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By C. M. Haight

THE mine blacksmith and drill-steel sharpening shop at the Franklin mine of the New Jersey Zinc Co. is on the surface, adjoining the main shaft. It is a brick building, 51 by 30 ft. inside dimensions, with a corrugated iron roof and concrete floor. About two-thirds of the steels used are brought up through the main shaft; the remainder through two auxiliary shafts. The latter are carried to the shop by team or truck. At each shaft sufficiently large stocks of sharp drills of various types are kept to replace all the dull steels that may be sent up; while at the shop enough sharp drills are kept to replace the dull steels in the stocks kept at the auxiliary shafts. Though this entails keeping a larger number of drill steels in service than might be required by other methods, there is less hurry in the sharpening shop and the steels have a longer period of rest. If a rest from use enables steel to recover from fatigue strains, this method secures that rest. The forms shown in Fig. 1 are supplied to each shift boss in books of 100. These are used to requisition sharp drills from the shaft stocks and enable the men at the tops of the shafts to sort out the required sizes and to have them ready to be sent to the various shaft stations. At one of the auxiliary shafts, the dull drills are placed on a platform from which they are dumped into the body of the wagon that takes them to the shop.

Jan 2, 1926

The thirty-ninth meeting of the Boston Section was held at the Engi- neers? Club on Monday evening, Dec. 4, 1916. Thirty-three members and guests sat down to dinner; There were present as section guests; Dr. L. D. Ricketts, and Prof. Bradley Stoughton, President and Secretary of the parent society, and each was called upon to speak. Mr. Stoughton spoke of the growth of the Institute during the past year and described the very numerous and important activities, of which the junction of the American Society of Civil Engineers with the other three societies is perhaps the most important. Dr. Ricketts, the advertised speaker of the evening, spoke on Recent Progress in Mining and Metallurgy of Copper Ores. In discussing the improvements in mining, he traced the mining methods from square- set mining to the modified Ohio System now so successfully used at Inspiration: In metallurgy, he described the growth of reverberatory-smelting ant1 allied problems such as the utilization of the waste heat for generating steam. He laid stress on the importance of sampling and bedding of

Jan 6, 1917

By A. L. Holley

It has been customary at our opening sessions, for the presiding officer to address you on the general development of one or another of our several professions, or upon some important feature of Mining or Metallurgical Engineering. It is somewhat embarrassing to his successor that our former President, Dr. Raymond, expert as he is in every one of these professions, has been accustomed to keep them all, in their turn, prominently before yon. In selecting for this occasion a subject necessarily connected with iron and steel, I have thought that a review of these manufactures, with reference to some of their more pressing needs for improvement, will be more timely than a general or statistical paper. I shall endeavor to confine my remarks to a few specific defects of practice and management, and to their equally specific and more or less developed remedies. That serious defects exist; that they must be remedied ; that the manufacture is indeed already on the verge of transition, will be generally admitted. But it cannot be revolutionized all at once, however desirable the technical results might he, for that would bankrupt the business at large. We cannot afford to pull down and rebuild all our blast-furnaces that do not make a ton of pig iron with 25 cwt. of fuel; nor to replace all our hand-puddling furnaces with revolving ones, even if we could select the best revolver. Although the soft steels promise to supplant iron for most structural purposes, there are neither money nor present market to warrant all at once replacing our iron works, or half of them, with steel works. Since, then, these manufactures can neither stand still nor be suddenly metamorphosed, their managers are saying to one another: " We must feel our way into larger development; we must work gradually into better practice; we must improve a little at a time."

By L. C. Graton

The federal taxes on incomes and excess profits are of course heavy. In 1917, the value of the mineral production of the United States was a little in excess of $5,000,000,000. The total of federal taxes for that year, for the mineral producing companies, as computed by themselves, amounts, according to tentative compilations, to about $207,000,000, and the total for the comprehensive group of mineral and metal industries to about $766,000,000, which figures represent respectively 9.5 per cent. and 35.1 per cent. of the total tax paid by all corporations. Because of greater complexities in applying the revenue laws to mineral properties than to most other industries, opportunity is afforded for wide differences of view. The taxes indicated above, therefore, are not final and may conceivably be very materially increased. For 1918, the taxes are expected to be still greater, but no compilations are yet available. Taxes at a high rate are to continue indefinitely. The subject is clearly of gravest import to the mining industry in particular. The Commissioner of Internal Revenue, who is charged by law with the administration and collection of the taxes, is determined that these functions shall be performed in a just and businesslike way. Fairness and finality are to be the chief objectives. In view of the peculiar conditions that attach to the tax program as applied to mines and other wasting industries, like oil, gas, and timber, the Commissioner has resorted to professional advice and assistance by manning a Sub-division of Natural Resources with competent engineers, brought in from the several industries, into whose hands he has placed for solution the technical questions involved. These engineers have a two-fold duty: (1) to devote to the solution of these problems their own knowledge and experience; (2) through their acquaintance with their respective industries, and with the men engaged in those industries, to focus upon these problems, by conferences and otherwise, the best opinion of the country. The principal object of this paper is to acquaint the mining profession with the attitude of the

Jan 1, 1923

By L. C. Graton

The federal taxes on incomes and excess profits are of course heavy. In 1917, the value of the mineral production of the United States was a little in excess of $5,000,000,000. The total of federal taxes for that year, for the mineral producing companies, as computed by themselves, amounts, according to tentative compilations, to about $207,000,000, and the total for the comprehensive group of mineral and metal industries to about $766,000,000, which figures represent respectively 9.5 per cent. and 35.1 per cent. of the total tax paid by all corporations. Because of greater complexities in applying the revenue laws to mineral properties than to most other industries, opportunity is afforded for wide differences of view. The taxes indicated above, therefore, are not final and may conceivably be very materially increased. For 1918, the taxes are expected to be still greater, but no compilations are yet available. Taxes at a high rate are to continue indefinitely. The subject is clearly of gravest import to the mining industry in particular. The Commissioner of Internal Revenue, who is charged by law with the administration and collection of the taxes, is determined that these functions shall be performed in a just and businesslike way. Fairness and finality are to be the chief objectives. In view of the peculiar conditions that attach to the tax program as applied to mines and other wasting industries, like oil, gas, and timber, the Commissioner has resorted to professional advice and assistance by manning a Sub-division of Natural Resources with competent engineers, brought in from the several industries, into whose hands he has placed for solution the technical questions involved. These engineers have a two-fold duty: (1) to devote to the solution of these problems their own knowledge and experience; (2) through their acquaintance with their respective industries, and with the men engaged in those industries, to focus upon these problems, by conferences and otherwise, the best opinion of the country. The principal object of this paper is to acquaint the mining profession with the attitude of the

Jan 1, 1923

By R. Stanford

In any discussion of steel pouring too often refractories quality assumes a high level of importance. Unfortunately when one considers the many and varied conditions to which pouring refractories are exposed, it is difficult to isolate the true role of refractories quality alone. Some of the more important, yet often overlooked, variable conditions bearing on pouring performance are heat size, tap time and temperature, steel chemistry, ladle additions, ladle height and preheat, mechanical conditions of the pouring mechanism, hot top or non hot topped ingots and, ingot size, which determine total number of shutoffs, direct or tundish pouring, ingot filling rates, metallurgical demands, etc, etc. These considerations apply for either conventional or slide gate pouring of ingots and, to a large extent, even strand casting. In any event probably the most significant factor on pouring performance in any individual shop is what is considered an "OK" pour. We find considerable variance in this qualification, not only between Republic Steel meltshops, but throughout the industry. Therefore, it is a worthless exercise to draw comparisons attributable to refractories quality alone, except for similar conditions in a single shop.

Jan 1, 1972

To the Members It has been, and is the endeavor of the A. I. M. E. to serve each and every member. One of the means of letting the membership know what is going on in the mining; metallurgical and chemical fields, and by far the most important, has been our monthly Bulletin. To publish this costs money, and to partly defray the costs, it was decided to accept such advertising as could be secured. The A. I. M. E. is the only one of the American National engineering societies whose dues are as low as $10 per year, and it actually spends more upon the Bulletin and Transactions than the sun total it receives for clues. Hence the need of advertising revenues. We are planning even greater improvements for your Bulletin-improvements that will help you in your work. It will mean a better publication, with more information than ever before. To successfully carry out our plans, we must have your co-operation. We are not asking you for financial, but for your moral support. With that we shall accomplish a great deal. What we ask of you, brother member, is to give evidence to those patronizing our advertising pages, that you not only read the editorial pages, but the advertising section as well, and that you have in mind the welfare of your Institute by consulting the advertising pages when in the market for equipment. Do you realize that if you mention your Bulletin when writing advertisers or purchasing supplies, that not only would your publication secure more advertising, but better satisfy present advertisers. We have reason to know that our advertisers secure business as a result of our publication, but they demand some evidence that you see their advertisement. Unfortunately, our members do not as a rule mention where they saw the advertisement, and as a consequence advertisers have no means of knowing whether their investment in the Bulletin is paying. The A. I. M. E. Bulletin can be made the best advertising medium in the mining, metallurgical and chemical fields, simply by each member doing his bit. It is very little to ask of you, and the returns to the mining industry will be enormous.

Jan 9, 1915

By Henry Louis

The object of the present paper is to call attention briefly to a novel method of analyzing the action of the ordinary gravity stamp, which has not only thrown much light upon the exact motion of the stamp-head, but promises also to be of value in determining the efficiency of a new mill before setting it to its work of crushing, and in this respect should be of service to constructors of mining machinery as well as to mining engineers. The method was devised by Mr. D. B. Morison, and developed in connection with his experiments on the comparative crushing-effects of his patent high-speed stamp and the ordinary cam-stamp, which were carried out at the works of Messrs. L. Richardson & Sons, Engineers, Hartlepool, and on which he read a paper at Newcastle in 1897.* Mr. Morison's experiments were of a very exhaustive nature; and having been consulted by him during his investigations, I had frequent opportunities of examining the methods employed and the results obtained. Experiments were first made with an apparatus resembling the indicntor of a steam-engine, inasniuch as the drum revolved alternately backwards and forwards, thus producing a closed diagram. This form was not found satisfactory, and it was therefore altered so as to cause the drum to revolve continuously in one direction, thus giving a continuous or open diagram. The arrangement is shown in plan in Fig. 1; a collar, A, surrounds the stamp-stem loosely and works between the guides B, B, which constrain it to move in a vertical line only. Immediately above it and below it, a couple of collars are clamped to the stamp-stem, so that the latter, while free to revolve,

Jan 1, 1899

By W. C. Phalen

SALT-MAKING PROCESSES THE production of salt in the United States divides itself at the outset into two distinct classes: (1) The mining of rock salt and its purification and separation into marketable sizes, and (2) the production of salt by evaporation from brines, bitterns, and other solutions. The processes employed at the present time in the manufacture of salt by evaporation may be outlined as follows: 1. Solar evaporation. 2. Direct-heat evaporation (a) in open kettles; (b) in open pans. 3. Steam evaporation, (a) in jacketed kettles, (b) in grainers. 4. Vacuum-pan evaporation. In this paper only the solar-evaporation processes practised in different parts of the United States will be described. SOLAR EVAPORATION Localities In the Eastern States the solar-evaporation process is not generally employed for climatic reasons. In the Western States, particularly in California and Utah, the great bulk of the salt produced originates in the solar-evaporation process. Of the Eastern States producing salt, this process, so far as the writer is aware, is employed in New York State only.

Jan 9, 1914

By David L. Rife

Fluid inclusions have been studied since the mid-1800s. In 1858, the famous English geologist H. C. Sorby, stated that ". . . there is no necessary connection between the size of an object and the value of a fact, and that, though the objects [inclusions] ... are minute, the conclusions to be derived from the facts are great."' This statement philosophically emphasizes why fluid inclusions should be studied. Fluid inclusions supply the economic geologist with "hard" data on the chemical environment and mechanisms of transport for ore fluids. Such studies enable geologists to understand more about their complex nature. The information that can be obtained from fluid inclusions is as follows: 1) Fluid inclusion "filling temperatures" measured with the microscope heating stage, reflect the hotness of an ore fluid at the time of its entrapment and are one of the most accurate methods of geologic thermometry. 2) Ore fluid densities indicate the extent to which ground water becomes mixed with ore fluids. Density is determined from the composition of inclusions, the ratios of gas to liquid (at room temperature), and from

Jan 1, 1973

By John D. Sullivan, Edwin J. Rogers, Chester R. Austin

THE problem of making a building unit combining the necessary physical and mechanical properties and good thermal insulation has been foremost in the minds of architects and ceramic and construction engineers for many years. This paper presents the results of studies on thermally expanding shales or clays to produce light-weight cellular products suitable for making building units. An expanded clay block suitable for building purposes should be large enough so that substantial savings may be effected in labor costs in laying the wall. The permeability should be low and it should have sufficiently good "dry-wall" characteristics to permit exposing the exterior surface to the elements, and to permit plastering directly the inside wall surface. The thermal conductivity should be low and the mechanical properties should be adequate. Obviously, a unit possessing satisfactory qualities for constructing an outside wall would be satisfactory for interior walls and for back-up purposes. The results of studies on bloating various shales or clays[t] and the properties of the expanded products are reported. In another paper1 basic factors involved in bloating of clays are discussed. Manufacturers of ceramic products, particularly structural clay, may encounter bloating of the ware during burning, and precautions must be followed to avoid this phenomenon. About 1927 the C. F. Burgess Laboratories, Madison, Wis., while carrying on an investigation for the American Face Brick Research Corporation, conceived the idea of intentionally bloating clay while holding it in a restrained condition, with the hope of producing a unitary cellular mass. Work was carried on until about 1931, when studies were terminated because of business conditions. These studies were continued later by The Western Brick Co., Danville, Ill., which developed a process of "inwardly expansive bloating."2 The major purpose of the latter investigation was to produce back-up tile to compete with concrete blocks made from Haydite or cinder aggregate. Haydite is a light-weight aggregate formed by heating certain clays or shales rapidly in a rotary kiln. While the investigations at the C. F. Burgess Laboratories or at Western Brick Co. were not carried far enough to lead to the commercial production of material for the construction of walls, particularly outside walls, they showed that certain clays could be thermally expanded and that it was possible to produce a material of low permeability with a large percentage of the total voids or cells closed. Commencing in 1939, the Ozark Chemical Co. sponsored a research program at Battelle Memorial Institute for the purpose of determining whether it is technically feasible to make thermally expanded building units, and specifically to get answers to the following questions:

Jan 1, 1942

By George E. Beavers

It is well to understand at once that converter gas is always mixed with copper blast-furnace gas at Copperhill before entering the Glover tower, and, at times, roaster gas is also added along with the converter and blast-furnace gas. Fig. 1 is introduced to show the variations in the sulfur dioxide content of the gas and the ability of the acid-plant operator to control the variations, resulting in a very even grade at the Gay-Lussac tower entrance. The sulfur dioxide content of the gas entering the Gay-Lussac tower must be low and regular to assure low niter consumption. The blast-furnace gas alone is rather uniform as regards sulfur dioxide content and the variations, as shown in Fig. 1, are chiefly caused by converter changes—out for charging, slag pouring, copper pouring, and, of course, the "finish." The combined gas during the converter finish is, at times, almost free of oxygen and the sulfur dioxide content reaches 13.0 per cent. At such times air is added at the Glover tower.

Jan 1, 1934

IN CIRCLES where mining men are wont to fraternize, a statement often heard is: "Yes, I spent six (or two, or ten, or thirty) years down at 'Chuqui.' " This means Chuquicamata, the site in Chile of what in all probability is the world's largest deposit of copper ore. One hears similar remarks regarding Braden and Andes, and, in fact, regarding a score of other big mines in South America, Africa, and elsewhere, but Chuqui seems to lead the others as the locale of engineers who have done a stint in foreign countries. One reason probably is that it is the Anaconda Company's premier foreign operation. Because of its unusual size and the diversity of its operations a great many men are needed. It is a sort of training school for young engineers; but, also, Anaconda has sent down a great many mature members of its big organization for special assignments like metallurgical research or plant construction. Chuquicamata is about 150 miles northeast of Antofagasta, at an elevation of 9,500 ft. It is in an almost rainless desert country where the wind (it is alleged by some) blows most of the time. However, the copper mining entrepreneurs have done their best to make up for what nature has neglected to do in creating a pleasant environment for the people who operate the mines. These include about 160 "foreigners" of whom 86 are from the United States, most of them accompanied by their families. There are 165 Chileans on the staff. Comforts, conveniences, and many luxuries are provided to offset in some measure the disagreeable features of the climate. Nevertheless, as I have implied, engineers at Chuqui generally jump at the chance to become "alumni" when opportunity offers. At the same time, they appear to take pride in their alma mater.

Jan 1, 1957

The opening session* was held in the hall of the Franklin Institute, on Tuesday evening, June 20th, President Holley in the chair. The President introduced Mr. Franklin B. Gowen, who addressed the Institute as follows: Mr. President and Gentlemen : It has been made my pleasant duty to welcome you to the city of Philadelphia, but in so doing I shrink, with some natural reluctance, from appearing before an audience so much better fitted than I am to cope with the subjects which are usually presented to your association, and I can assure you that no trembling neophyte, first venturing within the groves of the Academy, or walking, with sacred reverence, in the gardens of Plato, felt more natural dread at the consequence of his own temerity than I do in appearing before an audience composed of geutlenlen belonging to a scientific society of which I am but too sensible that until now I have been a member only in name. In olden times, upon entering a temple sacred to the worship of any deity, it was customary to lay some offering upon the altar, and, in following this custom, it will be my duty, before entering upon the more pleasant part of the task which is assigned me, to call your attention to a subject with which I have been somewhat familiar, and which is entirely within the scope of your investigations, in the belief that I may throw out some hints or some suggestions of a process that may be fully developed by some of you, and eventually lead to the introduction of that which may be of service to the human race. The satirist who described the philosopher whom he met, as engaged in the process of extracting sunbeams from cucumbers,

By C. S. Corbett

EARLY in the development of every oil field, the operators of relatively large tracts of land must decide upon a spacing plan for the wells to be drilled upon their respective tracts. Usually it is desirable to have a system of regular spacing laid out over the entire tract, making such adjustments as may be necessary near land boundaries. Unless the dip of the producing formation is very steep, the equilateral triangular arrangement is the one most generally preferred, for the very good reason that it gives the maximum amount of drainage area for the wells up to the limit at which mutual drainage interference begins. Assuming that the equilateral triangular pattern is to be used, there still remains to he decided the matter of distance between wells. Many variable factors enter into the problem of proper spacing, some of which are physical and some economic. It is not the purpose of this paper to discuss these factors, as that has been done in several comprehensive articles during the past few years. In the end the decision must be based upon an estimate of the relative importance of various factors which apply to the field in question and to economic conditions in the oil industry at the time the development is getting under way. Even if the best possible spacing distance should be chosen when the problem arises, changing economic conditions and variation in physical conditions in different parts of the field may cause the original choice to become more or less unsatisfactory. Obviously, it is advantageous, once a spacing plan has been adopted, to avoid alteration of it as the field becomes better known or as conditions in the industry change, and yet be able to vary somewhat, the acreage per well in extending the area of development. Or, it may be desired to provide for an ultimate spacing considerably closer than conditions seem to warrant early in the development of the field. With these contingencies in mind, it is of interest to examine the possibilities which the equilateral triangular system affords. Orientation of Coordinate System In this system the well locations may be considered as the inersectionst of three sets of coordinate lines, the lines of each set intersecting those of the other two sets at 60. For convenience in placing such a system

Jan 1, 1930

By Robert H. Richards

In the latter part of December a batch of amalgam was retorted and the tin in the retort uncovered while at a low red heat, and allowed to cool slowly to a temperature more suitable for ladling into moulds. It was then ladled and made what appeared to be nice, white, malleable block tin. On February 15th our attention is called to the fact that the tin is brittle, and on examination we find that the molecular condition of the pigs has changed to the extent of one-half its material. The change shows itself by an enlargement appearing on the surface something like crystallization, and comes in spots. The condition of the metal in these spots is very peculiar. It has changed from a malleable metal to a brittle one, with a structure somewhat resembling stibnite, and a color very considerably darker gray than tin. The analyses of the two parts of this tin pig showed the following results: Mercury. Tin. Specific Gravity. Crystalline part,.....2.62 97.24 6.175 Malleable part,.....2.38 97.50 7.387

Jan 1, 1883

By Alan English

INTRODUCTION During the Bicentennial Year in the United States of America, recognition should be given to the fact that 20 years ago the first large-scale commercial pelletizing plant was started and attained rated capacity. This was the beginning of a new industry. Twenty years ago the total production of pellets was principally from pilot plant facilities and totaled in the thousands of tons per year. At the present time the world production is slightly in excess of 280 million tons per year. This truly is a tremendous growth for any industry. Such a production growth obviously is accompanied by a similar growth pattern in the development of process, equipment, and facilities. During the growth and development period, different materials became more adaptable for processing. For example, initially the pelletizing of iron ores revolved around the magnetite concentrates where the heat of reaction constituted a very important part of the process fuel. During this growth period, specular hematite, earthy hematite, mixtures of hematite and magnetite, and even non-ferrous type materials were pelletized, a function previously thought not practical. The demand for the use of pellets has also broadened their concepts. At first they were made to replace the high-grade iron ores used in blast furnaces. Nowadays, not only have they replaced iron units, but they have had a major influence on the design of larger blast furnaces and have contributed to production rates in excess of 10 000 tons per day from a single furnace. They have also been used in the manufacture of steel, principally for coolants in the BOF practice. More recently, with the improved beneficiation techniques that have been developed over the same period of time, pellets have been used for the direct reduction process and can be used directly

Jan 1, 1977

By B. A. Kulp, R. R. Reeber

Lattice parameters for the wurtzite form of' CdS mere measured by powder X-ray diffraction techniques over the temperature range 26° to 1000 K'. A negative thermal -expansion coefficient was determined parallel and perpendicular to the c axis below 13.5°K. Near 808°K, the curves of the a, parameter, the differential thermal expansion, and the resistivitv vs absolute temperature exhibited a reversible discontinuity. j\. direct determination of the lattice parameters of CdS over an extended temperature range is of particular use in interpretation of the effects of high pressure on the band structure of semiconductor materials. For example, Langer' has studied the effects of pressure on the absorption edge of CdS from 77°K to room temperature. In order to properly interpret his results it is necessary to know the change in lattice constants as a function of temperature for the wurtzite, zincblende, and rocksalt2 modifications of this material. Thermal-expansion measurements for CdS, wurtzite phase, have previously been determined over a limited temperature range.s74'5 The zincblende phases, of other compounds with similar bonding, have been investigated by Novikova et a! .'' Previous thermal-expansion measurements for metals with hexagonal symmetry have for the most part used bulk sample techniques for low-temperature result. Most X-ray measurements at low temperature have been on materials with cubic symmetry.'jQ The use of X-ray powder-diffraction techniques offers a convenient and accurate method of measurement over a wide temperature range. The X-ray method, besides measuring unit cell size, also provides information about change in structure type and the nature of some of the stacking defects present. I) EXPERIMENTAL PROCEDURE The thermal expansion was measured by X-ray powder-diffraction techniques. Lattice parameters for the range 300" to 1000°K were determined in a 19-cm Unicam camera. From 26" to 300°K a 34-cm back-reflection camera with the Van Arkel" film arrangement was used. The sample was bonded to a copper cold finger below a helium, hydrogen, nitrogen, oxygen, dry ice, or ice brine bath in a metal cryistat. che inner bath was surrounded by another one for radiation shielding. Nitrogen was used in this outer bath for the very low-temperature runs while dry ice and acetone was used for the 195°K point. CuKa X-rays, filtered with a nickel foil, entered the cryostat through a 0.001-in.-thick aluminum window. During a typical 9-hr exposure the sample was continuously rotated through a 30-deg arc. Heat losses from the sample holder limited the minimum temperature attained to 26°K with helium in the inner dewar. Temperature calibration between 25" and 125°K was determined with an Allen Bradley 300-ohm carbon resistor. The resistor was attached to the back of the copper finger with a thin layer of silicone grease. Liquid He, HZ, N2, and O2 baths were used to calibrate the resistor. Temperature variation is estimated to be *2"K with a slightly higher uncertainty at room temperature and 264°K. The thermal expansion of high-purity germanium from 373" to 900°K was measured as a calibration for the Unicam camera. This value was compared with the known value1' for the thermal expansion. A discontinuity in the thermal-expansion coefficient of the CdS a, parameter was observed. Similar discontinuities in the resistivity and differential thermal analysis at the same absolute temperature indicate that the temperature error is *5°K in the temperature range above 500°K. Temperature errors in the Unicam camera below 500°K are appreciably higher due to large gradients in the resistance furnace. II) SAMPLE PREPARATION The CdS was Eagle Picher ultrapure grade. The crystallite size range of the as-received powder

Jan 1, 1965

By John Gross

The building of reverberatory furnaces (Fortschaufelungsofen) where ordinary brick, fire-brick and iron are comparatively cheap, is quite a different matter from the building of such furnaces in isolated camps, where proper material is only to be obtained at high cost and with long delays. Time is always a large factor in metallurgical operations, and the metallurgist may find himself in a position where it becomes necessary to erect apparatus and have it running in less time than it would take to obtain material from outside. It is here that he must make use of makeshifts. In Mexico, one of the most important of these is the alluseful adobe. Employed from prehistoric times, it still has its sphere of application in a surprisingly large number of instances requiring an article that can be quickly and cheaply produced. It is quite possible to erect serviceable reverberatory furnaces with no other materials than adobes, stone and wood. The old Mexican smelting shaft-furnace was an example of what can be done with adobes, and the large number of ruins of this class of furnace scattered through the mining districts of Mexico are silent testimony to the genius of a people who demonstrated their capability of adapting material at hand to their needs. The present paper will describe briefly the construction of an adobe reverberatory furnace which is giving good results, can be quickly erected at a low cost, and, if properly built and handled, will last a long time. The material being simply sun-dried, it naturally follows that the construction must be quite heavy. The adobes should be evenly made, with just sufficient straw to hold them together, and not too large in size (9 in. wide, 18 in. long and 4 in. thick

Jan 1, 1902

By John D. Sullivan, Chester R. Austin, Edwin J. Rogers

The problem of making a building unit combining the necessary physical and mechanical properties and good thermal insulation has been foremost in the minds of architects and ceramic and construction engineers for many years. This paper presents the results of studies on thermally expanding shales or clays to produce lightweight cellular products suitable for making building units. An expanded clay block suitable for building purposes should be large enough qo that substantial savings may be effected in labor costs in laying the wall. The permeability should be low and it should have sufficiently good "dry-wall" characteristics to permit exposing the exterior surface to the elements, and to permit plastering directly the inside wall surface. The thermal conductivity should be low and the mechanical properties should be adequate. Obviously, a unit possessing satisfactory qualities for constructing an - outside wall would be satisfactory for interior walls and for back-up purposes. The results of studies on bloating various shales or clays† and the properties of the expanded products are reported. In another paper1 basic factors involved in bloating of clays are discussed. Manufacturers of ceramic products, partitularly structural clay, may encounter bloating of the ware during burning, and precautions must be followed to avoid this phenomenon. About 1927 the C. F. Burgess Laboratories, Madison, Wis., while carrying on an investigation for the American Face Brick Research Corporation, conceived the idea of intentionally bloating clay while holding it in a restrained condition, with the hope of producing a unitary cellular mass. Work was carried on until about 1931, when studies were terminated because of business conditions. These studies were continued later by The Western Brick Co., Danville, Ill., which developed a process of "inwardly expansive bloating."² The major purpose of the latter investigation was to produce back-up tile to compete with concrete blocks made from Haydite or cinder aggregate. Haydite is a light-weight aggregate formed by heating certain clays or shales rapidly in a rotary kiln. While the investigations at the C. F. Burgess Laboratories or at Western Brick Co. were not carried far enough to lead to the commercial production of material for the construction of walls, particularly outside walls, they showed that certain clays could be thermally expanded and that it was possible to produce a material of low permeability with a large percentage of the total voids or cells closed. commencing in 1939, the Ozark Chemical Co. sponsored a research program at Battelle Memorial Institute for the Purpose Of determining whether it is technically feasible to make thermally expanded building units, and specifically to get answers to the following questions:

Jan 1, 1942