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By R. D. Caudle, Yoginder P. Chugh, V. K. Agarwala

Longwall coal mining is a growing mining technique in the United States. However, very little premining exploration data are collected presently by coal companies to 1) select coal winning equipment, 2) select and design face supports and supports in gate and tail entries, or 3) optimize operational parameters such as length, width, and orientation of face. The authors are of the opinion that much of the data needed for mine planning and design for longwall mining can be obtained during exploration. In this paper, the authors identify the data requirements, discuss how these data can be obtained during exploration, propose an exploration program and estimate the cost to obtain the necessary data.

Jan 1, 1982

RECENTLY, we were asked to name the greatest contribution to progress in mining technology during the past 25 years. Immediately, the introduction of the pneumatic hammer for making blastholes came to mind because it can be credited with speeding the excavation of rock and the elimination of hand drilling. Possibly this answer was so spontaneous because we were working on this "drilling issue" Of MINING ENGINEERING. Present drilling tools have devel¬oped so rapidly, that a great deal of engineering is. required in the selection of bits, steel, and machines for the drilling conditions at each mine. Formerly a modicum of engineering was utilized in selection of equipment for it was purchased from manufacturer preference. With the development of alloy drill steels, tungsten-carbide bits, throwaway bits, and the jackleg drill, mining companies began doing more experimental work before making selections. It is unfortunately true, that each operator must begin at the beginning by doing his own test work before choosing his drilling method, and tools. Some of this work has been done very well-under controlled conditions and obtaining proper data on the variables. Such data should be accumulated from the various mines, tabulated, and published. Such a volume would be of tremendous help to the small operator in selecting equipment and would permit the research departments of the larger companies to formulate some measure of rock drillability and to undertake more specialized research on the different phases of drilling.

Jan 1, 1952

By Raymond E. Funderburk

Today, there are four alternatives available for disposal of highly toxic, non-radioactive hazardous waste: deep well injection, chemical processing, landfill and incineration. However, based upon research conducted by the author, a fifth alternative now exists. Disposal in salt. Salt, because of its chemical characteristics, is an ideal medium for retention of inorganic hazardous waste. Except for a few elemental compounds such as lithium and potassium, there is no reaction with sodium chloride. In the family of inorganic wastes, there are basically seven suites of waste that may be mixed together without any chemical reaction. The process developed by the author would be to take a suite of waste, either dewater or add moisture, add a solidification agent to the mix and slurry pipeline the mass into a cavern. Residence time before hardening can be adjusted, but the nominal time until full solidification is 48 hours. Once solidified, the mass will reach compressive strengths exceeding 3000 psi. The slurry can be introduced into an evacuated cavern pumped free of brine, or it can be placed beneath the brine and the waste will force the brine to the surface. The latter technique requires a high degree of engineering control to prevent contamination of the brine leaving the cavern-thus creating more hazardous waste and additional problems. The Environmental Protection Agency endorses the concept both at the research level and within EPA Headquarters. The technology will soon be utilized in a salt formation in Texas.

Jan 1, 1985

By F. W. McQuiston

Teamwork is the key to an efficient organization. Cooperation among mining staff members is an obligation owed to the company. The more cooperation the metallurgist receives from underground, the higher milling yield will be, which in turn makes for a greater mine profit. There is no pay for metal left in mill tailings. The metallurgist is not in a position to be of help to either the geologist or mining engineer, but can receive valuable assistance from both. Therefore, the metallurgist must win underground cooperation. The mining engineer is usually interested in geology because of its relation to ore control; in milling because that is where the rock goes. However, any overlapping of interest between geologist and metallurgist is quite remote.

Jul 1, 1956

By A. M. Mirani

The Mine Planning System consists of two parts: 1. A Sales Forecast (Sales Planning) 2. A Production Planning. The mathematical methods of the sales forecast are the exponential smoothing and a method with Markov-Chains. By these methods the quantity of material (ore, coal) will be calculated for the time planned. These quantities constitute the points in the production-planning. In the production-planning , special kinds of networks are used for calculating the resources-equipment required, labor and costs. A special routine optimizes the sequence of the mining areas within the mine on the basis of the lowest costs. The resources can be limited. The activities will be shifted when the demand exceeds this limit. The basis of the production-planning are computer files, in which the geological data and economical evaluations are stored.

Jan 1, 1969

By Giovanni Barla

In engineering analyses, rock is frequently treated as a homogeneous, isotropic, and linearly elastic medium. However, rock material exhibits, in most cases, physical nonlinearity, time-dependency, and anisotropy. In some instances, anelasticity due to nonmechanical effects, such as density and temperature changes, must also be taken into account. The influence of these different anomalies in the physical behavior of a rock material is often neglected. An estimate of the discrepancies which are introduced when classical theory of elasticity is used is consequently required. The easiest theoretical path by which these discrepancies can be analyzed is to vary the constitutive equations of the rock material. The constitutive equations, representing various physical experiences with different types of media, define a class of ideal substances. Assuming different constitutive equations for the description of the rock physical behavior, one can establish a sensitivity analysis to determine how much information is contained in elastic theory for reliable design purposes. The method may be applied also using numerical techniques (e.g., finite element or finite differences) which, because of the nature of the formulation, require one to assume in each case the rock constitutive equations. Theoretical and experimental work is needed to be able to perform such analyses with confidence. Adequate and practical procedures for the determination of the material functions which enter the various constitutive equations must be established. This paper presents such an attempt with respect to the simulation of some behavior patterns of rock material. It is felt worthwhile to stimulate activity in this field and it is hoped to contribute to this objective.

Jan 1, 1970

In accordance with the requirements of our By-Laws I beg leave to submit herewith the report of the Library Committee for the year 1915. The activity shown by the sale of the institute publications during the year continues satisfactory, although not as large as last year. The total sales amount to $6,666.81, distributed as follows: Sale of Transactions...:: :. $4,585.42 Sale of Special Editions 553.17 Sale of Pamphlets and Bulletins 2,028.22 It should-be borne in mind that the sale of special editions was only begun last year,, and most of the members who did not have the special editions immediately bought them for their libraries. This year only a little less than half of the same number have been disposed of, and it is more than probable that from now-on the number will be considerably lessened.

Jan 2, 1916

By Orson Shepard

THE leaching method that was first widely used with the cyanide process consisted of percolation leaching of crushed ore in vats or leaching tanks. It was frequently necessary to separate the sand for cyanide treatment and discard the slimes, because only granular material allows the necessary amount of solution to percolate through it in a reasonable time. Later a slime process consisting of agitation followed by thick-ening and filtration was developed, and is extensively used to the pres-ent day. Even though the agitation-leaching slime process is considered satis-factory, the cost of plant and of operation are both greater than for a percolation-leaching plant of equal capacity. This situation has been recognized in the hydrometallurgical treatment of copper-bearing slimes; and a considerable amount of j work has been done at the Southwest Experiment Station of the U. S. Bureau of Mines in an effort to develop a percolation method of treating slimes. Experimental work on the copper-leaching problem was started by H. E. Keyes1, and later tests were made by J. D. Sullivan and A. P. Towne2. The Bureau of Mines work resulted in the development of a process by which slimes were moisture-agglomerated with sand and crushed ore, to form a permeable mass through which solution could be trickled without breaking clown the glomerules. The agglomeration trickle-leaching method was devel-oped on a small scale and finally tried out in a 12-ton vat. Successful results were obtained as long is the leach solution was added slowly, so that the agglomerated charge was never flooded. If the leach solu-tion flooded the charge, the glomerules broke down and, the charge became impervious. There are two important difficulties in the application of the agglom-eration trickle-leaching-method to the cyanide process for gold and silver ores:

Jan 1, 1937

By Clarence Seyler

THE technical difficulties of cutting thin sections of coal for examination by transmitted light have hitherto restricted the investigation of the important subject of the microstructure of coal to the few possessed of the requisite skill and time. Apart from this, the method fails with anthracites and other coals rich in carbon, owing to the opacity of the material. Occasional use of the method of polishing a surface, with or without etching, has been made, but it was not until Winter1 published an account of his results that attention was seriously directed to the method. In May, 1923, a specimen of dull anthracite came into my hands; I tried Winter's method on it and the presence of megaspores and other vegetable structures became clearly visible. A preliminary notice was published by me;2 but I soon abandoned the use of Schulze's solution having found that a mixture of chromic and sulfuric acids gave far better results. In the meantime Turner and Randall, in America, had independently developed the method of flame etching, as applied to anthracite, with great success. I have spent a year studying the method of chromic etching, which gives excellent results with bituminous coals and cannels, as well as with anthracite. For anthracites, I have used the chromic method and Turner's method of flame etching, whichever was the more convenient or as a check one on the other. The polishing is done, according to metallurgical practice, by the use of a polishing machine and successively finer emery paper, followed by polishing on cloth moistened with a suspension of levigated green oxide of chromium, and a final rubbing on "selvyt" (a cotton velvet polishing cloth) moistened' with alcohol. The polished sample is examined by reflected light with a 2/3 and 1/6 in. objective. Bituminous coals usually show considerable structure, and even anthracites show it faintly in places. The sample is then etched by immersion in a boiling solution made by adding 10 c.c. of concentrated sulfuric acid to 30 c.c of a saturated solution of chromic acid; enough water is then added to dissolve

Jan 3, 1925

By Charles E. Packard

Many coal producers have been faced recently with the problem of arranging their production facilities to accommodate recent trends in the transportation of their product. Each operator is normally faced with a different problem requiring a system to meet his specific needs. It may be that he would be required to load a seven or eight thousand ton integral train each day which would naturally call for a large storage pile, high loading rate, accomplished in a minimum of time On the other hand, it may be that he is faced with furnishing coal to make up one-half of a unit train that is to be assembled twice a week. Whether the problem is large or small, many considerations must be given to each specific problem to be certain that the proper scheme is applied. The operator actually has several choices as to what type of storage and loading facilities he may consider. The storage pile, for instance, may be open type, conical in shape, kidney-shaped, or long and wedge-shaped. It may also be enclosed by steel or concrete

Jan 8, 1964

G. A. ROUSH,* South Bethlehem, Pa. (written discussion?).-Mr. Frey is correct in his impression that ice floats, but "frazil" ice happens to be the exception to the rule. The requirements for the formation of

Jan 12, 1919

By Howard L. Hartman

There is reason to believe that ventilation systems so far devised for use with continuous mining machines fall far short of success. This is vividly demonstrated to anyone who has observed in a continuous miner section the localized ignitions of pockets of gas and the generation of dense clouds of dust by the cutting head of the machine. The alarming frequency with which major ignitions and disasters continue to occur in modern mechanical mining and the rise in incidence of pneumoconiosis serve as reminders that our ventilation systems are far from achieving the ultimate in providing protection from either short-term explosions or long- term dust diseases, both of which take lives. Human safety is the main concern in ventilation. But in this day of high-priced labor, let us not forget human comfort, either, for this is a major factor in motivation toward high productivity. The failure or inadequacy of most mine ventilation systems in providing the kind of working conditions at the face that are conducive to productive as well as safe operation is an indictment of our environ- mental control program in mining generally.

Jan 3, 1962

By Raymond Brandon, Marshall Pease

A pattern for providing a large utility, The Detroit Edison Co., with an adequate fuel supply is outlined. From the standpoint of both fuel procurement and utilization, consideration has been given competition relationships, fuel properties as well as operating conditions that must be met to provide dependable service and reliable plant operation.

Jan 2, 1951

By Clement K. Chase

The ammonia leach for copper recovery is discussed from historical and current practice standpoints. The chemistry of the system is presented together with Eh-pH and copper-ammonia solubility curves. A list of metals forming ammine complexes is presented. The advantages and disadvantages of the ammonia leach as applied to copper recovery in conjuction with modern liquid ion exchange techniques are compared.

Jan 1, 1980

We are advised by Second-Lieutenant Maxwell E. Erdofy, a member of the Institute, and athletic officer of the 602d Engineers, stationed at Camp Devens, Mass., that his regiment, representing all branches of the engineering profession, is in need of athletic equipment and supplies. The regiment will highly appreciate any assistance in the way of financial contributions, or of apparatus and equipment for their athletic needs.

Jan 5, 1918

By Walter Weeks

THERE is very little useful material in the litera-ture on the construction of manometers, so each experimenter must devise his own instrument. I have experimented for a number of years and have finally built one that is satisfactory. If we are to obtain accurate friction factors in mine-ventilation problems we must use accurate instruments. The most simple and convenient instrument for the mea-surement of small pressures is the inclined manometer or U-tube. By changing the angle at which the tube is set, any desired magnification of the pressure reading may be obtained. The first question in regard to the manometer is: What liquid shall be used? Alcohol, in my opinion, is the best. It does not cling to the glass and it does not attack the rubber tubes. The next problem is the setting of the instrument at the proper angle. One method is illustrated in Fig. 1. The base plate AC is made horizontal by a level bubble. The plate AB, which carries the U-tube, is hinged at A. The angle z which AB makes with the horizontal may be made any value by pinning the end B at the calculated position on the arm CD. Such an instrument may be designed to read directly in inches of water if a liquid of constant specific gravity is used. If the specific gravity varies, a calculation is necessary to convert the reading into inches of water.

Jan 1, 1923

By L. A. Schrider, J. A. Wasson

A method of predicting waterflood performance has been developed that combines certain facets of several previously published prediction techniques. The manner of combination has required the development and use of some new and some little-known relationships and has eliminated several of the weaker assumptions inherent in the original individual prediction methods. This approach, which was designed for computer solution, has removed the necessity of referring to plotted curves and permits the analytical prediction of water flood performance for a five-spot well pattern in either homogeneous or stratified reservoirs. The Predicted values are expressed in common oilfield units rather than in abstract or dimensionless terms. The calculation procedure has been programmed in FORTRAN IV and the entire program listing is available to potential users.* Introduction Prior to initiation of secondary recovery of oil by waterflooding, the possibilities of economic success or failure must be evaluated with the greatest practical accuracy. Although many prediction techniques are available, most, if not all, have serious limitations. In recent years, the Bureau of Mines has attempted to stimulate interest in the secondary recovery of oil from Appalachian pressure-depleted reservoirs. Waterflooding, because of its widespread acceptance and success, is the principal secondary-recovery method considered. During the life of the project, several performance prediction methods have been studied and applied. Because these methods, individually, have inherent assumptions and limi-tations, portions of some of them have been selected and combined in an effort to eliminate such shortcomings wherever possible. We believe that the resulting technique is as accurate as the necessary available data will permit and that it has several distinct advantages over previously published methods. Development of the Method The fractional flow equation developed by Buckley and Leverett' from Darcy's law is the fundamental mathematical statement describing immiscible fluid-fluid displacement in porous media. A generalized form of this relationship, whose derivation is readily available in the literature, is The formation dip, a, is usually very small in those petroleum reservoirs being considered for pattern waterflooding in the Appalachian area. Therefore. in many cases. a has an almist negligible value. In addition, Ap, the difference between the density of water and the density of oil, is relatively small. For these reasons the gravitational term may often be neglected. Capillary pressure is a function of saturation, which is in turn a function of distance from the upstream boundary of the system or the injection well. In this study it is assumed that the frontal zone of the waterflooding (or zone of capillarity) has negligible length and that only those saturations in the water-swept zone at breakthrough and later are of interest. As the distance in a waterflood pattern is comparatively large and the change in water saturation with distance is usually small, the change in capillary pressure with distance is negligible. The simplified form of the fractional flow equation is appropriate, therefore, in this application. Three variables must be considered in determining that fraction of the total fluid flow that consists of water: the viscosity ratio, saturation, and relative permeability ratio.

Jan 1, 1969

By L. O. Howard

TWO or three years ago there were submitted to me some reports of tests that had been made on a semi-oxidized ore of silver looking to its treat-ment by combined flotation and cyanidation, together with a sample of the ore, with a request that I check the tests and confirm them, if possible. These tests had been made by a machinery-supply house and with them was a flow-sheet for a proposed mill, with full details of equipment to be used in the mill. The limited data on which this was based at once attracted my attention and have caused me from time to time to put various groups of students at work to develop simpler methods of obtaining data, which it appeared should be at hand and could be obtained by simple tests before attempting to treat these ores commercially. A brief discussion of the working out of such methods may be of interest and may contribute somewhat to the de-velopment of better testing methods for the small operator who has not at his command a staff of metallurgists. Of several tests on samples of varying assay and mineralogical composition, by cyanidation alone, by flotation alone, and, by combinations of the two, the following report was perhaps the most complete and may well serve as a typical example: METALLURGICAL TEST REPORT Silver Mines Co. Semi-oxidized Ore Procedure: Ore ground to 65 mesh, given flotation treat-ment using pine oil and potassium xanthate. Flotation tailing was thickened and given cyaniding agitation in solution strength of 5 lb. cyanide per ton and 2 lb. lime per ton.

Jan 12, 1927

By A. A. Gustafson

The Freeport Sulphur Co. built a portable crusher in 1944 that solved a problem that none of the crusher manufacturing companies contacted were able to do. Two of these crushers have now been in service for 6 years, giving satisfactory service in handling a million tons per year, and having a capacity of over 2000 long tons per 8-hr shift. These machines reduce ton size blocks of sulphur to 12 in. and also feed the conveyor system at the rate of 350 long tons per hr per machine.

Jan 10, 1950

By E. S. Bumps, W. F. Craig, M. Baeyertz

Metallurgists have looked at fractures macroscopically for many years and have evolved a vocabulary in which such words as "cleavage," "brittle," "shear," "ductile," "granular," "fibrous," and "silky" are used to describe the appearance of the fractured surface; but the meaning of these words in terms of metal structure is not well established. Observations of the structural meaning of "brittle" and "ductile" fractures in plate steels have been made, notably, by Kramer and coworkers1 and by Tipper.2 Grossman3 has studied the fracture of tempered martensite and combinations of ferrite and martensite. Notwithstanding these and other less concerted attacks on the problem, present understanding of fracture rests more on assumptions and logic than on experiment. It is the purpose of this paper to add a little to the growing fund of experimental observations of the nature of fractures in steel. The particular fractures to be described were obtained in conventional impact testing of an ordinary structural steel shape. In impact tests of the Charpy type, the specimens fail in a characteristic manner that depends on the steel and the temperature of testing. With ordinary structural and many other steel products, an appropriate range of testing temperature will cause a considerable change in the energy absorbed before fracture. This change is known as the energy transition and is accompanied, more or less closely, by alteration in the appearance of the fracture. At testing temperatures below the transition, the terms "brittle," "cleavage," or "granular" are used to describe the fracture; above it, "ductile" or "shear" are often used. Within the transition, the fracture changes from "brittle" to "ductile" by a progression in appearance, wherein the "brittle" portion of the fracture becomes restricted to a smaller and smaller central area of the fracture, as the testing temperature is raised and the "ductile" type of fracture is approached. All this is well known to metallurgists. The specimens under consideration are of the conventional V-notch Charpy type. They were taken from a structural steel shape of the following analysis: C Mn P S Si 0.17 0.46 0.009 0.029 0.03 Both longitudinal and transverse specimens were tested and examined. Fig 1 shows the energy values plotted against testing temperatures in the usual way. The curves for both longitudinal and transverse specimens show an energy transition, although the maximum energy absorbed at testing temperatures above the transition is greater in the case of the longitudinal specimens. Fig 2 illustrates the changes in the macroscopic appearance of the fractures that are associated with the energy transitions shown in Fig 1. Macrographs of the fractured surfaces of the specimens have been identified with the fracture ratings at intervals on each fracture curve. The numerical fracture rating on the ordinate of Fig 2 indicates the percentage of the area of each fracture that was considered to be "brittle" on macroscopic observation. Such rating of the fracture type in impact tests is now customary in many laboratories. Hereafter the specimens will be identified by reference to Fig 2 as 90 pct "brittle," 80 pct "brittle," and so on, in accordance with this macroscopic evaluation of the appearance of the fractured surface. The discussion of the fractures is divided into three parts. The first two are concerned with the mode of fracture and its relation to general structural features. As the same metal-lographic features occur in both longi-

Jan 1, 1950