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By William E. Ford, Edward Salisbury Dana

The important BARITE GROUP is the only one among the anhydrous sulphates and chromates. Mascagnite. Ammonium sulphate, (NH4)2S0,. Orthorhomhic. Usrially in crusts and stalactitic forms. p = 1.523. Occurs about volcanoes, as at Etna, Vesuvlus, etc. Taylorite. 5K2SOa.(N&)ySOd. 111 small compact lumps or concretions. From the guano of the Chincha Islands. Thenardite. Anhydrous sodium sulphate, Na2S04. In orthorhombic crystals, pyrarnidal, short prismatic or tabnhr; also as twins (Fig. 384, p. 160). White, to brpwnish. 0 tically +. p = 1.477. Soluble in water. Often observed in connection with salt lates, as on the shores of Lake Balkhash, Central Asia; similarly elsewhere; also in South America in Tarapaca, Chilc. In the United States, forms extensive deposits on the Rio Verde, Aria. In Cal., at Borax Lake, San Bernardino Co. Aphthitaiite. Arranite. Glmerite. (Ii,Na)&O1. Rhombohedral; also massive, in crusts. Color white. From Vesuvius, upon lava; at DouglashaU near Weateregeln, Ger- many, in hloditc; Stassfurt, Germany; Rocalmuto, Sicily.

Jan 1, 1922

TO THE BOARD OF DIRECTORS AND MEMBERS Of THE AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS GENTLEMEN Submitted herewith are the reports of the Treasurer for the year 1947 and the reports of the following standing committees Membership, Admissions, Papers and Publications, MINING AND METALLURGY (Magazine), and Library 75th Anniversary Celebration The founding of the Institute at Wilkes-Barre, Pa, in 1871, vas appropriately commemorated by a three-day Celebration, March 17, 18 and 19, 1947, at The Waldorf-Astoria, in New York City The Celebration had been scheduled for the preceding September but had been postponed, perforce, because of conflict with meetings of the Assembly of the United Nations The Celebration immediately preceded the Annual Meeting which was deferred from the usual February dates The proceedings took the form of a "World Conference on Mineral Resources " More than three thousand people, including eight hundred ladies, participated in the proceedings in one way or another Twenty-eight foreign countries were represented, some of them by five or six individual delegates Likewise, official representatives were designated by fifty institutions of higher learning in the United States A special 820-page Anniversary Volume entitled "Seventy-five Years. of Progress in the Mineral Industry,".(which

Jan 1, 1952

By William Kelly, Frederick Laist

The slow, tedious and costly method of reducing copper matte to metallic copper in the reverberatory furnace, commonly known as the Welsh process, was displaced by the rapid and inexpensive converter process about fifty years ago. The art of refining copper was for many generations a carefully guarded secret among the Welsh furnacemen and was handed down among them from father to son. An attempt was made to apply it at Butte when the smelting of copper ore first started there but it proved too difficult and expensive under local conditions, and until the introduction of the converter process the entire output of copper was shipped to Swansea in the form of high-grade (60 per cent) matte. Before the construction of the Manhes converter, attempts had been made to reduce copper matte in the bessemer steel converter, but these failed, chiefly because the air was blown through the bottom of the vessel. The air holes became clogged with chilled copper as soon as the reduction started. Manhes partially overcame this difficulty by placing the tuyeres in the side of the vessel, some, distance above the bottom, thus allowing space beneath them for the copper to accumulate. Nevertheless the first attempts to operate such a converter at Butte were not successful, as no means had been provided for clearing away obstructions, which formed to some extent in front of the tuyeres. This difficulty was overcome by drilling holes in the outside wall of the air chamber directly opposite the holes in the shell and lining, so that these could be punched

Jan 1, 1934

By H. M. Roche

MAGNETITE is the important iron ore of New Jersey although bog ore, limonite and red hematite were mined in sizable quantity early in the state's min-ing history. The deposits of mag-netite are found in the Highland area in the northern part of the state. These ores outcrop a broad belt 20 miles wide, extending in a northeasterly direction from Phil-lipsburg, on the Delaware River, to Greenwood Lake, at the southern boundary of the state of New York, a distance of 60 miles. The area in which the magnetite is found (see map, Fig. 1) contains 1200 square miles and the center of the area is at Dover, 40 miles west of New York City. In the general area are found 18 parallel ranges or lines of ore deposits. These ranges may be re-garded as mineralized zones in which occur orebodies that are rich enough in magnetite to war-rant mining. Usually a number of the orebodies lie one above the other in the same plane, all dipping and pitching in the same direction. Within the ranges, there may be several parallel orebodies of work-able size. The average strike of the orebodies is N.41° 30' E., with an average dip of 55° southeast and an average pitch of 15 ° to the northeast. Orebodies suitable for mining range from 6 to 100 ft. wide, as measured from foot wall to hanging wall. Their heights, as measured on the dip and normal to the long axis of the orebody, vary from 200 to 3,000 ft. The length along the pitch has never been determined by mining, al-though several of the orebodies have been worked to lengths of 10,000 ft. The grade of the ore as mined today varies from 30 to 60 per cent iron, and the gangue min-erals are chiefly silica, alumina, magnesia, lime and phosphorus.

Jan 1, 1937

By Harold W. Aldrich, Frederick Laist

After a series of experiments covering a period of about three years, extending from the spring of 1912 to the spring of 1915, a 2,000-ton leaching plant for the treatment of the accumulated copper concentrator tailing was built and put into operation. During the experimental period, the first step was that of laboratory experiments or beaker leaches. The results on this small scale were so satisfactory that a small operating plant, capable of handling 5 tons of roasted tailing per day, was installed. Again, the results proved satisfactory and an 80-ton plant was built and operated continuously from August until February, 1913. In this plant, full-sized roasting and leaching units were

Jan 1, 1917

HAVING produced one ton of concentrate that contains the copper that can profitably be saved or recovered from anywhere between 3 and 60 tons of mine ore, the ore-dressing engineer passes the result of his handiwork over to the metallurgist for smelting. Essentially, the concentrate is a damp mass of finely ground material consisting of copper sulphide minerals; pyrite, the sulphide of iron; and gangue, usually silica and silicates of aluminum. The purpose of smelting is to produce metallic copper and a slag containing the iron and siliceous constituents by pyrometallurgy-the kind of metallurgy that employs fire and heat to produce the chemical reactions through which it attains its object. Though blast furnaces have been used to smelt Porphyry-mine concentrates, notably at Braden, more than 90 per cent of [ ]

Jan 1, 1933

By G. St. J. Perrott

During the past year, the Bureau of Mines has carried on an investigation of liquid-oxygen explosives (L.O.X.) to supplement the work described in previous publications.' The present paper gives results of the first part of this work, which was a laboratory investigation of the properties of typical combustibles used in L.O.X., and the relation of these properties to the absorption and retention of oxygen by the explosives and their explosive characteristics. No attempt will be made to describe the development of liquid-oxygen explosives, because this phase of the subject has been well covered.2 The L.O.X. cartridge consists of a paper wrapper filled with an absorbent combustible material that is saturated with liquid oxygen by soaking it therein. After saturation, the cartridge is removed from the liquid and fired with fuse and cap, or electric detonator, in a manner similar to other explosives. Certain types of cartridge may be detonated with fuse alone, requiring no cap to initiate the detonation. ' By suitable variation of the nature and density of the combustible, cartridges having a wide variety of explosive characteristics may be made.

Jan 1, 1925

By R. A. Flinn, John T. Norton

A CONSIDERABLE number of experiments in recent years have definitely established the fact that the internal friction or mechanical hysteresis of a metal under cyclic stress is a property that is highly "structure sensitive." Because of this fact, it has been suggested that an observation of this property, which often is referred to as "damping. capacity," might be a useful indicator of structural. changes taking place when a metal or alloy is subjected to any of a number of metallurgical treatments. Damping capacity is of interest to both engineer and metallurgist, but from a rather different point of view, and the information that each desires from such observations is of a different nature. The metallurgist is in search of various external indications of changes taking place in the interior of a metal; changes which are in themselves not directly observable. Even if the observed phenomenon cannot be explained in fundamental terms, it may be empirically related to certain characteristics of the material and prove of real value in research. Internal friction os mechanical hysteresis occupies such a position, and, although it is nor well understood in terms of basic metallic theory, an observation of itt changes can serve in a very useful capacity. Of course, there is nothing new in the measurement of damping, but the use of this property in metallurgical research constitutes a vast field, which has received all too little attention: The present work is essentially of an exploratory nature in this field and is an attempt to evaluate the process as a research tool. The phenomenon of age-hardening was chosen as a typical example of a structural change and one method of measuring damping was examined in considerable detail.

Jan 1, 1938

By Orson Shepard

TEXTBOOKS on fire assaying list the following standard methods of assaying sulphide ores: (1) scorification, (2) litharge-niter, (3) soda-iron, (4) roasting, (5) combination wet and fire. The litharge-niter method has proved the most satisfactory, and is the usual method for assaying sulphide ores and concentrates. It gives good results when suitably conducted and when lead buttons of uniform size are produced so that the cupellation temperature can be properly controlled. The main objection to the method is the inconvenience of determining the amount of niter to add to each assay charge to produce lead buttons of suitable size from a set of fusions. For the assay of different materials, the niter requirement varies with the particular sulphide minerals present, the amount of sulphide minerals present, the slag composition, and the rate of heating the charge in the furnace. Except for some materials, so uniform in composition that the same amount of niter can be used in assaying all samples, the amount of niter must be determined for each sample to be assayed. This is done by either: (1) calculation from an estimate of the kind and amount of sul-phide minerals present in the sample, or (2) a preliminary fusion. Some assayers use one method and some the other. The estimation method takes the least time; but much experience is required to obtain close estimates on a wide variety of materials. At best, the sizes of the lead buttons obtained vary considerably. The preliminary fusion method usually gives lead buttons of fairly uniform size, although sometimes there is a variation because the oxidizing power of niter varies a little with the charge. This variation can be eliminated by two preliminary fusions: one to determine the reducing power of the ore, and the other to determine the oxidizing power of niter in the charge. The objection to the prelimi-nary fusion is the extra time and expense involved.

Jan 1, 1939

By John V. Beall

Given: One large, but dated open-pit copper mine and processing plants, down about one third in production capacity in decade because of declining ore grade. Solve for: Restoration of former peak capacity without further losses during period of reconstruction. That is the problem that Kennecott's Utah Cop- per Division began solving in 1963. Most of the work went to a task force of engineers, several of whom were plucked out of line jobs and assigned to the so-called "Expansion Project" for the duration. There was no doubt from the beginning that effective cooperation between Expansion Project engineers and operators was critical to success, and personnel was chosen accordingly. This foresight paid off. The Expansion Project is all but complete, and the Utah Copper Division is returning to its rated capacity of 300,000 tons per year of copper metal.

Jan 6, 1967

By R. L. Stephenson

IN plants casting electric-furnace ingots and converting them immediately into blooms, billets, slabs, bars or forgings, the criterion of quality performance is the soundness of the semifinished or finished product. When rejections are necessary, it is not always obvious whether the defects were caused by an unsound ingot or by improper treatment during the heating and forming operations. To evaluate the effects of the numerous factors involved, it is necessary to accumulate a large number of detailed observations and to analyze and interpret these data properly. Even after a thorough investigation has been conducted, it is impossible, in some cases, to isolate the cause of the defect and say that it is definitely the result of an unsound condition in the ingot or mistreatment of the ingot during further processing. Two factors that are extremely difficult to evaluate are the chemical composition of the steel and time from finish pour to charge in the soaking pits or "track time," and it is necessary to evaluate their combined effects before many other factors can be studied. Plain carbon, fine-grained steel in the range of 0.18 to 0.23 pct carbon, is very susceptible to cracking and the longer the elapsed time between the pouring of the ingots and stripping for charging into the soaking pits, the higher the billet rejections for cracks are found to be. Below 0.15 pct carbon and above 0.30 pct the track time

Jan 1, 1947

By Walther Mathesus

INTRODUCTION THE use of high blast heats on furnaces melting Mesaba ores is still the exception, the average blast temperatures carried on Mesaba stacks seldom reaching 1,100° F. Some 15 years ago, when the use of fine Mesaba ores in larger proportions to the total burden first came into practice, it was found difficult to employ even those blast heats which it had been possible to carry with the Old Range ores. The furnaces refused to "take" high heats, and would persistently labor with irregular stock movement, which impaired the practice and increased the coke consumption. By lowering the blast temperature, the working of the furnace became smoother, and experience taught that with the softer and more easily reduced Mesaba ores, satisfactory practice could be obtained with comparatively low blast heats. Therefore a large number of Mesaba furnaces have ever since been operated on very low blast temperatures, ranging between 800° and 1,000° F. In the face of these difficulties, furnace men were slow to recognize that furnaces could be so designed as to permit a free movement of the charges in combination with the use of higher heats. Since higher blast temperatures did not seem to offer great advantages in the smelting of Mesaba ores, investments in hot-blast stoves were not as attractive to the furnace man as labor-saving devices and means of obtaining greater tonnages. The effect of this preference is keenly felt at the present time. It has brought about the peculiar situation, that the majority of our furnace plants (among them some of the most progressive) lack modern and efficient stove equipment. The result is that, even where the proper furnace lines have been adopted and conditions are now favorable to the successful employment of higher blast temperatures, the heats required for the greatest fuel economy are not available.

Jan 3, 1915

By J. L. W. Birkinbine

This paper is a discussion of a part of the mineral wealth of the States of Oaxaca and Paebla, Mexico. It does not refer to the precious metals, sonie mines of which, in these States, are said to have been worked before the advent of the Spanish conquistadores in the sixteenth century, as my purpose is to invite attention to the exploration of deposits of coal and iron-ores in the Mixteca region. The prominence given to coal is warranted by the great effect of the scarcity of fuel upon the industrial development of Mexico. Under the progressive administration of President Porfirio Diaz, the Republic has made wonderful advances in the past three decades; and this progress would have been greater but for the limitations imposed by expensive fuel. In the spring of 1906 I was detailed by the Birkinbine Engineering Offices, of Philadelphia, to accompany A. B. Adams, of New York, in a reconnoissance of reported deposits of iron-ores in the State of Oaxaca. The result of this expedition was the formation, in 1907, of the Oaxaca Iron & Coal Co., of which Mr. Adams became, and has remained, President and General Manager, and I have spent the past three years as Chief Engineer of this company in Mexico, principally in western Oaxaca, where field-headquarters were established. GEOGRAPHY AND POPULATION. Although the geographical and topographical features of the Republic of Mexico are well known, few realize that the majority of its population is domiciled in the States which immediately surround the capital city of Mexico, including the Federal District, Mexico, Tlaxcala, Morelos, Puebla,

Jan 1, 1911

By Persifor Frazer

A classification of natural objects is usually based either upon some fundamental and permanent attribute of the thing itself (as in the case of scientific classifications), or it embraces one or more generalizations convenient for use in ordinary life. Thus, it suffices for the statistician to know that so many tons of fish are annually taken by our fishermen, and that they realize so many thousands of dollars, whereas to the student of natural history the anatomy, habits, and relationships of the animals are of chief interest, as settling their respective places in the scale of animate nature. Many different classifications of coals have been attempted, as one would naturally anticipate from the immense extent of the coal trade, and the different localities whence the supply was derived. The English divisions were prevalent up to the date of the publication of the last geological survey of the State, except so far as they were modified by local designations. Indeed, Rogers' classifications made very little alteration in the English nomenclature, as may be seen by comparing the tables given below. To commence with the different kinds mentioned in Ure's Dictionary of Arts, Manufactures and Mines of 1845 : " 1. Cubical Coal.—Black, shining, compact, moderately hard and easily frangible. Comes out in rectangular masses, of which the

Jan 1, 1879

Jan 1, 1885

By W. J. Keep

Some explanation of methods of testing will be given before presenting the record of a series of physical tests of aluminum, other metals and alloys. I. The Methods Employed and Meaning of Diagrams. The test-bars used, 12 inches long and 4 inch square, are cast in green sand, with chills bedded in such a way that the ends of the bar run against them. By splitting the ends of the bar the depth of chill can be measured. The chills being held in the mould 121/8 inches apart, the space between the end of the bar and the face of the chill, after both are alike cold, is the amount of shrinkage, and is recorded in thousandths of an inch per foot.

Jan 1, 1890

By E. T. Dumble

In continuation of the geological work begun in Sonora, Mexico, a partial account of which has already been given in the Transactions of the Institute,* a similar reconnaissance was made of Cochise county, Arizona, and a part of the Whetstone mountains. The investigation resulted in the identification of beds of similar age and character to those of the Sonora region, and in the discovery of interesting deposits, which, so far as I call ascertain from the literature at my command, have not been described heretofore. Route.—Starting from Nogales, we followed the railroad to Crittenden, and then drove to the southeastern slope of the Whetstones. After a brief examination of some reported coalbeds we continued our route, following the wagon-road between the Whetstones and the Mustang mountains to Huachuca, and eastward to Tombstone. Crossing the Dragoon mountains at South Pass, we traveled south and west by way of Turquoise and Antelope Spring into the road from Tombstone to Bisbee. Our route over the Mule mountains lay through Mule Pass and Bisbee, where we stopped a day or two. Thence, crossing Sulphur Spring valley, we drove around the southern end of the Swisshelms, and N. through the valley between these mountains and the Chiricahuas, to White river. From that point our way led through Rucker canon into the San Simon valley, then northward along the eastern face of the Chiricahuas, and by way of Fort Bowie to Willcox, Arizona, from which place we returned to Nogales. It was greatly regretted that the extremely wet weather prevented us from including in our examination the Huachuca

Jan 1, 1902

By C. DeWitt Smith

"It just looks like everything is doing fine but humans," wrote Will Rogers fifty years ago. "Animals are having a great year, grass was never higher, flowers were never more in bloom, trees are throwing out an abundance of shade for us to loaf under. Everything the Lord has a hand in is going great, but the minute you notice anything that is in any way under the supervision of man, why, it's cockeyed." Do these words from two generations ago apply to oil shale? The United States has been blessed with deposits that can yield synthetic crude oil at a cost competitive with natural crude oil-under present economic conditions and with existing technology. Yet, the oil shale program is cockeyed because of the artificial obstacles that have been placed in its path "under the supervision of man." But more about this later. For the moment, let's focus on...

Jan 10, 1974

By John J. Porter

The requirements of the standard specifications under which Portland cement is sold have materially increased within the past 10 years, but practically all companies are now furnishing cement better than these requirements; in some cases exceeding them by nearly 100 per cent. From a sales standpoint, it is desirable to have a product that is uniform to a high degree and free from occasional quality troubles. A failure in quality, even if it affects only a few hundred barrels out of a yearly output of a million or more, is apt to be talked about in the trade and to affect the salability of the entire output. For these reasons, there has recently been great activity along the lines of quality control and improvement; and some of the most interesting problems of the industry are in this field. From the manufacturing standpoint, the quality of cement is chiefly a matter of uniform and proper chemical composition of the raw mix fed to the kilns plus proper burning in the kilns; the fineness to which the cement is ground, the proportions of gypsum, the method of seasoning, and the like are contributory factors. Uniform chemical composition of the raw mix has been one of the most difficult problems to solve. Most plants will use from 1000 to 3000 tons of rock per day and in but few cases is this material as it lies in the quarry even approximately uniform in composition. The problem, then, is to quarry and mix this raw material in such a manner that every handful passing through the kilns will have practically the same analysis as every other handful. To accomplish this purpose there are two methods of preparation: the wet and the dry. In each process, a stone storage is the first requisite of a successful plant. This storage place may handle the stone before or after crushing; its capacity may vary from two to three days' up to several months' supply, but it should be so designed that it can be filled as desired by the chemist and drawn at such points as will give a mixture of the various kinds of stone coming from the quarry and a reasonably uniform material going to the mill. The size of the storage place and the method of handling should be varied according to the nature of the material.

Jan 1, 1925

By W. J. Heck

The need for a better understanding of the effect of fluid pressure on the strength of intact and jointed rock has long been recognized. The behavior of pore fluid pressure was first pointed out by Terzaghi 1 who suggested the application of the effective stress concept to rock and concrete. While the effective stress concept has been used for some time in the design of mass concrete dams, it only recently has been applied to rock. Robinson 2 and Handin et al.3 evaluated the effects of pore pressure on a variety of sedimentary rocks and demonstrated the validity of the concept. Work using pore fluids other than water has been done by Boozer, et al.4 who considered strain rate and temperature as additional variables. According to the effective stress theory, the effective stress, [a], is the difference between the total stress, [a], and the pore pressure, u, and is the controlling factor influencing frictional strength of rock, other parameters remaining constant. Assuming the Mohr-Coulomb failure criteria applies, the shear strength, T, is given by the equation [r=d+ (a-u)tan ¢](1) where [~F], the angle of internal friction, and c, the cohesion intercept of "no load" shear strength, are the effective stress parameters.* Robinson,2 Handin,3 and others have demonstrated that moderately porous sand-

Jan 1, 1972