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By M. W. Von Bernewitz

AN important regional meeting of the American Institute of Mining and Metallurgical Engineers was held, at Salt Lake City on Aug. 22 to 26, jointly with the fifth annual meeting of the Western Division of the American Mining Congress. The whole meeting was marked by enthusiasm, keen attention to the subjects under discussion, and many renewals of personal contacts. The trips to the various plants were well attended and the local press paid much attention to the meeting. The A. I. M. E. sessions began Aug. 23, with a non-technical morning session. J. 0. Elton, manager for the International Smelting Co., presided. The purpose of this session was to present in a non-technical manner the relation of flotation to mining, smelting, and the State. Ernest Gayford, metallurgist with the General En-gineering Co. of Salt Lake City, gave the definitions of flotation as suggested by Rickard, the dictionary, Weinig, and Taggart. The active agent in flotation is the air bubble, and the two prime requisites are the formation of bubbles and the creation of selective action of the bubbles for metallic particles instead of for gangue particles. Broadly, all the sulfides are floatable minerals, but the oxides, carbonates, silicates and sulfates are not. As far as Utah is concerned, flotation has been one of the greatest means of conserving its natural re-sources, because it has converted millions of tons of waste rock into pay ore; it is recovering millions of pounds of metal formerly lost in tailings; it has con-verted the zinc from a liability into an asset; and has kept thousands of men at work and distributed millions in dividends for the benefit of the State. As to the future of flotation, Mr. Gayford can con-ceive that the next 5 or 10 years may see as much, if not more, advance than was made in the preceding period. The big problem is dressing oxides, carbonates, silicates, and sulfates, and simplification of the number of reagents, also the separation of different gangue min-erals from one another.

Jan 10, 1927

By Wheeler O. North

The United Eastern Mining Co.'s property is in the Oatman, Gold Roads mining district of Mohave County, Ariz. The mine and mill are 26 mi. (41.8 km.) southwest of Kingman, the nearest railway connection. The ore consists of a mixture of calcite and quartz with some andesite. The values, which are mainly gold, alloyed with approximately 34 per cent., by weight, of silver, are extremely fine so that fine grinding is a most important factor in extraction. The milling process, briefly, consists of single-stage, coarse-crushing, two-stage ball milling in cyanide solution, followed by combined mechanical and air agitation, and by straight counter-current decantation. The Merrill zinc-dust precipitation method is used to recover the values, and is preceded by the Crowe vacuum treatment of the solution. The most notable features of the plant are the absence of filters, and the use of short peb mills loaded with steel balls, for fine grinding. As originally designed, the capacity of the mill was to be 200 tons per day, although the grinding end was to be capable of handling double that amount. By adding extra agitators and thickeners and by some alterations to the grinding end, the daily capacity has been raised to 285 tons. This, it is hoped, may be increased to 300 tons during the warm months of the present year. Tonnage Milled per Day 1917 average....... 234; maximum month.... 272; minimum month..... 146 1918 average....... 253; maximum month,... 276; minimum month..... 217 As this article primarily deals with plant operations, those interested in the mechanical description are referred to the article by Mr. Otto Wartenweiler,1 the designing engineer, which gives the details and costs of design and construction. The following changes have been made since that article was published: Two special simplex Dorr classifiers have been substituted for the two duplex Callow screens and bucket elevator, which classified the Marcy discharge and returned the oversize for regrinding. Three Dorr

Jan 1, 1920

By E. C. Harder

BAUXITE is known mainly as the ore from which aluminum is smelted but it has large use also in the manufacture of artificial abrasives and as a basis for certain chemical industries. A small amount is used for refractories and for other purposes. COMPOSITION Dana and others give the mineral formula of bauxite as A1203.2H20 and the composition as A12037 73.9 pct; H2O, 26.1 pct. It has been definitely shown, however, that bauxite does not exist as a specific mineral but rather as a rock. The term is now used synonymously with aluminum ore and it embraces gibbsite (hydrargillite or alpha trihydrate), A1203.3H20 (A12037 65.4 pct; H2O, 34.6 pct); boehmite (alpha mono¬hydrate), A1203.H20(Al203) 85 pct; H2O, 15 pct); diaspore (beta monohydrate), A1203.H2O(A12037 85 pct; H2O, 15 pct), and mixtures in various proportions of any two of them. Bauxite of the Mesozoic and Cenozoic in Europe is predominantly a mixture of gibbsite and boehmite, subordinately a mixture of boehmite and diaspore, or gibbsite and diaspore. The bauxite of North and South America, tropical Africa, Asia, and Australasia consists largely of gibbsite. Corundum (A1203) is not included under bauxite, although gradations from bauxite to emery or corundum exist. All bauxite, irrespective of the aluminum minerals composing it, contains certain impurities, including silica, in the form of clay minerals (kaolinite, halloysite, and others) or quartz, iron oxide (as hematite or goethite), titania (as leucoxene or rutile), iron sulphide (as pyrite or marcasite), iron carbonate (siderite), and calcium carbonate (as calcite); the last three mentioned in minor amount and of local occurrence only. Bauxite belongs to a group of partly consolidated materials called laterites, formed by surface weathering. This group includes also impure siliceous and ferruginous bauxite and siliceous and

Jan 1, 1949

By J. H. McCormick

THIS plant, near Marysville, Mont., was planned to treat the ore from the Piegan and Gloster mines, the latter being one of the early and famous producers of the Marysville district. When the mill was closed in 1888, treatment consisted of stamp milling, followed by pans and settlers for pan amalgamation. The extraction was evidently poor; because, a few years later, thousands of tons of tailings were re-treated by the ranchers in the valley below the mill, by the then new cyanide process, and gave a handsome profit. In 1914, the present owners, after laboratory tests and an experimental mill run, decided upon the following treatment: crushing to 40 mesh in cyanide solution, concentration, amalgamation, classification, and cyanidation of sands by leaching, and of slime by agitation and decantation in charges. The ore averaged about $7 per ton, gold and silver, the ratio of weight being 1 oz. gold to 7.56 oz. silver. The ratio of gold and silver in tailings was 1 oz. Au to 36.6 oz. Ag; the quartz vas sharp and, sandy, however finely ground, and rather difficult to slime. The mechanical 'equipment was a No. 5 Symons gyratory crusher; three 10-ft. Lane slow-speed Chilean mills; one Wilfley roughing and one finishing table; one submerged-type Akins classifier; five 26 by 10-ft. fir leaching tanks; one 24 by 7-ft. Dorr thickener; four 14 by 16-ft. Dorr agitators; four 6-compartment double-row zinc-boxes having compartments 18 in. wide, 18 in. deep, and 34 in. long; Johnson zinc lathe; acid and vacuum filter tanks for treating precipitate; roasting furnace; and Case tilting No. 275 crucible furnace for melting precipitate. The mill is driven by electric power supplied by the Montana Power Co. at the following rates, per kw.-hr.: 200 to 300 hp.,.0.68 c.; 300 to 500 lip., 0.61 c.; 500 to 750 hp., 0.55 c.; plus $1 per month per installed motor horsepower.

Jan 8, 1918

By Howard N. Eavenbon

The low-volatile, or smokeless, coal field of southern West Virginia is in Fayette, Raleigh, Wyoming, Mercer, Summers and McDowell counties, in the extreme southern portion of the state, and extends into the adjacent counties of Tazewell and Buchanan in Virginia. McDowell County is the largest producer, with Fayette and Raleigh counties next. The total area of the field (Fig. 1) is approximately 1600 square miles, or 1,024,000 acres. The percentage of volatile matter in the various seams ranges from 15 to 26 per cent, The upper limit of true low-volatile coal is usually considered to be 23 per cent volatile matter; above this point, the coal usually is classed as medium volatile. This limit will be used in this paper. Geological Position of Seams The smokeless seams are among the oldest coal seams in the country, as the Pocahontas group of rocks is the lowest member of the coal-bearing series and rests on top of the Mauch Chunk red shale, in or below which no coal seams of any importance occur. The Pocahontas group, or Lower Pottsville measures, has a thickness of 750 ft. in southern McDowell County, which decreases to about 350 ft. at Prince, on the New River, in Fayette County, 50 miles to the northeast. In this group, at various points, 12 coal beds have been found, of which 4 have been found in workable thickness and are now being mined. The New River group, or Middle Pottsville measures, is just above the Pocahontas group and varies in thickness from 1300 ft. in southern McDowell County to about 700 ft. along New River. At various places, 16 beds of smokeless coal have been identified in this group, of which 5 have been found in workable thickness and are now being mined. A general columnar section of these strata is shown on Fig. 2. The workable seams in these strata, arranged in geological sequence, are as shown on page 77.

Jan 1, 1932

By Samuel B. Christy

Columbia College has the honor of founding the first well-organized School of Mines in America. The University of Michigan, however, shared with her the honor of graduating the first class, in 1867. Prof. Thomas Egleston was the pioneer in the new movement. He drew up the original plan for the Columbia School of Mines in 1863, and was in 1864 appointed its first professor. The Massachusetts Institute of Technology turned out a class of mining students a year later, and others followed in the order of their first graduating class, as shown in Table I., condensed from the Engineering News of August 11, 1892. Besides those mentioned, mining schools have been organized in the States of Arizona and Nevada, and more or less instruction is advertised in connection with other engineering schools. It will be noticed that Columbia easily heads the list with reference to the number of graduates; the Massachusetts Institute of Technology stands second ; the California University third, and then follow Lehigh, Washington University, the University of Michigan, Lafayette College, Michigan Mining School, Missouri, Colorado and the others. The total number of graduates from these 16 schools in 26 years, has been 871, or an average of 33 per year; but as all these schools give a partial education to many who do not graduate, it is probable that from 2000 to 3000 mining students have received from them considerable training. An interesting comparison of the rate of growth of the engineering schools has been recently instituted by the Engineering News, for the period between 1860 and 1892. Table 11. shows that civil engineering had the advantage in numbers from the start, and maintained the advantage until 2890, when it was surpassed by mechanical engineering. The development of the latter course may be said to date from 1880. There are many interesting facts evident in Table 11. It will

Jan 1, 1894

By D. Argyriades, G. Derge, G. M. Pound

The electrical conductance of molten FeS was studied as a function of temperature and composition. It was found that stoi-chiometric FeS (36.5 pct S) shows a minimum specific conductance of 400 ohm-1 cm-1. For the Fe-rich melts the conductivity increases with increasing amount of iron to about 4850 ohm-1' cm-I at 26 pct sulfur. For the sulfur-rich melts the conductivity increases with increasing amount of sulfur until it reaches a maximum of 1300 ohm1 cm-1 for 37.4 pct S and decreases to 800 ohm-1 cm-1 for 38.3 pct sulfur. It is concluded that molten stoichiometric FeS is an intrinsic semiconductor in which the forbidden gap in the electron energy level diagram is quite narrow. Excess sulfur acts as an acceptor impurity in providing a component of positive hole conduction, while excess iron acts as a donor impurity to increase the n-type conduction. K. Bornemann and G. von Ftauschenplatl used a four-terminal, direct-current cell to study the electrical conductance of molten copper sulfide. Their measurements showed a high conductivity, of the order of 100 ohm-1 cm-" and a positive temperature coefficient. From electrolysis studies, Savelsberg2 concluded that molten Cu2S and molten FeS are electronic conductors. Further. he found that molten FeS has a high specific conductance, of the order of 1500 ohm-' cm-', and a small negative temperature coefficient. Pound, Derge, and Osuch,3 using an ac Kelvin circuit and a four-terminal cell, measured the specific conductance of molten Cu,S, molten FeS, and various mixtures. They found that the specific conductance of the solutions followed a roughly additive rule of mixtures. Yang, Pound, and Derge4 showed from electrolysis measurements that the mechanism of electrical conduction in molten Cu2S, FeS, and mattes is primarily electronic. Further, they observed that small additions of CuCl suppress the electronic conduction whereupon the system behaves ionically.

Jan 1, 1960

CONTENTS PAGE FOGLER, M. F., and QUINN, E. J.-Scratch and Brinell Hardness of Severely Cold-rolled Metals. Discussed by H. S. Rawdon, Carl Benedicks, M. F. Fogler, A. L.Davis 1 GREEN, C. H. Eutectic Patterns in Metallic Alloys. Discussed by Carl Benedicks, Carle R. Hayward, G. E. Dalbey, George F. Comstock, C. H. Green. 3 ARCHER, ROBERT S., and JEFFRIES, ZAY.-New Developments in High-strength Aluminum Alloys. - Discussed by F. B. Coyle, M. F. Fogler, Zay. Jeffries, D. J. McAdam, Jr., Horace C. Knerr, Ernest Schweizer 6 FLICK, FULTON B.-Etching Aluminum and Its Alloys for Macroscopic and Microscopic Examination. Discussed by Samuel Daniels 22. MERICA, PAUL D., and WALTENBERG, R. G.-The Malleability of Nickel. Discussed by H. W. Gillett, Ancel St. John. L. W. McKeehan, A. L. Feild, A. L. Davis 23 ANDERSON, ROBERT J., and NORTON, JOHN T.-X-ray Evidence Versus the Amorphous-metal Hypothesis. Discussed by Zay Jeffries, Chu Phay Yap, Francis B. Foley, H. H. Lester, Edgar C. Bain, Ancel St. John, L. W. McKeehan, Carle R. Hayward, R. P: Heuer, Jerome Alexander, Carl Benedicks 26 COOK, MAURICE, and EVANS, ULICK R.-Recrystallization and Grain Growth in Soft Metals. Discussed by M. F. Fogler 36 POLUSHKIN, E. P.-Determination of Structural Composition of Alloys by a . Metallographic Planimeter. Discussed by H. S. Rawdon 36 BASSETT, WILLIAM H., and DAVIS, C. H.-Corrosion of Copper Alloys in Sea Water. Discussed by W. B. Price, W.. R. Webster, George A. Orrok, A. E. White, William H. Bassett, D. K. Crampton 38, Scratch and Brinell Hardness of Severely Cold-rolled Metals Discussion of the paper of M. F. FOGLER and E. J. QUINN, presented at the New York Meeting, February, 1925, and issued as Paper No. 1395-E with MINING AND METALLURGY, January, 1925. H. S. RAWDON, * Washington, D. C.-We had the privilege of looking over the data just given before they were published and we were not able to suggest any convincing reason for the differences that were secured

Jan 6, 1925

By Albert E. Wiggin, Frederick Laist

Early ill 1914 it was decided to test, on a fairly large scale, the treatment by flotation of Anaconda slime and mill tailing. For this purpose a standard-type Minerals Separation machine was installed at the Washoe Reduction Works during May and June, 1914. This was followed by the installation of a full-size Callow pneumatic machine plant. Experiments were also made, on a smaller scale, with the Froment, the Towne, the Fields, and the Anaconda flotation machines. The last-named machine was developed at this plant. In addition to the tests made in the standard-type Minerals Separation machine some tests were made using a Minerals Separation machine of the sub-aeration type. During the series of experiments a large variety of oils was tested. Experiments were also conducted using both round-table feed and tailing to determine whether it would be better to displace the round tables by flotation for the treatment of the slime, or to supplement the round tables by flotation of the round-table tailing. A series of tests was also made on the treatment of the mill tailing by grinding followed by flotation to determine the relative merits of flotation and leaching for the treatment of this product. In addition, flotation tests were made on mixtures of mill tailing and slime. The round-table feed referred to above is the total slime from the mill. It contains about 35 per cent. colloidal solids and approximately 90 to 95 per cent. of the total solids will pass through 200 mesh (0.067 mm.). It assays from 2.3 to 2.6 per cent. Cu. The mill tailing referred to above is the total discard from the mill, exclusive of the slime. It is all finer than 2 mm. and about 90 to 95 per cent. will remain on 0.25 mm. It assays about 0.60 per cent. Cu. A brief summary of the experimental flotation results follows:

Jan 1, 1917

By C. R. Keyes

Discussion of the paper of C. R. Keyes, presented at the Chattanooga meeting, October, 190S, Bulletin No. 26, February, 1909, pp. 119 to 166. E. R. BUCKLEY, Flat River, Mo. (communication to the Secretary*) :-Some statements in the paper of Mr. Keyes relative to the nature and formation of the Ozark lead- and zinc-deposits seem to me erroneous and misleading, and I respectfully present the following criticisms, placing Mr. Keyes's original statements in quotations. Referring to the Ozark dome: (P. 127.) "It is a region that has been repeatedly upraised and planed off, until in the middle portion the oldest known' rocks only are exposed." Does he mean that the St. Francois mountains, which have always been considered as lying on the eastern flank of the Ozark dome, are the middle of the dome? Or does he mean that the Cambrian rocks of the generally-accepted middle are the oldest known rocks ? Certainly not the latter, and if the former, his idea of the middle of the dome is not in accord with that of others who are familiar with the region. (P. 138.) " . . . the ore-deposits are definitely associated with, or localized by, geologic structures of some kind that .produce in effect basins in which' the underground waters are impounded, or their flow retarded." This statement does not appear to be altogether consistent with the facts, since the ore- bodies of the Joplin district, as the rule, occur in those parts of the Mississippian formation which have a tendency to accel¬erate the flow of ground-water rather than retard it. I might name the open, breeciated ground near Joplin, Webb City, and Oronogo as especially noteworthy illustrations. The ore-bodies, everywhere, occur in positions where there must have been a free and copious circulation of dilute lead- and zinc-solutions in the presence of reducing constituents. The inequalities in the distribution of the ore-deposits are

Oct 1, 1909

By R. W. Metsger

The metamorphic zinc-iron-manganese ore in the Grenvillian rocks of the Reading Prong m Sussex County, N.J. is unique. The singularity of its mineral composition and associations has fueled controversy among economic geologists and mineralogists for more than a hundred years. The silicate-oxide ore, in two synformal concentrations has been mined since about 1838. The Franklin mine was depleted in 1954, while the one at Sterling Hill is still producing. Although the two mines are perhaps best known for their almost three hundred mineral species and have been a mecca for collectors, they -- as importantly -- have provided a window through which to observe more than a billion years of geologic history. When pieced together, studies reveal a sequence of probable sedimentary deposition, intense folding, pseudo- viscous flow with attendant negative diapirism, uplifting, erosion, karstification, hydrothermal alteration, burial, faulting, igneous intrusion, uplift , saprolitization, and glaciation.

Jan 1, 1985

By AIME AIME

THE fifth annual fall meeting of the Petroleum Division of the A. 1. M. E. went down into history as being one of the best ever held by this Division and marked progress was made in the concentration of sentiment regarding several matters-particularly the principles of unit control or operation of oil pools. The first day's program was devoted to the discussion of well spacing and many valuable data were assembled and presented and the discussions following the reading of the different papers was interesting and spirited. However, throughout the whole trend of the discussion it was noted that in the background there was the idea of unit control of the pool and if such a condition could be secured the well spacing theories could be applied much better than could be hoped for if each lease in the pool was treated as a separate and individual unit.

Jan 1, 1929

An extended investigation by the chief engineer of the Bureau of Mines shows that North Dakota has immense beds of lignite. War conditions have stimulated the use of North Dakota lignite until it is now being used at the rate of 1,000,000 tons annually. This North Dakota lignite is coming into extensive local use and considerable of it is being shipped to various parts of the state. The great problem at the present time is to find a market for the gas, which is the principal-by-product of lignite preparation. Bureau of Mines specialists will complete their reports of the studies of lignite in this country and will then make a recommendation as to the lignite field which is best suited for the establishment of the proposed Government's experimental plant. "Broken eggs cannot be mended."-(Lincoln.) Neither can "cashed in" War Saving Stamps grow to their maturity value.

Jan 8, 1919

Members of the American Institute of Mining and Metallurgica Engineers can now secure copies of the Journal of the Institute of Metals of Great Britain at a special price of $5 for the two volumes issued during the year, postage extra amounting to approximately 25 cents. This Journal is one of the best books dealing with the subject of non-ferrous metals and alloys and this arrangement with the Institute of Metals permits our members to take advantage of this specially low price. Back numbers of the Journal can be purchased on the same basis. The Journal can be ordered directly through the office of the Institute of Metals, Great Britain 36 Victoria St., Westminster, S. W. I., London, England. The letter should be accompanied by an international money order and a copy sent to Secretary of the A. I. M. E. in order that the membership record may be checked.

Jan 9, 1919

PICK AND SHOVEL CLUB, CASE SCHOOL OF APPLIED SCIENCE The last meeting of the year of the Pick and Shovel Club of Case School of Applied Science was held on May 20, 1919. The speaker, Dr. Zay Jeffries, gave a very instructive and interesting talk on the Metallography of Non-ferrous Metals. The club has had a very successful year in spite of the loss of a few months time through the S. A. T. C. Among the speakers for the year were Dr. F. R. Van Horn, Dr. C. H. Fulton, and Dr. W. R. Veazey of our school; Dr. E. S. Moore of Penn. State College; Dr. Ansel St. John, of the National Carbon Co.; and Mr. V. S. Bidle, of the W. S. Bidle Co. The graduating members wish the club the best of success for the coming year. BERTRAND R. WARMELING, Secretary.

Jan 7, 1919

R. B. T. KILIANI, Denver, Colo. (written discussion *).-Mr. Len-nox's paper is decidedly interesting in that he shows that a field exists for the Chilean mill, in which its efficiency compares favorably with that of more modern grinding devices. The figures he has given clearly indi-cate that a coarse feed is conducive to higher efficiency than the fine feeds which the Chilean mill has usually been called upon to grind. The fact is also apparently indicated that operating the Chilean mill in closed circuit with a mechanical classifier results in still higher efficiency, and that in such cases the percentage of returns should be kept below 100 per cent. to obtain best results. It would be interesting to see the results of further tests with what Mr. Lennox calls "Mixed Feed," since the data given in Table 4 seems to' point to the fact that a mixed feed,

Jan 12, 1919

If world oil prices stabilize at $ll/bbl, if the US decides on the "accelerated supply" case for domestic fuel resources, if investment capital is available, if environmentalists' demand become reasonable, if land withdrawals are halted, if government grants generous depletion allowances and fast depreciation write-offs, and if many other "iffy" conditions are met-then shale oil production may reach the 1-million-bpd level by 1985, according to the Project Independence Report. In the "base case" scenario, oil shale production would be, at best, about 250,000 bpd at $11 prices, and "much lower if expectations for $7 oil prices prevail." In this regard, the FEA study reflects the conclusion reached by companies engaged in oil shale development work. Thus, except for some new technological breakthrough in mining, the birth and growth of the US oil shale industry will occur only if oil prices stabilize at about $ll/bbl.

Jan 5, 1975

By W. E. Glenn

The years immediately ahead-1961, 1962, 1963- will be critical years from every standpoint for the young engineer. In the next few years, he must learn to grow professionally. Most often, the rate and extent of this growth will be governed by his own initiative and perseverance. Habits and attitudes acquired during these early professional years relate very closely to, and even foreshadow, future accomplishments. The future goal of the young engineer is a moving target. It will change with professional growth, family requirements, changes in predominant interest, general economic and business conditions and geographic location. However ambitious and stead-fast in his goal he may be, the young engineer should not hesitate to adjust or change-for he really does not know initially what he is best fitted for and will not know until he has tried a number of things patiently and persistently.

Jan 1, 1961

By Harry Huntington Miller

In spite of its recognized irregularities, the cyanide-assay for copper has always been popular among volumetric methods, being easy and rapid, and reasonably accurate when the solution tested contains nothing but pure copper and ammonium salts. In order to secure this condition, however, especially in operati~ig on low-grade ores, tailings and slags of complex composition, it is the practice to precipitate the copper from the ore-solution,—usually by means of metallic zinc or aluminum. The copper thus precipitated in the metallic form must be dissolved again; and the separa tion is never, in practice, complete, since an appreciable amount of the copper remains behind in the first solution, and the second solution always contains some of the other metals of the gangue; so that the result is at best but partially satisfactory. On the other hand, if this course is not pursued, but (as is

Jan 1, 1902

By Rafael Errazuriz

About eighty miles north of the city of Antofagasta, Chile, located just below the Tropic of Capricorn, there spreads a wide desert area where copper oxide outcrops can be seen with the naked eye. Numerous old mining works and dump heaps with the green of atacamite and chrisocolla shining in the blazing sun, attest to the work done by miners in the beginning of this century. The dry desert air preserves the footstep marks, paths and trails of old cartwheels from years back. The mining area known as Michilla and Panizos Blancos, is located on the high plateau at 3000 ft above sea level. Around 1920 a Bleichert ropeway was built, which carried ores from the best known mine to a wharf at the Michilla bay. High grade silicious ores were shipped to the Gatico Smelter further north or to smelters in the United States or Japan.

Jan 8, 1973