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By Mark Sheppard

This paper is the third of a series recording the results of tests made at various quarries throughout the United States to determine (1) the relation between the size gradation of feed to, and product from, primary crushers, (2) the particle shape of the crushed product, (3) the differences in gradation and particle shape produce- by different types of primary crushers, and (4) the differences in gradation and particle shape caused by crushing different kinds of stone. Progress reports 1 and 2 dealt with comparisons of different types of crushers crushing the seine tyre of stone. This report deals with relationship between feed and product of two different limestones, as to size distribution and particle shape, when crashed in the same crusher.

Jan 1, 1938

After a stagnant performance in 1982, gross national product (GNP), industrial production, and employment increased during 1983 in nearly all industrial nations, with the U.S. performance generally leading the uneven worldwide recovery. Real U.S. GNP increased 3.3 percent in 1983 (table I). Although investment in nonresidential structures declined, total nonresidential fixed investment in the United States was up 1.5 percent following a 1982 decrease. The increase in worldwide industrial activity and demand in 1983 put greater pressure on prices in many countries. Prices increased from less than 3 percent in the Federal Republic of Germany, Japan, the Nether-lands, and Switzerland to as much as 10 percent in nearly all the other Organization for Economic Cooperation and Development nations. The annual inflation rate in the United States was 4.3 percent (based on the GNP fixed-weight price index).

Jan 1, 1984

A major hazard to workers in underground mines is fire and the resulting contaminated air. Fire reaches miners thousands of yards away with carbon monoxide gas and other toxic fumes. The same ventilation system that furnishes fresh air to miners can also be the vehicle to carry contaminated air to remote locations. To reduce these problems, the U.S. Department of the Interior's Bureau of Mines entered into Contract H0242016, "Mine Shaft Fire and Smoke Protection System," with FMC Corporation, Santa Clara, California, to evaluate mine shaft fire and smoke hazards and to develop and demonstrate a low-cost, reliable mine shaft fire and smoke protection system that would be applicable to a majority of metal and nonmetal mine shafts, including raises and winzes, especially in deep mines.

Jan 1, 2011

By G J. I dos Santos

The risk assessment of mining projects is directly related to the possible failure in estimating, and as estimates are made from sampling results, this activity should be done in a judicious and planned manner, to avoid surprises at the start of project operation. Pierre Gy’s (1995) sampling theory addresses the issue of sample representativeness and indicates that only the certainty that the sampling procedure was performed with quality may result in samples being recognised as representative. To validate the representativeness of samples from sampling boreholes selected for studies of mineral processing, the team of geology resource assessment of VALE has proposed a methodology based on the use of statistical analysis tools, which in addition to considering the spatial distribution of these samples in deposit, considers whether they are representative of the populations studied, allowing the geologist to make a quick analysis of sample representativeness.

Jul 11, 2011

By J. Edgar Pew

As MOST of the oil production comes from leased-lands and not fee property, I shall refer to "leases" as covering the producing tracts. To produce oil, leases on land must first be obtained. Well-selected leases are all important. Not many years ago, the location for drilling for oil in wildcat territory was too frequently determined by the nearness, of adequate water and fuel supply, or with a view to cheapness of transportation. To some extent, the "creekology" theory is the result of the number of wildcat tests made near streams, to obtain water for operations. Now, an up-to-date operator will depend on his geologists for his location and, in many cases, will spend thousands of dollars to get water to it. The wisdom of following the geologist rather than the creek has been abundantly demonstrated in the past few years. In vast territories, where dry holes are spotted at intervals of a few miles or less. apart, and by reason of which these territories have been condemned for oil, the geologist is now finding many more spots that are producing large quantities of oil. No better tribute to the work of the geologist can be found than the surface and subsurface work being done in practically all parts of Oklahoma and the development had as a result of this, work. A land department is usually organized by placing in charge a man who is not only acquainted with the oil development, but who is a shrewd buyer, a first requisite for which should be unquestioned integrity. It takes a shrewd buyer to resist the persuasive lease broker, frequently backed by a geological picture from which the oil fairly drips. The geologist can help a lot by being absolutely honest when he makes these pictures; he will also thus strengthen his own cause. A geologist should interpret his own work and put his name behind his interpretation. If he does not he is liable to be misquoted and often discredited, as a result, by some overzealous lease broker giving an interpretation never intended by the geologist.

Jan 8, 1925

By Charles Will Wright

Brief descriptions of the occurrence of the various deposits of strategic minerals then known in South America are published in "The Mineral Deposits of South America," by B. L. Miller and J. T. Singewald, 1919; in "Ores and Industry in South America," by H. F. Bain and T. T. Read, 1934; and in many publications on the individual countries. To give a gen.era1 idea of the situation today and possibilities for future output of strategic minerals in several of the countries, the following notes are offered. All tonnages are in metric units.

Jan 1, 1940

By J. Engel

The talc deposit in Gemerská Poloma lies 350 to 400 m under the surface; the whole deposit is located at the highest-level drinking-water-source protection zone, therefore, opening in this mining area (a well, a ramp) requires higher investment, operational and water protection costs. The adit, outside the mining area, with a length of 4200 m, rising with a gradient of 3? and a diameter of 10.3 m2, allows free passage/runoff of mining-water through the adit, and guarantees low costs for transporting produced material and equipment. This solution is in total less demanding from both investment and operational point of view.

Jan 1, 2007

By F. M. Waring

produced when zinc is substituted for a certain amount of tin are decidedly unsatisfactory. The substitution of aluminum for tin is entirely impractical, and such castings are worthless. This does not, however, exhaust all the possibilities of substituting other metals for tin in the copper-tin-lead alloys, but it is my opinion that the substitution of any other metals, in those alloys, can be made only by sacrificing the quality of the alloy. The possibility of substituting alloys of an entirely different type presents an attractive field for research. The copper-tin-lead alloy has attained its position as the most desirable bronze bearing alloy, but this does not mean that some other alloy may not be found which may give equally good or better results. In the search for such a substitute alloy it should be borne in mind that a bearing metal should possess the following properties: (1) It should be sufficiently rigid to support the load or resist the impact, but yet not so brittle that it will easily crack. (2) It should have as great a yielding or plastic nature as is consistent with its ability to support the load or resist the impact without deformation of the bearing as a whole. (3) The ideal structure combines a hard matrix to support the load and a softer metal or alloy contained within such matrix, to permit the bearing surface to adjust itself to irregularities of service. (4) It should be easy to handle in the foundry and machine shop. (5) It should be capable of being remelted without deterioration. (6) For use in babbitt-lined bearings, it should be capable of being tinned, so that the babbitt can be applied thereto. (7) It should have good heat conductivity in order to dissipate the heat generated by friction. Pennsylvania Railroad Anti-friction and Bell Metals F. M. Waring," Altoona, Pa.—Thc necessity for conserving tin has recently been very forcibly brought to the attention of all consumers, and efforts are now being made to reduce the tin content in certain alloys or to substitute other alloys not containing tin. The approximate composition of the non-ferrous alloys in general use on the Pennsylvania Railroad are given in the accompanying table. Phosphor bronze is used principally for rod bushings, main-rod brasses, and crosshead shoes. Ex. B bronze is used to a small extent for backs of car and coach bearings, but the majority of these are now made of the car-journal bronze, which contains, on the average, about 5 per cent. tin.

Jan 1, 1919

By Scott Lewis, Andrew Kositsky

"INTRODUCTIONThe South Napa Earthquake of 2014 caused ground motion at numerous reinforced concrete-lined (shotcrete-lined) winery tunnels in Napa County and Sonoma County, California. The occurrence of seismic ground motion at these tunnel complexes, known as wine caves, presented an opportunity to reevaluate seismic performance of reinforced concrete and reinforced shotcrete lined tunnels. The authors of this paper updated the most recent comprehensive compilation and evaluation of case studies by Power and others (1998), which correlates peak ground acceleration (PGA) at tunnel sites to damage. For this update, the authors evaluated the seismic performance of 31 wine caves near the South Napa Earthquake epicenter; including some of the 90 wine caves they designed since 1991, some caves designed by others, and additional caves constructed by contractors that they frequently work with. Tunnel designers can use the new data presented in this paper to help evaluate the usefulness of detailed seismic design analyses. THE SOUTH NAPA EARTHQUAKE The South Napa Earthquake occurred at 3:20 AM Pacific Daylight Time on August 24, 2014. Figure 1 shows the approximate location of the epicenter, the measured/estimated PGA contours, and the location of wineries with wine caves added to the database where the PGA was at least 0.2 g. The epicenter was along the West Napa fault, about 5 miles south-southwest of downtown Napa, California. The earthquake moment magnitude was 6.0, and measured/estimated PGAs were up to about 0.7 g. The duration of strong shaking was about 10 seconds. This earthquake was characterized by right lateral strike-slip fault movement, ground surface rupture, and after slip at the ruptures. Increased surface water flows were observed at seven creeks after the earthquake. Groundwater level rises of up to 5 feet were observed in Sonoma County wells after the earthquake. The earthquake was the largest seismic event in the San Francisco Bay Area, which includes Napa and Sonoma Counties, since the 1989 Loma Prieta Earthquake. The Napa event caused an estimated $400 million in damage. This damage included moderate to extensive structural damage to older commercial buildings and to some newer buildings in downtown Napa. This damage resulted from ground motions, subsequent fires, and failed underground utility systems."

Jan 1, 2016

By E. Onal

Mining operators are faced with complex information delivered by technology-centric rather than user-centric systems. The ability to achieve high situation awareness (SA) in the face of this data overload is a key challenge for effective decision making and information exploitation. Incidents that result in loss of revenue and even life, and compromise safety that are attributed to human error are often the result of system designs that overload human cognitive capabilities. This paper focuses on defining SA as it relates to mining operations and presents methods for improving SA through a scientific approach for electric shovel operator user interface development.

Aug 1, 2013

By G. Sachs, A. W. Dana, C. C. Chow

A great number of the investigations on the plastic flow of metals have been concerned with the establishment of a "universal" stress-strain relation. In such a relation some stress function when plotted against a strain function should yield identical curves for the various stress states. In the first investigation of this type, Ludwik and Scheu1 plotted the maximum shearing stress as a function of the maximum principal strain. Later Ros and Eichinger2 introduced two universal stress-strain relations, the one relating the maximum shearing stress to the maximum shearing strain, and the other relating a stress invariant, suggested by von Mises and Haigh, to the corresponding strain invariant. (In more recent investigations the stress and strain invariants are frequently supplemented with some factor to render their meaning more lucid.) A further suggestion which has not attracted appreciable attention is that by Baranski³ who used stress and strain deviators. The most common means of experimentation to determine the relation between stress and strain consists in subjecting thin walled tubes to combined internal pressure and axial tension.4a,4b,4c This method allows the study of plastic flow under stresses which are variable in two directions. However, the plastic flow which can be obtained in this manner is comparatively small, being limited by either tension failure or instability. For copper,'. only the relation between maximum shearing stress and maximum shearing strain yielded good agreement. On the other hand, tests on a stee14b and on an aluminum alloy4c. resulted in systematic deviations if any of the discussed universal stress-strain relations were used. It would seem, therefore, that the agreement mentioned above for copper is only incidental and explained by its high rate of strain hardening compared to that of other metals. Much larger strains than experienced in the tube tests can be obtained by subjecting a thin membrane of a ductile metal, which is restrained at its periphery, to a uniform hydraulic pressure. The thin sheet forms a deep bulge before it fails. The stresses and strains in such a bulge increase with increasing distance from the edge of the clamping "die," the maximum stresses and strains occurring at the pole (crown) of the bulge. While the stress and strain states are determined by the contour of the bulge, the absolute magnitude of the stresses and strains depends upon the hydraulic pressure. The bulge contour is in turn correlated with the geometry of the die opening. The deformation and fracture characteristics of circular bulges, that is, bulges formed with circular clamping dies, have been the subject of numerous experimental and analytical investi-gations.5,6,7 It has been shown that plastically deformed circular bulges develop large and comparatively uniform strains before failure by instability"6b,6c,6d and closely assume a spherical shape.6d Also the distribution of strains across the contour of the bulge is dependent on the metal being investigated and is correlated with, but cannot be predicted from, the metal's stress-strain characteristics. On the other hand, oblong or elliptical bulges, that is, bulges formed with elliptical clamping dies, are not as susceptible to analytical analysis and have not been investigated to the extent that circular bulges have. The few available data6c,7c indicate that stress states are obtained at the poles of the bulges, varying between plane strain and balanced biaxial tension, depending upon the geometry of the die opening. In this paper, the strain state and curvatures exhibited by three bulge shapes, a circular and two elliptical bulges, Fig 1, are analyzed experimentally using methods described in previous publications.6a,6c An attempt is made to derive the stress-strain relations for these bulges, which represent strain states in which the ratio of the two positive principal strains varied between 1.0 and 0.35. In addition, tension tests yielded data for a value of —0.5 for this strain ratio. Such an analysis should indicate the applicability of the various laws correlating stress with strain to the stress and strain states occurring in bulged shapes. Definitions and Nomenclature The definitions of the major stress and strain quantities used in this paper are as follows: s1, s2, s3 = principal normal stresses Sl > s2 > S3 t = shear stress e = conventional (unit) strain e = In (1 + e) El, E2, E3 = principal natural strains 7 = shear strain The maximum shear stress: , _ S1 — S3 lmax = 2 Frequently, the flow stress, s1 — s3 = 2lmax rather than the maximum shear stress is used.

Jan 1, 1950

By Haydar Güneş

In this study, a hydrometallurgical process was evaluated for the recovery of Nd from a Nd-Fe-B magnet. Each leaching test was performed at the solid (weight) to liquid (volume) ratio of 1:50 and was mixed at 400 rpm at ambient temperature. The effects of 3 different acids (HCl, HNO3, and H2SO4) on the extraction of Nd were investigated and H2SO4 was found to be more effective than other acid solutions. Under the optimal conditions, pregnant leach solution was produced with H2SO4 for subsequent Nd precipitation testing. Each precipitation test was carried out using 100 mL of feed solution mixed at 600 rpm at 25°C. NaOH and H2C2O4 were used for Nd precipitation. The highest Nd was precipitated as Nd2(C2O4)3, 10H2O with C2H2O4 at 20 min.

By B. A. Monkman

"IntroductionONE OF :THE most effective methods by which the construction industry is combatting mounting building costs is by making increased use of lightweight materials, thus reducing the dead load to be carried •by structures. This applies to non-metallic materials as well as to metallic ones, and particular attention has been given to developing lightweight aggregates for use in concrete.The use of lightweight aggregates is not new and, in fact, dates back to the Roman Empire, when pumice was used in the walls and domes of the Roman buildings. More recently, and up to a decade or so ago, the demand for these aggregates was met from deposits of volcanic cinders, pumice, scoria, etc., and from the by-products of blast furnaces and coal burning boilers. However, these sources of supply are no longer sufficient to meet the demand, for transportation costs pretty well restrict the use of the natural lightweight aggregates to the western cordillera regions where the deposits of these materials occur, and the use of expanded slag aggregates to the areas neighbouring the plants where slags are produced. As for cinders, the supply has been greatly reduced by the conversion of industry to fuel oil, natural gas, and powdered coal, and the large stockpiles which existed previously have been pretty well exhausted.Industry's approach to the problem of a decreasing supply, in the face of an increasing demand, has been characteristically direct. The solution has been to construct plants whose sole .purpose is to produce economically an acceptable light-weight aggregate from materials close at hand."

Jan 1, 1955

By Richard R. Klimpel

INTRODUCTION The process of froth flotation as a means of upgrading the quality of coal by removing water and/or ash and/or pyrite has been receiving increasing attention since the 1960's by the world-wide coal industry. Historically, coal preparation practice has involved the use of primarily gravity based separation techniques, screening, and/or water washing in removing the larger fragments of inert material from coarse raw feed coal. The preparation, handling, and cleaning of raw coal finer than 500 micrometers was deliberately avoided. Most often the fine coal that was produced would be judiciously incorporated into the bulk of the larger sized cleaned coal product or simply discarded. Since the 1960's and accelerating in the 19701s, the desirability of performing some type of coal cleaning or upgrading on the finer raw coal feed materials has been increasing. There are several apparent industrial incentives for implementing fine coal ((500 urn) processing alternatives including the gradually increasing value of the normally lost fine coal product; the additional amounts of fine coal being produced due to changes in mining techniques; the need to appropriately dewater and upgrade fine coal streams in order to meet increasingly stringent environmental regulations on water quality. storage of fines, etc.; the increasing need to lower undesired sulfur and ash contents in some coal end-use applications; and the increasing development of speciality coal use processes that require inherently finer and cleaner coal particles such as in gasification, liquefaction, fuel injection, etc. Looking at the over 70 years of mineral oriented fine particle separation successes at the industrial level, the use of froth flotation in fine coal would also seem to be a natural process to utilize at the industrial level. In the world of strictly mineral processing technology and, more importantly in the world of mineral commodity economics, there are clearly a number of advantages to using froth flotation that are well documented and universally accepted. These include: the relatively low capital and space requirements required when compared to other process options available to upgrade minerals; the extreme flexibility inherent to the froth flotation process both with regard to throughput and differences in raw feed characteristics; the general availability of a wide range of equipment sizes and reliable suppliers of equipment; and the general availability of appropriate and relatively cheap chemicals that are the major driving forces behind mineral flotation. Just how has the implementation of froth flotation fared in coal upgrading over the last 20 years? It is towards answering this question that this paper will be oriented. As such, the discussion will be somewhat philosophical. The comments offered are based on the personal experiences of this author who has worked in the basic side of inventing new flotation chemistry and flotation analysis techniques with the major overriding goal of implementing this new technology successfully at the industrial level in both coal and mineral flotation throughout much of the world. This paper is not intended to be a complete reference to all published scientific work on the subject of industrial froth flotation of coal. As a brief background to what will be expanded upon in this paper, the author would like to offer the following summary comments: 1) the industrial practice of fine coal froth flotation is qualitatively similar but quantitatively different than industrial mineral froth flotation when viewed from either research considerations, operating viewpoints or economic evaluation criteria; 2) it is clearly possible to invent and/or develop new technology (such as new chemistry and/or equipment) that can do statistically better than current plant practice in well-controlled tests in either coal or mineral flotation circuits; 3) there is so much inherent variability to the raw feed coal streams and other operating parameters that even if there is a documented technical incentive to implement some new piece of technology, the people, instrumentation and control methodology required are often simply not available or not economic unless the potential payoff is quite large.

Jan 1, 1988

By C. G. Massey, L. C. Acton

A first-class haulage level railroad was considered of prime importance during planning of San Manuel because successful operation of the mine would hinge heavily on the ability to move large tonnages of ore rapidly, safely and efficiently. These principles, plus certain techniques developed from experience on the 1475 level, are being employed in preparation of the 2075 level. At full production, twelve 23-ton trolley locomotives, each pulling fifteen 12-ton capacity ore cars, and fifteen 8-ton battery locomotives engaged in development, service and supply, will be in operation on the 2075 level 24 hours per day, seven days a week. More than 35,000 tons of ore will be transported every 24 hours. GENERAL DESCRIPTION The rail haulage system is designed to comfort- ably move twelve 180-ton payload trains per hour through the rotary dumps pulled by 23-ton trolley locomotives. The rail system is laid out as a simple double loop with one-way traffic of continuous haul as shown in the above diagram, and is comprised of about 30 miles of track on the 2075 level.

Jan 3, 1962

By E. D. Gordner

Irrespira ble gutses issuing from the rock fofflb tions ere tJ source of expense ond danger in some metGLl mines. There is a great Variation in the compos i-· tion of such gdses and, os shown 'by recent sampling by the Bureau of ines, the gas rr;;,.y consi$t mostly ct carbon dioxide, (Rocle Strata Gtsses in the Mines of the East Tintic Mining District, by G. E. McElroy, Bu.retau of Mines Serial 2Z75) or f methone (Metruine in Ccalifornia C.old Mines, by B. 0. Picl-Q:lrd i:lnd !.. D. ("iordner, Bure, cf Mines Serial 2303), or nitrogen, sin the present instonce. A nl.liilber of unventilated rt:t.ises in some of the mine of l:l Neva&. district conuin «i'ccumulCltions of l;i hih-nitrogen gas the1t will not supi:ort life or combus­tion. The rdises ore in different geologiecil formations and in widely sep1:1rated. loecslities in the mining district. One ot" two ri::lises in the sme fc.rtr.ation may be full of the gos cand einother nec-r'by be t'ree ot· it. Lives have been lost t:lnd a number of men heave been overcome on enteing unvetilated rtsises in which their­respircable tss hcsd c1ccuni..1.l1::1ted between sldfts. Gener1:1lly, however, the gas see:ns to noozett from the .t'onrbtio:1 ond to ecc1: .. ,i.-1,;.1:.1te so slowly tMt its presence is not suspected t the tfr.1e, bu.t discovered. ed:'t&.c' the raise is t)band.oned. OcCE.isionelly 1 t issues from a ne•.,ly cut cre·tice or fissure under considerca ble pressure and in lar!?e enough '3.'16ntities to overcome or drive 011t men working in unventilated places.

Dec 1, 1922

By J. J. Sammarco

Computer-aided control of a mining machine pl aces its operator in a safe, remote location, thus reducing health and safety risks, Sensing systems that provide machine position (xy coordinate) and heading (yaw), are extremely useful in aiding remote positioning of mining machines. The U. S. Bureau of Mines has developed two sensing systems for position and heading information: A scanning laser system based on the Lasernet sensor and a mechanical position and heading system based on linear-position transducers. The Bureau is also investigating a system from Honeywell, the modular azimuth and positioning system that employs ring-laser gyroscopes. This paper presents a brief background and status of these sensing systems as applied to the remote positioning tasks of a continuous mining machine. Included are field test results of each system operating in a room-and-pillar research section at a cooperating mine in West Virginia.

Jan 1, 1992

By Donald F. Reed

During the first 6 months of 1948 the Bureau of Mines investigated the titania, deposit on the Wynn 0. Christy property in northern Hot Spring County, Ark. The property is situated in Magnet Cove, about half a mile north of the Magnet Store and U. S. Highway 270 (fig. 1). The purpose of the investigation was to determine the extent and grade of the ore body and to obtain a representative sample of the ore in as nearly natural condition as possible for use in metallurgical testing. All of the titania that has been marketed from Arkansas mines has been in the form of rutile from a deposit about 2 miles west of the Christy property. The titania in the Christy property occurs principally as brookite, which, with fragments of novaculite, quartz, and limonite, is imbedded in red clay. It is difficult to recover a core of the material. Three types of drills - a diamond drill, a bucket drill, and a Baker cable-coring tool operated on a churn rig - were employed in an effort to procure proper samples in their natural state. The Baker tool was found to be the most efficient and to be capable of drilling to a depth of 150 feet, making 80 to 100 percent core recovery (fig. 8). Total footage drilled was 1,536.9 in 21 holes, of which 7 were diamond-drill holes, 13 were bucket drill holes, and one was drilled with the Baker tool. The ore body was found to be 900 feet long, 500 feet wide, and more than 141 feet deep and contained 5.8 percent TiO2 and 0.52 percent 1720. Most of the deeper drill holes bottomed in ore, and there is a possibility that the ore may persist to a depth of several hundred feet. The Metallurgical Division of the Bureau of Mines is conducting experimental work at the Mississippi Valley Experiment Station at Rolla, Mo., for the purpose of developing methods of concntrating and utilizing the ore.

Jan 1, 1949

By Y. Zhan1, T. Moodley, M. A. H. Zahid

Mining operations are under growing pressure to improve safety and efficiency while dealing with aging infrastructure, complex processes, and workforce constraints. Although many sites are equipped with surveillance cameras and control systems, critical events often go unmonitored or under-analysed due to the lack of intelligent interpretation tools. Cameras typically act as passive recorders, requiring manual review by control room operators; a process that is labour-intensive, error-prone, and reactive. Vision AI is emerging as a transformative solution, combining computer vision and artificial intelligence to deliver real-time, actionable insights. This technology has evolved along two key phases: traditional object detection, and more recently, multimodal large language model integration. This paper presents solution architectures, deployment results, and key insights from real-world implementations across underground operations, open-pit truck-shovel operations, and smelter operations, demonstrating how Vision AI is reshaping mining operations to become safer, more efficient, and more intelligent.

Mar 6, 2026

By Charles W. Huggins

Electron diffraction and electron microscopy were used to determine the unit cell parameters of garnierite [(Ni,Mg)3 Si2O5 (OH)4] and to examine its crystal habit. Bundles of ribbons, many less than 200 A. in cross section, make up the bulk specimen of the garnierite Electron diffraction revealed the unit cell to be monoclinic. Unit cell parameters were: a, 5.33 A,; b, 9.23 A.; c, 14.96 A.; and ß, 94°441.

Jan 1, 1961