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Operator efficiency and control capability along with cost effectiveness have been the quest of mining, industrial, and mobile hydraulic engineers for years. The majority of the functions in present day fluid power systems are controlled by on/off control valves. They are inexpensive and provide easy installation and operation, but they lack the quality of fine control of load flow or what is sometimes known as "feathering the load". An alternate approach to obtaining this capability is the use of electro-hydraulic servo-valves, but their implementation into a system is complex, and they are expensive. As a result, electrohydraulic systems are still used primarily in the aerospace industry. Of late, a compromise seems to have evolved between the on/ off control systems and the servo-technology is the so-called proportional flow control valves. A proportional flow control valve meters fluid to the load in proportion to the input command from the operator. In principle, it is similar to a conventional flow control valve and is tailored to meet the control requirements from the load point of view. The hydraulic system using this valve usually works in an open-loop mode with the operator closing the loop. Incorporating load-sensing mechanisms and adoption of electrical/electronic signalling into the valve make it the "ideal valve" which designers have been looking for from a techno-economic point of view.

Jan 1, 1983

By E. D. Gardner

This bulletin, which discusses open-cut mining at the metal mines of the United States, is the last of a series of such papers by the Bureau of Mines describing the principal methods of mining.4 Open-cut mining is applicable to flat-lying mineral deposits relatively near the surface. Vein deposits seldom are amenable to this method, although outcrops of veins sometimes are worked as open pits. Most of the iron ore of the country is mined from open pits; according to the Minerals Yearbook, 67.4 percent was mined from open pits and 32.6 percent from underground mines in 1937. Open-cut mining is relatively new in the copper industry but yields more copper than any other method; in 1937 about 52 percent of the copper ore mined in the United States was taken from open pits. Lead-zinc ore has been produced from open pits in the Joplin (Mo.) district, but most of the deposits in this area, although flat-lying, are too deep to be mined economically by the open-cut method. In 1937 one company at Oronogo, Mo., was stripping overburden and mining mixed oxidized and sulfide ores by this method.

Jan 1, 1941

By H. H. Schrenk

The purpose of respiratory protective equipment is to prevent the inhalation of harmful or objectionable atmospheres. Although constituents or contaminants that may render an atmosphere irrespirable or objectionable are numerous, they may be classified broadly as follows: I. Gaseous substance: n. A. Toxic. B. Inert (oxygen deficiency). II. Particulate matter (dispersoids). A. Solid. a. Dust (formed by disintegration). b. Pure (formed by condensation). B. Liquid. a. Mist (formed by disintegration). b. Fog (former by condensation).

Jan 1, 1940

By Paul M. Tyler

According to Lindgren , the economic importance of pegmatites stems from the fact that they represent the principal natural storehouse of two classes of mineral products : (1 ) common minerals in exceptional size and purity and ( 2 ) several of the rarest minerals , which are not commercially available from other types of deposits . Most pegmatites can be described simply as coarse- to very coarsegrained granites . Pegmatite includes coarse -textured igneous rocks of any composition , such as syenitic , alkali syenitic , dioritic , or gabbroitic ; but basic pegmatites are far less common than those that are associated with acid rocks and correspond approximately to the mineral composition of ordinary granite . Moreover , only a very few basic pegmatites can be considered as economic sources of useful minerals . Whereas , in ordinary granitic rocks the individual minerals usually measure 1/8 to 1/4 inch across , in pegmatites they are characteristically over 1 inch and often more than 12 inches in diameter . Although some of the constituents of the pegmatite may be only a fraction of an inch in length , single crystals more than 10 feet long are by no means unusual , and some crystals are enormous . A whole quarry was operated in the Urals within a single crystal of feldspar . Huge quartz crystals are quite common although usually imperfect . Muscovite plates 10 feet in diameter have been mined in India , and the Purdy mica mine in Canada contained a mica crystal measuring 6.5 by 9.5 feet and weighing nearly 7 tons , which supplied more than $20,000 worth of trimmed mica sheet . A loglike crystal of spodumene in the Etta mine in the Black Hills of South Dakota was 42 feet long . Giant crystals of beryl weighing several tons apiece have been mined from several properties . Because so many rare minerals are found in substantial concentration only in pegmatites , it is a common fallacy to suppose that pegmatites are always enriched in rare elements . Traces of most of these elements , of course , are found in almost all igneous rocks , and they reappear in the sediments derived from igneous rocks . It does not follow , however , that all or even most pegmatites contain higher percentages of rare elements than other granitic rocks . Geological evidence points to the probability that notable concentrations of rarer minerals or elements in pegmatites are more or less fortuituous , such additions often being ascribed to events subsequent to the original emplacement of the main body of the pegmatite . Most pegmatites consist principally of potash , feldspar , and quartz . Even mica , although commonly present , is not an essential constituent . Probably

Feb 1, 1950

By W. W. Adams

With production of coal per man-hour of work at a higher level than ever before, the coal-mining industry of the United States established a near-record in lowering the accident rate of nonfatal injuries per million man-hours of exposure in 1940, the injury rate being lower, except for 1939, than in any year since 1930, the first year for which comparable figures for nonfatal accidents were collected by the. Bureau of Mines, United States Department of the Interior. The rate for fatal accidents, on the other hand, was not as low or favorable as in 1939, nor was it as low as in many years since 1910, the earliest year for which fatality rates were complete for all coal-mining States. Accident and employment reports received from mine operators and fatal-accident reports from State mining departments and inspectors showed that 533,267 men were employed at coal mules in 1940, exclusive of the number employed at coke ovens, Although this number represented 6,108 fewer employees than in 1939, a large increase was made in the volume of work performed and in the quan¬tity of coal produced. In 1940 the amount of labor performed at coal mines was 748 million man-hours, a gain of more than 10 percent over the previous year. The average employee worked 199 days, an increase of 20 workdays per man. Production of coal was nearly 513 million tons, an increase of 14 percent, of which more than 461 million tons was bituminous coal and more than 51 million tons was Pennsylvania anthracite. Accidents to mine workers caused the death of 1,388 employees; in addition, 59,781 employees were injured, and each injury resulted in disability of the employee for more than the remainder of the day on which the accident occurred.

Jan 1, 1942

"M bed, Matanuska valley, Alaska, coal carbonizingproperties B 510M spectral lines, low-energy, study RI 5538Mab shaft, Leadvile district, Colo., investigation RI .1518Maberry process, for aluminum chloride TP 321"

Jan 1, 1960

By Robert H. Ridgway

This circular outlines salient facts regarding the pyrites industry of the United States and the world. It is founded chiefly upon published information available in the literature of the subject. The United States Bureau of Mines has in its files additional and more detailed data upon many of the subjects presented very briefly here, and will endeavor to assist the mineral industries and the public by giving further information in response to individual inquiries. The bureau will welcome comments, criticisms, and contribu- tions of data that may assist in making later editions of this circular of information more accurate, or may aid in developing more fully the files pertaining to pyrites.

Sep 1, 1931

By P. James

"INTRODUCTION Control of target stream acidity is widely used in MIW (mining influenced water). Tailoring pH (a measure of acidity) finds application for controlling key chemistry in both process and waste streams. Traditional lime addition for neutralization and precipitation is most often used but has high reagent costs and results in large amounts of mixed metal sludge requiring costly disposal. A new adaptation of BPS’s patented DEMET™ technology (Dynamic Electrolytic Metal Effluent Treatment) platform offers a potentially improved and “reagentless” alternative to traditional chemical addition for pH adjustment. Electricity rather than chemical addition utilized in BPS’s proprietary approach controllably tailors target stream pH. The method offers a simple, low-cost processing technique yielding cleaner treatment chemistry. BPS’s “green” approach may yield lower operating (OPEX) and life cycle costs and significant reductions (up to 50%) in sludge generation compared to conventional lime treatment. It can also allow new opportunities to generate revenue via selective recovery of valuable processing byproducts. Specific savings and revenues depend on the target site chemistries, details, and processing goals. A more detailed discussion of the process and its operational principles may be found in Reference One.[1] Here application of the BPS treatment to POx (Pressure Oxidation) leaching as an alternative to traditional chemical addition is examined. An example operation process flow for gold mining is considered.[2] Promising processing points for potentially replacing conventional processes with DEMET are noted. The possibilities for lowering OPEX costs, lessening sludge creation, and capturing various valuable byproducts and residuals are examined. Financial life cycle benefit estimates of the principal gains provided by DEMET application to the example operation are noted. Extension and generalization of the analyses to a wider range of scenarios is explored."

Jan 1, 2016

By G. Adderley, A. Wetherelt

The problems of poor drilling in underground operations have been highlighted on many occasions. Incorrect collaring and poor angular deviation can all lead to an increased block size, dilution, over-break adding to both cost and time, while in a tunnelling operation sidewall damage and a poor percentage pull from a blasted round has similar consequences. This paper sets out to further investigate the ability of the laser scanner method of obtaining drill hole deviations and collaring errors at the face as described by Wetherelt and Williams (2006). Tests were carried out to compare measured inter-hole burdens from this method in comparison to that obtained using a total station survey. To investigate the ability of these methods to accurately determine drilling errors, a field test was carried out through an analysis of a series of pre-drilled blast holes of known inclination and direction. A time-motion study was also conducted for a varied number of holes to assess the usability of each method. In line with current research into blast vibration being undertaken at the Camborne School of Mines, 6 cut blasts were carried out to establish the effect of poor drilling on a blasts success to see whether an increased burden at the toe of a hole had an influence on vibration.

Jan 1, 2009

By Rob Domotor

This paper tells the story of using controlled surface and underground blasting methods to excavate hard rock in three areas on Australia’s largest road infrastructure project; the Airportlink Project in Brisbane; worth a total value of AUD $4.8 billion. The project used blasting methods including design, modelling, drilling and loading of the explosives that had never been used before in Australia, some of these were probably unique in the world.

Jan 1, 2012

An understanding of the origin of mineral deposits and their relationship to local and global geotectonics is essential if regional targets for mineral exploration are to be chosen. Volcanism, metamorphism and tectonism are especially significant for the origin and emplacement of mineral deposits, which, far from being fortuitous oddities of nature, occupy well defined positions within distinctive lithofacies. Thus, suggestions for mineral exploration targets can be made taking into consideration the position of 'fossil' convergent and divergent plate tectonic boundaries to indicate areas of specific types of mineralisation. To be borne in mind, though, that level of exposure, time and location of magma generation are all additional and important controlling factors. To further understand the importance of the above parameters, one must refer to the concept of paired metamorphic belts (Miyashiro 1973) which develop during an orognic cycle. These belts are generally constructed in such a way that an ophiolite type complex with metamorphic grades related to high pressure and moderate temperature regimes is flanked by an area of calc-alkaline volcanism and granitic activity with metamorphic grades within a region of high temperature and low pressure. The former situation is usually the seat of primary magmatic mineralisation, whereas the latter contains base metal. Deposits of acid plutonic and volcanic association. As will be seen later, this particular metamorphic-volcano-orogenic situation is well developed in some parts of New Zealand. For the present purpose a distribution of potential ores as related to plate tectonic processes is given below:a) Divergent plate boundaries: primary magmatic Ni-Cu, Pt,Cr, PeS2 and Cu, Pb,Zn in hot brines-hydrothermal environments Mn deposits.b) Convergent plate boundaries: stratabound Cu-Fb-Zn-Ag of felsic volcanogenic association. Porphyry eu-Au of island arc type, porphyry Cu-Mo of continental type. Cu, Au, Y, Sn, Hg, Sb of vein type and replacement lode related to granitic activity.c) Au of hydrothermal vein association, related to late dynamo-metamorphic events. By virtue of ocean floor spreading, regions of divergent plate boundaries are eventually juxtaposed or welded n to areas where plate collisions occur. This is then followed by partial melting due to various causes, just above the descending plate; thus creating a zone of acid to intermediate magmatism. The final picture is that of an orogenic zone with the paired metamorphic belts outlined above.

Jan 1, 1976

Kaiser Aluminum & Chemical Corp. announced that it planned to spend $66 million to increase the efficiency of its Baton Rouge, Louisiana, alumina plant. The improvements are designed to reduce energy consumption but will not change the annual capacity of the plant, now rated at about one million short tons. The project was expected to be initiated immediately and be completed by 1982. ALUMINUM Producers in this country posted unalloyed 99.5 percent aluminum ingot at 53-57.5 cents per pound, yet actual selling prices were closer to 53 cents. Domestic merchants quoted unalloyed ingot on a spot basis at 54-56.3 cents. London Metal Exchange 3-month forward contracts fell during November's trading from 55,2 cents to 52.8 cents per pound.

Jan 1, 1978

By Eleanor Sonley

In October 2000, temporary seismographic stations were installed above the Trail Mountain Mine, Emery County, Utah, USA to supplement a regional network. Over seven months, 1826 mining-induced seismic events were recorded with a magnitude range of M 0 to M 2.2 (Arabasz et al., 2002, 2005). Routine event locations for this dataset cluster around the longwall mining activity during the recording interval. However, applying a double difference relocation technique to the routine locations significantly improves the correlation between mining activity and event location. The resulting relocations depend greatly on station distribution and the number of arrival time picks. We use this dense temporary array to assess station distribution requirements for applying the double difference technique at other mines by systematically removing data from available stations, thus simulating sparser networks. The insight gained using the Trail Mountain dataset is used to develop a metric for assessing the usefulness of above-mine networks and to develop a tool for expanding seismic network coverage. To verify the appropriateness of these tools for wider application, we examine data from two additional mines located in the western United States. Improving the relative locations of mining-induced seismic events highlights the association of these events with active portions of the mine. Clusters, regions of quiescence and relative timing of events can be used by mine operators to assess hazard, optimize production, and evaluate performance of mine plans. The lessons learned from this study may be used in future network design to improve accuracy of event locations at other mines.

Jan 1, 2009

By ERNEST F. . SURCEIARD

work have been published from time to time by the Survey.' A detailed report on the Birmingham district, with maps, has been completed, and will be published within the next year." In the following paper it is aimed to present only an outline of the geologic relations of the ores, since the Appalachian geology of Alabama has been discussed by many previous writers, but to describe rather fully the ore of the Birmingham district, and to discuss its relations and probable extent. IT. OUTLINE OF THE GEOLOGY. 1. Stratigraphy. The pre-Pennsylvanians rocks exposed in and along the borders of the valley-regions of Alabama, range from middle Cambrian to Mississippian (Lower Carboniferous), and at the SW. extremities of the valleys these rocks are overlain by coastal-plain deposits of Cretaceous and Tertiary age. A generalized section of the pre-Pennsylvanian Paleozoic rocks for the valley-regions is given in Table I. TABLE I.-Section of Pre-Pennsylvanian Paleozoic Rocks in Valley-Regions of Alabama. System. Formation and character. Thickness. Ft. Shale and sandstone 300 to 2,200 Carboniferous (Mississippian- Limestone and shale 300 to 800) I Sandstone and shale 50 to 200 1 Fort Payne chert and limestone 100 to 300 Devonian Chattanooga shale 0 to 30 Silurian Clinton (" Rockwood ") shale, sand¬ stone, and iron-ore 200 to 700 Ordovician Chickamauga ("Trenton") limestone.. 200 to 800 Cambro-Ordovician Knox dolomite and chert 1 2,200 to 2,700 basal dolomite 500 to 600 Cambrian Conasauga shale and limestone 1,000" to 1,500 - I a Base not. exposed.

Nov 1, 1908

By W. C. Phalen

During the search for deposits of soluble potash salts in the United States, carried on by the United States Geological Survey, much infor- mation was collected on the salt resources and industry of the United States. The more important features of the information thus gath- ered, compiled, and digested may be classified under five headings, as follows: 1. Geology of the salt deposits of the United States. 2. Theories relating to the origin and formation of salt deposits. 3. Chemical composition of saline materials in the United States, principally rock salt and natural and artificial brines. 4. Statistics of salt production in the United States. 5. Technology of salt production. The first four items are not discussed in this report, but their treatment will comprise a separate report published by the Geologi- cal Survey, which will supplement this report, relating to salt- making processes, and will describe comprehensively the salt resources of the United States. Persons desiring a copy of that report should apply to the Director of the United States Geological Survey, Wash- ington, D. C. In addition to the discussion of processes, this report gives a brief description of the more important sources of salt in the United States. This description has been abstracted from the much length- ier description contained in the report to be published by the Geo- logical Survey.

Jan 1, 1917

By Emily Wortman-Wunder

As the 2010 president of the Society for Mining, Metallurgy, and Exploration, Inc., I am pleased to present the 2010 issue of Transactions of the Society for Mining, Metallurgy, and Exploration, Vol. 328. A significant portion of the contribution that we as a professional society make is the publication of professional and technical papers that accelerate the advancement of scientific knowledge and enable transfer of technology. Communication within the mining community is the key to a successful society. Through books, magazines, meetings and electronic media, we accomplish the technology exchange that is fundamental to the existence of the Society. This technology exchange continues a tradition that dates back to the 1871 meeting of 22 mining engineers in Wilkes-Barre, Pennsylvania, that resulted in the founding of AIME; those individuals envisioned that these transaction volumes “would form a most valuable and greatly needed addition to our professional literature.” This volume certainly fulfills that pledge. The 2010 Transactions is the first Transactions to take advantage of new publication technologies. It appears solely as an e-book. The decision to go to an all-digital format for this longstanding publication was a difficult one, but one which will certainly better serve the mining community. I am excited about this development and the opportunities it presents. The 2010 Transactions also contain some of the most exciting research from the past year, including new developments in mineral processing, safety and exploration. Be sure not to miss the two Minerals & Metallurgical Processing issues on the subject of gold hydrometallurgy. This 2010 Transactions comprise of a total of 78 technical papers (582 pages including index), including all 21 papers (136 pages) that were published in 2010 in the Technical Papers Section of Mining Engineering magazine (Vol. 62) and all 34 papers (231 pages) that were published in 2010 in Minerals & Metallurgical Processing (Vol. 27). Addition, this volume contains 23 papers (194 pages) that are being published for the first time in this issue. The papers presented in this volume were written by some of the most distinguished professionals in the industry worldwide. All 78 technical papers were peer-reviewed. The process of review and publication requires much hard work by authors, reviewers and our publications staff. As the 2010 president of SME and on behalf of all our members, I would like to extend our gratitude to all whose volunteer efforts contributed to the publication of this volume.

Jan 1, 2010

By Thomas S. Jones

This report discusses processing and use of the principal forms of manganese. The focus is on trends in the United States in the 20th century and specifics of domestic manganese material flows as of about 1990. To protect proprietary data, quantitative assessments are limited to the iron and steel industry, which accounts for about 90% of consumption. Nonmetallurgical uses are considered qualitatively. Approximate disposition of a U.S. cumulative consumption during 1901-90 of an estimated 69 million st of manganese is estimated to be iron and steel slag, 69%; nonmetallurgical uses of a dissipative na¬ture, 10%; iron and steel scrap, 9%; National Defense Stockpile, 3%; unidentified and/or including items in service, 10%. In slag from iron blast furnaces and steelmaking, manganese is present as a minor, relatively im¬mobile component, which so far has been uneconomical to recover. Construction and road building are main applications for these slags. Steel slag contains the greater amount of manganese. Studies by others of global manganese fluxes and the effect of human activities on them also are discussed. One source concludes that the main effect of human activities, via deforestation and agricultural activities, has been to increase the rate of transport of manganese to the oceans.

Jan 1, 1994

By J. R. Heberger, B. H. Ngo

The Safety Pays in Mining v2.0 web application, developed by the National Institute for Occupational Safety and Health (NIOSH) Mining Program, helps mines determine the potential costs associated with mining injuries. This web app categorizes injury cost by part of body injured, by the cause of the injury, or by the nature of the injury. When the user selects one of over 150 common types of mining injuries, the app provides information on the distribution of costs of workers’ compensation claims for that type of injury. Based on other user inputs, Safety Pays in Mining v2.0 will estimate the total costs of the selected injuries and the estimated impact of total injury costs on mining company profits and will provide some examples of services and personal protective equipment on which companies could spend the savings that result from the prevention of injuries. This paper reviews the Safety Pays in Mining version 2.0 web application by discussing the development and updates to the app, how it is used to show the true costs of mining injuries, and how mines can benefit from using this app.

Feb 1, 2024

By C. A. Pickles, D. K. Xia

"In the last few decades, microwave energy has been widely employed in food processing, rubber and plastics curing, and in ceramic sintering. Recently, the application of micro waves as an energy source in extractive metallurgy has received considerable attention from a number of researchers. During the period from the mid-1960s to about 1988, the majority of the research was focussed on the behaviour of materials in microwave radiation. These research activities will continue to be important, since fundamental data on the interaction of microwaves with materials are vital for the successful application of the technology. Since1990, a number of potential applications of microwave processing have been investigated.These include: pretreatment of ores and concentrates, leaching, reduction, preheating of refractories, heating of slags and waste treatment. In this paper, the interaction of micro -waves with materials of interest in extractive metallurgy are reviewed and potential applications are discussed.IntroductionMicrowaves were first used in 1946 for the heating of materials, shortly after radar equipment was invented during the second world war. It was evident that microwaves were very effective for heating water and the technology was quickly adopted for drying and cooking. Since the introduction of the first microwave oven by Raytheon in 1952, many millions of domestic microwave ovens have been sold annually (National Research Council,1994; Atomic Energy of Canada and Voss Associates Engineering, 1990).In extractive metallurgy, microwaves are in the early stages of development (National Research Council, 1994; Atomic Energy of Canada and Voss Associates, 1990; McGill and Walkiewicz, 1987; Bradhurst and Worner, 1990;Peng et al., 1993). However, there are several reasons for the growing interest in the use of this technology in the field of metals extraction. These include the following potential advantages of microwaves: (1) rapid and selective heating of materials; (2) reactions can be catalyzed because the heating occurs on a molecular or atomic level; (3) clean and controllable energy source; (4) the gas volume is reduced and the atmosphere can be controlled as there are no gaseous combustion products; (5) the material is heated internally in comparison to external heating with conventional methods; (6)the temperature of the refractory can be minimized; and (7) the working environment is improved."

Jan 1, 1997

By R. R. Brandenthaler

The development of the Seminole area into one of the major oil-producing sections of the country has been accompanied by many innovations and departures from former methods of development. On July 1, 1929, two years and nine months from the date of discovery, 20,490 acres were considered proved, and additional acreage is constantly being developed. Because of its peculiar conditions, extent, and rapid rate of development, the Seminole area provided numerous problems, the solution of which necessitated research in connection with practical field operation; as a result, there was a radical departure from methods usually employed in the development of a new field in the Mid-Continent area.

Jan 1, 1930