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By R. L. Slobod, W. L. Prehn, Adele Chambers

The centrifuge has been found to be an extremely useful tool for determining capillary pressure curves and for establishing connate water and residual oil in small core plugs. The use of the centrifuge for determining the properties of small core plugs has been discussed in the literature,',' but practically no experimental evidence has been presented justifying the use of this method in preference to other methods (mainly disc method) now in use. Data have been accumulated and are now presented demonstrating the advantages of the centrifugal method, some of which are: (1) rapid establishment of equilibrium, (2) excellent precision yielding very reproducible results, (3) availability of high pressure differences between phases, (4) simple operational procedure, and (5) ability to establish connate water, residual oil, or to obtain complete capillary pressure curve in one day or less. A commercially available centrifuge capable of speeds up to 3,800 rpm, and a high speed attachment providing a maximum rate of rotation of 18,000 rpm were used in this work in conjunction with core holding tubes designed specifically for this application. In view of the outstanding advantages associated with the use of the centrifuge the conclusion has been drawn that this method should be used in place of the more tedious, slower, and less reliable disc method for determining capillary pressure curves and for establishing connate water and residual oil in small core plugs. INTRODUCTION The need for accurate values of connate water, residual oil, and capillary pressure curves in reservoir engineering has been recognized for many years, and the extent of the effort devoted toward solving these problems is reflected in the large number of papers3-" which have appeared in the literature during the past decade. Most of the methods discussed in the recent literature employ a porous disc as a semi-permeable membrane to separate two immiscible phases and make pos-ible the application of an explicit difference in pressure between two phases in the core. Thus, in the determination of the capillary pressure curve the wetting phase (water) is displaced by the non-wetting phase (air or oil). Several investigators1,2 have used centrifugal forces to develop pressure differences between phases. As a result of the first work' in this field the conclusion was reached that "the more rapid centrifugal method for measuring irreducible saturation may have equal value, (compared to use of discs) but more work is required to establish this point." This work was followed in 1945 by a more detailed study2 in which the concepts of this experimental work were more clearly enunciated. A method for calculating saturation for any given speed of rotation based on the observed volume of water displaced was developed and a wider application of the method was suggested. The absence of any subsequent pertinent literature on this subject is interpreted as indicating that no additional work has been completed to substantiate or deny the earlier claims and suggestions of promise contained in the original papers on this subject. One purpose of this report is to provide evidence designed to establish the practical value of centrifugal methods in determining core properties such as connate water and capillary pressure curves. It is also our purpose to suggest a broadening of the scope of this tool to include determinations of residual oil by gas or water drives. THEORY AND PRACTICE IN USE OF CENTRIFUGE Hassler and Brunner2 have clearly presented the basic concepts involved in the use of the centrifuge by relating the performance of a small core in a field of high acceleration to the

Jan 1, 1951

THE developments in construction and operation of the basic open-hearth furnace that have taken place in recent years have placed new emphasis on the vital influence played by regulation and control of the combustion system in both furnace production and furnace life. The several factors influencing flame development, such as regulation of fuel supply, air supply, air preheat, furnace draft, and furnace reversal, must be controlled closely if successful furnace performance is to be accomplished. Rugged instrumentation of distinctive design is required to sup- ply dependable information concerning operating conditions, which is requisite to proper regulation of combustion. This chapter attempts to give a practical discussion of the various features of open-hearth practice and instrumentation related to the efficient heating of the furnace, control of temperature, and protection of the furnace structure from accidental overheating. The appended references will be helpful to readers wanting a more detailed treatment of individual topics. OPEN-HEARTH FUELS The most important open-hearth fuels are listed in Table 4-1 together with their compositions and other data useful for combustion calculations. A detailed discussion of open-hearth fuels is not attempted here, but certain factors peculiar to their application to this type of process are briefly indicated on the following pages. Very often an open-hearth shop is forced by economic factors to use a fuel to which its furnaces are not very well adapted, because the general fuel-allocation scheme for the works as a whole seems to demand it. Often a variable marginal supply of coke-oven gas or tar must be consumed by the open hearth, together with another fuel such as producer gas, natural gas, or oil, to fill out total requirements. Most furnaces employ more than one kind of fuel during their useful life; however, the partial redesign

Jan 1, 1964

By Gary B. Williamson, Barton K. Cross

Digital simulation is a modern analysis tool which allows the mine operator to evaluate the result of making a decision without actually changing the organization or buying the equipment. The purpose of this paper is to demonstrate the use of digital simulation in evaluating a decision of whether or not to introduce dispatching in an open pit mine. The analysis shows that appreciable savings can be realized by dispatching. In certain cases, an operator can reduce the number of trucks required to move a specified tonnage. A second analysis evaluates the alternatives of using one large shovel or two smaller units. In this case, the operating cost of the haulage equipment necessary to support the shovels turns out to be the critical factor in this decision.

Jan 1, 1969

By Rip Thompson

ALTHOUGH the metallurgical treatment for the Ophir Hill tailings was developed more than 20 years ago and in the interim a vast amount of experimental work was done with later-developed flotation rea-gents, it was found necessary to revert to the original oil reagents and their combina-tions with specific chemical reagents in order to obtain results of economic value. This is of especial interest because in present ore-treatment investigations later-developed flotation reagents are used almost exclusively and the coal-tar deriva-tives, except in certain patented reagents, are virtually neglected. These coal-tar oils and derivatives still have a definite field of application, especially in the treatment of some oxidized ores when modified sulphidi-zation is desirable. The Ophir Hill tailings deposit is in Ophir Canyon, Tooele County, Utah, about 55 miles southwest of Salt Lake City and 25 miles south of the Tooele smelter of the International Smelting and Refining Co. A road good for trucks leads directly from the Ophir mill to the smelter.

Jan 1, 1940

By Chester Lee

Introduction THE Atlin Mining District is in the northwest corner of the Province of British Columbia. Ruby Creek, where the operation to be described is situated, is 17 miles east of the town of Atlin and about 18 miles south of the south line of Yukon Territory (Fig. 1). Gold was discovered in the district in January, 1898, and the production to date from placer mines has been $4,518,000, according to the reports of the Minister of Mines for-the province. Geology The essential points in the regional geology are given in the following paragraphs. Long erosion produced a plane-like surface slightly above sea level with a few peaks and ridges.1 A gradual uplift followed and. erosion increased, the streams cut deeper, the cuts so made being afterward increased by glaciation. The ice straightened and planed the slopes of the main valleys and widened and lowered their floors, in some cases flooring the valleys with silt, sand, gravel, and clay. As the glaciers rapidly retreated, lakes were formed.

Jan 5, 1916

By Linn Bradley

R. J. WYSOR, So. Bethlehem, Pa. (communication to the Secretary*). At our plant (Bethlehem Steel Co.), we have had several Bradshaw burners under course of construction and erection for some time, but up to the present we have not had opportunity to put them in service. I regret that I can not take part in the discussion with some actual results from these, burners. Mr. Huessener properly emphasizes the importance of obtaining the highest combustion temperature practicable in boiler practice, which demands a near approach to perfect combustion conditions. The ideal burner is the one which, while meeting the various mechanical, requirements, fulfills the above condition under a wide range of gas pressure. The question as to the relative value of hot raw gas and cold washed gas for boiler use is a very interesting one. I think that in the past the importance of low temperature of washed gas sometimes has been over-emphasized. Mr. Huessener has pointed out that so far as temperature is concerned, no advantage accrues in washing gas below 100° F. In

Jan 3, 1917

By Clarence E. Killebrew

The key to the successful use of any tool, more than anything else, depends upon proper application assignment. To achieve this, the individual having such machine responsibility must maintain fresh knowledge of technical improvements that broaden machine uses. 8.3-1. Tractor Shovel. This type machine is available in a wide range of sizes mounted either on crawler tracks or rubber-tired wheels, with both two-wheel and four-wheel drive. The original concept in both crawler and rubber mounting was that of an attachment to be added to a tractor already in existence. This served as an important expedient for the introduction of the tool, but the basic tractor proved to be inadequately designed for the additional loads. In spite of these structural inadequencies, customer acceptance generated sufficient revenue that further development could be financed for product improvement. The evolution of the product is continuing in many ways-including engines, drive line components, tires, hydraulic pumps, hydraulic valves, structural steel, etc. With each improvement, the operating capability of the machine is extended. This is resulting in the rubber-tired, four-wheel-drive concept making an invasion of the job applications that were formerly considered suitable only for crawler-track mounted machines. Both rubber- and crawler-mounted tractor shovels have invaded the market of small excavator shovels. Larger tractor shovels are challenging the larger size excavators. It is important that each job application be carefully considered so that the proper machine is put in operation. The performance varies widely in operating cost, production efficiency, and job flexibility. Factors to be considered in equipment selection are: 1. Nature of material to be moved 3. Distance material must be moved 2. Surface over which material must be moved 4. Quantity to be moved 5. Secondary or alternate use capability

Jan 1, 1968

By O. H. Eschholz

The electrostatic process of fume precipitation is an excellent example of the successful application of scientific knowledge to an industrial operation. Originally proposed for the precipitation of sulfuric acid mists, it has been extended until at present there is practically no fume-carrying gas to which the method cannot be applied. Among the more common applications are: the recovery of non-ferrous smelter flue-dust, iron blast-furnace dust, cement dust, and potash fume. It should be borne in mind that the process is restricted to the precipitation of suspended particles, either liquid or solid, and does not separate gaseous constituents. However, by proper temperature control, mixtures of vapors having different temperatures of condensation to either solids or liquids may be selectively precipitated. The process consists essentially of subjecting suspended particles, including those too minute to be effectively acted upon by centrifugal or gravitational forces, to such an electrical force that they are driven from the gas stream, acting as a conveyer, and deposited upon a suitable receiving surface. This directional impulse is obtained from the interaction of charged particles and an electrostatic field of definite intensity gradient existing between two dissimilar electrodes, known as discharge and receiving electrodes. In principle, the equipment is equally simple. As shown diagrammatically in Fig. 1, it consists of: (1) A source of high-potential direct, current,, requiring: (a) Source of alternating-current energy. (b) Means of transforming from low voltage to high voltage. (c) Means of converting alternating to direct current. (2) Precipitation chamber having: (a) Transmission tubes for fume-laden gases. (b) Suitably designed and disposed electrodes. (c) Means for affecting removal of deposited solids. Although Hohlfeld demonstrated, in 1824, that a smoke-laden atmosphere could be cleared by applying an electrostatic field, and while Sir

Jan 1, 1919

W. H. BLAUVELT (author's reply to discussion *).-The prevention of smoke from byproduct-oven plants is not as simple as would appear from Mr. Moss's statement. All well designed byproduct-oven plants are equipped with ample exhauster capacity, and the suction on the ovens is controlled by highly sensitive pressure governors that control the pressure within a fraction of a millimeter. Of course, this apparatus can get out of order, causing the batteries to smoke, but this does not often happen. As stated by Mr. Thompson, the smoke produced is made almost entirely during the time of charging the ovens, when they are cut off from the hydraulic main. The amount of smoke that escapes at this time is extremely small, compared with -the amount produced by a beehive-oven plant, but the mechanical difficulties in preventing any escape of smoke at charging time are considerable. Several devices are in operation at a number of plants which collect most of the smoke made during charging and several devices are being worked on for its complete

Jan 12, 1918

By Franklin Moeller

CONSIDERING the really short time that has elapsed since hydro-metallurgical processes of extracting copper from ores have been extensively developed, and the large scale on which this method is practised at Ajo, the successful operation of the plant must excite the admiration of every visitor. The application of the mechanical unloader to the purpose for which it is employed at Ajo is but an extension of the use for which it was originally designed, some 20 years ago, for unloading iron-ore vessels at the lower lake ports. At a time when the maximum output of a single machine, with men shoveling the ore into buckets, did not exceed 40 tons per hour, G. H. Hulett invented and constructed a mechanical unloader with a bucket of 10-ton capacity. This machine was of the steam hydraulic type, and it is still in operation after nearly 20 years of service. Several more machines of the same type were built, but the difficulties of power transmission, and the rapid development of electrical machinery, soon led to the adoption of electrically operated machines, and practically all of the later installations have been thus equipped. This electrically operated unloader has proved so well fitted for the work that the design of the lake boats has been practically revolutionized, with special view to the ease and rapidity of unloading. It is now possible to unload a 12,000-ton vessel with four machines in a little over 2 hr. This has necessitated an increase in the capacity of the machine, and the largest yet built handles an average load of 17 tons, with a possible maximum of 20 to 21 tons.

Jan 8, 1918

By Ben L. Seegmiller

Artificial support of rock slopes in mining applications may consist of rock anchors with and without auxiliary support systems, but- tresses or shotcrete. The use of artificial support systems is not applicable in all cases of slope instability. Some pit slope problems simply cannot be cured with a support system. In other cases, a sup- port system which would solve the problem would be uneconomical. Rock anchor design may be undertaken using an active or tensioned system or a passive or untensioned system. Failure problems to which artificial support systems are most commonly applied include planar, wedge, rotational and toppling failures. Design of auxiliary support systems and rock anchor peripheral items may be initially estimated using analytical concepts, but field trials are commonly used to determine final requirements. Field procedures usually require a close coordination between mining personnel and the support installation team. Great care must be exercised during installation to prevent numerous potential problems including poor anchorage, excess bearing and corrosion. Displacement monitoring of the completed system is a must if the effectiveness is to be closely judged by means other than total slope and/or support system failure. The cost of a support system is relatively high when compared to other remedial measures that may be taken to solve a slope instability problem. Therefore, the system costs play a vital role in determining whether or not artificial support should be considered beyond the initial assessment stage. Case histories are few, but do include examples of each type of support system.

Jan 1, 1983

By Jed H. Mosgrove, Paul M. Budzak

INTRODUCTION Good mine ventilation starts at the drawing board. A coal mine will either be adequately ventilated or not, depending upon how good a job was done in the planning. Poor planning will not only result in inadequate ventilation, but may also lead to low productivity. A mine foreman cannot achieve high productivity while trying to maintain 4.2 m3/s (9000 cfm) of air at his last open crosscut. PLANNING What will provide adequate ventilation? A rule of thumb in laying out a coal mine is to provide enough entries in the main entry system to keep air velocities at 2.5 m/s (500 fpm) or less; at this rate of flow, good ventilation may be expected. The intake and return air courses of a coal mine do not improve with age. Entries will deteriorate, ribs will slough, roof will fall, and clutter will accumulate. The resistance offered to air travel will continue to increase with each passing year. Providing enough airways for the present and the future cannot be emphasized too strongly. In order to better appreciate good planning and bring it into better focus, assume a hypothetical mine has the following features: entries 1.5 m (5 ft) high and 6.1 m (20 ft) wide; one intake and one return entry; the mine development is 4.8 km (3 miles) from the intake and upcast ventilation shafts; and the ventilation requirement is 141.6 m3/s (300,000 cfm). Air travel of 4.8 km (3 miles) into a mine and the same distance back to the fan is not unusual. However, to do so with one intake and one

Jan 1, 1981

By Jed H. Mosgrove, Paul M. Budzak

INTRODUCTION Good mine ventilation starts at the drawing board. A coal mine will either be adequately ventilated or not, depending upon how good a job was done in the planning. Poor planning will not only result in inadequate ventilation, but may also lead to low productivity. A mine foreman cannot achieve high productivity while trying to maintain 4.2 m3/s (9000 cfm) of air at his last open crosscut. PLANNING What will provide adequate ventilation? A rule of thumb in laying out a coal mine is to provide enough entries in the main entry system to keep air velocities at 2.5 m/s (500 fpm) or less; at this rate of flow, good ventilation may be expected. The intake and return air courses of a coal mine do not improve with age. Entries will deteriorate, ribs will slough, roof will fall, and clutter will accumulate. The resistance offered to air travel will continue to increase with each passing year. Providing enough airways for the present and the future cannot be emphasized too strongly. In order to better appreciate good planning and bring it into better focus, assume a hypothetical mine has the following features: entries 1.5 m (5 ft) high and 6.1 m (20 ft) wide; one intake and one return entry; the mine development is 4.8 km (3 miles) from the intake and upcast ventilation shafts; and the ventilation requirement is 141.6 m3/s (300,000 cfm) . Air travel of 4.8 km (3 miles) into a mine and the same distance back to the fan is not unusual. However, to do so with one intake and one

Jan 1, 1981

By E. G. Dean

A method of top slicing has been devised at the Miami Copper Co.'s mine at Miami, Aria., which differs radically in some ways from the customary methods of top slicing. The area of that section of the orebody in which top slicing is used is about 800 ft. square. The ore, while for the most part soft, is, nevertheless, considerably harder than the capping. The latter is siliceous, seldom containing any clay or other binding material, and breaks into fine particles so that it runs like sand if given the opportunity. Because of these facts, and because the ore is above the average grade of the mine ore, it has been mined by top slicing. Haulage levels are opened up 150 ft. apart, vertically, with two sub-levels between at 50-ft. intervals, to facilitate the putting up of ore chutes. These sublevels are used during slicing for distributing air in the ventilation system. On the haulage level the drifts are spaced on 50-ft. centers, and raises along these drifts are also spaced on 50-ft. centers, except the incline raises as hereafter noted. The raises are cribbed where necessary. Where the wear will be excessive, 1/4-in. iron plates are spiked to the top of every third set of cribbing, for its protection. When top slicing was first used, an attempt was made to carry a slicing face from fifty to several hundred feet long. Timber and other supplies were brought in through long drifts from an auxiliary shaft. Great difficulty was experienced in keeping these drifts open, the side pressure breaking the posts and the top weight breaking both caps and posts. Furthermore, the men could not work efficiently while these drifts were being repaired. The slicing faces advanced irregularly, due to varying conditions, and in many ways the results were not all that could be desired. It was then decided to divide the slicing area into blocks 200 ft. square and this was later changed to 250 ft. square. At the center of each block a two-compartment raise is put up as a supply raise, the compartments being 2 ft. 6 in. and 4 ft. by 4 ft. 4 in., the smaller being used as a manway. Station sets of 12 by 12 timber with

Jan 1, 1917

By J. E. Hilliard

It is proposed that shape anisotropy in the internal structure of materials be defined by distribution functions which specify what fraction of the total line length or boundary area lies in a given direction. Methods are descriibed for determinirg these distribution functions from measurements on sections through an opaque material. New derivations, that have certain advanifages over those given previously, are Provided for well-known expressions used in estinzating the total density of lineal or areal features. INCREASING attention is being given to the quantitative description of imicrostructures in metals and other materials. This interest stems from the recognition that the structure often provides a convenient half-way point between the properties on the one hand and the processing variables on the other. Such cross correlations become increasingly desirable as materials become more complex and the demands on them more stringent. One of the principal aims in structure analysis is therefore to find parameters that are readily measurable and specific enough to be correlated with other properties of the material. Certain properties, such as magnetic and mechani cal behavior, are strongly influenced by structural anisotropies; in order to relate such properties to the structure it is obviously necessary to have means of specifying and measuring the type and degree of anisotropy. For the determination of preferred orientations in crystal structure, X-ray diffraction methods are available and are widely used, but scant attention has been given to the estimation of anisotropy in the shape of grains and particles. It is the latter problem that will be considered in this paper. It is evident that shape anisotropy can be describe in terms of preferred orientations of lineal and area elements of the structure. It will be shown that these preferred orientations can, in turn, be specified by distribution functions that define what fraction of the total line length or boundary area lies in a given direction. Methods will be given for determining the distribution functions from measurements on sections through the structure. Even when the orientation distributions are of no interest per se, they still have an important bearing on the measurement of the total line length or boundary area by means of an intercept analysis. The treatment in terms of orientation distribution functions leads to new derivations, that have certain advantages of those given previously, for the well-known expressions used in estimating the total density of lineal or areal features. The treatment is divided into two main sections. The first deals with the orientation distribution of a two-dimensional array of lineal features such as occurs in the projected image of dislocations in electron transmission microscopy. The other section treats the estimation of the distribution of lineal and areal features dispersed in three dimensions.

Jan 1, 1962

By E. J. Rapperport, C. S. Hartley

I TTRIUM is a close-packed-hexagonal metal with a c/a ratio of 1.5712.1 This low c/a value prompted a cursory examination of the deformation modes to obtain more data on the deformation characteristics of hcp metals with subideal c/a ratios. The chemical analysis of the arc-melted stock from which the specimen was cut is given below in Table I.

Jan 1, 1960

By George Collins

AT the meeting of the Western Division of the American Mining Congress, held in Denver last September, papers were read by F. H. Brownell, a vice-president of the American Smelting and Refining Co. and chairman of its finance committee, and by H. Foster Bain, former director of the United States Bureau of Mines and now secretary of the A. I. M. E.. which dealt thoroughly with certain phases of my sub-ject. These addresses can hardly have failed to awaken serious reflection in all who listened to them; but their implications have apparently not penetrated the con-sciousness of bankers, economists and statesmen, whose business it is, or should be, to prepare for the economic and social changes which must inevitably follow, if the conclusions which I shall outline hereinafter are true. In discussing this subject I wish to disclaim any intention or desire to forecast the course of the metal markets or the immediate prospects of the mining in-dustry. The facts' adduced must inevitably influence the value of metals, the activity and profitableness of mining, and perhaps also the social status of those en-gaged in it. But my forecasts do not refer to this year, next, year, or the year after. The nearest ap-proach to a date on which I will venture is that the relative scarcity of gold may begin to make itself felt in something like ten years from now, but its effect will not culminate for several years thereafter. Scarcity of new gold is likely to be offset, to some extent, by increasing use of currencies based on credit; but unless it is found possible to dispense with the gold standard altogether, this can hardly prevent a great ultimate fall in commodity prices. This fall, moreover, is likely to be more severe in manufactured goods than in what are, popularly termed raw ma-terials; and most of all in those manufactured goods which are susceptible to the greatest degree to cheapen-ing by mass production, and which are least counter-affected by increasing metal prices; by which I mean those in which the cost of metal contained forms a relatively small, element in the total cost of production.

Jan 6, 1927

By C. W. Chen

MARTENSITE transformations in ß Cu-Al alloys have been studied by Greninger1 and other investigators. According to Greninger, the parent phase ß1 an ordered body-centered-cubic structure obtained from ß phase by suppressing the eutectoid decomposition, transforms into an ordered hexagonal-close-packed phase in composition containing 12.9 to 14.7 pct Al. The M, temperature decreases with increasing aluminum content; for the alloy containing 14.5 pct Al, for example, the ß1??' transformation occurs below room temperature. More recently, Kurjumow2 studied the transformation in ß Cu-Al alloys with the addition of nickel. His report stimulated new interest in the subject due to the observation of completely reversible transformation without hysteresis in the transformation temperature ranging from 10° to —10°C. In the present paper some characteristics are described of the transformation of Cu-Al-Ni alloys that were partly studied by Kurjumow. Experimental Procedure High purity copper (99.999 pct) and aluminum (99.99 pct) and electrolytic nickel were used in the preparation, by the Bridgman technique, of single crystal specimens which contained aluminum and nickel of 14.5 and 0.5 to 3.0 pct, respectively. Polished surfaces were prepared mechanically. Specimens were then chemically etched to remove distorted material, homogenized at 1000°C for several hours, and quenched drastically to room temperature in a 10 pct NaOH bath to produce the parent phase ß1. The transformation was studied under a microscope and, in some cases, recorded by means of motion pictures. A device similar to that designed by Greninger and Mooradian3 was used to cool and reheat the specimens. Results and Discussion When the specimens were cooled below room temperature, the ß1 to ?' transformation began at 10°C with the appearance of ?' crystals In relief, Fig. la. As the specimen temperature dropped further, the transformation continued, either by the growth of the ?' crystals, with the ß1 — ?' interface moving into the ß1 phase, Fig. 1c and 1d, or by the formation of new ?' crystals, Fig. 1b. As a consequence of the former process, banded structure is observed as a common feature of the low temperature phase. According to the theory of the formation of martensite by Wechsler, Lieberman, and Read,' the bands of ?' phase are probably twin-related, as is the case in the diffusionless phase change of In-T1 alloys,5 but this was not revealed by X-ray tech- niques. New ?' crystals, in needle form, often emerged suddenly across the ?' bands during the transformation. These acicular crystals then grew, both in length and in width, see Fig. 2a through 2d. The transformation on cooling is completed at about -35°C. Upon heating, the reverse transformation started at —10° C, in a manner nearly opposite to the transformation on cooling, and completed at 35°C. There was no noticeable change in the transformation temperature when the nickel content was varied within the limits previously mentioned. Through control of the specimen temperature, the transformation can be started, stopped, or reversed at will. This phenomenon has frequently been observed in the martensite transformation of many nonferrous alloy systems. Other systems are Au-Cd6 and In-Tl.5 ow-- ever, in the latter systems, the transformation is accomplished by single interface motion if the specimen composition is homogeneous and the temperature gradient in the specimen is uniform and sharp, whereas in the Cu-Al-Ni specimens, only multiple interface transformation is observed. The speed of the interface motion appears to be a functionof the rate of temperature change and the temperature gradient across the specimen length. In one case, in which the temperature increased at the rate of 10°C per min and there was no temperature gradient along the specimen axis, the speed of the disappearance of a ?' plate was determined, by the study of the motion pictures made, to be 26 µ per sec. Quench markings were observed on the polished surfaces of specimens. The markings were grouped into one or more sets of different orientations, and were parallel in each set. The ?' plates formed in subsequent transformation were parallel to the markings, indicating that the ?' plates and the quench markings had the same geometric relation-ship to the ß1 matrix. The quench markings on two intersecting surfaces of a specimen were therefore used in the determination of the habit plane of transformation, by the trace method suggested by Barrett.' Results obtained from five sets of markings in three specimens indicate that the habit plane is an irrational plane about 2" from one of the {221} planes. This is very close to the habit plane (3" from 221 planes) of ß Cu-Al alloys containing more than 13.0 pct Al.1 The martensite transformation of Cu-Al-Ni alloys is reproducible. No sluggishness was found between consecutive transformation cycles, although a slight difference in the distribution pattern of the ?' plates was observed, compare Figs. Id and 2d. The transformation can be strain-induced. This characteristic has been tested by a simple method. When a specimen was elastically strained slowly in a vise, ?' plates were gradually produced in the same fashion as during transformation on cooling, This test was done at room temperature, and thus above the M,

Jan 1, 1958

By S. R. Elliott

The Spies mine is located in the eastern half of the northwest quarter of section 2443-35, near the village of Iron River, Mich., and is operated by The Cleveland-Cliffs Iron Co. Speaking generally, the jasper hanging walls of most of the deposits in the Iron River district dip at a steep angle and are exceedingly strong, standing without caving, even after mining has been continued for years and after large excavations have been made. The ore is fairly hard and tough and contains no slippage faces. It occurs in large masses, which are often egg shape, with the smaller end down, and can be mined in open stopes without the use of timber. The common system employed in the district is the shrinkage stope, or some modification of it. The Spies system was developed to utilize the advantages of the open-stope method and to avoid the disadvantages of the shrinkage stope. The Spies shaft was sunk to such a depth that the bottom, or third level, was in rock at a short distance below the bottom of the orebody, the shape and extent of which had been previously determined by diamond drilling. This is shown in plan and by the ore contours at the first, second, and third levels in Fig. 1, and in section in Figs. 2 to 7. In order to provide the necessary mills and raises, three parallel crosscuts were driven on 25 ft. centers on the bottom level. Drifts on the second and first levels were driven to the orebody and followed the foot wall in a southerly direction to the end of the ore. In crosscut 3, Fig. 1, raises 30, 40, 50, and 60 were carried up on the foot wall and holed into the second level, and were ultimately carried up and holed into the first level. These foot-wall raises carry the pipes and ladders, provide a means of ventilation, and furnish safe communication to all working places in the stope. From crosscuts 1, 2, and 3, raises were completed to a height of 32 ft., or the elevation of the first sublevel. They were then connected by east and west crosscuts to the main foot-wall raises 30, 40, 50, and 60, shown in Fig. 4. The crosscuts in raises 1 to 5 were then driven west and the

Jan 1, 1923

By S. R. Elliott

The Spies mine is located in the eastern half of the northwest quarter of section 2443-35, near the village of Iron River, Mich., and is operated by The Cleveland-Cliffs Iron Co. Speaking generally, the jasper hanging walls of most of the deposits in the Iron River district dip at a steep angle and are exceedingly strong, standing without caving, even after mining has been continued for years and after large excavations have been made. The ore is fairly hard and tough and contains no slippage faces. It occurs in large masses, which are often egg shape, with the smaller end down, and can be mined in open stopes without the use of timber. The common system employed in the district is the shrinkage stope, or some modification of it. The Spies system was developed to utilize the advantages of the open-stope method and to avoid the disadvantages of the shrinkage stope. The Spies shaft was sunk to such a depth that the bottom, or third level, was in rock at a short distance below the bottom of the orebody, the shape and extent of which had been previously determined by diamond drilling. This is shown in plan and by the ore contours at the first, second, and third levels in Fig. 1, and in section in Figs. 2 to 7. In order to provide the necessary mills and raises, three parallel crosscuts were driven on 25 ft. centers on the bottom level. Drifts on the second and first levels were driven to the orebody and followed the foot wall in a southerly direction to the end of the ore. In crosscut 3, Fig. 1, raises 30, 40, 50, and 60 were carried up on the foot wall and holed into the second level, and were ultimately carried up and holed into the first level. These foot-wall raises carry the pipes and ladders, provide a means of ventilation, and furnish safe communication to all working places in the stope. From crosscuts 1, 2, and 3, raises were completed to a height of 32 ft., or the elevation of the first sublevel. They were then connected by east and west crosscuts to the main foot-wall raises 30, 40, 50, and 60, shown in Fig. 4. The crosscuts in raises 1 to 5 were then driven west and the

Jan 1, 1923