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By B. C. Burgess

This paper, describing the milling practices at the Minpro plant of the Tennessee Mineral Products Corporation, Spruce Pine, N. C., is the first of a series being prepared by the U.S. Bureau of Mines on feldspar milling methods and costs in the various feldspar producing areas in the United States. It describes not only the latest practices in feldspar grinding but includes studies of the cost of producing ground feldspar. These cost studies, obviously of interest to every consumer and purchaser of feldspar and to all feldspar grinders, are also of value to the small operator, who is generally prone to understimate his real costs. It describes the latest practices in feldspar milling and includes detailed costs of grinding. The cost tabulations presented show operating expenditures only and not total production costs. Details of costs are given only to the extent that they are essential to the technical discussion and study of the methods employed. A description of the recently installed milling unit for the preparation of granular glasspar by graded crushing, and magnetic separation is of particular interest. It illustrates how highly specialized feldspar milling has become, and to what an extent grinders are going to supply consumers with the products best suited for their particular needs.

Jan 1, 1931

By W. P. Campbell

In the course of the development of the Red Coulee field, northwest of Coutts, Alberta, a considerable amount of information has been gathered by the Department of the Interior regarding the chemical character of waters encountered in the drilling of wells in this area. The writer, in this paper, has undertaken to assemble the available material with the idea of deducing what relations, if any, may exist between the different waters from the same well, and also how these compare with waters encountered in similar horizons in other wells. From no other district, with which the Department of the Interior has had to do, have there been received so many samples of water, and yet not all the waters logged in the drilling reports were sent in for analysis. The information, therefore, herein contained is not as complete as the writer would have desired, but sufficient evidence has been accumulated to indicate some very definite tendencies in the chemical nature of the waters of this field. The drilling of Red Coulee wells has been carried out exclusively by percussive tools. These permit 'dry' drilling, and, consequently, water-sands are recognized when encountered. Had rotary tools been used, information regarding water-sands would have been very meagre, if not entirely lacking, since, in the mudding-off process, water-sands would have been overlooked, with the result that, should water break through into a completed well, its source would not be known and remedial efforts would be greatly handicapped, if not entirely defeated.

Jan 1, 1931

By David, Cole

THE years 1914-15-16 were a pioneering period in mining, milling, and copper metallurgy generally. It was uncertain just what path the crushing, grinding, and concentrating processes would take. This situation was quite embarrassing to the directors of some of our large porphyry properties, then being equipped for production. Inspiration had already made several designs for its proposed 15,000-ton concentrator, incorporating in them the latest devices developed in the art of gravity concentration, only to have the work vitiated by the rapid march of events. In a little improvised plant, built on ground that is now in the crater of subsidence over the Inspiration- Miami orebodies, flotation was being experimentally ' applied to Inspiration ore by Minerals Separation engineers in 1914, with results indicating that this process would be of major importance in the concentration of the sulfides. How best to apply it, and especially how to crush and grind the ore to the very much finer sizes required for the new process, was a serious question, properly to be answered only by doing it, in full- sized machines, under regular 'operating conditions.

Jan 1, 1931

By Wallace Thorneycroft

This paper by Mr. Thorneycroft, Past President of the Institution of Mining Engineers (Great Britain), and chairman of its Subsidence Committee, is a valuable contribution to the assemblage of data on ground movement and subsidence from coal mining. It deals with the effects of advancing longwall, a method almost universal in Europe but as yet little used in the United States outside of Northern Illinois and in a few scattered places elsewhere in thin coal beds, as in the Lexington field, Missouri. Canon City field, Colorado, and the Birmingham field, Alabama. Although by advancing lougwall, a maximum recovery of coal is obtained and it has to be employed where there are weak shale roofs, especially in deep mines, it is a more expensive method of operation unless the mining conditions are suitable, which is unusual in the United States. On the other hand, there is a growing use in this country of what is essentially retreating longwall, with an approximately straight break-line as described by Rayburn.1 With this method, in which the pillars are substantial, it was shown that the ground movement effect is practically identical with that of advancing longwall, hence the value to mining engineers of the precise data given by Mr. Thorneycroft. His study is unusual in several respects; it deals with conditions connected with the mining of a coal bed 20 in. thick, about 490 ft. below the surface, over a mined-out area in a 5-ft. bed about 90 ft. below, which had been mined about 12 years earlier. Both mines passed under Plean House, a building of massive cut stone construction built over a century ago, in which Mr. Thorneycroft resided throughout the under-mining period. Slight cracks opened in the walls as the longwall face approached the house in mining the upper seam, and closed after the face passed and subsidence took place. In the northwest wall, the last wall the face passed under, some stone blocks were broken, which was attributed to a strike period when the advance of face came nearly to a standstill. Other than this there was no perceptible permanent damage, as indicated by the photographs taken by the undersigned in 1923 (Figs. 1 and 2). Mr. Thorneycroft used a novel means of studying the successive positions of the corners of the building: he hung plumb bobs from the eaves and traced the paths of the respective plumb bob points on level surfaces. The angles made by the house walls with the plumb bob lines gave measures of the slope of the subsidence wave at the respective points. A slight upward wave was indicated by the surveys ahead of the subsidence, which would appear to be due to a tilting over of the massive sandstone stratum in the roof measures near the surface, the edge of the coal face acting as the fulcrum.

Jan 1, 1931

By H. Lundberg

Introduction The world has been suffering from an excessive production of all kinds of raw materials, and the metals and petroleum are no exception. As a consequence, at the moment, the urge to find new mineral deposits is almost non-existent and prospecting languishes. But from previous experience we know that sooner or later new supplies will be needed. Mineral deposits become exhausted, and to keep up the supplies of our metals and petroleum, new deposits must be found. Even now, a supply of petroleum of domestic production would not be unwelcome in Canada. It is not, therefore, so entirely malapropos to discuss means of finding ores and oil as it would seem. Almost any physical property connected in definite manner with minerals and rocks may be made the basis of geophysical exploration. This is particularly true of electrical resistivity, and its utilization in electrical prospecting has been the deciding factor in the discovery of such big ore-bodies as Buchans mine, Newfoundland, and the large copper ore-bodies in northern Sweden, etc., as well as in the solution of many foundation and structural problems. The importance of electrical prospecting has been growing steadily, and already there exists hardly any exploration project involving geological problems which may not profit by its application. Electrical prospecting is marching on, and neither temporary failures, nor incompetence, nor over-optimism, nor ill-will and pessimism, nor bad times and business depression, will be able to halt its progress.

Jan 1, 1931

By C. Schlumberger

INTRODUCTION The object of the present paper is to discuss, from a geological point of view, the practical results obtained by the authors with the method of the 'resistivity map of the subsoil' in the study of various mining problems. Some of the studies described date from 1920, 1922, and 1923. They are, therefore, quite old, at least as far as geophysical research is concerned (1). Others, on the contrary, are very recent (2). We shall deal only very briefly with the theoretical and technical sides of the processes employed. This paper has, essentially, a practical purpose, and it has seemed unnecessary to enter into a detailed discussion of the methods. Such a discussion cannot be presented without introducing ,quite. Complex considerations both of mathematics and experimental physics, which interest only the geophysicist: whose work is highly specialized.

Jan 1, 1931

By J. A. Woolf, E. S. Leaver, N. K. Karchmer

"In the cyanidation of silver ore, the need of oxygen is well recognized. Various methods have been introduced for supplying the oxygen. In usual practice, air is the source of oxygen and the methods of application are mechanical.This article gives the results of touts made to show the rate of dissolution of silver from each of the common silver minerals in cyanide solution, under conditions similar to those used in the practical recovery of silver from its ores. The effect of oxygen in aiding the dissolution of the silver from each mineral is also shown by a comparison of the methods of supplying the oxygen. Oxidation by preliminary roasting (500°C.) of each mineral sample gives the maximum extraction of the silver by treatment with cyanide.Each silver mineral5 used in these experiments was as pure as could be obtained from the mineral dealer. In their natural occurrence, silver minerals are not usually free from mineral impurities. They are usually closely associated with other minerals often forming, a complex mixture. The form of crystallization, the proportions, and properties of the diluent that incases or has been dispersed with the silver mineral may decidedly affect the dissolution rate of the silver from each mineral. While the following results should aid in the cyanidation of silver ores, each ore should be studied from the basis of the form and condition of the silver that is to be recovered.All the tests reported in this article were made on synthetic samples, prepared by mixing the particular silver mineral with clean sea sand. Each mineral was ground in an agate mortar to pass 100-mesh before mixing with the sand which had previously been ground in a porcelain pebble mill to 100-mesh. Such proportions of each mineral and the sand were used as to give a head assay of approximately 20 ounces of silver per ton to the synthetic sample.Agitation was carried on in stoppered bottles approximately one-third full of pulp, method apparently supplied all the atmospheric oxygen that would be taken up by the solution under usual conditions, because tests conducted in open bottles did not show increased recovery,"

Jan 1, 1931

By R. D. Leitch, W. P. Yant, R. R. Sayers

In 1924, the United States Public Health Service was requested to undertake a special study of stream pollution. The Public Health Service asked the United States Bureau of Mines to take up the study because the training and experience of the personnel of the former was considered not to be as well suited to this type of investigation as that of the Bureau of Mines. Under H. Foster Bain, then Director of the Bureau, field investigations were begun in the spring of 1925. Along with mine-drainage wastes, the problem of gas-house and coke-oven waste was investigated in the laboratory and a method of treatment by sodium hydrate and benzol was found to be promising. The idea was obtained by A. C. Fieldner, chief engineer of the Bureau Experiment Stations, on a trip to Germany in 1924. He saw a practical application of the process, but obtained no information as to definite chemical or mechanical processes. Because of the then pending American patent applications by the German firm, we made no attempt to develop our findings further. Shortly afterward, a similar method of treatment was developed in the United States,' and since that time we have devoted our attention entirely to mine drainage. This paper is a presentation of some general facts and information gathered during the past five years on coal-mine drainage. Scope of Work There was such a diversity of opinion at the time this work was begun, on the whole subject and apparently so little accurately known, that it was decided to undertake a basic study from which first, certain definite information might be evident, and second, what might be considered

Jan 1, 1931

By G. L. Oldright

In the previous study that has been made by the authors on smelting in the lead blast furnace,4 the furnace examined was one that operated under conditions that have been considered as more or less normal up to the present time. That is, although the furnace had in its charge a large portion of sinter, it also handled considerable quantities of naturally oxidized direct-smelting ore. Other ingredients, such as the limestone, were also added as fairly coarse material. The charges contained only about 24 per cent of lead. Until the changes incident to modern flotation began to take effect, many lead plants doing semicustom smelting in districts where competition was keen and much of the bonanza ore was exhausted were faced with the difficulty of obtaining enough lead to get a sufficient "lead fall" in the blast furnaces to clean the slag thoroughly and to separate it from the lead. A charge containing 24 per cent of lead would have been considered a very rich one by such smelters.

Jan 1, 1931

By R. L. Dunsmore

Introduction If one had been called upon to describe petroleum oil refining seventy-five years ago, he could have acceded to the request quite satisfactorily in about fifteen minutes. Fifteen years ago, an hour and a half would have been sufficient to give a general idea of oil refining, and of the equipment used for this purpose. Today, so extensive has been the research into all phases of the refining and manufacturing of petroleum products, and so rapid the strides in improvement in technique and equipment, that I doubt if a week would suffice to give an adequate outline of ail the ramifications of present-day oil refining. I propose to only 'hit the high spots', dealing particularly with the equipment and methods employed at the Imperoyal refinery, which you are to visit. Crude oil, the refiner's raw material, contains essentially only two elements, hydrogen and carbon. These are not present in the free state but are combined in various proportions as 'hydrocarbons'. A given crude oil is not made up of just one hydrocarbon, but of myriads; some solid, others liquid, and still others gaseous at atmospheric temperature and pressure, ail dissolved one in the other. Moreover, the nature and the relative amounts of the several hydrocarbons vary very considerably in crude oils from different sources. That is, a 'crude' from Oklahoma will contain hydrocarbons not present in crude from Mexico, and is different again from the Venezuela crude. Not only this but oil in a certain well in, say, Peru may be differently constituted from that in a well half a mile distant from it.

Jan 1, 1931

By R. L. Marek

The number of Persons fatally injured in the petroleum industry in California in 1930 was 50, a decrease of 20.6 per cent from 1929, when 63 men accidentally lost their lives. The decrease in the number of fatalities for 1930 has caused the first downward trend in the fatality curve of the California petroleum industry since 1927 and is coincident with a period of little active development in new fields, the shutting in of many wells, and reduced activity in the older fields of the State. That a direct relationship exists between the number of accidental deaths and the rapidity of new field development is particularly emphasized by the fact that in 1929, a year of intensive field development in California, 48 men were killed in the drilling and producing division, whereas in 1930, a year of less development work, only 25 men were killed in this division. The figures for the average number of drilling and producing wells in 1930 decreased appreciably from comparable figures for 1929 and a greater percentage of producing wells were shut-in in 1930 than in 1929.

Jan 1, 1931

By T. A. Rickard

The use of the verb in this mood is not as common as formerly: at the time, for' example, when the Bible was translated and the plays of Shakespeare were written. Nevertheless it is an essential part of literary English. In editing the `Mining and Scientific Press' I do not insist upon the use of the subjunctive in articles that are contributed from the outside, but it is deemed proper in all our editorial writing. To speak plainly, the subjunctive is I a mark of scholarship; it is ignored by those that are not particular in such matters, and unfortunately it is a source of perplexity to many that are entirely unfamiliar with the use of it. Therefore, as an editor, I think it well to allow the indicative mood to be used by contributors in sentences in which, to be strictly correct, the verbs .should be in the subjunctive mood. The fact that most subjunctives are indistinguishable in form from indicatives is another cause of trouble to the uninitiated.* For example, the verbs in such phrases as "Suffice it to say ", "So help me God ", and "God save the King" Fare in the subjunctive. One reason why the subjunctive is becoming uncommon is the growing habit of expressing the subjunctive meaning by aid of auxiliary verbs that are coupled with the infinitive; thus: "It will suffice' to say" and "May God save the King". The subjunctive is common in subordinate clauses, and that is how it obtained its name, `subjunctive', meaning * The student is referred to `A New English Grammar', by E. A. Sonnenschein, published by the Clarendon Press, Oxford. This textbook (see pp. 60-71 in Part III) discusses the subject luminously.

Jan 1, 1931

By H. C. Boydell

Introduction Situated in the district of South Lorrain, some 16 miles southeast of Cobalt, Ontario, and reached from that centre either by branch line of the T. & N. O. railway or by what, for a mining camp, is a reasonably good road, the Keeley mine, owned by the Keeley Silver Mines,' Ltd., has had its history recorded by C. W. Knight (1). Silver was first discovered in South Lorrain, in Woods' vein, on Keeley property, in 1907, and the Keeley mine has been described by Knight (2) and Bell (3). The total production to February 28th, 1930, has been 10,760,107 ounces of silver and 1,285. 434 pounds (weight) of cobalt.

Jan 1, 1931

By The Staff

Introduction In this paper it is proposed to discuss briefly some of the problems confronting the management of a gold mine in choosing a method of milling to recover the gold from various classes of ore. In order to simplify the discussion, the more common types of gold ores are classified from a metallurgical point of view as follows: Class 1?A: Free-milling ores which require only relatively coarse crushing. B: Free-milling ores which require finer grinding to release the gold. Class 2?A: Gold ores which contain the gold partly in the flee state and partly associated with a small amount of iron sulphide, and which do not require fine grinding. B: Gold ores similar to 2A, but which require fine grinding. Class 3?A: Gold ores containing copper in quantities insufficient to interfere to a serious extent with cyanidation. Gold ores containing copper in sufficient quantity to interfere with cyanidation but in which a large proportion of the gold is in the free state, the remainder being chiefly associated with the copper mineral, chalcopyrite. Gold ores containing copper and other sulphides, such as pyrite, etc., in which the gold is principally associated with these sulphides.

Jan 1, 1931

By T. A. Rickard

The key-note of good writing, as of good manners, is B natural. Sincerity is the first requisite for effective writing. When a man says what he knows or believes, he is likely to be interesting, because each human being possesses an individuality, a point of view, or a range of sympathy that makes him different from his fellows. To say or to write what you do no6 think, for the mere sake of talking or writing, is a verbal exercise that must be performed with extraordinary skill if it is to be attractive. Affectations are rarely attractive, rarely effective. To be natural is to be yourself, not a poseur; to give the reader the best of yourself, instead of re-warming the baked meats of yesterday. Quotations-which are second-hand thoughts-will serve occasionally when the thing you want to say has been said so well by another that it would be waste of energy to try to say it better; but, as a rule, the utterance of the writer himself is more interesting than the quotation, because the writer brings something of himself to bear on the subject, and for the moment is more in touch with the reader than any dear departed author. Therefore, say things as best you can in your own way, neither in borrowed words nor in the phraseology that mimics another. Write as if you were speaking to a person whom you desire to persuade or convince. You will then write better than you speak, because, in the first place, you can be more deliberate, and, secondly, you can revise what you have written. Speaking and writing are similar mental acts, with a difference: the difference between eating food raw and eating it cooked. Some kinds of food gain nothing by being cooked; likewise some kinds of utterance are not bettered by being written down first; but most expressions of thought, especially

Jan 1, 1931

By S. M. Marshall

The investigations recorded in this bulletin were conducted by the Pacific Coke & Coal Co. in cooperation with the United States Bureau of Mines and the University of Washington. They cover one phase of a comprehensive investigation to determine whether coals from an extensive, undeveloped area of Pierce County, Wash., can be used in the manufacture of coke for the iron blast furnace. The completed investigation had three parts: (1) A geological survey of the coal property, (2) washing and crushing tests of the coals, and (3) coking and by-product tests. The geological survey, which was not conducted in cooperation with the Bureau of Mines and the University of Washington, included systematic tracing of the coal beds by test holes throughout the property, except some portions covered by an impenetrable layer of glacial drift. By this means all of the beds were correlated, their thickness and general character were determined, and tonnage estimates were made. Only such parts of the survey results as are necessary to a full explanation of the investigations described herein are included in this bulletin.

Jan 1, 1931

By J. Mullins

Coal was first banked by the Dominion Coal Company, Limited, in 1898, near No. 2 Colliery, the same site as is presently used for that purpose. Though today there are banks at Glace Bay, Sydney, and Sydney Mines, these notes, except when otherwise desirable, will be confined to describing the practice as developed at the No. 2 Banking Station, Glace Bay, as being typical of methods obtaining at all sites. Storing The manner in which the coal was piled is illustrated diagrammatically in the accompanying sketch. A train of coal was brought on the main trestle, which extended the full length of the banking ground at a height of 22 to 39 feet above the natural surface, and dumped into bins which were integral with the trestle work. Chutes from these bins permitted the coal to be fed into 3-ton cars, which were horse drawn laterally on narrow gauge tracks laid about 10 ft. centres, to a maximum distance of 400ft. from the trestle. These cars were end-dump and as the pile extended laterally the narrow gauge tracks were lengthened by shorter or longer filling pieces, so that their ends were always kept at the brow of the bank. Much coal, however, had to be dumped directly on the tracks and hand trimmed to fill the valleys, and level off, between the tracks.

Jan 1, 1931

By Chas. F. Jackson

This paper is one of a series dealing with mining methods and costs, prepared and published under the sponsorship of the United States Bureau of Mines and made possible through the cooperation f many mining companies in the United States and foreign countries. The preparation of this paper follows a field study of top-slice mining during which the author visited and discussed with operating officials a large number of iron mines in the Lake Superior region. During this study special note was made of changes in top-slicing practice during the past decade, prior to which the author had acquired several years experience with the method through active connection with a number of mines employing top slicing.

Jan 1, 1931

By Williams, J. A.

THE Alaska Juneau mine has been developed through an adit driven at the elevation of the top of the mill and all mining is done above this main haulage level. As a result of wholesa1e"mining operations about 11,000 tons rock containing one dollar' per ton in gold is, hauled to the. concentrator during every 24 hr. Due to the method of mining, whereby a system of oreways delivers-the.ore direct from the stope to the bottom level of the mine, no tramming of ore is done on any of the upper levels. However, ;in doing exploratory drifting and crosscutting on the upper levels, the broken material is trammed by hand in 1-ton 18-in. gage cars to a nearby raise connecting with one of the several oreways. This constitutes the only tramming operation except that on the main level.

Jan 1, 1931

By N. A. Elmslie

This subject covers much ground, therefore it must be treated in a general way rather than in detail in this paper. Personnel To approach the measure of a mine, it is, of course, essential that the personnel be measured, and this measuring must be done in a circumspect manner and conclusions must be reached slowly. There may be one unit in the personnel of an organization that may be out of step with the remainder of the organization, not always because of lack of ability, but because of misplacement or lack of proper measurement of his capabilities. Too much time can scarcely be spent in the study or measure of the personnel ; in fact, a manager or a superintendent of a mine never completes his work along this line. Mine or Plant Just as no two men are alike, so no two mines or plants are alike; and yet there are many similarities. Find out what the similarities are, and this will help to make clear the dissimilarities. Try to visualize details of the difficulties, not because you will have to deal with them yourself, but to consider them in later studies of general problems. To outline all the steps to be taken in familiarizing oneself with a plant or operation would be impossible, but the following points may be of interest in any investigation. The study of a mine is generally made backwards-—that is to say, one sees the finished product first-—-but this is immaterial, because each step must be considered separately in any event. As a rule, there are certain heads under which the different features of mining can be placed, as follows: Ventilation.—Ventilation is usually the most important item in power cost and safety, especially in gassy mines. Quantity of air, water gage and power consumption, and finally analysis of the return air in full return and separate splits should be considered. Type of fan and type of power unit should enter into this study because it is important to view expenditures which are going on 24 hr. a day and 36.5 days in the

Jan 1, 1931