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By E. C. Harder

HERBERT K. SCOTT, London, England (communication to the Secretary*).-I am acquainted with the manganese-ore deposits of Russia, India and Brazil, and agree generally with the statements contained in the paper regarding those deposits. The information given by Mr. Harder regarding the Chilean deposits is very welcome. When examining the Caucasian deposits, I endeavored to determine the quantity of ore originally contained in the deposit, and by deduction, the amount remaining for extraction. These calculations were rendered possible by the great extent of the outcrop and the extensive work that had been carried on in the deposit. In making the first estimate, the quantity of manganese ore and associated sterile material in the bed was measured in a large number of

Jan 12, 1916

Jan 1, 1898

By A. P. Woods, J. A. Elias, A. J. Heckler

A method is described by whichX-ray pole figures and axis density figures may be plotted automatically. The X-ray data are obtained using a Siemens texture gonionleter and the Schulz reflection method. Composite sampling methods are used to obtain a full quadrant of the pole figure. The contour lines of the pole figure and axis density figures are drawn using a computer-controlled x-y plotter. The computer program used to draw the contours was obtained from ZBM. POLE figures used to describe crystallographic orientations of poly crystalline sheet materials are usually plotted manually from X-ray diffraction output in the form of a strip chart recording of the intensity distribution of a given crystallographic pole in physical space. Today's computers and associated plotting equipment now make it possible to plot pole figures and axis density figures automatically. Inverse pole figures have been determined by mathematically "inverting" X-ray pole figure data.'-' In general, these methods require complicated, time-consuming numerical calculations. A more economical but less accurate method is to determine the axis densities of low-index crystallographic poles using an X-ray diffractometer. When these axis densities are plotted in a unit stereographic triangle contour lines can be drawn to represent the axis density distribution. This can now be done automatically. Computers were used to plot pole figures by a method developed by Holland, Engler, and powers.' In their method intensity ratios based on a random standard sample were obtained from a strip chart recording, and the stereographic (x, y) coordinates of these ratios were determined by a computer. Symbols characteristic of different intensity ratio levels were then plotted using an automatic x, y plotter and intensity contours were drawn manually. The present paper describes a method by which pole figures and axis density figures have been automatically plotted from digital data obtained from a Siemens X-ray unit. Plotting was accomplished using an IBM 1620 computer and a Calcomp 563 digital plotter. COMPUTER PROGRAM The computer program was obtained from IBM Systems Reference Library, No. 1620-CS-05X, and was designed to plot contour maps from randomly distributed data. It consists of a set of twelve separate subprograms, four of which were used in this work. The program takes a given distribution of data points and by a numerical method determines the values at mesh points of a square grid system superimposed over the input data. The output data from this program is in a form suitable for input to the contour plotting program. A smoothing program is also available which calculates new mesh point values from a continuous function fitted to neighboring mesh points. The degree of smoothing depends on the number of points around a given grid point which are used to adjust or smooth the grid value. The contour plotting program is designed to allow the user to specify the interval, scale, and annotation of the contours to be plotted. EXPERIMENTAL PROCEDURE Pole Figure Data Points. Diffracted X-ray intensities were determined using a Siemens texture goniometer and the schulzs reflection method. Due to geometric

Jan 1, 1968

By T. S. Lovering

The use of geothermal energy is expanding very rapidly. This type of energy has proven commercially profitable for generation of electricity, for space heating, process heating, auxiliary heating of water in conventional steam power plants and for recovery of chemicals contained in natural hot water and steam. Two types of geothermal energy sources are recognized: 1) hot springs in regions of nearly normal heat flow that tap a deep reservoir through which water moves slowly to a hot springs conduit and then rapidly to the surface; 2) hyperthermal areas in which the water is heated by a relatively concentrated heat source related to volcanicity. If there is a geologic trap that provides a geologic analog to a steam boiler, as at Larderello, Italy, the hyperthermal area will have a convecting system that develops superheated water at relatively shallow depth and may provide natural steam in large quantities. If a hyperthermal area is to be productive for a long time, the underflow into the reservoir should be slow enough to allow the heat source and convective system to heat the underflow to the working temperature, and the production rate must not exceed this rate of underflow. A model based on a typical aquifer suggests that the rate of movement of water through the reservoir be such that a few years are spent in transit between isotherms that are spaced about 2°F apart. The possibility of finding blind geothermal areas is illustrated by discussion of the techniques developed in evaluating the subsurface temperatures in the East Tintic district of Utah where a map of isotherms at water level (2000 to 2000 ft below the surface) shows that a hyperthermal area may exist a short distance southeast of the mining district. Very nearly all of the energy that man currently uses comes ultimately from the sun's radiation. This includes water power, fuels such as wood, peat, coal and petroleum, the wind and all our animal power. In the paper summarizing a conference on solar energyl6 the average amount of solar energy received daily on the earth is taken at about 1 cal per m2 per min or slightly less than 2 pcal per cm2 per sec; this is almost exactly the amount of energy on the average that the earth liberates in regions of normal geothermal gradient due to its own internal heating. In many places, however, the energy released is many times the average and in some of these hyperthermal areas, geothermal steam is used for generation of electricity, and hot springs are used for heating buildings and private dwellings, process heating, auxiliary heating of water in conventional steam power plants, and chemicals may be recoverable from both hot water and steam. The use of hot springs waters for heating houses goes back hundreds of years but until recently was confined to a few dwellings close to the hot springs. In Korea, some houses had hot spring water channeled through conduits in the floor centuries ago and thus the Koreans can be credited with pioneer development of radiant heating. In Iceland at present nearly a third of the population uses natural thermal water for domestic heating." The Reykjavik system pipes hot spring water at about 94°C throughout the city and has devised insulated double pipes that allow the water to be piped for some 25 km with a drop of only 1°C for every 5 km. The actual cost to the Icelandic consumer is only one-third the cost of heating by imported coal and yet the industry is one of the most profitable in Iceland. The most profitable use of geothermal energy has been its conversion into electricity which can be transmitted economically much greater distances than hot water. The largest installation at the present time is that at Larderello, Italy, where the Count of Larderello began to experiment in the production of electricity from geothermal steam 60 years ago — in 1904. He installed his first steam turbine, with a capacity of only 250 kw, in 1912 as the result of a local quarrel with the power company which furnished the current required in the Larderello chemical industry - an industry that then dated back nearly a century. As experience was gained in drilling deep holes to tap geothermal steam and in converting it to electric power, the capacity of the installation of Larderello gradually increased, but was all destroyed by the Germans during their retreat from Italy in the closing

Jan 1, 1965

By AIME AIME

THE annual session for the election of officers and transaction of other official business of the Institute, which must be held, in accordance with the By-Laws, in New York on the third Tuesday in February, was the only session scheduled for the morning of Feb. 19. Many members gathered in the auditorium at 10 o'clock, and President George Otis Smith presided. He said that his report was best set forth in the reports of the other officers and committees, which were avail-able in printed form. Productive activity had characterized the Institute's year and a number of new ventures had been successful. He felt that he had "rattled around" in the office of president, as he had traveled some 39,000 miles during the year in visiting the various Sections, having visited everyone that had held a meeting during his term of office. He spoke of the educational effect on a president of these broad contacts and suggested that a three-year course would be even more enlightening than one.

Jan 1, 1929

By Chas. F. Jackson

IN these days the headlines and spotlight have been focused largely upon the new processes developed and new plants erected to meet the multiplied demands for mineral products required for prosecution of the war. By comparison, the less spectacular achievements of the miner, who is meeting the demand for raw material without which these processes and plants would be useless, have received little attention. Attendance at the mining meetings here reported was small, averaging about 35 to 40, but interest was as keen as ever, and evidenced to your reporter that the miner is no less on the job than is the metallurgist. It is evident that the mine operators are not neglecting any improved methods and practices in their struggle to produce more in the face of diminishing labor supply.

Jan 1, 1943

By AIME AIME

The following report is published for the information of the members: Meetings. Two meetings for the reading and discussion of papers, etc., have been held during the year 1907-namely, the Ninety-second meeting, held April 16 to 20 in New York, N. Y., and the Ninety-third meeting, held July 23 to 30 in Toronto, Canada. The proceedings of these meetings, including descriptions of the entertainments and excursions connected therewith, have already been published and distributed to the members of the Institute; the New York meeting in Bi-Monthly Bulletin, No. 15, May, 1907, pp. 541 to 559, and the Toronto meeting in Bi-Monthly Bulletin., No. 17, September, 1907, pp. 847 to 875. In addition to these " Proceedings," there were also published in Bi-Monthly Bulletin, No. 15, May, 1907, an illustrated description of the United Engineering Society building (p1 vi. to xxvi.), and a record of the exercises attending its dedication, including the addresses of Andrew Carnegie, Arthur T. Hadley, Samuel Sheldon, Frederick R. Hutton, John Hays Hammond, and T. C. Martin (pp. xxxviii. to lxv.). At the New York meeting, 43 papers and- discussions were presented, and the names of 297 members and guests were registered at the Institute headquarters., this number, however, does not represent all who were present at the sessions and excursions. At the Toronto meeting, 23 papers and discussions were presented. The number of members and guests registered at the Toronto headquarters was 191, which doubtless does not include the names of all who were present at the sessions, or took part in the numerous excursions and visits around Cobalt.

Mar 1, 1908

By AIME AIME

ALL sessions of the Mining Geology Committee at the Annual Meeting this year were held jointly with other groups, a plan that seemed to work out to the satisfaction of every one. Certain of these sessions are reported in this issue by others; the ones held on Wednesday are covered here. Ten papers, as published in the February M&M, were on the program for the Wednesday morning session, held jointly with the Society of Economic Geologists. Mr. Eckel made a brief presentation of his paper, on which there was no discussion, and Mr. Peoples presented that of which he was a joint author. D. M. Fraser then discussed a gravimeter survey for chromite in Cuba, which blocked out some 50,000 tons of ore, and F. G. Wells told of work on chromiferous sands in Oregon.

Jan 1, 1943

By AIME AIME

THE session* on Non-ferrous Metallurgy held Monday morning was conducted in a most satisfactory manner with F. F. Colcord, vice-president, U. S. Smelting Co., in the chair. In spite of the early hour and the fact that members desired to register first, the meeting started quite promptly, with almost every chair in the room occupied. About 65 men were present and during the morning many more came but, not being able to find room, drifted away to other fields of activity. The first paper presented, "Lead Refining Practice of the Bunker Hill Smelter of the Bunker Hill & Sullivan Mining & Concentrating Co.," by Alfred F. Beasley (T. P. 303), was read in abstract by Edward H. Robie, and an animated discussion followed in which Messrs. Johnson (written discussion), Brewer and Jones and Professor Hayward participated. The discussion hinged principally on the liquation of the zinc crusts, but Professor Hayward called attention to the fact that the practice of keeping the gold and silver crusts separate was not new and the present scheme illustrated the axiom that processes based on fundamental principles should not be considered as extinct; one can never tell when it may be found advantageous to make use of them again.

Jan 1, 1930

By Edward Steidle

OUR citizenry must comprehend the cold, fundamental, economic truth that the ability to create wealth depends upon primary wealth; that only primary wealth can insure our economy, liquidation of our debts, national solvency, national security. And irreplaceable minerals furnish a major part of all primary wealth.

Jan 7, 1950

By Eugene Guccione

After discovering that past materials shortages were caused by government policy, the National Commission on Supplies and Shortages wants to prevent future shortages by increasing government's role in planning the economy.

Jan 4, 1977

By Jerome S. Nelson, William S. Johnson

Seismic investigations at pre-construction sites commonly are limited to obtaining velocities and thicknesses of subsurface intervals which are useful in estimating construction costs, but are sometimes difficult to apply to project designing. This paper shows through a case history of the San Bernardino Tunnel Intake Tower, a part of the California State Water Project, that dynamic rock properties and dynamic resonant frequencies can be determined and velocity models constructed from in situ field studies and that these are theoretically correct after simplifying assumptions are made. These data can be used to confirm and extend information obtained by conventional methods such as drilling and laboratory static testing.

Jan 1, 1971

By Stefan Boshkov, Malcolm T. Wane

The validity and accuracy of velocity measurements underground have been questioned repeatedly by those in mine ventilation work. The general disagreement on the subject is well illustrated in an AIME publication.' Although the presence of errors is readily admitted, their magnitudes are not known and often are described by practical operators merely as "great," "small," or "of no importance." The belief that errors are of academic interest only prevails because of a justifiable claim that actual volumes of air circulated are well in excess of those required by law and safe mining practices. Poor understanding of the source and nature of errors inherent in velocity measurements, coupled with questionable determination of cross-sectional area, result in faulty techniques for the purpose of expediting ventilation surveys and render doubtful the calculated volume. Often consistency of readings is confused with accuracy. A succession of check readings showing a maximum deviation of 5 pct in the measured value of velocity usually signifies nothing more than diligent application of technique in a stable ventilating current.

Nov 1, 1955

By V. S. Rood

Typical System of Workings THE general system of workings at the Utah-Apex is similar to that found in many of the western metalliferous mines. There is a vertical three-compartment shaft extending to the surface, from which the various levels have been driven to the orebodies. The 1000-ft. (305-m.) level, about ¾ mile long, was driven as a haulage and drain adit. Geology The formation is a flat north-dipping series of alternating limestone and quartzite beds. Extensive north-south faulting and-fissuring have taken place, resulting in the formation of large replacement orebodies in the crushed zones in the limestone. The orebodies are irregular in shape and size, but follow closely the trend of the mineralizing fissures. The ore consists of galena, pyrite, sphalerite and small values in silver and gold. Large masses of non-commercial pyrite are frequently found in or adjacent' to the orebodies, and more or less pyrite is found for some distance in the walls of the orebodies. Lenticular bodies of a black pyritic shale also occur in the zones where extensive faulting has taken place.

Jan 6, 1918

By Grover J. Holt

Open-pit mining on the iron range has been in a stage of transition for several years from the standpoint of mechanization. The most radical change in open-pit mining methods was started in open-pit haulage in 1937 with the departure from the then standard system of locomotive and car transportation and the advent of the heavy duty truck as a replacement. The initial use of trucks was followed shortly by the first installation of a conveyor belt for open-pit ore haulage. The growth of the combination of trucks for gathering units delivering to a conveyor system for transportation out of the pit, has been rapid and this transition appears to have reached a peak in 1949 with locomotives and cars now being used in only a few of the largest open pits. One point which must be considered, if we assume that the maximum equipment change- over point has been reached, is that the largest pits have probably passed their peak of production. Future ore replacement must come from smaller pits wherein the truck conveyor system has done an outstanding job.

Jan 1, 1950

By J. M. Donkers, R. de Groot

The various objectives of dredging at sea require different methods and radically different equipment for their optimum fulfillment. In the majority of cases, sea dredging is done by means of dredging equipment connected to a pontoon or ship floating at the surface. As the supporting hull is subject to the influence of waves, swells, currents and wind, the connecting point of the dredging equipment to the hull will generally move relative to the sea bottom with 6° of freedom. The more important hull motions are surge, heave, pitch and roll. Depending on the actual sea and weather conditions and the size of the hull, some of these motions can be so large that dredging equipment of rigid construction (normal or inland dredges) cannot be used. In those cases where mechanical disintegration of the bottom is necessary and where accurate dredging is required, the designer must find a solution for this problem. For cases where the bottom consists of soils that can be handled by plain suction, highly sophisticated dredging equipment such as the trailing suction hopper dredge permit dredging under all but the most severe sea state conditions. This type of dredge picks up the soil from the sea bottom while slowly underway. The drag suction head is fitted on a suction pipe of such flexibility that the supporting ship can carry out all six movements in relation to the draghead (heave, pitch, roll, sway, yaw and surge), while the draghead remains in firm contact with the bottom. The suction pipe is fitted with flexible hoses, a universal hinge, a horizontal hinge, axial turning gland and sliding turning gland with horizontal axis and is suspended flexibly from the ship incorporating swell compensating buffer gear, keeping the wires taut and the draghead bottom contact pressure fairly constant while the dredge moves up and down. Due to the fact that the draghead has a low bottom contact pressure and has little tendency to sink into the bottom, this compensation is not difficult to realize.

Jan 4, 1974

By J. S. Aronofsky

The first step in a quantitative analysis ot the mechanism of oil displacement by water in a fractured reservoir is usually conceded to be the solution of the differential equation describing the saturation distribution of two immiscible fluids flowing in a porous medium, where the capillary pressure is taken into account. In such a system the production mechanism may consist of displacement of oil both by the flow of water due to natural or artificially imposed pressure gradients and by imbibition, which implies a flow of water not due to external pressure gradients. Owing to the presence of the two oil displacement mechanisms, the mathematical model given by the differential equation intended to describe the system may not properly represent the behavior of the physical system. In fact, in the reservoir the rate of water advance may be very slow, and in the case of a fractured reservoir with a great number of large fractures, the pressure difference determining the flow of water through the matrix may be much less than 1 lb/'psi over lengths of a few feet. In such a case, imbi-bition (the exchange between oil in the matrix and water in the fractures resulting from capillary forces) may become, with time. a significant element of the production mechanism. It occurred Lo the authors, however, that without going into a physical analysis of the process of production, it might be possible by means of simple abstract reasoning to throw some light on the variation of recovery with time under conditions occurring in a highly fractured oil reservoir with rising water table. The object of this paper is to present both the reasoning and its application to a reservoir of the highly fractured type. Specifically, the analysis given here was undertaken to try to explain the increase of recovery (as defined later) with time as observed in this reservoir, without having to assume unlikely variations in the reservoir parameters with depth. This attempt has been successful as will become clear upon comparison of the computed recoveries with the actual field data. ABSTRACT MODEL Let us consider a small volume. of porous matrix saturated with oil at time, t = 0. Let the process of oil displacement by water start at time, t = t,,. At some time, t, the process will have terminated. Then a volume of oil equal to or smaller than the original oil contained in the matrix will have been produced. The first basic assumption that describes the model and guides the forthcoming reasoning is that the oil production from the small volume. dv, is a continuous monotonic function of time and that it converges to a finite limit. Such an assumption is not inconsistent with the results of laboratory waterflood tests as well as with results of imbibition tests where this is, in fact, observed. The second basic assumption is that none of the properties which determine the rate of convergence change sufficiently during the process to affect this rate or the limit. Let it be assumed that the form of the function of time relative to production from the matrix volume. dv, is given by where V,(t) is the volume of oil produced up to that time t. R is the limit toward which the recovery converges, A is a constant giving the rate of convergence, and V,(t) is the volume of oil originally in place in the volume, dv. It should be noted that recovery at time I will be understood here to he It follows that r. tends to R as t tends to infinity. CONSTRUCTION OF RESERVOIR FROM ABSTRACT MODEL Let the reservoir consist of a series of identical blocks of porous matrix stacked vertically and separated by fractures. Let each of these blocks satisfy the conditions of our abstract model. These conditions are: (1) that recovery is a continuous mono-tonic function of time converging to finite limit, and (2) none of the properties that determine the rate of convergence change sufficiently to affect the rate or the limit. Let water be rising in fractures so that oil production from any part of the block starts when the water comes in conLact with it. TOTAL RECOVERY FROM THE RESERVOIR COMPARED TO RECOVERY FROM A SINGLE MODEL ELEMENT As stipulated in Eq. 1, in the case of the abstract model,

THE Fall Regional Meeting of the Institute, which has now for some years been held in cooperation with the Western Division of the American Mining Congress, will be held this year at Joplin, Mo., in the heart of the great Tri-State district. This year the Tri-State Zinc and Lead Ore Producers Association is joining in the meeting. The Society of Economic Geologists will also take part though not offering any papers. The district in which the meeting is held includes adjacent parts of Missouri, Kansas and Oklahoma. Out in the heart of a fertile prairie farming country, it is one of the major mining districts of the world. It produces normally approximately one-third of the zinc ore mined in the United States which is equivalent to nearly one-half the zinc since the concentrate has always been notable for the height of its grade. Even in the depressed business year 1930, the American Bureau of Metal Statistics credits the district with 434,460 tons of concentrates equal to 217,230 tons of zinc out of 1,503,095 and 576,630 respectively for the country as a whole. This was equal to about one-seventh of the world's output of zinc, more than that of any foreign country. In addition about 75,000 to 100,000 tons of lead is annually furnished by the same mines. Elsewhere we present a general description of the district prepared for this meeting by J. C. Heilman, a Lehigh graduate, who has spent the past eleven years there and has had charge of explorations for many of the companies.

Jan 1, 1931

By Arthur T. Ward

DESPITE the intense preoccupation of most of those members connected with the mining, concentration, and reduction of iron ores, the luncheon and subsequent technical session of the Eastern Magnetite Committee were exceedingly well attended. Many of the older faces were absent, but new ones took their places. More than sixty, all told, took in the technical session. Chairman Crockett opened the session by calling upon Meredith E. Johnson, whose paper, with its accompanying graph, was in reality a comprehensive historical review of iron mining from colonial days to the end of 1941. with some notes on current expansion which indicates that New Jersey is destined to become a still more important. factor in the production of magnetite ores.

Jan 1, 1942