the coal dust, and by eliminating ignition sources. The effectiveness of rock dust in arresting explosion propagation was proven by experiment and practice (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11). The precise mechanism by which rock dust (generally pulverized limestone dust) quenches flame has not been fully explained, but is believed to be absorption of thermal energy from the heated gases and absorption of radiant energy, which reduces the preheating of unburned coal particles ahead of the flame front. One measurable aspect of explosibility is incombustible content. In order to determine whether enough rock dust is applied, 30 CFR1 § 75.403, Maintenance of Incombustible Content of Rock Dust, requires at least 80% incombustible content on the roof, ribs, and floor of underground coal mines. 30 CFR § 75.403-1 further defines the incombustible content as follows: ?Moisture contained in the combined coal dust, rock dust and other dusts shall be considered as a part of the incombustible content of such mixture.? In order to determine the incombustible content of the mine dust, samples of deposited dust from specified areas in a mine must be collected, analyzed, and then compared with the minimum standard of 80%. The traditional low temperature ashing (LTA) approach to determine if a coal and rock dust mixture is compliant with the inerting requirement consumes the coal dust and considers the remaining material to be inert. Compliance with the law is then determined by comparing the measured percentage of inert material of the representative band sample with the pre-established requirement of 80%. The incombustible content of the sample includes rock dust, the amount of moisture as received at the lab, and the inherent ash in the coal. The LTA method is not itself a direct measure of explosibility but is a surrogate that calculates a single parameter associated with large-scale Bruceton Experimental Mine (BEM) explosion test results conducted with dry rock dust. This method assumes a homogenous mixture with no layering of rock dust and coal dust. Float coal dust is a serious explosion hazard if it accumulates on top of the rock dust and is not mixed with the rock dust (12). Mitchell and Nagy (13) studied the effectiveness of water as an inerting agent for the coal dust explosion hazard. The study emphasized that surface water evaporates readily from dusts. Thus, in a passageway where the dust is wet, changes in weather or the ventilation system could dry the dust and make it unsafe in a relatively short period of time. Where adequate rock dust has been applied, this drying effect is not a factor. However, if the mine depends upon the moisture content as part of the incombustible content, fluctuations in the dust surface moisture within a mine can render moisture content an ineffective and inconsistent measure of safety. Additionally, if sufficient moisture is absorbed and subsequently relinquished by rock dust, a cake can form and render the rock dust ineffectual. The trend has long been recognized that mine explosions occur primarily during the winter season when the humidity is low for long periods of time (14, 15, 16). In light of this trend and due to the potential variability of the moisture content of the dust, it may not be prudent to include variable surface moisture in the total incombustible content of the sample. Instead, surface moisture should be viewed as an additional safety measure as long as the rock dust is dispersible. However, moisture limits the ability of the rock dust to disperse and can significantly reduce its capacity to effectively inert propagating explosions (2, 13, 17, 18, 19, 20, 21, 22). Given the methods by which the as-received moisture and incombustible content are determined, dust samples from the 2010 MSHA database were assessed to determine the variability of the moisture content throughout a year and how often the measured as-received moisture might have affected the dust explosibility determination if removed. The findings were then verified by observation in laboratory studies and within the NIOSH OMSHR Safety Research Coal Mine (SRCM).

Feb 23, 2014

By A Mooney, G Balog, P Burns, R Brooks

This paper outlines the rationale for the location of the crusher, geotechnical analysis and basis of ground support design, design and scheduling of the chamber and supporting excavations as well as the operational outcomes and lessons learned. Contributions from mining operations, planning, geotechnical and infrastructure teams enabled the Crusher Station One excavation to be completed on schedule, with opportunities taken for underground mining and infrastructure to work safely in parallel to deliver crusher station infrastructure on schedule. Installation of crusher infrastructure was ongoing at the time of writing.

Mar 15, 2021

By C. Hilton

Arch Coal Inc. has implemented and sustained Best Practices at its four western mines through utilizing foremen in ongoing time studies. A prime benefit is the unique opportunity provided to front line supervisors. To date, 48 supervisors have participated in this program. Each quarter a new team is assembled with members from each operation. During three month blocks the supervisors conduct studies at each mine and identify best practices to implement at their own mine. Ongoing Best Practice and Action Item lists are reviewed each study. Mine management edits, prioritizes and monitors the completion of the proposed action items.

Jan 1, 2010

By Alan C. Richter

Introduction The East-West Gateway Coordinating Council is an organization of local governments formed in 1965 to identify regional problems and to formulate policies, plans and programs to resolve them. The major goal of the Gateway Council is to improve the quality of life for the citizens of the St. Louis Region. While East-West Gateway Coordinating Council is the organization I represent and it only deals with the St. Louis Metropolitan Area, you will find one or more similar organizations in each of our nation's urbanized areas. As a result, for illustrative purposes, I will use my organization to portray what is happening nationwide. For example, in order to eliminate duplication, the Council reviews local applications for approximately 100 federally funded programs in such areas as highways, mass transit, parks, water treatment, and sewers before they can be sent to the appropriate funding agency. The Council's varied functions place it in a unique position of receiving more and more responsibility for developing strategies of implementation of various environmental regulations. This is due to the fact that environmental control is a relatively new field and we, as a country, are relatively inexperienced. The resulting regulations and guidelines will depend, to a great extent, on what the general public is willing to accept in terms of controls and what price they are willing to pay in terms of taxes and increased costs. Land Use: Growth vs No Growth This is perhaps the most encompassing environmental issue. We, as a nation, are beginning to realize that land is a limited natural resource and that the way we choose to use 'this resource affects many other aspects of our lives--whether we can catch edible fish in the Mississippi, how much we pay for sewer services, if we can swim in a

Jan 1, 1977

By Aurel Goodwin

I chose the title "Let's Clear the Air" for this afternoon's presentation because it has two meanings, the literal and the figurative. Most of you know what MSHA is. Most of you know what MSHA does. And, for the most part, most of you know why. What I hope to accomplish today is to "clear the air" around our health standards, to clarify for you how MSHA views its congressional mandate under Title I Section 101(a)(6), (7), and (9) of the Mine Safety and Health Act. Asbestos, silica, radiation, noise, welding fumes, carbon monoxide, lead, hydrogen sulfide, nitrogen dioxide - the list of physical and chemical hazards encountered in the metal and nonmetal mining industry is as diversified as the industry itself, possibly even more so. In addition, miners are often exposed to several of these health hazards simultaneously.

Jan 1, 1980