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By R. F. Bell, R. W. James, L. W. Eastwood

Among those concerned with the annealing and heat-treating of aluminum and aluminum alloys, it is well known that after co1d-working a coarser grain is usually produced by slow heating than hy more rapid heating. Consequently, for the control of the grain size produced by annealing or heat-treating cold-worked aluminum and aluminum alloys, the heating rate is of considerable practical importance. References in the current literature on the effect of heating rate are numerous, but it appears neither necessary nor desirable to give here a review of the former nark done on this subject. It became evident during some preliminary work on the recrystallizn-tion of aluminium and aluminum alloys that the effect of heating rate depended upon the type of microstructure of the metal. This observation led to the following study of the relationship of the type of microstructure of the alloy to the effect of the heating rate. Materials Investigated Analyses of the aluminum and aluminium alloys investigatted are given in Table 1. Three classes of material are listed, as follows: Class I.— Belonging to the first class are pure aluminium and aluminium containing a second constituent that is soluble in the aluminium matrix at

Jan 1, 1939

By Frank L. Nason

The complete statistics of zinc-ore production in the United States for 1916 are not yet available. The following figures are, therefore, only approximate. The total production of concentrates for this year, including New Jersey and Tennessee, amounts to 1,280,000 tons. Of this tonnage, five mines produced approximately 536,000 tons, or about 42 per cent. The remaining concentrates came mainly from the "Valley States," Missouri, Wisconsin, Kansas, Oklahoma, and Arkansas. The 1,280,000 tons of concentrates represent about 25,000,000 tons of crude or run-of-mine ore. Of the five mines producing the 42 per cent., the dimensions of three are approximately 25 by 1500 by 2000 ft. (7.6 by 457 by 610 m.) or more: Four of the five mines are undoubtedly veins in the common acceptance of the term. They are located in great vein systems. The mines of "Valley States" have not, so far, been classed as veins; simply as "secondary deposits." The origin of these secondary deposits has been a warmly debated subject. Many geologists contend that they are the results of leaching from overlying and adjacent rocks carrying but traces of zinc, these traces leached out and deposited in favorable places. If this theory is correct, deposition is strictly limited to shallow depths. No volume of ore comparable to that of "true fissure veins" is to be expeeted. Just what this means to the future of zinc mining in these States is here indicated. The total zinc-bearing areas of these States amount to about 9124 sq. miles (23,631 sq. km.). Assuming that 10 per cent. of this total will be more or less productive, there are 912 sq. miles (2,362 sq. km.) of "mineral" ground. The average depth of the operated mines is something like 100 ft. or less. In Bulletin 606, U. S. Geological Survey (1915), p. 202, Siebenthal makes the following statement: "The writer is informed by William Waugh, one of the drillers of the Stone City well, that cuttings from other wells which he drilled in the vicinity of Pittsburgh, Kan., have shown galena and sphalerite taken from a depth of 591 ft. (180.14 m.) and that the showing of ore at some places would be considered good enough to justify the sinking of a shaft had it been found in the Joplin district and at shallower depths." Leaving out of the question the prohibitive cost of such a shaft, there is

Jan 1, 1918

By S. Maemura

Miike Colliery of Mitsui Coal Mining Company, the biggest and oldest coal mine in Japan, is producing a quarter of the national coal production, about 5.2 million tons of clean coal annually and almost a half of which is now being mined under the "slicing Mining System". The slicing system is a mining method to mine a thick coal seam dividing it into two faces, upper and lower. Its history started nearly 20 years ago. However, the all-around modernization of this system has made little progress up to recent years, while mining methods for single longwall faces has made a remarkable progress together with the improvements in mining machineries, self advancing supports and so on. The reason was that the tremendous difference in adaptabilities of mechanized face equipments existing between the upper and lower faces has made it very difficult to increase the total production capacity of slicing system. After our persistent study for seventeen years, we have recently realized successfully the quite satisfactory slicing system, applying the combination of shield type self advancing supports and double ranging drum cutter at both faces. We are now fully convinced of that the high efficient, quite safe and improved slicing system has been basically established for the present. This paper intends to brief the transition on the combination of self advancing supports and mining machines, its results and further to detail the development of shield type self advancing support for upper face and artificial roof material which shall be the key point to be successful in full mechanization of slicing faces.

Jan 1, 1976

By Otto H. Henry, J. J. Cordiano

Though powder metallurgy is one of the oldest of metallurgical processes, it is in its infancy as a branch of the modern field of metallurgy. As early as 3000 B.C., the ancients produced implements and weapons of iron by reducing iron ore in a charcoal fire and forging the resultant sponge while still hot into the desired shape. Melting and casting soon superseded the powder metallurgy practice, and it was not until the turn of the twentieth century that powder metallurgy was applied to the commercial manufacture of tungsten lamp filaments. From this beginning, the use of the powder metallurgy process spread" to the manufacture of porous oil-impregnated bearings, cemented carbide tools, contact points, diamond grinding wheels, clutch facings, starter brushes, resin-bonded radio cores, magnets, metallic filters, and other parts. More recently, and particularly during the present war, there has been a definite trend toward the manufacture of machine parts by this process in competition with the more conventional fabricating methods. Notwithstanding these many developments, scientific progress has been slow. While many articles on powder metallurgy have appeared in the press and various publications, there have been too few contributions to our technical societies, with the result that there is a dearth of the type of information necessary for the full development of this science. It is of primary importance that the results of research and development be freely disseminated if powder metallurgy is to realize its fullest potentialities. Purpose of Investigation Excluding the refractory metal field, all commercial powder metallurgical products made by a cold compressing and sintering operation contain voids. These voids can be substantially eliminated by subsequent severe working and heat-treatment, but ' such practice has not proved economical in most applications. By applying heat during the compressing operation, plastic deformation of the powder particles is substantially increased, and the resultant compact or briquette is practically free of voids. However, hot-pressing has many attendant problems, which at present preclude its use in the manufacture of precision parts. The more important of these are to devise: 1. A die steel capable of withstanding high pressures at elevated temperatures. 2. A high-temperature lubricant capable of preventing excessive die wear and welding of the compact to the die walls. 3. A method of retaining a neutral or reducing atmosphere in the compacting zone of the die assembly. 4. A means of ejecting the hot-pressed specimen into a neutral atmosphere until reasonably cold.

Jan 1, 1946

By Otto H. Henry, J. J. Cordiano

Though powder metallurgy is one of the oldest of metallurgical processes, it is in its infancy as a branch of the modern field of metallurgy. As early as 3000 B.C., the ancients produced implements and weapons of iron by reducing iron ore in a charcoal fire and forging the resultant sponge while still hot into the desired shape. Melting and casting soon superseded the powder metallurgy practice, and it was not until the turn of the twentieth century that powder metallurgy was applied to the commercial manufacture of tungsten lamp filaments. From this beginning, the use of the powder metallurgy process spread" to the manufacture of porous oil-impregnated bearings, cemented carbide tools, contact points, diamond grinding wheels, clutch facings, starter brushes, resin-bonded radio cores, magnets, metallic filters, and other parts. More recently, and particularly during the present war, there has been a definite trend toward the manufacture of machine parts by this process in competition with the more conventional fabricating methods. Notwithstanding these many developments, scientific progress has been slow. While many articles on powder metallurgy have appeared in the press and various publications, there have been too few contributions to our technical societies, with the result that there is a dearth of the type of information necessary for the full development of this science. It is of primary importance that the results of research and development be freely disseminated if powder metallurgy is to realize its fullest potentialities. Purpose of Investigation Excluding the refractory metal field, all commercial powder metallurgical products made by a cold compressing and sintering operation contain voids. These voids can be substantially eliminated by subsequent severe working and heat-treatment, but ' such practice has not proved economical in most applications. By applying heat during the compressing operation, plastic deformation of the powder particles is substantially increased, and the resultant compact or briquette is practically free of voids. However, hot-pressing has many attendant problems, which at present preclude its use in the manufacture of precision parts. The more important of these are to devise: 1. A die steel capable of withstanding high pressures at elevated temperatures. 2. A high-temperature lubricant capable of preventing excessive die wear and welding of the compact to the die walls. 3. A method of retaining a neutral or reducing atmosphere in the compacting zone of the die assembly. 4. A means of ejecting the hot-pressed specimen into a neutral atmosphere until reasonably cold.

Jan 1, 1946

By C. A. Herbert

WITHIN the past few years, considerable development has been made in the coal-mining industry in Illinois and Indiana and it is the purpose of the authors to record its most important phases. Perhaps the two most striking features are the entry into the producing fields of certain large consumers of coal and the magnitude of some of the new operations. Mines are now being equipped by the. Chicago & Northwestern R. R., the Chicago,. Burlington & Quincy R. R., the Standard Oil Co., of Indiana, and the Union Electric Light & Power Co. of St. Louis. Besides, the U. S. Steel Corpn. has increased its coal-mining activities by commencing operations on its large holdings northeast of Benton, Franklin Co., Ill. Until recent years, the supply of coal has commonly been adequate and prices have generally been favorable, especially to large consumers, as the magnitude of their purchases enabled them to obtain satisfactory quotations from producers. In fact, most consumers of coal have believed that they could buy their fuel more satisfactorily in the open market than they could produce it themselves. The entry of the United States into the war was accompanied by various disarrangements of industrial conditions, and a demand for coal in excess of the supply seemed likely to be experienced for an indefinite period. Under these circumstances it seemed that the greatest assurance of a supply of fuel was its production by the operation of mines. In the case of the Chicago & Northwestern R. R. and the U. S. Steel Corpn. the production of coal has been carried on for many years with satisfactory results, but the C. B. & Q. R. R., the Union Electric Light & Power Co. and the Standard Oil Co. of Indiana had not been producers of coal, at least in this district. Apparently the most impressive feature of the newest mines is their capacity, for in some cases it is planned that production shall be in the neighborhood of 1000 tons per hr. There are mine, now in this field having nearly that output, but these were not planned for such

Jan 9, 1919

By M. B. Ramachandra Rao

THIS paper records the results of the earth resistivity surveys made in the Godavari river in connection with the Ramapadasagar project. After describing the topographical and geological features of the area, the results of the investigation at the several sites have been mentioned. Further, a detailed account has been given of the resistivity methods adopted, the apparatus used and the interpretation of the curves. The resistivity measurements carried out over the water course have been specially outlined, and a review of the verification of the electrical indications by drilling in a number of cases, has also been presented.

Jan 1, 1947

By D. O. Ehrenburg

DURING the earlier period of electrical prospecting, the search for orebodies was by far the most important application of this method of geophysical prospecting. In the past few years, however, increasing attention has been paid to the possibilities of this method in the investigation of subsurface structures. Not only have fault zones been located, but attempts have been made to determine the depth to certain strata and thus contouring on some bed which proves to be a good "electrical marker." Many workers have published the results of field tests showing how their particular interpretations have agreed with the actual field conditions, but very few have stated their method of interpretation. Weaver, Hummel and Stefanesco and Schlumberger1 have given a more theoretical discussion of the resistivity methods. Hummel and Stefanesco and Schlumberger have published mathematical solutions for the flow of electricity in a medium involving four layers. In this paper the authors present a solution for the flow of electricity in a medium of any number of horizontal strata. By means of this solution, curves showing the relationship between the apparent resistivity and the electrode spacing can be computed for ideal cases.

Jan 1, 1931

By R. W. Smith, R. W. Lai

Very recently there has been a quickening of research effort in the field of silicate mineral flotation, particularly as regards the flotation of beryl.' These studies have already contributed much to the understanding of both anionic and cat-ionic flotation of silicates. Of particular interest concerning anionic flotation has been the work done on heavy metal activation of silicates by M. C. Fuerstenau and co-workers.4,7 In addition. in the paper by Fuerstenau, Rice, Somasundaran and Fuerstenau7 attention was paid to low pH anionic flotation of beryl in the absence of activators. This subject was also covered in the papers by Avotins,3

Jan 1, 1967

By G. K. Manning, C. H. Lorig

TWO metallurgical tools have acquired wide use within the past several years as a means of studying the transformation characteristics of steel. One is a technique used first by Bain and Davenport for determining the transformation characteristics of a steel at constant temperature; the second is the end-quench hardenability test. Constant-temperature transformation curves like those of Bain and Davenport have done much to rationalize the metallography of steel; however, in commercial practices, constant-temperature transformation is seldom encountered, therefore only rarely can such curves be directly applied. The real reason for the determination of such curves lies in the fact that they provide a way of thinking about transformation that is both convenient and productive. The end-quench hardenability test is a more practical means of studying transformation, for, by correlating positions on the hardenability bar with shapes of different masses, an almost direct application of the results can be made. Unfortunately, the end-quench test, though practical, can do very little toward improving the metallurgists' way of thinking about transformation. These two metallurgical tools, dealing with precisely the same phenomenon, should be very closely associated in metallurgists' minds. Actually, they are frequently pushed into separate mental corners and considered as being more or less distinct and unrelated. The reason for this is that no strong connecting link between them has been developed. An attempt is sometimes made to relate these two tools by projecting the critical cooling rate on the isothermal transformation plot as illustrated in Fig. I. The critical cooling rate is considered as a constant rate-though in practical applications, cooling rates are never constant—and this constant cooling rate is given uniform significance from the Ae temperature down to the temperature of initial transformation. A little thought indicates the errors of such a procedure. Certainly the time interval spent just below point A of Fig. I cannot be as effective in promoting nucleation as is the time interval spent just above point B. Yet the procedure represented in Fig. I considers all the time spent between temperatures A and B to be just as effective in promoting nucleation as though all the time were spent at temperature B. Furthermore, change the shape of the isothermal curve between points B and C in any way desired, and the required critical cooling rate is not changed one iota. This cannot possibly be true. Such a way of thinking about critical cooling rates not only is incapable of giving any results that are quantitatively satisfactory but is likely to give very misleading qualitative results.

Jan 1, 1947

By G. K. Manning, C. H. Lorig

TWO metallurgical tools have acquired wide use within the past several years as a means of studying the transformation characteristics of steel. One is a technique used first by Bain and Davenport for determining the transformation characteristics of a steel at constant temperature; the second is the end-quench hardenability test. Constant-temperature transformation curves like those of Bain and Davenport have done much to rationalize the metallography of steel; however, in commercial practices, constant-temperature transformation is seldom encountered, therefore only rarely can such curves be directly applied. The real reason for the determination of such curves lies in the fact that they provide a way of thinking about transformation that is both convenient and productive. The end-quench hardenability test is a more practical means of studying transformation, for, by correlating positions on the hardenability bar with shapes of different masses, an almost direct application of the results can be made. Unfortunately, the end-quench test, though practical, can do very little toward improving the metallurgists' way of thinking about transformation. These two metallurgical tools, dealing with precisely the same phenomenon, should be very closely associated in metallurgists' minds. Actually, they are frequently pushed into separate mental corners and considered as being more or less distinct and unrelated. The reason for this is that no strong connecting link between them has been developed. An attempt is sometimes made to relate these two tools by projecting the critical cooling rate on the isothermal transformation plot as illustrated in Fig. I. The critical cooling rate is considered as a constant rate-though in practical applications, cooling rates are never constant—and this constant cooling rate is given uniform significance from the Ae temperature down to the temperature of initial transformation. A little thought indicates the errors of such a procedure. Certainly the time interval spent just below point A of Fig. I cannot be as effective in promoting nucleation as is the time interval spent just above point B. Yet the procedure represented in Fig. I considers all the time spent between temperatures A and B to be just as effective in promoting nucleation as though all the time were spent at temperature B. Furthermore, change the shape of the isothermal curve between points B and C in any way desired, and the required critical cooling rate is not changed one iota. This cannot possibly be true. Such a way of thinking about critical cooling rates not only is incapable of giving any results that are quantitatively satisfactory but is likely to give very misleading qualitative results.

Jan 1, 1947

By H. M. Chance

Within the last 10 years the subject of mine taxation in its relation to coal-mining interests has come to have growing importance, not only to those engaged in the mining of coal, but also to the owners of land underlain by coal.

Jan 1, 1915

NEW MEMBERS The following list comprises the names of those persons who became members during the period of Apr. 10, 1918, to May 10, 1918. BALLARD, JOHN I Supt., Cable Mining Corpn., Cable, Mont. BURKMAN, JOHN M. F., Constr. Engr., U. S. Smelt. Refin. & Min. Co., Care -University Club, Mexico City, D. F. CALLEN, ALFRED COPELAND, Head, Mining Engineering Dept., West Virginia University Morgantown, W. Va. CHADWICK, LAWRENCE, Chem., Mt. Elliott Copper Co., Ltd., Selwyn, via Townsville, North Queensland, Australia. CODY, FRANK W., Skimmer, Reverberatory Furnace, Arizona Copper Co., Clifton, Ariz. COOLBAUGH, MELVILLE F., Prof. of Chem., Colorado School of Mines, Golden, Colo. DODGE, ALLAN WAYNE The Dodge Agency, 104 East Iron Ave., Salina, bans. DONNELLY, LEONARD G., Pet. Geol., Sinclair Oil & Gas Co., Sinclair Bldg., Tulsa, Okla.

Jan 6, 1918

By William E. Ford, Edward Salisbury Dana

The NATIVE ELEMENTS are divided into the two distinct sections of the Metals and the Non-metals, and these are connected by the transition class of the Semi-metals. The distinction between them as regards physical characters and chemical relations has already been given (Art. 453). The only non-metals present among minerals are carbon, sulphur, and selenium; the last, in one of its allotropic forms, is closely related to the semi-metal tellurium. The native semi-metals form a distinct group by themselves, since all crystallize in the rhombohedra1 class of the hexagonal system with a fundamental angle differing only a few degrees from 90°, as shown in the following list :

Jan 1, 1922

By A. W. Ross, William Marsh Baldwin, T. S. Howald

The related subjects of preferred orientation, directionality in physical properties, and earing tendencies of wrought metal strip have attracted the attention of metallurgists to such an extent that in the past 20 years hundreds of researches have been published on this one general problem. The anisotropy of tensile strength and elongation have been exhaustively studied in their relationship to the occurrence of ears in cups drawn from strip'-~O.~g and, to a lesser extent: yield strength7."-l7 and stress-strain curves'5 have been investigated. Despite the tremendous fund of knowledge thus accrued, no simple quantitative correlation of directionality and earing tendencies has yet been found. In a sense, this is not surprising. The formation of ears in a drawn cup clearly is a special phase of the general study of metal flow; in particular (as will be brought out in the course of this paper), ears are due to anistropy in the rates of deformation of the metal in the radial, circumferential, and "thickness" directions of the original blank. It would be difficult to effect a correlation between caring tendency and a property that may be completely independent of the flow of metal, or at best related to metal flow in an exceedingly complex fashion. Yet, it is this correlation that has been attempted; tensile strength and elongation are attributes of metal rupture. a phenomenon that has quite admirably been shown to be distinct from the phenomenon of metal flow,21 while yield strength and stress-strain

Jan 1, 1946

By J. O. Lewis, Carl H. Beal

Introduction ............................... 492 Theories Relating to the Recovery of Oil.................. 493 Methods Commonly Employed for the Estimation of Future Production..... 495 Saturation Method........................... 495 Production Curve Method....................... 496 Production per Acre Method.....................: 496 Appraisal Curves.............................. 498 Derivation and Construction...................... 498 Comparison of Appraisal Curves of the Osage and Nowata Fields...... 505 Use of Appraisal Curves........................ 506 Accuracy of the Apprais?l Curves and Their Sources of Error........ 508 Relation Between Future Productions of Wells of Equal Output....... 510 Use of Appraisal Curves for the Derivation of Generalized Future Decline Curves. 513 Theory of Generalized Curves Showing the Decline in Production...... 513 Suggested Methods for Making Closer Estimates.............. 517 Use of Logarithmic Coordinate Paper.................... 518 Summary................................ 520 Introduction Oil wells usually reach their maximum daily output shortly after they are completed. From that time they decline in production, the rapidity of decline depending on the output of the wells and on other factork governing their productivity. The production curve of a well shows the amount of oil produced per unit of time for several consecutive periods; if the conditions affecting the rate of production are not changed by outside influences, the curve will be fairly regular, and, if projected, will furnish useful knowledge as to the future production of the well. By the aid of this knowledge the value of a property maybe judged, and proper depletion and depreciation charges may be made on' the books of the

Jan 1, 1918

By William Marsh Baldwin, T. S. Howald, A. W. Ross

The related subjects of preferred orientation, directionality in physical properties, and earing tendencies of wrought metal strip have attracted the attention of metallurgists to such an extent that in the past 20 years hundreds of researches have been published on this one general problem. The anisotropy of tensile strength and elongation have been exhaustively studied in their relationship to the occurrence of ears in cups drawn from strip'-~O.~g and, to a lesser extent: yield strength7."-l7 and stress-strain curves'5 have been investigated. Despite the tremendous fund of knowledge thus accrued, no simple quantitative correlation of directionality and earing tendencies has yet been found. In a sense, this is not surprising. The formation of ears in a drawn cup clearly is a special phase of the general study of metal flow; in particular (as will be brought out in the course of this paper), ears are due to anistropy in the rates of deformation of the metal in the radial, circumferential, and "thickness" directions of the original blank. It would be difficult to effect a correlation between caring tendency and a property that may be completely independent of the flow of metal, or at best related to metal flow in an exceedingly complex fashion. Yet, it is this correlation that has been attempted; tensile strength and elongation are attributes of metal rupture. a phenomenon that has quite admirably been shown to be distinct from the phenomenon of metal flow,21 while yield strength and stress-strain

Jan 1, 1946

By A. B. Kinzel

THE demands of the petroleum and chemical industries for steels to be used in pressure vessels and similar structures at artificially low tempera-tures are continually increasing, and the writing of proper specifications with suitable tests becomes increasingly important. Likewise, the selec-tion of suitable steels for such applications is of increasing concern to the metallurgist. It is generally recognized that highly alloyed steels of the austenitic stainless type retain their properties even at very low tempera-tures and represent the best technological solution of the low-temperature steel problem. However, in many instances less expensive carbon or low-alloy steels suitable for service within limited temperature ranges are available. The problem thus becomes one of defining the various factors involved in the production and fabrication of these less expensive steels and determining the temperature ranges in which their properties justify engineering application. Most of the applications involve welded structures, and the heat effect of welding as well as the nature of the weld metal are matters of prime concern. The first problem that the metallurgist faces is the determination of the type of test to be used as a criterion of the performance of the steel in low-temperature service. It has been generally recognized that the static properties of steel as determined in the ordinary tensile test undergo a gradual and relatively slight change as the temperature of test is lowered in the range of current interest; i.e., from room temperature to minus 120° C. It is further generally recognized that the behavior of steel under impact involving notch sensitivity is definitely affected at the lower temperatures. While the major subject of this paper is the effect of grain-refining deoxidizers, of low-alloy additions and of welding on the low-temperature notched-bar impact properties, an inquiry into the general behavior of steel under low-temperature impact testing is included. This is a pertinent portion of the investigation and the results thereof are

Jan 1, 1937

By W. H. Blauvelt

The technical and engineering problems in the manufacture of coke are today the problems of the byproduct oven. Except in a few special localitics, practically no beehive ovens have been built in the United States for the last 5 or 6 years except as renewals of old plants, and during these years the total number of beehive ovens in existence has been steadily falling. On the other hand, the number of byproduct ovens has increased from 4624 in 1911 to a total of about 7660 in operation at the end of 1917; with 2800 building, this makes a total of about 10,460 which will be in operation in 1918, or shortly thereafter. Preliminary Government estimates place the total production of coke for 1917 at 56,600,000 tons, the largest tonnage in the history of the industry. Of this 34,000,000 tons, or 60 per cent., was beehive, and 22,-600,000 tons, or 40 per cent., was byproduct coke. Some time in 1918 the production of byproduct coke should pass the beehive output, and when the byproduct ovens now building are completed the total byproduct capacity will be about 40,000,000 tons of coke per annum, which is over 70 per cent. of the record-breaking total coke production of 1917. The reasons for these changes in the coking industry are familiar to all of us, and need not be discussed here. Improvement in Oven Design Since the byproduct oven was brought to this country from Europe, in 1892, it has been radically improved, and from the point of view of American metallurgical practice it is safe to say that the American ovens arc superior to those of Europe. The points of superiority are mainly those of larger units and larger output per unit, and the greater extent to which labor-saving machinery has been introduced. The increased output is largely due to the use of silica refractory material, which permits higher heats and shorter coking time than are employed in Europe. The modern American oven will carbonize commercially more than 20 tons of coal per day, and contrary to the European idea that slower

Jan 1, 1920

By Ronald W. Utley

INTRODUCTION The ''Do's and Don'ts" of installing equipment in a comminution circuit begin during the study stage of a proposed project, continue through preliminary engineering, detail engineering, procurement, the actual placement of equipment at the job site, and end with turnover to the owner. Equipment supplied for a modern comminution circuit will be high quality, rugged machinery designed according to appropriate manufacturing standards for long hours of trouble-free service. However, certain precautions and procedures must be observed in plant design and layout, equipment handling, installing and servicing in order to obtain optimum performance. This chapter contains general installation "DO'S and Don'ts" for the major equipment in the circuit. •Primary Gyratory Crushers •Rock Breakers (Hammer) •Belt Conveyors •Apron Feeders •Weigh Belt Scales •Secondary Crushers •Vibrating Screens •Grinding Mills •Mill Liners •Open Gear Sets •Speed Reducers •Electric Motors •Cyclones •Slurry Pumps Some questions will not be covered in this chapter, or may not be applicable to the actual equipment purchased, as requirements do vary from manufacturer to manufacturer. Additional specific information can be obtained by contacting the manufacturer's local representative or the factory. All inquiries should be accompanied by the following information: •Unit size and type of equipment •Manufacturer's shop order number (after order placement) •Serial number (after manufacture) DO'S 8 DON'TS FOR INSTALLATION OF ALL COMMINUTION CIRCUIT EQUIPMENT Installation By Design DO obtain tables of weights and clearances from manufacturer. DO obtain WR2 forces from manufacturer to determine that the foundation is adequate. DO determine compression strength of foundation soil and/or rock. DO obtain manufacturer's recommended typical foundation drawings. If substantial alteration to manufacturer's drawings is required, check with the manufacturer before proceeding.

Jan 1, 1982