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By Clintford R. Jones, Om P. Pande

This chapter presents a survey of instrumentation and control systems used on ball mill circuits from the past to the present. It is based on the concept of optimization of plant practice, and addresses the influence of the circuit design on the control strategy and on the instrumentation philosophy. Methods of optimization of the grinding circuit, within the constraints of the mill design requirements, are reviewed. The modern use of automation and circuit optimization is critically reviewed for known and possible conceptual control loops. A comparative study of circuit variations due to instrument hardware, location and installation is provided. Future trends i.e., computer control (DDC) and the effects on both the control stratagems and the optimization stratagems are described.

Jan 1, 1982

By S. A. Braley

DRAINAGE of acid mine water into surface streams of coal mining areas is one of the most serious problems of stream pollution, since there is no known method that completely prevents its forming and no economically feasible treatment after it has formed. The mine acid problem differs from other pollution hazards because acid production does not end with cessation of mining but actually becomes more evident when pumping is stopped. The acid problem in the Pennsylvania, Ohio, West Virginia, and Kentucky bituminous coal areas of the U. S. began with the first operation in 1761, and the volume of acid discharge today is largely the cumulative result of years of mining. Provided they lie above the drainage area, the oldest mines, now long abandoned, are almost without exception producing acid in the same manner as those now operating or recently abandoned. It is well to consider some of the many procedures that have been used to determine the composition

Jan 1, 1957

By S. P. Goplen, M. Henriksen, T. F. Barron

In the past decade, numerous large scale drilling projects have made use of reverse circulation air lift methods. Reverse air lift pumping can be established by injecting gas into a column of liquid; the subsequently decreased density of the gas-liquid mixture allows atmospheric pressure outside the lift conduit to establish flow. The rate of flow can be controlled by varying the gas to liquid ratio. A typical reverse circulation air lift system is depicted in [Fig. 1]. Allen 1 has described a number of reverse air lift drilling projects. Although cited examples are generally related to large diameter holes, the method has seen use in other applications such as sand dredging, chemical pumping, water well pumping. and continuous coring. One particular benefit obtained with enclosed reverse circulation drilling is elimination of lost circulation. The required air/water ratio for pumping at a given submergence and lift has been established experimentally by Gibbs.2 His data, however, do not reflect sensitivity of flow rate to air/water ratio. Further, in Gibbs' work, air apparently is injec-

Jan 1, 1980

By Robert Glass Cleland

BECAUSE of the country's vast mineral resources, Alexander Von Humboldt, the great German scientist who visited Mexico, or the Kingdom of New Spain, a hundred and fifty years ago, very aptly called that country the "Treasure Chest of the World." During the three centuries of Spanish rule, mining was the principal industry of the kingdom, the largest contributor to the country's prosperity, the chief common denominator in Mexican economic life. Public revenues and private fortunes, employment and markets, agriculture and trade, charities and churches, the incentive for frontier settlement and exploration, and the funds for outfitting the expedition of colonizer and conquistador-all were dependent upon the streams of precious metals that flowed century after century from the mines of Guanajuato, Zacatecas, Real del Monte, San Luis Potosi, and scores of other minería that lay scattered everywhere throughout the land. Sonora, one of the oldest and most renowned of the frontier provinces of New Spain, had been the scene of a hundred rich strikes, sudden stampedes, and widely heralded bonanzas long before the famous and frenzied Gold Rush

Jan 1, 1952

ON THIS page is a photograph of a machine that has played a key role in the recent history of Kennecott's Ray mine, situated in the Mineral Creek District, Pinal County, Arizona. It is a huge, rugged, Diesel-powered, rubber-tired truck, having a capacity for carrying fifty tons of ore. It has, to a substantial degree, revolutionized the business of moving broken rock by cutting down both maintenance and operating costs. From 1911 until the end of 1954 Ray had produced 79,000,- 000 tons of ore by underground block-caving. However, in 1947 [ ]

Jan 1, 1957

By Richard D. Snouffer

Prime topics of conversation these days are the new concepts of rail haulage for bulk items such as iron ore, potash and coal. We have heard such ideas as the "integral train" and the "unit train" discussed frequently during the past two years at various AIME meetings, and progress reports have kept up a steady appearance in the technical press and in local newspapers. While no railroad has a complete "unit train" in service at this moment, one has 50 fast-discharge cars under construction and the Pennsylvania Railroad has experimented with radio-controlled motive power distributed at intervals throughout the train. To a great extent, however, the promise for greater efficiency and lower costs held out to industry by these new haulage methods is dependent not on greater speed or larger cars or more dedicated equipment alone but, rather, on the utilization of modern practices in the loading and unloading of rail cars. It is the purpose here to examine these two key steps and the up-to-date procedures and equipment they entail.

Jan 7, 1963

By D. J. Salley, M. Burke, G. L. Simard

The depression of dithiophosphate by phosphate was investigated by correlating radiotagging measurements of competition in sorption with measurements of flotation. Competition in sorption was as complex as the sorption of the individual ions, thus strengthening the conclusion that more than one process was involved in the interaction of the ions with galena. The depression of flotation was chiefly a result of reducing the amount of dithiophosphate sorbed.

Jan 1, 1951

By M. D. Cooper

Production of both anthracite and bituminous coal in 1954 was about 16 pct below 1953. Estimates on Dec. 1, 1954, indicated 27 million tons of anthracite and 385 million tons of bituminous. Decline in production was due principally to lower demand by the steel industry and the railroads, although competition from other fuels also affected coal. The year was notable for vigorous effort by the coal industry to promote the use of its product. A Cabinet Committee on Energy Supplies and Resources Policy and an Interdepartmental Committee on the Soft Coal Industry were set up by the Administration in Washington. A Governors' Fuel Conference was also organized.

Jan 3, 1955

By Rossiter W. Raymond

The term " pipe-vein " has recently been applied in this country to certain deposits of lead ore in magnesian limestone. The use of the term has been twofold. It has been revived as a term found in textbooks on mineral veins, with the implied or declared assertion that the ore-deposits thus named in this country are similar to those which have borne the title abroad. It has also been advanced as an appropriate name for a new class of deposits, even if such a class had not previously been recognized. In either case, the assumption is that pipe-veins form a group or class by themselves, and are not merely interior and subordinate features in larger deposits. The peculiar mining law of the United States, which regards " the vein," whatever that may be, as the basis of title, lends a special interest to these claims. But the object of this paper is rather to discuss the subject from the standpoint of geology and technical literature. I shall briefly answer two questions: (1) What are pipe-veins as described in technical literature? and (2) Is the name appropriate or necessary for a new class of deposits ? The term " pipe-ore," as applied, for instance, to irregular, cylin-

Jan 1, 1879

By Rossiter W. Raymond

(Read at the Amenia Meeting, October, 1877.) THE term "pipe-vein" has recently been applied in this country to certain deposits of lead ore in magnesian limestone. The use of the term has been twofold. It has been revived as a term found in textbooks on mineral veins, with the implied or declared assertion that the ore-deposits thus named in this country are similar to those which have borne the title abroad. It has also been advanced as an appropriate name for a new class of deposits, even if such a class had not previously been recognized. In either case, the assumption is that pipe-veins form a group or class by themselves, and are not merely interior and subordinate features in larger deposits. The peculiar mining law of the United States, which regards " the vein," whatever that may be, as the basis of title, lends a special interest to these claims. But the object of this paper is rather to discuss the subject from the standpoint of geology and technical literature. I shall briefly answer two questions : (1) What are pipe-veins as described in technical literature? and (2) Is the name appropriate or necessary for a new class of deposits ? The term "pipe-ore," as applied, for instance, to irregular, cylin-

Jan 1, 1878

By A. Eilers

ALTHOUGH the process to which I refer in this paper has been in successful operation for nearly five years, during which time it has been introduced, superseding all other processes having in view the same end, in almost every lead refinery in the country, no description of it, giving economical data, has ever appeared in print, nor has the process been known in its details to any considerable number of engineers beside those conducting it at their works. A discussion of this subject at the present time becomes especially interesting in view of a late publication in the Prussian ministerial organ for Mining and Metallurgy, by Dr. Wedding, in which the method of treating the zinc-silver-lead alloy by distillation, as finally settled upon at Tarnowitz, is very minutely and fully described. It is the more interesting, because in that article reference is made to the American method in an unfavorable light, while, at the same time, it is clear from the article itself, that the most important details of the process, besides the one that it is conducted in black-lead retorts, were not at all understood. In publishing herewith the details of our American method, one of my objects is to invite comparisons between our simple and direct process and the elaborate one at Tarnowitz. In extracting the silver from work-lead by means of zinc, it is always the intention, in this country, to obtain a zinc-crust so rich in silver that the rich lead resulting from subsequent distillation

Jan 1, 1875

By Samuel S. Wyer

Over 8,000,000 people in the United States depend on natural gas for their cooking, heating and lighting service. This service has been made possible only by the investment of large amounts of capital in transportation lines connecting the gas wells to the various communities, thus combining a hazardous mining operation with a public utility service. The effect that making these lines " common carriers" will have on the present and future service to these 8,000,000 or more people is of far reaching ethical and economic importance, and deserves careful consideration. As an introduction, it must be conceded that: 1. Natural gas, although a mineral and obtained by a mining operation—with more uncontrollable and uncertain features to cope with than exist in the mining of coal or other minerals—when served to the public becomes a public utility service. 2. The governmental power to regulate all public utilities in the interests of the public cannot be successfully disputed. 3. Mere suggestion of inconvenience to the utility is wholly irrelevant, as it cannot be considered or allowed to influence in making a defense against governmental regulation. Unfortunately it is not generally appreciated that:.. I . 1. Legislative enactments are not necessarily laws, and cannot abrogate economic laws or alter engineering facts. 2. There is a clear distinction between "common carrier7' and "public utility," although the terms are frequently confused. "A common carrier is one who undertakes for hire to transport persons or goods, or both, from place to place for all persons indifferently, the term implying indifference as to whom shall be served, and an equal readiness to serve all who apply, in the order of their application." On the other hand, property becomes a "public utility" only "when for a particular purpose the public have a right to resort to the premises and make use of them." It is, therefore, important to note that not all public utilities can be regarded as common carriers. The U. S. Supreme Court has already

Jan 1, 1915

By J. Visman

FOR more than 25 years evaluations of coal cleaning units have appeared in many publications, and during this time considerable progress has been made in developing the theory and techniques of calculating washery results. A variety of characteristics have been defined over the years, many receiving general recognition during the first post-war Coal Preparation Conference in Paris in 1950. Coal preparation has become a science, and the approach to preparation problems is being revolutionized. Formerly, for example, if a coal operator wanted to know the performance of a given cleaning unit for a particular grade of his run-of-mine, he either shipped a carload to the manufacturer for a test run or relied on a report of a test carried out on a coal similar to the one he intended to clean. In modern practice the expensive, time-consuming test work generally can be avoided if the washability curves of the coal in question and the error curve of the cleaner are known. Normally a guarantee can be given on the strength of this information. General acceptance of modern standards has thus reduced the need for pilot-scale models of existing types of coal cleaners. Needless to say, the method requires exhaustive and accurate information on the cleaning unit and on all the additional circumstances affecting its results, in- formation that ultimately can be secured only from actual tests made in the laboratory or in the washery.

Jan 10, 1954

By Otto F. Pfordte

In my paper on " The Refilling of Sulphides Obtaihed in the Lixiviation-Process with Hyposulphite Solutions " (Trans., xx., 37), I gave the outlines of a process for refining sulphides. In a subse-

Jan 1, 1893

The mining companies on the page opposite are among the elite industrial 500 in Fortune magazine's June Directory of U. S. firms that rang up the largest dollar sales volume in 1967. The companies are listed according to their 1967 sales rank, which is given along with their 1966 rank for comparison. Mergers played an important role in the addition and deletion of several companies to the list. Tenneco, Occidental Petroleum and Gulf & Western Industries made the list of mining companies by their purchases of Kern County Land, Island Creek Coal, and New Jersey Zinc, respectively. In turn, these three companies disappeared from the list. General Aniline & Film acquired Ruberoid, and Ideal Cement is now a part of Ideal Basic Industries -a name change only. Only two companies, St. Joseph Lead and U.S. Smelting, Refining & Mining, were actually displaced from the list. The mining industry increased its sales 14.5%, placing fourth among the 22 industrial classifications listed in the Directory. However, among the ten biggest losers in sales were four mining companies-Kennecott Copper, -33.8% ; Asarco, -21.8% ; Amax, -16.5%; and Anaconda, -15.1%.-which was mostly a result of the copper strike, except for Amax which suffered strikes at its molybdenum and aluminum operations. Mining heads the list of industries for return on sales and assets per employee, while it rests at the bottom with respect to sales per dollar of invested capital.

Jan 8, 1968

Jan 1, 1891

Dimitri Konstantinovitch Tschernoff, was horn in Petrograd, Russia, on Nov. 1, 1839, and died in Yalta (Crimea) in the south of Russia, on Jan. 2, 1921. He obtained his early education in the Russian Gymnasium, corresponding to the American high school, and in the Technologic Institute. On graduation from this Institute in 1858, he was engaged as a professor of geometry and algebra and later became a librarian and superintendent of the museum in the same Institute. He also attended lectures in the mathematical physics section at the Univrrsity of Petrograd from 1859 to 1862. In 1866, Professor Tschernoff left the Technologic Institute and entered the employ of the Obouchoff steel plant, founded in 1863 for the manufacture of guns. Here he did his most important work on the heat treatment of steel, its crystallization and metallography. In 1880, he left the Obouchoff plant and went to the south of European Russia, where he discovered and developed some rock-salt mines. This enterprise brought him a rather large fortune. In 1884, he returned to Petrograd and during the next four years held several prominent positions in government departments. In 1899, he became professor of metallurgy in the Michael Artillery Academy, and retained that position until the time of the Russian Revolution. In 1902, Professor Tschernoff was elected an honorary member of the American Institute of Mining and Metallurgical Engineers. In September, 1917, Professor Tschernoff was sponding his vacation, as usual, in the city of Yalta (Crimea) in the south of Russia, with his wife and one of his daughters. The revolution progressed so rapidly that they were unable to return to Petrograd, and were compelled to stay in Yalta without provision for the winter season. Suffering from hunger. and lack of sufficient clothing, and deprived of his books, Tschernoff nevertheless continued his studies and gave a number of lectures on steel at the Polytechnic Institute. At the same time he worked hard on some. mathematical problems. His health broke down through long-continued under-nourishment. His works in the metallurgical field are well known to the students of metallurgy; good abstracts of his most important papers were published in Revue de Metallurgie (1915, pp. 829-882) in commemoration of his 75th birthday.

Jan 1, 1922

Dimitri Konstantinovitch Tschernoff, was horn in Petrograd, Russia, on Nov. 1, 1839, and died in Yalta (Crimea) in the south of Russia, on Jan. 2, 1921. He obtained his early education in the Russian Gymnasium, corresponding to the American high school, and in the Technologic Institute. On graduation from this Institute in 1858, he was engaged as a professor of geometry and algebra and later became a librarian and superintendent of the museum in the same Institute. He also attended lectures in the mathematical physics section at the Univrrsity of Petrograd from 1859 to 1862. In 1866, Professor Tschernoff left the Technologic Institute and entered the employ of the Obouchoff steel plant, founded in 1863 for the manufacture of guns. Here he did his most important work on the heat treatment of steel, its crystallization and metallography. In 1880, he left the Obouchoff plant and went to the south of European Russia, where he discovered and developed some rock-salt mines. This enterprise brought him a rather large fortune. In 1884, he returned to Petrograd and during the next four years held several prominent positions in government departments. In 1899, he became professor of metallurgy in the Michael Artillery Academy, and retained that position until the time of the Russian Revolution. In 1902, Professor Tschernoff was elected an honorary member of the American Institute of Mining and Metallurgical Engineers. In September, 1917, Professor Tschernoff was sponding his vacation, as usual, in the city of Yalta (Crimea) in the south of Russia, with his wife and one of his daughters. The revolution progressed so rapidly that they were unable to return to Petrograd, and were compelled to stay in Yalta without provision for the winter season. Suffering from hunger. and lack of sufficient clothing, and deprived of his books, Tschernoff nevertheless continued his studies and gave a number of lectures on steel at the Polytechnic Institute. At the same time he worked hard on some. mathematical problems. His health broke down through long-continued under-nourishment. His works in the metallurgical field are well known to the students of metallurgy; good abstracts of his most important papers were published in Revue de Metallurgie (1915, pp. 829-882) in commemoration of his 75th birthday.

Jan 1, 1922

By W. A. Griffith

Fractional replication of factorial design, a general method for planning experimentation and for analysis of data obtained, is described as applied to a flotation investigation. This method leads to determination of optimum process conditions with minimum experimental effort. Its advantages over simple factorial design are demonstrated. A METHOD for planning experimentation and for analyzing the data secured will be demonstrated. This method, termed fractional replication of factorial design, employs a relatively small number of individual experiments to determine which of a large number of process variables are controlling, to determine which combination of levels of these variables is most likely to produce optimum results, and also to predict what results will be obtained with a particular combination of conditions not already tested. Although the general method is not new, having been developed by Finney in 1945,' the extent to which it can improve the effectiveness of applied research generally has not been recognized by metallurgists. The fractional replication procedure is particularly useful in flotation experimentation and an example from such an investigation will be used in the paper. However, it has equal value in any investigation in which similar experimental difficulties are encountered. In developing a flotation process for a particular mineral separation, the investigator is inevitably confronted with the following difficulties: 1—There are a large number of potentially important process variables. 2—Results of individual experiments are not highly reproducible, due in part to the difficulty in precisely controlling all the variables. 3—Considerable effort is expended in conducting individual experiments. 4—There are practical limits on the number of individual experiments which can be made. In situations of just such a type, modern statistical methods of planning experimentation and analyzing data have their greatest value. Applications of one such technique, called factorial design, to problems of this type have been described by Dorenfeld and others.'-' The simple factorial design is an efficient procedure when the investigator hopes to provide a comprehensive understanding of the effects and interrelationships of a small number of variables over a limited range. In applied research, this is seldom the main objective. Rather, the investigator usually wishes to determine which of the many potentially important variables are in fact controlling, which levels of the controlling variables will provide opti- mum metallurgical results, and what these results will be at optimum conditions. Interest in detailed trends is limited to the controlling variables and to levels in the region of optimum conditions. Simple factorial design has serious deficiencies for such objectives and is not the most efficient method of experimental design. Deficiencies of Factorial Design In a simple factorial design, an experiment must be made at every possible combination of each level of every variable, once these have been chosen and the levels of each to be included have been decided upon. As the number of variables or levels of each increases, the experimental program quickly reaches prohibitive size. For example, an investigation of only four variables, each at four levels, requires 256 individual experiments. Often upon completion of such an extensive program, it is found that one or more of the variables has metallurgically unimportant effects or that a poor estimate has been made as to the appropriate range of levels to be investigated. The result is that only a small proportion of the data obtained falls in the range of real metallurgical interest. Indeed, it frequently can be anticipated that certain combinations of levels of variables will not produce results of interest, but they still must be included so that the essential balance, or orthogonality, of the design will be retained. It may be true that factorial design will provide the greatest amount of information from a given number of experiments, but it does not necessarily follow that it will lead to the desired information with a minimum number of experiments. Much of the information provided may be of little value. Advantages of Fractional Replication The disadvantages of simple factorial design are overcome to a great extent by a modification known as fractional replication. This is a technique for sampling systematically the potential data of a full factorial experiment, that is, the data which would have been obtained if the complete factorially designed program had been completed. Only a fraction of the total array of experiments is made, but the experiments are chosen in such a way that the important advantages of factorial design and the accompanying analysis of variance are retained. The data obtained from the first group of experiments are used to determine which of several variables are controlling and which levels of these variables are most likely to produce the desired result. Unimportant variables and levels of variables then may be

Jan 1, 1956

By Charles F. King

The only investigations on record of the reactions occurring (luring the Bessemer blow are of charges containing a large percentage of manganese, with the exception of' two partial analyses by Snelus and Barker of the English method, where a low percentage of manganese was used. They do not give the analysis of the spiegel, [lor do they report any graphitic carbon after the first stage of the process. Both report only traces of manganese after the first stage until the addition of spiegel. The slags corresponding to the samples of metal were not analyzed.

Jan 1, 1881