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By W. M. Myers

MINERAL Economics is the most recent profession to be recognized as a separate division of the mineral industries. It has originated from the increasing awareness of the importance of the economic aspects of industries concerned with discovery, extraction, and utilization of minerals. It is concerned with the interrelated fields of economics and technology. The individual trained in economics alone cannot qualify. The curriculum in the School of Mineral Industries at The Pennsylvania State College was approved in May 1946, and enrollment begun in September of that year. Due to the transfer of advanced students from other courses, particularly metallurgy and electrical engineering, it was possible to graduate the first seniors in June 1947. The next class was graduated in February 1948. From experience derived from placing these graduates in industry, and from information supplied by prospective employers, valuable data have been obtained in the organization and operation of the course of study.

Jan 1, 1948

By Ross R

Although mining is an old industry its management is quite a new science, and its complications are now being recognised as demanding expert knowledge in many branches of technical and professional education. Not the least amongst these isaccountancy, for probably its most important problem is "How to control the expenditure." Unlike most businesses a mining company stands almost entirely in the light of a purchaser in the world's markets, and not as a seller, except say for product so the established and perfected systems of modern industries cannot be adopted for mining purposes. For this reason it has been left for late years to consider the matter seriously, and now a number of well-managed concerns have devised costs systems to suit their own requirements.Very little, however, has been published and even that is disjoined and difficult to make use of. Some of the costs systems in vogue, although elaborate and imposing, are not of very great value for keeping check on wasteful expenditure, or for displaying the commercial effect brought about 'by any particular change in practice, or by an addition or alteration to a portion of existing plant.

Jan 1, 1912

By S. C. Termes

To help develop the basis for new fine-particle separation methods, the Bureau of Mines has investigated the use of cross-linked starches containing four chelating groups--carboxylate, iminodiacetate, dietha-nolamine, and xanthate--as flocculants for selected metal oxide and hydroxide mineral fines. It was found that those starches capable of interacting with the mineral surface by a chemisorpti,on mechanism (as indicated by zeta potential measurements) produced the highest recover-ies and'grades of the metal oxide or hydroxide when flocculated from a binary mixture with quartz. The effects of pH, dispersing agent, stirring rate, stirring time, and starch dosage on selective flocculation were studied for binary mixtures of hematite and chromite with quartz. Floc strength becomes important in achieving maximum recoveries by mechanical postflocculation separations.

Jan 1, 1985

By M. Krasowska, W. Skinner, R. K. Asamoah

Understanding chemical interactions at solid-liquid interfaces have played a pivotal role in improving mineral flotation performance, increasing the rate of mineral crystallisation and profitable leaching of valued minerals and metals. This paper highlights gold leaching with links to surface and interfacial chemical processes occurring, and opportunities to maximise extraction while reducing usage of more recent scarce resources. From the review, there is a significant link between surface and interfacial processes and gold leaching performance. Evidently, gold leaching kinetics could be increased by changing leaching conditions, including manipulating the surface and interfacial interactions. Control of surface and interfaces during gold extraction could enhance rapid, smarter gold extraction and mitigate formation of passivation layers. Keywords: Surface and interfaces, refractory ores and concentrates, gold leaching, reaction mechanism and kinetics

Jan 1, 2020

To investigate mine ventilation problems which do not lend themselves to conventional anemometer and smoke study techniques by use of SF6 (sulfur hexafluoride) tracer gas. Approach SF6 tracer gas is released in-to the air at a given mine location. By collecting air samples at various other locations and analyzing these samples for SF6, the amount of air traveling from the release location to each sampling location can be quantitatively determined. Travel time between these locations can also be deter-mined. How It Works SF6 is ideal as a mine tracer gas. It is safe, odorless, chemically and thermally stable, and it generally has no background concentration. Furthermore, it is instrument detectable at concentrations as low as 10 parts per trillion. The SF6 is generally released from a pressurized lecture bottle, and air samples are taken in syringes or evacuated bottles. During the past several years, SF6 tracer gas has been employed to study a wide variety of mine ventilation problems such as: recirculation of return air into In-take airways, air leakage from adjacent mines and gob areas, air transit times through stoped areas, airflow patterns during a mine fire, leakage of gases from an underground oil shale retort into mine workings, face area ventilation patterns, methane flows in metal/nonmetal mines following a methane out-burst, and many other problem areas. Examples of some recent uses of SF6 follow.

Jan 1, 1982

By W. N. B. Armstrong

CORROSION of metals, for the purpose of this talk, may be divided into two general classes, namely, atmospheric and chemical. Atmospheric corrosion is caused by the natural agents -water, air, salt, and temperature -as well as by the agents arising from industrial operations which pollute the atmosphere. Chemical corrosion affects metals in refineries and chemical plants where severe conditions exist due to .acids, alkalies, salts, solvents, gases, ?steam, etc. A special condition is encountered on road equipment and motor vehicles due to the large amounts of corrosive salts which are used on our roads in the winter. Exposure to corrosive conditions such as those referred to above causes metal to be destroyed and, therefore, it has to be protected. The non-metallic or organic coatings used to protect the metal are themselves destroyed ultimately by these same conditions. Since all types of organic coatings do not have the same kind and degree of resistance to degradation, a particular kind of -coating must be used for a particular set of conditions in order to obtain the maximum benefit. In ?addition to the above mentioned agents, organic coatings are degraded ?by sun-light, which is probably the severest single factor in the breakdown of organic coatings exposed outdoors. We can divide organic coatings, in a general way, into the following classes: (1) Conventional coatings, and (2) Special coatings.

Jan 1, 1958

By William J. Priestley

Much time has been devoted, by metallurgists, to the study of steel after solidification and remarkable strides have been made in the heat treatment of steel, but less knowledge is available of the thermophysical activity of the constituents of steel prior to solidification in the mold. It is known that certain elements added to steel produce marked changes in physical properties, also that other elements added to steel produce similar changes, but we have only meager knowledge as 'to. how these elements combine in steel under different conditions of solidification. It is not sufficient to know, from chemical analysis, that a certain element is present in steel. We should know how this element is in combination with the other elements and whether the combination is such as will give the greatest physical properties. Certain elements go into solid solution with the iron, while others segregate to the grain boundaries and combine with the impurities collected there. Until it is known where an alloy produces the most beneficial effect and a means is determined for controlling its physical location by altering solidification conditions, or otherwise, we will not obtain the maximum value from our alloys. When molten steel freezes, it forms a heterogeneous mass of various crystalline constituents; and as the transformation of steel from a liquid state to the solid crystallized state is a critical step, involving as great a transfer of heat as any other operation in the making of finished steel, a variation in the rate of this heat transfer will have much to do with the arrangement of the various constituents in the solid state. The object of this paper is to show some of the effects on steel caused by variations in the rate of cooling in the ingot mold, particularly as to ingotism, segregation, dendrites, and intergranular material.

Jan 1, 1924

By P. T. Perdue, F. F. Haywood

INTRODUCTION Monitoring devices used for detecting and measuring airborne radon in mines are limited due to the rugged environment in which they must operate. Personnel monitors now available are either passive or require filters and an air pump. Area air monitors usually have bulky batteries or require electric power service to the instrument. Thus, there are few instruments presently in use in mines capable of discriminating between the various radon isotopes and their daughters. Occasionally it is desirable to determine which radon daughters are the principal dose contributors in mine air. In some areas, such as the Elliot Lake mine in Canada, there exist sizable quantities of 220Rn in the mine air due to 232Th in the ore (Cote and Townsend, 1981). Since there has been recent interest in radon daughters in homes and factories, as well as caves and mines, methods and instrumentation are being developed to address these cases. Some of these methods can be employed in uranium mines. Although there have been very few determinations of the three radon isotopes (222Rn, 220Rn, and 219Rn) and their daughters made in uranium mines, these isotopes have been measured in process buildings and in private homes under circumstances that suggest these isotopes could also be present in uranium mine air (Perdue, Leggett, and Haywood, 1980; Yarborough, 1980) METHODS Cryogenic air sampling was developed about 15 years ago (Rasmussen, 1972) to concentrate various airborne chemicals for later fractional distillation and measurement of various organics using gas chromatography. A version of this technique has been developed to measure tritium, krypton, and other radioactive gases in nuclear power station buildings (Anon, 1980). In this method, fractional distillation is used in conjunction with various detectors to identify the radionuclides present. The cryogenic method to be discussed here was developed at Oak Ridge National Laboratory (ORNL). It uses the liquid air accumulated in a sampling device for a direct analysis of all gamma-ray emitters present. The air sampler (Fig. 1) could be employed in a mine to liquefy air, using the difference between the point of liquefaction of air (~80 deg. Kelvin) and the boiling point of liquid nitrogen (77 deg. Kelvin) to liquefy an air sample. By using a proper orifice at the entry to the sampling vessel, air of any dust concentration and relative humidity [ ] may be sampled. The energy for sampling is provided by the slow evaporation of the liquid nitrogen; no other power source is required. This type of sampler could be used to augment the usual filter and pump, or passive system presently employed to estimate personnel dose from radon daughters. It would also allow measurement of any combination of daughters from the three radon isotopes. Upon completion of sampling, the sampler is closed and removed from the mine. This sampler, with its liquid air contents maintained by the slow evaporation of liquid nitrogen, is taken to the place of measurement. There, the sampler is opened, the accumulation of water and ice in the neck is chiseled down into the liquid air, and the sample is transferred quickly to a precooled counting dewar (Fig. 2). This counting dewar is then placed upon a gamma radiation detector; we recommend a high purity germanium detector. A determination of all the radon daughters can be made in 1 to 4 hours after the sample is taken.

Jan 1, 1981

By V. Blet

Rare earth elements (REE) are regarded today as highly critical raw materials but currently lack suitable recycling processes. A combined hydro- and pyrometallurgical process aimed at REE recovery from used NdFeB permanent magnets was recently developed by the CEA. The process integrates the physico-chemical treatment of magnets, followed by a solvent extraction step for the recovery and intra-REE separation using a selective extractant. A subsequent pyrometallurgical treatment via molten chloride salt electrolysis allowed the isolation of pure Dy metal. Technical-economic assessment and life-cycle analysis were also conducted. Following this first successful demonstration, a new project aimed at the recovery of REE from end-of-life nickel-metal-hydride batteries is currently being developed in association with industrial and academic partners. The project aims at evaluating from an experimental and economic perspective different processes converging at the production of value-added products such as cermet materials for catalytic applications, purified REO concentrates, or metallic alloys.

By Naiyang Ma

"High oil concentration is one of the major barriers for recycling of mill scale of steel hot rolling mills. It is of vital importance to find cost-effective technologies of reducing oil concentration in mill scale in order to recycle the mill scale without causing detrimental effects on production and environment. This paper discusses in-process separation of mill scale from oil at steel hot rolling mills. Formation of mill scale and status of oily wastewater at hot rolling mills are reviewed in the first place. A mathematical model is then formulated to relate oil concentration in mill scale to physical properties of mill scale, chemical and physical properties of wastewater and interacting parameters between mill scale particles and wastewater. From this model, three approaches of in-process separation of mill scale from oil are derived: (1) avoiding contacts between mill scale particles and oily wastewater, and (2) maintaining low oil concentration in wastewater, and (3) collecting mill scale in upper streams of wastewater flows. In-process separation of mill scale from oil might have advantages of lower capital cost, lower operating cost and less additional environmental concerns, compared to other strategies of separating mill scale from oil.IntroductionHot rolling is an inevitable step in producing finished steel products. Figure 1 schematically shows a steel hot rolling process. Semi-finished steel products, slabs here, are reheated first, and then the reheated slabs are discharged from the furnaces and transported on hot rolling trains to descaling units for removing scale with pressurized water. After being descaled, the slabs are rolled by roughing mills. After treated with cropping and the second descaling, the slabs are finally rolled into finished products, coils here, by finishing mills."

Jan 1, 2012

By John B. Hastings

THE reconnaissance of the Goldfield mining-district, described in this paper, was made in May and June, 1905, and, though this time was too short for a complete report, the work accomplished may serve as a basis for more thorough future research. Dr. Berkey has examined the rocks collected by myself, and I am using his classifications. As a result of further field-work, and Dr. Berkey's examination of the rocks, this paper is an elaboration and correction of my views expressed in the Gold-field Sun, May 12, 1905. The sketch-map, Fig. 1, illustrates the geology of the Goldfield mining-district. Goldfield is an eruptive complex, consisting of alaskite (binary granite), hornblende-andesite, hornblende-dacite, rhyolite, pyroxene-andesite, pyroxene-dacite (sometimes containing, a small quantity of olivine), quartz-felsite, olivine-pyroxene-ande¬site, and basalt. Considering this list to be arranged in the order of eruption, the age-sequence of the rocks conforms to Richthofen's law, formulated in 1868. From his observations in Europe and America, propylite, andesite, trachyte, rhyolite and basalt, occurring together, succeed one another. In a general way, the medium and more acidic rocks precede the most asic-a result supposed by some to have arisen from their relative position beneath the surface, and due to a rude stratification by gravity in the original cooling magma during the older history of the earth, or to the same differentiation occurring during a quiescent (molten ?) period preceding eruption, being aided by the ease with which acidic rocks, mixed with water vapors, become fusible. In effect, the more basic and less re-

Mar 1, 1906

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during the first half of March: James C. H. Ferguson, San Francisco, Cal. Capt. A. F. Lucas, Washington, D.C. Henry Adams, Stamford, Conn. Dexter P. Cooper, New York, N. Y. H. A. Wheeler, St. Louis, Mo. L. D. Moore, Chatham, N. J. John M. Sherrerd, Easton, Pa. Hennen Jennings, Washington, D. C. R. T. White, formerly General Manager of the Braden Copper Co., Chile, is to take charge of a copper company in Caucasus, South Russia.

Jan 4, 1914

By David E. Siskind

The Bureau of Mines studied airblast from surface mining to assess its damage and annoyance potential, and to determine safe levels and appropriate measurement techniques. Research results obtained from direct measurements of airblast-produced structure responses, damage, and analysis of instrument characteristics were combined with studies of sonic booms and human response to transient overpressures. Safe levels of airblast were found to be 134 dBL (0.1 Hz), 133 dBL (2 Hz), 129 dBL (6 Hz), and 105 dB C-slow. These four air-blast levels and measurement methods are equivalent in terms of structure response, and anyone could be used as a safe-level criterion. Of the four methods, only the 0.1-Hz high-pass linear method accurately measures the total airblast energy present; however, the other three were found to adequately quantify the structure response and also represent techniques that are readily available to industry. Where a single airblast measuring system must he used, the 2-Hz linear peak response is the best overall compromise. The human response and annoyance problem from airblast is probably caused primarily by wall rattling and the resulting secondary noises. Although these will not entirely be precluded by the recommended levels, they are low enough to preclude damage to residential structures and any possible human injury over the long term.

Jan 1, 1980

By AIME AIME

COAL preparation will be the main topic discussed at the first fall meeting of the Coal Division at Pittsburgh, Sept. 11, 12 and 13, though valuation, mergers, safety, stream pollution and other topics will not' be neglected. It is particularly appropriate that the great changes taking place in preparing coal for the market should be discussed at length where in the plants of the Pittsburgh Coal Co. and others the opportunity is afforded to see on a large scale just what is being accomplished. In wartime, the United States broke all records in coal production, but, as the late Franklin K. Lane pointed out, every fifth car shipped consisted of dirt. Obviously that constituted a big bur- den on industry and, in the remaking of the business which is now taking place both in the anthracite and bituminous fields, clean coal has properly enough be- come a watchward. Central coal-cleaning plants are being erected as a part answer to the puzzled inquiry of those familiar with metal mining as to why miners of coal have so long been content with what are relatively small units of production. Gradually big collieries comparable in tonnage output to the biggest copper mines are being built, and excellent examples are to be seen near Pittsburgh. Even the age-long tradition of the coal operator in favor of the single shift is

Jan 1, 1930

By Caroline Gerwig, Joseph R. Wickline, Zach Agioutantis

In longwall mining, the progressive caving of the roof allows stored energy to dissipate over an extended time. However, in some cases, the roof strata above the longwall panel are unusually strong and do not break with the movement of the working face. Instead, the roof material bridges over the expanse of the longwall, forming an unstable beam. Later, when this beam breaks, the stored energy can release suddenly, causing a seismic event to propagate to surrounding mine workings. The focus of this paper is to estimate the size of beams that form over longwall panels to the seismic energy recorded by the mine. Analytical calculations are used to verify two-dimensional models of longwall roof beams to determine the strain energy and gravitational energy developed, which is then released upon strata failure to surrounding mine workings. Models are developed using RS2 to model the stress, strain, and deflection along the bottom of the longwall roof beam to calculate gravitational and strain energies. Gravitational energy is shown to be the main driving factor in energy release, except for the beams with low heights. Analyses allow the determination of beam characteristics based on seismic data. The analysis is refined using swelling factor to compare various beam drop heights. The models show an increase in seismic magnitude for higher drop heights. However, the actual data provided by the Buchanan mine displays a decrease in seismic magnitude with increasing drop height, indicating that energy is dissipated into the broken gob material as drop height increases.

Jul 1, 2023

To improve the reliability of the Bureau developed bore-hole gage now widely used to determine the absolute state of stress in rock. Approach Use the knowledge gained by extensive field tests to design a more rugged and reliable Instrument using lighter and stronger materials. How It Works The original gage consisted of a stainless steel cylinder 1-3/8 Inches In diameter and 10-1/2 inches long. The new gage is made from titanium. This lighter material reduces the weight of the gage by 43 percent, which enhances the gage placement and depth of overcoring in vertical up? holes. For added strength, the titanium case and placement end are now threaded to the gage body instead of using screw fasteners. Three pairs of strain gaged transducers are positioned to measure the diametral deformation of a 1-1/2 diameter borehole at 60-degree intervals around the Inner surface of the borehole. Each transducer consists of a beryllium copper cantilever with a strain gage cemented on each side. These transducers are secured Into the gage body by a tapered shank for minimal creep. The transducers opposite each other are wired together to form a 4-arm external bridge circuit. A pair of transducers is referred to as a component. Any deformation of the borehole, which occurs during overcoring, is detected by pistons which translate the motion to the components. Each

Jan 1, 1982

By W. K. Wedge

The chemical composition of the Pennsylvanian Bethany Falls Limestone Member of the Swope Formation was investigated using optical emission spectroscopy and both flame and flameless atomic absorption spectroscopy. Elements determined were Ca, Mg, Fe, Mn, AI, Si, Na, K, P, Ti, Zn, Cd, Ni, Co, Cu, Pb, Cr, V, and Mo. Over 100 samples were collected from active quarries along a 320-km-long (200-mile) outcrop in northwestern Missouri. Intervals were sampled representing uniform lithology to determine vertical and lateral geochemical variation. The Bethany Falls Limestone is the most extensively quarried Pennsylvanian limestone in Missouri. In 1975, 42 active quarries produced almost 5.4 million tons (6 million st) of stone valued at over 15 million dollars.

Jan 1, 1977

By C. E. Cartwright

That the construction of the Pacific Great Eastern railway has not been accompanied by an immediate and great development of traffic is not due to lack of natural resources in the district traversed, but to conditions that have delayed their development. Prior to the commencement of construction of the railway there was no inducement to prospect for any other mineral than gold, on account of lack of transportation. The war began soon after the commencement of construction; diverting practically all capital that might have been available for opening up the country; and since the war, capital has continued shy of new investments. If the war had not occurred it is probable that prospecting and development would have been carried out concurrently with the railway construction. Moreover, much of the district is covered deeply with drift, marine and alluvial deposits, rendering prospecting for lode mines a more expensive and slower proceeding than can generally be undertaken by the ordinary prospector, without capital. On the other hand, the presence of large porphyry dykes, granitic intrusions, and the finding of rich float in places are indications that rich miIY.ral deposits probably exist in several localities in the Lillooet district, in the Cariboo proper, and also nearer the coast. Two or three mines producing the tonnage of the? Britannia would materially alter the earnings of the railway and pay interest on the bonds. There are, however, other possibilities, in addition to large metaliferous mines, in the non-metallic minerals of the district.

Jan 1, 1925

By H. J. LONGMORE

MORE improvements have probably been made in the diamond-drill field in the past decade than were accomplished in the entire prior period since diamond drilling was discovered in 1864 by a French engineer named Leschot. True, machines were improved, and new accessories were adopted from time to time up to 1929, but no radical changes were made. The basic principle instituted during the early years of the industry were still in use in 1929. At that time, practically the only diamonds used were "black diamonds" or "carbon." These came from Brazil through a rather round- about route, and by the time they got to the drilling trade their cost was excessive-$175 per carat and even higher at the peak. Perhaps because of this. or perhaps because of increased competition, the industry sought ways to reduce expenses even in the face of constantly increased labor costs due to higher wages and reduction in hours worked. The solution seemed to rest in two things-use of a cheaper cutting medium to replace the carbon diamond and the development of new machines to drill faster and thus produce more hole per shift of operation.

Jan 1, 1940

By Samuel R. M. Burton

This Bureau of Mines report describes a method for determining parts per million (ppm) of helium-4 (He-4) in helium-3 (He-3) to an accuracy of ±5% by mass spectrometry. Gravimetrically prepared primary standards were used for the calibration of a Dempster 1800 magnetic sector mass spectrometer. A comparison between a 2.49% He-4 in hydrogen mixture and a 2.49% He-4 in He-3 mixture shows that He-3 can be replaced with hydrogen as a diluent for standards with comparable mass spectrometry sensitivities for He-4. Using hydrogen as a diluent allows analysis of He-3 samples for He-4 when He-3 for preparation of standards is not available and also conserves the rare He-3 isotope. Standards of He-4 in Hz were prepared for calibration of the mass spectrometer for quantitative determinations of He-4 in the 2-to 100-ppm range. A minimum detectable limit of 2 ppm He-4 is obtained by this method.

Jan 1, 1989