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By William Carton, Cyril U. Cooledge

BecauSe the rich La Colorada orebody of the Cananea Consolidated Copper Co. does not outcrop at surface, after its discovery (by churn drill) and before mining was begun, a large amount of development work was done to learn the shape and extent of the ore and to provide for economic and effective mining. As these openings progressed, the actual shape of the orebody became known and with this knowledge came the realization that mining this rich and unusual deposit without loss of ore or danger to workmen presented several difficult problems. This paper will describe one of these problems; namely, the handling of an inverted cone-shaped core of barren rock, on the periphery of and below which the ore occurred. It mas clear that as the ore was mined out from around and under this inverted cone of rock, weighing about 3,000,000 tons, it would hang over the workings, held suspended only by its own tensile strength and threatening to crash into the stapes below with disastrous results to men and mine. The method of mining developed during the years 1928,1929 and 1930 anticipated and provided for the eventual collapse of this core of rock. In November 1936 the core settled down gradually on the edges of the stopes, descending a total of about 50 ft. vertically. The men in the stopes had ample warning and no lives were endangered. There were no air blasts in the mine. The core broke loose from its top support at the 500-ft. level along old fracture planes and evidently is crushed to the ninth level. Movement was of short duration; the following shift went to work in the stopes as usual. No ore was lost. Geological Structure The shape of the orebody is illustrated in Fig. 1. The geology of the Colorada orebody has been described by V. D. Perry1 and by W. G.

Jan 1, 1940

By Cyril U. Cooledge, William Carton

BecauSe the rich La Colorada orebody of the Cananea Consolidated Copper Co. does not outcrop at surface, after its discovery (by churn drill) and before mining was begun, a large amount of development work was done to learn the shape and extent of the ore and to provide for economic and effective mining. As these openings progressed, the actual shape of the orebody became known and with this knowledge came the realization that mining this rich and unusual deposit without loss of ore or danger to workmen presented several difficult problems. This paper will describe one of these problems; namely, the handling of an inverted cone-shaped core of barren rock, on the periphery of and below which the ore occurred. It mas clear that as the ore was mined out from around and under this inverted cone of rock, weighing about 3,000,000 tons, it would hang over the workings, held suspended only by its own tensile strength and threatening to crash into the stapes below with disastrous results to men and mine. The method of mining developed during the years 1928,1929 and 1930 anticipated and provided for the eventual collapse of this core of rock. In November 1936 the core settled down gradually on the edges of the stopes, descending a total of about 50 ft. vertically. The men in the stopes had ample warning and no lives were endangered. There were no air blasts in the mine. The core broke loose from its top support at the 500-ft. level along old fracture planes and evidently is crushed to the ninth level. Movement was of short duration; the following shift went to work in the stopes as usual. No ore was lost. Geological Structure The shape of the orebody is illustrated in Fig. 1. The geology of the Colorada orebody has been described by V. D. Perry1 and by W. G.

Jan 1, 1940

By B. G. Reisdorf

This paper describes the microstructural changes that occur when quenched ultrahigh-strength steels containing OA pet C and various amounts of nickel, silicon, and cobalt are tempered. The changes that occur in hardness, yield strength, and martensite diffraction-peak widths when these steels are tempered are related to the precipitation of the carbide phases. An unea$ectedly high silicon content (about 30 pct) was found in the E -carbide phase in a steel containing only 1.5 pct Si. TEMPERED martensitic steels have such wide-spread utility that they have been the subject of numerous investigations, and a sizable amount of literature has developed on this subject.M This investigation, which is a part of a larger program to correlate microstructure with mechanical properties at a variety of strength levels, is limited to the microstructural changes that occur when a quenched 0.40 pct carbon steel (USS Airsteel X-200 steel) is tempered, and to the effects of the alloying elements—nickel, cobalt, and silicon—on these microstructures. Used in this investigation were electron microscopy, electron-diffraction identification of the carbide phases, electron-probe micro-analysis of the carbides, X-ray determinations of retained austenite, and measurements of martensite X-ray diffract ion-peak widths. MATERIALS AND METHODS The chemical analyses of the eight heats examined eats No. 30 through 37) are shown in Table L Heat No. 30 has the chemical com~osition of Airsteel X-200, and the remaining seven heats contain various amounts of nickel, chromium, cobalt, and silicon. The heats were air-melted in an induction furnace and cast into 8 by 8 in. ingots that were subsequently heated to 2300 and rolled to 1-in.-thick plate. Oversize 0.505-in.-diam tensile specimens were rough-machined from the plates and austenitized in air at 1700° F for half an hour and oil-quenched. The specimens were then tempered in air at temperatures of 400° to 1000 for tempering times of 1, 4, and 16 hr, and finish-machined to 0.505-in.-diam tensile specimens. Electron micrographs were prepared from Formvar replicas of the midthickness of tensile-specimen shanks that had been electrolytically polished and etched in nital. Electron-diffraction patterns were obtained from carbon-extraction replicas. The replicas were prepared by etching the sample surface in the same manner as for microscopy, evaporating carbon on the etched surface, and re-etching the sample to free the carbon film and the precipitate particles. Electron-probe microanalysis was performed on some of the extraction replicas. To obtain adequate fluorescent X-ray intensities, several thicknesses of replica were exposed to the electron beam so that the results represent an average composition of the extracted particles rather than an analysis of single precipitate particles. The retained austenite contents of the specimens were determined by an empirical X-ray diffraction

Jan 1, 1963

By C. C. CONCANNON

POTASH is an essential. It is necessary as an ingredient in fertilizers or as a plant food, and certainly one of the great problems, and one of increasing gravity, is the maintenance of agricultural fertility that we may have adequate food supplies. When one thinks of potash one thinks of Germany. The first and most important deposits of soluble potash salts were found in Germany, and it was through Ger- man research and the application of a highly developed knowledge of chemistry that the value of these deposits was recognized and appreciated in the field of agricultural fertilization. The Germans knew that they had something of great value in their potash resources, not only because of the advantage derived from the extensive use of it in their own intensive farming operations at home, but also because of the pressing need for it on the part of other countries. Appreciating the economic value of this in international trade, they fostered the industry to the fullest extent and devoted much attention to well organized propaganda designed to bring out the essential need for potash of German origin throughout the world. Thus every one came to believe that potash was an essential commodity of only German origin and as such it held an extraordinary position in world trade prior to 1914.

Jan 1, 1926

The papers presented at the International Congress, held in San Francisco, Cal., Sept. 20 to 25, 1915, are published in 11 volumes of Transactions. In addition, an index volume is published, containing .besides the author and title index, a report of the business meetings of the Congress, and a brief digest of each paper presented. The following is a schedule of the volumes: Index and Digest.-General proceedings, indexes and digests. Vol. I. Panama Canal. II. Waterways and Irrigation. III. Municipal Engineering. IV. Railway Engineering. V. Materials of Engineering Construction. VI. Mechanical Engineering. VII. Electrical Engineering and Hydro-electric Power Development. VIII. Mining Engineering. IX. Metallurgy. X. Naval Architecture and Marine Engineering. XI. Miscellaneous. Aeronautics; Refrigeration; Agricultural Engineering; Engineering Education; Heating and Ventilation. Remember the New York Meeting, Feb. 14 to 17, 1916.

Jan 12, 1915

By H. Q. Golder

INTRODUCTION The stabilization of slopes is not a design problem. A slope is designed before it is made. For a slope to be stabilized it must already exist. The basic problem has existed for a long time. It started with cuts in soil and rock made in the 18th century during the construction of the canals which were developed at that time, and continued into the 19th century with the development of the railways, and in the 20th century with motor roads and lately open pit mining. It is not difficult to stabilize a slope, but certain questions must be asked and answered. These are: i) How much stability is required? ii) For how long is it required? iii) How important is the cost? These three questions indicate the basic problem of Civil Engineering, which is that the solution to any problem is a compromise between safety, cost and time. Stabilization of slopes is no exception. If the slope exists why is stabilization a problem? There are many possible reasons, for instance, a neighbouring and similar slope may have failed, or it may be necessary to change the conditions of the slope, steepen it, increase its height, put weight at the top, or construct a building at the foot in which case added security is required, or guarantee its stability for a longer time. MECHANISM OF FAILURE In order to pick the correct method of stabilization the mechanism of failure must be understood and the immediate cause of failure known. Often to remove the cause is the best remedy. The mechanism of failure has been studied over a period of many years in landslide problems. Pit slope failures are very similar to some types of landslides. (1) (2) (3) (4) In one sense there are many causes of landslides. Terzaghi lists 19. This means that there cannot be a standard solution to a stabilization problem. In another sense, it can be said that there is only one cause, which is gravity. This is a constant, never failing force which cannot be

Jan 1, 1971

By Benjamin C. Craft

A review of development in North Louisiana during 1936 centers around the Rodessa field, in Caddo Parish. Continued extension of the

Jan 1, 1937

By WALTER S.

(New York Meeting, February, 1912,) THE earliest example of attempting to form finely-divided materials into larger masses for better adaptation to commercial use was probably the briquetting of peat and lignite-waste at Paris by the use of a clay binder. It was from this attempt that our word briquette has arisen (Fr. la brique), the formed masses being shaped similar to ordinary bricks. This term does not, however, lend itself to the many shapes of such formed material as are now being produced, as few of them aside from some of the European brown-coal products bear any resemblance to the shape of that well-known article. The term "agglomeration " has therefore been chosen as more accurately descriptive of the products now being manufactured, this term including the molding as well as the sintering. With the increasing prices of fuel and ores and the greater demand for economy in the operation of industrial plants, more ,attention has been paid in recent years to the utilization of waste products and low-grade ores and fuels. Much of the waste has been occasioned by the inability to utilize finely ,divided ores and fuels in the furnaces because they could not be kept there, or else because they clogged up the furnace-shaft so that gases could not be forced through under ordinary conditions of operation. As a result, all such fines were thrown on the dump. Again, with the exhaustion of the richer deposits of ores, concentration of lower-grade ores becomes a necessity, and most concentrates are produced in a finely-divided condition. Aside from these considerations, there is also the economy in the cost of operating the plant; a furnace running on agglomerated material will have a much greater output than one working on fines. In one instance the charge of an iron blast-furnace was changed from fine concentrates to briquettes and the output was increased four-fold; better results could have been obtained had facilities been at hand for taking care of the increased output.

May 1, 1912

By S. F. Emmons

Br far the greater number of the members of this Institute are men who are engaged in the strenuous work of the technical part of their profession, and find little time for the abstract scientific work which is less distinctly practical and pecuniarily emunerative. There is, however, a small but increasingly numerous class whose members devote themselves to broad geological problems which underlie the systematic development, and whose work, theoretically, ought to precede and form a basis of that of their more practical brethren. These are the so-called mining or economic geologists, who are, for the most part, connected with State or National geological surveys. From the character of their work, the life of these men necessarily follows rather different line's than that of most of their colleagues, and is not generally familiar to them. It seems admissible, therefore, that to the life of a prominent member of this class, who died during the past year, having literally sacrified his life to his work, a more extended notice should be given than the relatively small number of his contributions to the Transactions might seem to justify. George Romans Eldridge, son of Ellery and Sarah (Mathews) Eldridge, was born on Cape Cod at Yarmouth, Mass., Christmas day, 1854. His boyhood education in the public school at Yarmouth was followed by a six years' course in the Public Latin School at Boston, from which lie entered Harvard Uni¬versity in 1872, being graduated with the highest rank in his class in the natural sciences in 1876. During his college course he spent the summers of 1875-6 at Cumberland Gap, Ky., as volunteer aid to Prof. N. S. Shaler, who was then in charge of the State Geological Survey of Ken¬tucky. This vacation work, undertaken by him rather as a pastime, gave him his first leaning toward geology. Soon

Mar 1, 1906

By Raymond B. Ladoo

TIIe milling of talc, as is the case with many non-metallic minerals, until recently, has not received adequate technical consideration, for the talc industry has become of importance only within the last decade. At first, talc was used only in the massive form, for foot warmers, griddles, and so on, and milling methods were unnecessary. As the demand for ground talc increased, producers adopted the machinery used in the milling of flour; in fact, many talc mills were rebuilt flour mills. Improvement has been slow, but today several types of grinding and separating machinery are in use; many of them, however, are still inadequate and inefficient. To determine the best methods of milling talc, it is necessary to understand the essential properties a talc must possess to fit it for a particular use. For toilet purposes, whiteness, freedom from lime and grit, fineness of grain, and good "slip" are essential. As a paper filler or coating, the talc must be white, uniform, and fine grained, have a good slip, and be free from grit and iron; freedom from lime is a disputed point. Fibrous talc is supposed to be superior to massive on account of the interlocking of grains in the paper, thus increasing its strength; this point, though, is in doubt. In general, talc for the paper industry need not be of as high quality or as fine grained as that used for toilet purposes. Talc is usually bought by sample, for which reason it is difficult to state the essential properties for use in paint, rubber, roofing, and so on. The adoption of standard screen tests and standard grades by producers is necessary before an accurate basis for manufacturing or selling standards can be established. Off-color talcs might be utilized, as in Germany and Austria, by the establishment of standard grades of colored talcs. The machinery to be used depends on whether the talc is fibrous, foliated, or massive; hard or soft; of uniform or variable grade; pure or impure. In some cases, it is possible to change the mining practice or to utilize different sections of the deposit in order to vary some of these factors, but in many cases these factors are fixed, so the milling must be designed to suit the conditions.

Jan 1, 1922

By A. H. Larson, L. G. Twidwell

The influence which Au, Ag, Sb, Bi, Sn, and Cu have, both individually and collectively, on the activity coefficient of sulfur in liquid lead at 600"C zuas studied by circulating a H2S-Hz gas wlixture over a specific lead alloy until equilibrium was attained. Subsequently, the H2S concentration in the equilibrium gas mixture and sulfur concentration in the condensed phase were deterruined. The elements gold, silver, and antinzony (above 8 at. pct) increased the activity coefficient of sulfur. Bismuth had no apparent effect. Tin (above 3 at. pct) and copper decreased the coefficient. The influence of an individual element, i, on sulfur is best reported as the interaction parameter, riS, which is defined as The values o these first-order interaction zus are: ESzu = —55.0. These interaction parameters are used to predict the activity coefficient of sulfur in six fouv-component alloys and one seven-component alloy. Comparisons are made with direct experimental determinations. INTERACTIONS in dilute solution have been studied by many investigators. Most of the experimental work has been confined to solute-solvent interactions in simple binary systems and solute-solute interactions in ternary systems. Dealy and pehlke"~ have summarized the available literature on activity coefficients at infinite dilution in nonferrous binary alloys and have calculated from published data the values for interaction parameters in dilute nonferrous alloys. Interaction parameters are a convenient means of summarizing the effect of one solute species on another in a given solvent. Only a few investigators have studied interactions of the nonmetallic element sulfur in a metallic solvent. They are as follows: Rosenqvist,~ sulfur in silver; Rosenqvist and Cox,4 sulfur in steel; chipman, sulfur in alloy steels; Alcock and Richardson,% ulfur in copper alloys; Cheng and Alcock,' sulfur in iron, cobalt, and nickel; Cheng and ~lcock,' sulfur in lead and tin. The only reported work on the Pb-S system in the dilute-solution region is that of Cheng and Alcock.' Their investigation involved a study of the solubility of sulfur in liquid lead over the temperature range 500" to 680°C. The results may be summarized by the following relationship: S (dissolved in lead) + Pb(1) = PbS(s) log at. %S = -3388/T + 3.511 Experimentally, it was found that Henry's law was valid up to the solubility limit of sulfur in lead, i.e., at 600°C up to 0.43 pct. Their investigation did not include the study of sulfur in lead alloys. More accurate calculations could be made in smelting and refining systems if activity coefficients of solute species could be accurately predicted in complex solutions. One of the objectives of this study was to compare the experimental data with the values calculated from the equations derived from models for dilute solutions proposed by wagner9 and Alcock and Richardson. A temperature of 600°C was chosen as the experimental temperature to attain reasonable reaction rates and to minimize volatilization of the condensed phase. EXPERIMENTAL Materials. The Pb, Au, Ag, Sb, Bi, Sn, and Cu used for preparation of the alloys were American Smelting and Refining Co. research-grade materials. All were 99.999+ pct purity except the antimony and tin which were 99.99+ pct. The initial alloys prepared for this study consisted of twenty-one binary alloys, eleven ternary alloys, and one six-component alloy. The constituent elements were mixed for each desired alloy and were placed in a crucible machined from spectrographically pure graphite. The crucible was placed in a vycor tube which was evacuated with a vacuum pump and gettered by titanium sponge at 800°C for 8 to 12 hr. After the gettering was completed, the chamber containing the titanium was sealed and removed. The remaining sample chamber was placed in a tube furnace at 800°C for 2 hr and quenched in cold water. The final operation consisted of homogenization of the alloy for 1 to 2 weeks at a temperature just below the solidus for the individual system. The resulting master alloys were sectioned into small pieces and a random choice made for individual equilibrations. Cobalt sulfide (Cogs8) used to control the gas atmosphere in the circulation system was prepared by passing dried HzS for 24 hr over a Co-S mixture heated to 700°C in a tube furnace. This material was then mixed with cobalt metal to give a two-phase mixture which, when heated in hydrogen to a particular temperature, produced a desired H2S/H2 gas atmosphere in the circulation system. A Cu2S-Cu mixture also used in this study was prepared in a comparable manner. Apparatus for Equilibrium Measurements. The experimental technique of this study required apparatus

Jan 1, 1967

By AIME AIME

L H. DUSCHAK gave an interesting talk at a recent meeting of the. San Francisco Section, based -011 experimental work with a variety of ores at the laborator of the Treadwell-Yukon Co., in Berkeley, Cal. He was of the opinion that the customary "cut and try" method of flotation testing was still in evidence and that the flotation process was more of an art than an exact science. Propounded theories have enabled investigators to' classify reagents as well as to suggest new ideas both in the metallic and nonmetallic fields, but the application of theory has riot as yet been able to solve many of the unknown factors in operation.

Jan 1, 1932

By N. H. Emmons

(Canal Zone Meeting, November, 1910.) AN interesting development of copper blast-furnace construction has been brought about in adapting the blast-furnace to be a "burner" for sulphuric acid making. When the Tennessee Copper Co. first decided to construct an acid-plant, the standard type of brick-top furnace, supported by structural steel, was the only one in use at this plant. All the tests for temperature and strength of gas had been made on these furnaces, and had been satisfactory. When, however, the acid-plant was put on the flue, and the flue had to have a damper put in it to force the gas into that plant, troubles began. The furnaces were fairly tight, and for a few months the work was quite satisfactory., Fig. 1 shows the old type of furnace-top used at the start. It was soon found that this top would not stand the temperatures, particularly when dampered back, as was necessary to force the gas into the Glover towers. The structural steel, of which the furnace skeleton was constructed, warped and twisted so badly that it was not safe to use the furnaces. This effect is shown by Fig. 2, which is a photograph of old No. 4 furnace, after the brick-work had been removed. It became apparent that a new type of top was necessary and the engineering force was started oil the design of a new furnace-top, with the result that a low top, with brick-lined flues at each end below the feed-floor, leading to the main concrete dust-chamber, was constructed. This furnace, No. 7, is shown in Fig. 3. The charging-doors are made of cast-iron sections, three sections to a door, and three doors to a side. A door to the furnace was made of cast copper, but the heat was so great that the copper bent readily, due to the jarring of its * General Manager, Tennessee Copper Co.

Feb 1, 1911

By KENNETH CROPPER

USUALLY we forget about the things which move along smoothly. There are no causes for worry when there are no troubles. But when troubles arise we must put forth some thought and effort to alleviate them. No one "worries about his automobile until it begins to knock, develop flat tires, or refuses to start. However, when these ailments become apparent we get wide awake on the spot, and do our best to repair the car. So we find ourselves now. The old bus seems to hit all the ditches. There is rough ground on all sides and none of us is able to do anything toward improvement. A state of pessimism stares us in the face, and there is sufficient cause for it. With lead at 3.75 cents, copper about 8 cents, zinc under 4 cents, -and silver about 26 cents, one has a reason for grief. When we think of the 5000 or less men employed in Utah mines and smelters in 1931, as compared with about 12,000 in 1929, the calamity seems even worse. In view of the present economic crisis we cannot even think of new men getting a job.

Jan 1, 1931

By C. K. Leith

THE outstanding fact of the mineral world today, at home and abroad, is the surplus of current production, and particularly of capacity for production, over current requirements. This is not by Any means a new condition, but never before has it loomed up in such' menacing form. - Those of us who have devoted most of our professional efforts to the discovery and development of 'new mineral supplies now suddenly find ourselves with the job apparently accomplished, waiting for some one else to find an outlet for excess mineral production before we can further. The management of the industry is in much the same boat. The psjrcho16gy of the industry has been so grooved in the direction of acquisition of, minerals that at the present moment the mineral industry confronts the new problem of surplus in more or less of a daze.

Jan 1, 1931

By WILLIAM WATERS

L HISTORY. THE Pierrefitte mines, situated in the South of France, in the district of the Hautes-Pyrenees, owe their name to the fact that the first mining operations of any extent, and of comparatively recent date, were carried out in the neighborhood of the vil¬lage of Pierrefitte, which is a branch terminus of the Midi railway. The Pierrefitte mines, however, embrace a wide extent of country and several different concessions, on most of which comparatively little exploration-work has been done. The portion of the property presently to be described is a zone running roughly E-W., over a distance of about 5 miles from the valley of Cauterets to the valley of Estaing, the ridge dividing these valleys being a spur of the main chain of the Pyrenees, and running more or less at right angles to it. According to local tradition, which various indications tend to confirm, these mines are of ancient date, the first workings being attributed to the Romans, who are supposed to have sought not only the lead but also the silver which is contained in the ore. Old slags have been found in the neighborhood which might well have been produced from the cupellation of lead-ores. These old workings, while of considerable extent at times, do not seem to have extended beyond a depth of 100 ft., even this depth being somewhat exceptional. The old notarial records of the district show that mines were known to exist, and that they were even worked, in the sixteenth century, but since the mines were abandoned (by the Romans or others) considerably prior to this period, very little

Nov 1, 1908

By Francis Cameron

Mining is both exciting and rewarding-although at times somewhat frustrating-and we all can have real pride in our industry, in its people, and in its accomplishments. It is, however, with concern that I have noted a deterioration in this Country in what might be called mining's stature and in the growth of a belief in many quarters that our mineral reserves are rapidly approaching exhaustion. In other words, there is a popular image that we are fast becoming a "have not" nation in many respects and that the domestic mining industry can no longer be considered, in the vernacular of Wall Street, to offer much in the way of "growth potential." I do not subscribe to this hypothesis, nor do I believe that the record of the mining industry bears this out. However, let me add that we can, in time, talk ourselves into this frame of mind and we can hasten the day when this very well might come about by unnecessary and unwise legislation or regulation. My remarks today are basically designed to give my reasons for refuting this negative philosophy and to review our record. With your help, I know we can improve our image, and the public's recognition of our industry's peculiar problems.

Jan 4, 1968

By George C. Coupland

Ecstall Mining Limited, a wholly owned subsidiary of Texas Gulf Sulphur Company, is the owner and operator of the Kidd Creek Mine including the concentrator complex located near Timmins, Ontario. Canada, approximately 450 miles north of Toronto. The mine, concentrator and Timmins form a triangular arrangement with a 17-mile rail link connecting the mine and concentrator and both of these facilities 18 and 14 miles respectively by road from Timmins. A core drilling program in the spring of 1964 established the presence of a large massive sulphide orebody which was to become the Kidd Creek Mine. Texas Gulf Sulphur had been conducting an intensive search for base metal in various parts of Northern Ontario and Quebec since 1957. Of several thousand anomalies detected in airborne electromagnetic surveys, several hundred warranted ground inspection, but only one of more than sixty drilled became a commercial orebody, the Kidd Creek Mine. The geophysical exploration work has been well covered in a paper written and presented by Van Donohoo, presently a Vice-President of T.G.S., at the American Mining Congress in San Francisco in October 1969. GEOLOGY The orebody lies within a series of overturned rhyolitic flows and pyroelastics with a major peridotite intrusive to the east. The hangingwall and footwall are composed chiefly of intermediate volcanics, andesite and dacite. The southern end of the orebody appears to terminate abruptly against greywacke while the north end is bifurcated and the structure obscured.

Jan 1, 1970

Jan 1, 1923

Jan 1, 1923