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Jan 1, 1942

Jan 1, 1949

By Paul Hunt

UP to June, 1923, the Park-Utah mine had shipped about 94,000 tons of a direet-smelting ore of a gross value of $4,200,000, or about $45. a ton. These values were in gold and silver only, although the ore carried small amounts of lead, copper and zinc. Freight, treatment and deductions had averaged $15.40 a ton. At the expiration of the Pittman Silver Act there was in sight about 30,000 tons of a similar ore with a gross value of about $15 a ton in gold and silver, and a large body of partly developed lead-zinc ore of a gross value of about $20 a ton, 40 per cent. of which was represented by the lead-zinc content and the balance by the silver and gold. Mine costs had been high during the life of the Pittman Act, but as a large part of the profits had gone into equipment of the mine and the orebodies were large and had good walls, we knew that mine costs could be greatly reduced. We were therefore faced by the necessity of getting lower freight and smelter rates or of concentrating the ore. We did obtain better freight rates on lower grade ore, and a favorable smelting rate on the small tonnage of siliccous silver-gold ore, but this smelter rate could not be applied to the lead-zinc ore with any profit to ourselves. The Judge mill of the Park City Mining & Smelting Co., with which we were affiliated, was running to capacity; if we built our own mill it ineant a 5-mile freight haul to a satisfactory millsite and a year's delay. Fortunately, the International Sillelting Co. had just inherited a mill at Tooele which, with some changes, was about double the catpscity required for its own ores. Flotation tests were run on Park-Utah ore and a contract entered into with a low base treatment charge per ton, the tariff being largely fixed by the metallurgical deductions. This contract has been admirably calculated so that the miner can follow a lean orenbody to its limit. Such a procedure has no doubt made it difficult for the smelting company at times, but it has resulted in finding ore extensions that otherwise might have been missed, so In the long run it has profited too. A flat rate per ton would have been like mining up to the claim endlines in a great many of the stopes. In order to offer such a contract it can be inferred that the smelting company must have been able to make high reeoveries and high-grade products on a very lean ore.

Jan 1, 1928

Jan 1, 1910

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Jan 1, 1938

Jan 1, 1894

Jan 1, 1893

By S. A. Braley

DRAINAGE water from coal mines is probably the most serious water pollution problem today, varying in importance according to location of the mines and geological structure. Drainage may be either acid or alkaline in character. Acid discharge, the most severely detrimental to a stream, is caused by natural oxidation of the sulfuritic material (FeS2) in the strata associated with the coal seam. Since the acid is the result of a natural reaction the acid water differs because it does not cease with abandonment of the mining operations. There is no known economical method of neutralizing acid mine water or any practical method to prevent oxidation of exposed pyrite. Since production of acid from a mine does not stop when mining stops, the total quantity produced depends entirely upon the excavated areas. The increasing volume of acid water in manv mines has greatly increased operating costs. Pumping is expensive and acid mine waters are destructive of all equipment, especially metals in pumps and piping, and necessitate the use of corrosion-resistant materials. Discharge of the acid mine drainage into streams neutralizes their normal alkalinity, causes them to become acid, and produces an environment unfavorable for aquatic life and unsuited for industrial or domestic use without costly treatment. Mine drainages vary in percentage composition over wide limits, although the usual dissolved substances are ferrous and ferric iron, aluminum, calcium and magnesium sulfates, and lesser amounts of sodium, potassium and manganese sulfates and chlorides. Some alkaline discharges may contain heavy concentrations of iron as iron bicarbonate. These waters may produce iron hydroxide deposits in the receiving stream but do not cause it to become acid. In the extensive literature on acid mine water there appears to be a great deal of confusion about the importance of various components and the methods for their determination. In many instances faulty conclusions have been drawn from use of unsuitable methods of analysis. It is desirable that the factors and terms used in evaluation of analyses of mine waters should be so clearly defined that any interested person could properly appraise any analytical report. Some analysts report complete chemical analyses of mine waters and neglect to record drainage volumes. Others report only a minimum of analytical data after taking no precautions to preserve the original composition of the water during the time elapsing between collection and analysis. Some use methods of analysis intended for so-called pure waters of the potable and boiler water classes. These methods are not applicable to highly buffered waters such as mine water. Probably the most common criteria for evaluation are pH, free acidity, or acidity or alkalinity to methyl orange or methyl red, total acidity or acidity to hot phenol-phthalein, and the sulfate content. If these determinations are made on carelessly collected samples after a few days to weeks standing in warm rooms, they do not in any way represent the character of the water flowing from the mines. It is hoped that a brief discussion of the fundamental value of some of these factors may lead to a bettqr understanding of the need for more careful evaluation of mine water discharges. The term pH is one used by chemists to express relative acidity or alkalinity in terms of concentration of effective hydrogen ion in a solution. It is defined as the negative logarithm of the hydrogen ion concentration or activity in equivalents per liter. pH = logarithm A neutral solution, which is one containing the same number of hydrogen and hydroxyl ions, has a pH of 7. As the hydrogen ions increase and the solution becomes more acid, the pH decreases toward zero; and as the hydroxyl ions increase and the solution becomes more alkaline, the pH approaches 14. When dissolved in water to a dilute solution acids like sulfuric and hydrochloric, commonly known as strong acids, ionize completely, and the pH or hydrogen ion concentration varies with molar concentration of the dissolved acid. However, in high concentrations of such acids, the pH or hydrogen ion concentration is less than the acid concentration because the acid does not completely ionize. In only very dilute solutions does the pH represent the total amount of acid that can be neutralized by an alkali. All ionization reactions are equilibrium reactions. If other chemicals are added to the solution of an acid and the added chemical produces an ion that is the same as one of the ions of the acid, the degree of ionization of the acid is altered and the pH changes to some value that represents the active hydrogen ion of the new solution. Thus if iron sulfate is added to a solution of sulfuric acid the pH increases, since the common sulfate ion suppresses the degree of ionization of the sulfuric acid and decreases the effective hydrogen ion. However, the total acidity of the solution is increased. There are two salts composed of iron and sulfate— ferrous and ferric sulfate. In these salts there is no hydrogen ion that can ionize to give an acid solution, but when they are dissolved in water, the pH is less than 7 and the solution becomes acid. This is caused by a reaction known as hydrolysis and is represented by the equations FeSO4 + 2H2O ? Fe(OH)2 + 2H + SO,: or Fe,(SO,)3 + 6H2O ? 2Fe(OH)3 + 6H+ + 3504 A solution with a total acidity of 5000 ppm according to the first equation will have a pH of 4.40 but one with an acidity of 75 ppm, according to the sec-

Jan 1, 1958

By John Birkinbine

A specimen of brown hematite, taken from an iron-ore mine near Anniston, Alabama, exhibits a metallic streak or thread running throngh it. This specimen having been sent to me, I have no personal knowledge of its occurrence; but Mr. Albert E. Noble

Jan 1, 1895

Jan 1, 1932

Jan 1, 1954

Jan 1, 1936

For the convenience of members who may be traveling from place to place, the Secretary has compiled a list of libraries or other places in the United States and foreign countries where MINING AND METALLURGY or the Transactions may be consulted. This list will be sent to members if they so request.

Jan 1, 1925

"No true conception of the Park City mining district can be obtained without first giving consideration to the part it has played as a consistent producer of mineral wealth. Its position in this regard is almost unique in the annals of a lead silver camp. For over fifty years it has been a continuous producer of lead and silver and for twenty years it has added to the world's supply of zinc. Few camps with its productive history are so little known to the mining fraternity for the reason that its life has never been punctuated by periods of ""boom"" which serve to attract general attention, neither has it been the field of operation for promoters who temporarily focus attention upon their scene of action. Its history is one of legitimate mining operations. These were at first carried on by a number of smaller companies. A period of consolidation followed and at the present time the entire production of the camp is in the hands of two major companies and one smaller company. These are flanked by a number of prospecting properties, which are at this time actively engaged in the search for ores and later events will doubtless put some of them in the producing class.A technical discussion of the ore occurrence and mining operations in the camp will be the subject of a paper to be read before this meeting of the Institute. The mission of this article is to supply a ""Baedeker"" where Baedeker is lacking.The town of Park City is a typical, up-to-date, western mining camp which owes its existence as a town of 4,500 inhabitants solely to the mining industry. The camp is located 7,000 feet above sea level, thirty-two miles east of Salt Lake City. It is situated on the Victory Highway seven miles from its junction with the Lincoln Highway and has the benefit of excellent automobile communication with the metropolis of the state. Both the Denver and Rio Grande and the Union Pacific Railroads give daily train service to the camp and effectively solve the transportation problems of the mining companies."

Jan 1, 1925

By C. A. Schempp

STUDY of the adaptability of Tintic Standard ores to concentration dates back to somewhat before January, 1921, when the chloridizing mill at Harold, Utah, was put into operation. The operation of this mill has been fully covered in the TRANSACTIONS (Vol. 73). The process consisted essentially of a chloridizing roast followed by a percolating leach with a nearly saturated solution of common salt, acidified with sulfuric acid; precipitation of silver on sponge copper, and of copper and lead on tin-plate cuttings. This mill was built to treat the low grade siliceous ores having an average content of

Jan 1, 1933

By R. C. Ruder, C. E. Birchenall

The method of decrease in surface activity was used to determine the rates of diffusion of Co" into cobalt and into nickel. Since the absorption curves for cobalt radiation were quite complex under the conditions of these experiments, the effects of geometry and surface preparation on the diffusion results were investigated. The cobalt self-diffusion coefficients obey the equation DCoco = e-61100/RT cm2 per sec. For dilute cobalt diffusing in nickel, DConi, == 1.46 e-/R' cm2 er sec. AS part of the general program to measure the self-diffusion and dilute-solution diffusion rates of the iron-group metals, the diffusion coefficients of cobalt into cobalt and nickel have been measured using the radioactive isotope Co"'. Self-diffusion studies in iron have been previously reported by Birchenall and Mehl.' The technique of measurement used was the decrease in surface activity method described by Steigman, Shockley, and Nix.' It has been determined that scattering of the measured beta radiation by the specimen matrix is significantly influenced by the condition of the surface and the counting geometry. Accurate diffusion coefficients can be calculated from the activity data provided that the specimens have plane diffusion surfaces and that the absorption properties of the emitted radiation are determined under geometrical conditions duplicating with external absorbers the absorption and scattering in a thin film at the specimen surface as nearly as possible. The cobalt used in this research was originally in the form of hydrogen reduced rondels 99.9+ pct pure. The nickel had been prepared by the carbonyl process and was found by spectrographic analysis to contain 0.03 pct Fe, 0.04 pct Co and smaller traces of other metallic elements for a balance purity of 99.9+ pet Ni. Both materials were vacuum melted and cast in rectangular ingots. Specimens 7/8x7/8x1/4 in. were machined from these ingots. The specimens were then ground to 4-0 emery paper and annealed in hydrogen for at least a day at 1200°C. Some of the specimens were used in preliminary experimentation after which their diffusion faces were machined to remove the radioactive material from the previous diffusion experiments. After grinding, the specimens were polished using an electrolytic lapping technique described by Mazia." This lapping was continued until at least 0.005 in. was removed from the diffusion surface. The final surfaces were metallographically smooth except for a few fine scratches caused by the glass cloth. A large percentage of the area was undisturbed as determined by microscopic examination. The grain diameters of the diffusion specimens varied from 0.1 to 5 mm. There were no effects due to grain boundary diffusion in the experiments

Jan 1, 1952

By W. W. Svendsen, J. F. Hoffmeister, W. C. Larson, R. E. Cozad

The paper presents the background, history, and current development of the retractable core bit for the wireline drilling system. Design criteria, concept development, and system design of the retractable bit system are discussed, including laboratory test results.

Jan 1, 1983

Correspondent. Must be able, by virtue of, connection, to forward; daily ands weekly, reports, outlining, conditions affecting economics of. industries, particularly the metallurgical, and chemical, industries. New. York, City. R-1982. Sales Lubrication. Engineer. Preferably with experience, as chief marines engineer familiar with internal-combustion; engines and, with, automobile trade. Must be good salesman, of goody appearance and be able to meet people. Middle West. Salary $27.00: to start. R71984.

Jan 12, 1919

ASIDE from the John Fritz Medal, in which the Institute participates through its representation on the John Fritz Medal Board, the Institute itself has three major awards to make annually and one special prize for excellence in technical papers, as follows: The Robert W. Hunt Medal and- Prize, The J. E. Johnson, Jr., Award, the James Douglas Medal, and The Lewisohn Platinum Prize to senior members. ROBERT W. HUNT MEDAL AND PRIZE The partners of Robert. W. Hunt established a fund which was presented to the Institute at a fitting ceremony on May 27, 1920, to establish an annual medal and a sum of money to be awarded under the following rules: 1. The award shall consist of two prizes; first of a gold medal, second of a sum of money; a certificate to accompany each prize. The money prize shall not be awarded to a member over 40 years of age, but under unusual circumstances, both prizes may be allotted to one person provided that he is not over 40 years of age. In general it will be understood that the Committee shall award the money prize to the younger men, rather than the medal. 2. The awards shall be made not oftener than once a year to that person or persons contributing to the Institute the best on al paper or papers on iron and steel. The scope of the term "iron and steel" shall determined by the sub-committee considering the awards. In general, papers dealing with the practical side of the subject have preference over those dealing with the theoretical side in recognition of the fact that Captain Hunt's main contributions to the industry have been in the improvement of production and quality of material. 3. A sub-committee of three to five, including the Chairman of the Iron and Steel Committee, shall be appointed by the Iron and Steel Committee annually to adjudge the award subject to approval. 4. The awarding committee shall submit its report to the Iron and Steel Committee at its October Meeting, and the award be certified to the Secretary of the Institute in time to permit the presentation to be made at the Annual Meeting of the Institute. 5. The recipient of the award shall be designated "The Hunt Medallist." This prize is administered by the Iron and Steel Committee. J. E. JOHNSON, JR., AWARD This award is made from' the income of a. fund of $3000 donated by Mrs. Margaret Hilles Johnson in memory of her husband, J. E. Johnson, Jr., who was a prominent engineer, author of two valuable volumes on iron blast-furnace construction and practise, vice-chairman of the Institute's Iron and Steel Committee, and a frequent contributor of papers. to the Institute's Transactions. This prize is administered by the Iron and Steel Committee. The intent of the donor is to encourage young men in creative work in branches of the metallurgy or manufacture of pig iron with which the professional activities of Mr. Johnson were chiefly concerned. The control of the fund and distribution of the awards having been vested in the Board of Directors of the Institute, this Board has made the following regulations concerning it:

Jan 1, 1925

By J. L. Gregg

A STUDY of copper and silver base alloys was made with the object of finding, if possible, useful alloys subject to dispersion hardening. These studies led to the discovery of several alloys showing considerable dispersion hardening, the most important of which, the alloys of copper with iron, nickel, cobalt and chromium silicides, have since been very ably reported by M. G. Corson.1 This paper is offered as a few notes covering alloys other than those described by Corson and some further data on the silicide alloys.

Jan 1, 1929