Search Documents

By Harold A. Linke

The following article presents notes and data compiled and computed by the writer for use in the determination of: size and slope of mill launders, details of junction boxes and downspouts, and distribution of pulp. It also includes pulp formulas, volume of discharge through bushings, paths of discharging streams, banking of turns and curves. In the design of a concentrating mill, the draftsman usually considers launders to the extent of providing ample "head" for transmission of pulp from one department of the mill to another. The superintendent of construction aims to build his launders wide and deep, and on a slope steep enough to ensure positive flow. So launders are laid generally on too steep a slope, with the result that the repair gang works to maintain launder bottoms and sides against the erosive action of the conveyed pulp. To this end many kinds of liners have been devised: concrete, mastic, white iron, glass, rubber. True, the reduction of slope to the point where a pulp will flow with minimum wear, will minimize labor and expense; but when the desired slope is not predetermined, the millman hesitates to readjust his launder slopes by cut-and-try methods. To the end that the desired size and slope may be found readily, the writer has: (1) conducted experiments with pulps of different specific gravity, screen analysis and dilution; (2) gathered a few graphic data from standard reference works (such as Peele's Mining Engineer's Handbook and Taggart's Handbook of Ore Dressing); (3) computed several tables; and compiled results that have proved dependable for Utah Copper ore. It is quite possible that the following tables and graphs may not be applicable to all ores, but it is hoped that they may prove helpful, even in slight degree, in alleviating a portion of the trouble and migraine of some other millman. Launder Slopes The main object in the study of launder slopes is to provide grade steep enough to prevent "sanding" by a safe margin, and to avoid

Jan 1, 1943

By H. J. Wasson

At the close of 1927 Venezuela was producing at the rate of 205,000 bbl, per day, making it the third country in the world in point of present daily production. For the year, the total was close to 64,000,000 bbl., representing an increase of about 70 per cent. over the 37,000,000 bbl. in round numbers produced in 1926. All of the 1927 production canie from fields opened up before the beginning of the year. While no new fields were added to the list of shippers, the past 12 months' wildcatting yielded a fair quota of new discoveries which, in the light of prcsent results, may be considered likely sources of production in due time. Altogether three such promising finds were made Of first importance, at least for the immediate future, is the completion by the Lago Petroleum Corpn. of the San Matins well, 4 miles north of the present edge of the Lagunillas field. Although rated as only a 125. bbl. well, at 3217 ft., it indicates a probable extension of the field over the intervening 4 miles between the two. The two other wildcat discoveries of importance were the Los Manueles well in the District of Colon, which has in all probability opened up a new field about 7 miles north of the present Tarra oprations; and the Honibre Pintado well of the Standard Oil Co. of Venezuela,. in the State of Falcon, which is considered to be a promising clc~vc~lop~ncnt. Neither of these last mentioned two discoveries will apprcciably affect production during 1928, as the Manueles area must await the carrying out of a general plan for the exploitation of the District of Colon, a problem requiring time. The Hombre Pintado area is being tested further, but doubtless several wells will be put down before. anything definite will be done towards making the pipe line. arrangements that rnust necessarily precede the commercial exploitation of the field. The San Matias Well The San Matias well is a highly significant dcvelopment,. It is located along the trend of the La Rosa-Ilagunillas producing formations, and when drilling started, production in the Lagunillas field was 4 miles

Jan 1, 1928

By Persifor Frazer

MR. Theodore D. Rand has made some interesting observations on the serpentines of Chester and Delaware counties, Penna., in which he suggests that the outcrops of this rock are detached from each other, and that while a comparatively narrow belt, running nearly east and west, mill include them all, the strike of each outcrop differs considerably from the direction of this narrow belt; and that it results that these isolated exposures exist on the map, as it were, in echelon, the easternmost end of each lying northwest of the western extremity of its neighbor. As he elsewhere remarks, this is important, if established, and the writer spent a day or two recently on the ground in the study of this phenomenon. One thing would seem to follow from such a state of facts, viz., that this serpentine at least must have been of secondary origin, for it is difficult to conceive of a rock which occurs intercalated in numerous horizons of a different formation, and agreeing with the latter in bedding, unless the former were an altered product of the latter. It is true that one might account for it by the supposition of an original unconformable deposit, which had been broken by a number of faults and distorted by throws to the northwest; but this hypothesis would do violence to the observed facts relating to the measures along with which the serpentine occurs, and in which no such distortion has been observed. * Thus for determining, by evaporative test, the calorific power of a coal, the ultimate constitution of which is known, it is requisite, that, besides the quantity of coal consumed and the weight of the water evaporated, the temperature and chemical composition of the escaping gases, or gaseous residue, shall be quantitatively determined, the same as solid residues of ash and unconsumed fuel. In observance of such requirements, the Heizversuchstation of Munich has been in operation since 1879. This consists of a permanent boiler plant, constructed on the principle of the calorimeter, with special provision for avoiding errors from loss of heat—snch, namely, as arise from radiation and conduction, and from the varying proportions of water in steam.—Muck. Steinkohlen-Cliemie, 1881, 146. See Proc. Min. and Geol. Sect., Acad of Nat. Sci., 1850 and 1881, pp. 9 and 28.

Jan 1, 1884

By John S. Alexander

The typical block coal of the Brazil (Indiana) District differs in chemical composition but little from the coking coals of Western Pennsylvania. The physical difference, however, is quite marked; the latter has a cuboid structure made up of bituminous particles lying against each other, so that under the action of heat fusion throughout the mass readily takes place, while block coal is formed of alternate layers of rich bituminous matter and a charcoal-like substance, which is not only very slow of combustion, but so retards the transmission of heat that agglutination is prevented, and the coal burns away layer by layer, retaining its form until consumed. This property permits the use of raw block coal in the furnace but theo-

By Howard Scott

THE GREAT advances made in mechanical engineering during recent years through the use of alloy steels, as illustrated by the development of the airplane and automobile, may be ascribed primarily to the application of nickel as an alloying element. The ternary system iron-carbon-nickel has a wide industrial application and forms, further; the fundamental basis of the even greater class of the widely used quarternary steels such as nickel-chromium, nickel-silicon, and nickel-vanadium. As is not uncommon with such cases of virile growth in an industry, the application of the alloy steel in a largely empirical manner has outstripped its scientific development so that a fertile field for metallographic research still remains. In this field, the basic nickel steels require first consideration and are the subject of the present investigation, which is offered as a preliminary to the study of the more complex alloys of industrial importance. Of the principal tools of metallography-microscopic examination, determination of -mechanical properties, and thermal analysis-the last has developed much more slowly in its application to industrial needs so that the situation often exists that heat treatment operations are based on empirically determined temperatures; that is, temperatures determined without regard to the actual transformation characteristics of the alloy. This situation is undesirable as there is no uniform standard for comparison of results. It is due, outside the usual difficulties involved in temperature measurements, to the pioneer character- of much of the published work; to the lack of definiteness of the Ac2 transformation,1 particularly in low-carbon steels; to the failure to define operating conditions completely; and to the paucity of information correlating thermal characteristics with results of heat treatment.

Jan 2, 1920

By William P. Blake

The importance to the growing steel industry of the United States of a domestic supply of ferro-manganese or "spiegel" of a high grade, induces me to bring to your notice some details of the method by which a superior article is produced in the Austro-Hungarian Empire. At Reschitza, Hungary, and probably at Laibach also (the Krainische Industrie Gesellschaft), ferro-manganese is made in a blastfurnace, with charcoal as fuel, and limestone as the flux. The ore is a ferruginous mixture, containing about 37 per cent. of sesquioxide of manganese. It is silicious, and somewhat, resembles, in its appearance, the manganese ore from Red Island, in the Bay of San Francisco, California. It contains about 29 per cent. of silica and some alumina, shown by the subjoined analysis:

By J. M. Cabal, M. Chica Olmo, J. P. Laille

One of the main goals of a simulation of a coal deposit mining is to predict a series of parameters considered by the miner to be useful, e.g. ash content, sulphur content, seam thickness etc). The idea is to simulate different ways of mining a multi-seam brown coal deposit (the Mine Puentes de Garcia Rodriguez deposit, ENDESA, Spain ), which is exploited by several bucket-wheel-excavators (BWE) . Two mining models are used: a geostatistical model which provides a numerical way of re- presenting the three-dimensional ore-body, then a deterministic model, consisting of simulating the technical aspects of the mining. The main purpose of this simulation is to show how the mining operations can be reproduced using these two techniques.

Jan 1, 1983

By Allen D. Gorrison

EFFORT to develop fundamental quantitative information and improved technique in the production of petroleum has long been faced with difficulties of a particularly evasive nature, owing to a combination of circumstances. In the first place, petroleum comes from far below the ground, out of sight, so that information derived from indirect observations must be extrapolated to reservoir conditions. If one does not force the analogy too far, the petroleum engineer may be said to be somewhat in the position of the astronomer. The actual phenomena which he wishes to observe in detail appear at a place so deep in the earth?s crust that personal observations and direct experiments are impossible.

Jan 1, 1942

By Jan Wolski

Today's rapidly shrinking world requires a common language of measurements, a consistent system which could be used by everyone. The S.I. system of units is generally accepted as such and is already in use by a great majority of nations in the world. The change to S.I. units is also slowly taking place in U.S. engineering practice. The transition period is difficult and long because it takes time to get familiar with the new system, to start "feeling" values in new units. Instruments, formulas, computer programs, survey grids, etc. have to be converted or exchanged. The transition period should be used not only for substitution of units, but also for rationalization of presently used calculation methods. This paper examines the major parameters of mine ventilation from the above point of view and discusses a system which is much simpler and more consistent than the American Unit System still in use in the United States. In October 1979, the Society of Mining Engineers of AIME decided to introduce the S.I. unit system in all its publications including the periodical "Mining Engineering", and since February 1980 the system has been used consistently, not only in SME publications but in all conferences and meetings organized by this Society. The authors have no intention of explaining the details of the S.I. system in general. Any reader can find this information in many available publications and conversion tables, and in particular in the ASTM Standard for Metric Practice, E380-79. A comparison is made between various units used in mine ventilation from the past and those presently in use. This will allow an easy translation from one system to another, important when reading publications from abroad. S.I. and customary U.S. formulae are shown side by side for easier visualization of similarities and differences. Recommendations for the necessary steps in order to switch from American to S.I. units conclude the paper.

Jan 1, 1982

THE great subject of interest in American affairs during February was the consideration of the proposed soldier bonus. This proposal was based upon the idea that, because most of the workers of the United States had enjoyed high wages during war, the soldiers were entitled to "adjusted compensa-tion" in order to equalize things. It overlooked the fact that the soldiers, themselves, had the opportunity to enjoy high wages in 1919 and 1920, when rates were highest. Apart from this, the whole project was founded on fallacies and involved what would be nothing less than economic crime. Although it looked as if the measure were destined to be railroaded through Congress, so great a storm of protest was pelted upon Congress that the present outlook is that the whole project will be abandoned. There was probably some increase in the physical volume of business during February. A rise in prices for agricultural products assisted the farmers mate-rially. These developments, however, are not to be construed as presaging any general upward movement. On the contrary, the current year is to be contem-plated as one of serious labor troubles, following inevit-able reductions of wages. These began in February in the form of an extensive strike in the cotton textile industry of New England, accompanied by some rioting in Rhode Island. The coal miners have had numerous conferences, without coming to any encouraging results, and the stage appears to be fully set for a general strike beginning Apr. 1. About the only question now is whether this will comprise both the bituminous and anthracite miners. If the latter refuse to go out, no serious shortage of coal is anticipated, the belief being that the existing stocks together with the output of the non-union mines will supply the demand, which is sub-normal even now. In the metal industries, lead and zinc were dull but stable. The weakening tendency in iron and steel that was manifest during January appeared to be checked, at least temporarily. Copper was charac-terized by a distinct weakness and a considerable decline in the market. This downward movement was inspired by the news during January that several of the important mining companies were taking steps to resume production. During February the demand for copper, both foreign and domestic, was poor.

Jan 3, 1922

By R. Hogg

The mathematical description of solids transport in mills is an important aspect of the development of comprehensive models for the analysis, simulation and control of grinding systems. The basic mechanisms of particle transport and mixing, including gravity flow, carrier fluid transport, and "diffusion", are reviewed and their relative importance in wet and dry ball mills is discussed. Specific models for transport and mixing in dry, grate-discharge and wet, overflow ball mills are described. The limitations of the models, parameter estimation problems, scale-up criteria etc. are discussed and the conditions which lead to particle size dependent transport, and hence to internal classification in the mill, are described in detail.

Jan 1, 1984

By Howard E. Kremers

Since the discovery of the first-known rare earth elements more than a century ago, these metals have always been of academic interest. It is not so well known, however, that a rather stable, respectably large industry based on rare earths and their related materials has been in operation for more than 60 years. Rare earths, of course, are the elements having atomic numbers 57 through 71--lanthanum through lutetium in the periodic table. The most important commercial members of this group are mixtures of the lower atomic-numbered rare earths, and cerium. Although yttrium is not a rare earth, it occurs with rare earths and its properties are so similar to them that. it must be included in a discussion of these elements. In addition, thorium is important to most producers of rare earths because their ores generally contain this element. Thorium extractive metallurgy and technology is closely related to rare earth chemistry due to the frequent similarity of properties.

Jan 4, 1962

By J. A. Benell

DIOXIDE of silicon, commonly called silica, is one of the greatest single constituents of modern in-dustry. It is brought most clearly to the mind when we consider the various kinds of sand and their rela-tion to industry. The major portion of.all sand is silica, and should be its principal component part in building materials. As an abrasive for cutting, polish-ing and sand-blasting, sand serves a vital purpose in many industries. Even lumber is now being sand-blasted, to cut away the softer grains of wood, leaving the harder grains in relief. The result not only in-creases the beauty of the wood, but adds to it an ap-pearance of antiquity. The common uses of silica in industry may be classified about as follows: Chemical industries-filtering medium; manufacture of carborundum; manufacture of water-glass. Paint-inert extender. Mineral fillers-wood filler; filler in rubber, hard rubber, pressed and molded goods, phonograph records.

Jan 5, 1928

By Philip E. LaMoreaux

Fluoride, generally less than 0.5 ppm, is present in ground water from rocks of Paleozoic age and older, in northern and eastern Alabama. Some of the water-bearing formations in the Coastal Plain area of the State yield water with as much as 6.8 ppm fluoride.

Jan 1, 1950

By S. J. Page

Introduction Dust from cutter machines and face drills is controlled in most mines by water. However, the large quantities of water used in metal and coal mines for dust control and suppression pose serious operational problems in water soluble ores, such as salt, trona, or gypsum. This paper reviews the strategies to suppress and collect dust on cutter machines and face drills where water usage must be restricted to very low flow rates - typically 3.78 L/min (1 gpm) or less.

Jan 1, 1985

By L. C. Armstrong

Twice in the past two years and in two widely separated localities-one near Williamsville, Mo., and the other in the Allard Lake district of Quebec- the Contract Drilling Division of the Longyear Company has experienced perplexing difficulties in drilling granitoid igneous rocks. The rocks in both places are characterized by appreciable amounts of feldspar intimately intergrown with quartz particles of microscopic dimensions. The disappointingly slow rate of advance and the exceptionally high bortz loss, obtaining during the life of these two projects, are ascribed largely to the resistance to abrasion of these two minerals when arranged in this intergrown pattern. Whether all intergrowth-bearing igneous rocks would offer extraordinary resistance to bit progress cannot be stated with assurance on the strength of these experiences alone. More data on diamond drilling this sort of material in a number of localities are needed before any generalizations can be made safely.

Jan 1, 1949

What do you think are the major problems that the mining industry is facing? While I don't have any intensive knowledge of the various problems that plague our industry, I know that they are all part and parcel of a more complex and fundamental question: What must we do to make mineral extraction successful, safe, and profitable? Obviously, as mining people, we must continue to expand our technical know-how and to make better use of it. In today's context, however, that is not enough. We must also improve the "public image" of the mining industry. Why? Because the key word in the term "public image" is: the public. Many people in our country and in Congress, for instance, are against strip mining-and some are even against underground mining. Pressures from the public, from voters, have affected past, present, and new legislation. And government controls can be a major problem in any industry, let alone mining. At first, people ask government to intervene, act, or resolve problems, even in management and labor contract negotiations. But later, after Washington gets involved, there are clashes between departments and personalities, and eventually there is resentment against the interference with mining operations or our daily lives.

Jan 3, 1975

By Bruce T. Stanley

The concepts of ore reserve estimation at the Henderson mine are reviewed presenting a geostatistical approach and procedure as applied. Specific problems encountered are recapped and explained as to the nature and resolution thereof. The methodology and results are shown, along with an approximation of computer usage and capacities needed. The scope of the paper is to set forth an example of actual application, usage, and benefits realized from such a procedure. Local Conditions The Henderson molybdenite deposit is located in central Colorado about 69 kilometers west of Denver. The geology consists of a classic subvolcanic ryolite porphyry sequence with quartz-molybdenite mineralization occurring in an extensively fractured granite stock complex. Being assymetric and bilobate in section, the orebody measures approximately 300 meters thick and 600 meters by 1200 meters in plan. The orebody is sampled by means of underground drill holes which create an east-west fan pattern spaced roughly 60 meters apart in the north-south direction. Approximately 27,000 meters of drill hole assayed on 3.04-meter intervals were available for analysis. Recovery on the core is about 95 to 100 percent, thereby affording us with reliable data all prepared to the same standards.

Jan 1, 1977

CLARENCE M. HAIGHT, Franklin, N., J. (communication to the Secretary*).-In that hart of Mr. Wilson's paper describing the Gilman cut-and-fill system, a few features do not appear to be fully explained. In what way is the waste used for filling obtained? The text mentions that, if waste is encountered when driving the filling raises, these raises are stopped until the fill is needed; that seems to suggest mining the capping for fill, which might make the backs of the stopes had as the stopes approach the top of the ore. If, on the other hand, the fill is brought to the raises in cars, are the crosscuts that are necessary in ore or waste? Is the cost of this fill included in the stoping costs given?

Jan 5, 1917

By Dr. Egleston

While I thoroughly appreciate the United States testing-machine at the Watertown Arsenal, and regard it as the most accurate testing-machine that has yet been built, I wish that I could say that it is complete in all respects. I not only fully appreciate it, but I have given up advising thesending of material to be tested anywhere else. It is five or six times more expensive to use this machine than any of the others, but the results which are obtained from it are, I think, perfectly reliable, and of such a character that the tests are all comparable with each other. It has proved, beyond a doubt, that the system of testing specimens of' diminished area, and then calculating that the metal examined will be as many times stronger as its area is greater, is an absolutely vicious one. I am quite prepared to say, that, either from their limited size or faulty construction, most of

Jan 1, 1882