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By Elliott J. Roberts

In spite of the fact that the percentage of true colloids in an ore grind is very small,' these pulps exhibit many of the properties of true colloidal suspensions. A quartz particle, appreciably finer than 10 microns in diameter, has a settling rate so low that at a dilution of 5:l or over, the capacity of a settling tank to settle such particles would be uneconomical if the individual particle rate prevailed. However, by grouping the finer particles into aggregates or flocs, the settling rate can be increased to an economical value. The colloidal chemistry of pulp thickening is thus chiefly concerned with particles having diameters of between 1 and 10 microns, although particles as coarse as 40 microns in diameter are more or less involved. These particles must be associated in such a manner that they settle at an economical rate and give a clear, supernatant liquid or overflow. The treatment of the subject may be divided into three phases, cach phase having a more or less different colloidal aspect. The first phase is the problem of getting the pulp or suspension into the proper condition of flocculence; the second is the behavior of the flocculent pulp in its initial and intermediate stages of settling; the third is the behavior of the flocs in the find period of settling or thickening stage. Let us look first into the methods and mechanism of obtaining the flocs and then consider their behavior and properties. Flocculation Colloids are merely ordinary substances reduced to a very small particle size, the upper limit being placed by definition at 1 micron (0.001 mm.) diameter by the soil chemists and at from 0.2 to 0.1 micron by various other colloid chemists. The lower limit is reached only when the particles approach molecular dimensions. The term L'colloid" should not necessarily imply lack of crystallinity. Particles as small as 0.01 to 0.02 micron give perfect X-ray patterns, while with 0.005 micron particles the bands on the powder photograph are merely broaderled and diffused.2

Jan 1, 1935

By Guy Bjorge

IN recent years the Homestake mine has been served by three shafts, the B. &. M., the B. & M. No; 2 and the Ellison, supplemented by an inside shaft, the Milliken, extending from the 2000-ft. level to the 3200-ft. level. In 1932, when a new operating shaft was under consideration, the bottom of the mine was at the 3200-ft. level. The B: & M. and the B. & M. No. 2 shafts were down to the 1550-ft. level and the Ellison was being deepened from the 2600 to the 3200-ft. level. All ore was hoisted at the B. & M. and-Ellison shafts. Levels below the 2600 level, which were under development only, were served by the Milliken shaft. Below the 1550-ft. level, the mine was served only by the Ellison shaft from the surface. Within a few years, when ore reserves above the 1550-ft. level would be depleted, operation would be limited to the Ellison shaft and the auxiliary underground shaft. The Ellison shaft alone was not adequate for hoisting the entire output from the deeper levels and also handling all men and supplies. Further-more, assurance of safety and uninterrupted operation required- two fully equipped shafts to the deeper levels. Therefore a new operating shaft was authorized in November, 1932, and was named for A. J. M. Ross, the mine superintendent.

Jan 1, 1935

By Hugh M. Roberts

The important place in the economic life of the country that is occupied by the United States Geological Survey and the various state surveys is appreciatcd by most members of our Institute. To the public at large, the functions of these surveys are no doubt largely unknown, and taken for granted. Possibly a realization of the value of the work of these government branches is brought home most fully to that group of our members whose duties as examining engineers and mining geologists take them to mines and prospects in many different parts. The examining engineer or geologist is usually seeking for a judgment on the value of an enterprise from the standpoint of the useful minerals that may or may not be present; he must also attempt some prediction as to future market prices. On his opinion rests the determination of the expenditure of money, which rendered into other language means the expenditure of human effort. An opinion on an exploring venture or the reasoning out of the probable extensions of an orebody requires among many other things a background of knowledge covering the geologic horizons not only of an immediate area but of the surrounding area, a knowledge of the structural geology and of the causes that have operated to form the ores as they are. The great storehouses of this knowledge are the statistics, reports and maps issued by the various geological surveys. They supply the groundwork for additional observations. To these, reference is always made when going into a new district. The technique of work in the field and laboratory, and to some extent the hypotheses that underlie our methods of approach, have been formed by men such as Van Hise, Leith, Kemp, Spurr, Emmons and Lindgren, who developed their powers in the service of the geological surveys. In addition to whatever originality of thought, or power to observe facts and analyze them, may be our portion, we require, in the application of the arts and sciences, a knowledge of what has already been done. We stand on the shoulders of those who have gone before, and the extent of our vision often depends upon the thoroughness with which we form earlier work into one whole and make use of it.

Jan 1, 1935

By Henry M. Bates, Roscoe Pound

Mr. Chairman and Gentlemen: I accepted your Chairman's invitation to speak to a group of experts in this field with the greatest hesitation, because I know little or nothing about it. Certainly I can make no detailed suggestions, or suggest planning along very definite lines. You cannot do that sort of thing in a vacuum, and as I have suggested, my knowledge of the whole oil problem is next to nothing. It is possible that as a student of our public law, constitutional law particularly, for a number of years, I have acquired a perspective that may enable me to offer, for what they are worth, some general thoughts on these problems. I think that nothing in the whole field of law requires more definitely and clearly the functional approach than does the problem of a sound legal solution of the difficulties of the oil and gas industry. The industry is dealing with substances that are peculiar, and one must know how those substances act and what has been the history of the industry, to undertake to make anything like specific suggestions. I certainly am not qualified.

Jan 1, 1935

Jan 1, 1935

By Arthur E. Bousu, C. T. Eddy, L. W. Eastwood

THE recrystallization and grain-growth phenomena of cold-worked metals have considerable industrial importance because of their role in the fabrication of metals. For this reason, and because of the general academic interest in the subject, these processes have received considerable attention since the time of J. E. Stead's paper1 on The Crystalline Structure of Iron and Steel. There are considerable differences of opinion regarding the theory of recrystallization and grain growth and also differences in the observation of the modus operandi of the processes themselves. The value of many of the existing quantitative data on grain growth is decreased by the failure to distinguish between the grain sizes just after complete recrystallization and those resulting from coalescence. For this reason also, the value of the diagrams of stable grain sizes, like those produced by . Bass and Glocker2 and Czochralski3, is lessened in so far as an interpretation of the facts of recrystallization is concerned. It is hoped that the data presented in this paper will help to clarify and to simplify the facts relating to recrystallization, and at the same time will show that some of the present-day conceptions are untenable. A paper on the theory of recrystallization with additional data will be completed in the near future by the writers.

Jan 1, 1935

By D. J. Parker

The ease of ignition and violence of explosion of Utah coal dusts, together with the large volumes of methane given off in some of the mines of the State, made it imperative to abandon obsolete equipment and obviously hazardous practices for up-to-date equipment and safer methods of mining if reasonable progress wore to be attained in fire and explosion prevention. Although much can still be done to improve safety conditions in Utah coal mines, considerable progress has been made in the past 10 years. The fundamentals of such progress include increased use of permissible electrical equipment in gassy mines, closed lights, rock-dusting, more liberal use of water at the face, butter ventilation, permissible explosives fired electrically both within and without the mine, partial inhibition of blasting while the shift is in the mine, 100-percent first-aid training, increased supervision and inspection, and mass safety meetings.

Jan 1, 1935

By R. R. Sayers

IT has long been common knowledge that workers in anthracite are prone to develop a disabling disease of the lungs. Some of the earliest scientific contributors dealing with anthracosis were: Pearson1, in his report in 1813, on the coloring matter of the bronchial glands and black spots in the lungs; Stratton2, in 1838, who first termed the condition anthracosis; Greenhow3, who reported to the pathological society in 1865, on the Black Lung of the Collier, and Pick4 in 1870, who reported on the chemical composition of the ash of a collier's lungs. Visconti5, in 1870, is accredited with being the first to use the term "silicosis" to denote the pathological condition of the lungs resulting from the inhalation of silica. Rovida6 confirmed the reports of Pick and Visconti in 1871, in his report on a case of silicosis and chemical examination of the lungs for silica content. The relationship of pulmonary infection, as associated with disabling pneumoconiosis affecting the coal miner, has frequently been discussed. While most reports have emphasized the role of infection, there has been some disagreement regarding the prevalence of tuberculosis among those suffering from anthracosis. The report by Wainwright and Nichols7 in 1905 has frequently been cited to show that the incidence of pulmonary tuberculosis among coal miners was -less than that among the general population. It was their opinion that pulmonary tuberculosis was more prevalent among the miners' families than among the miners themselves.. Collis and Gil-christ8, in 1928 in their study of the Effects of Dust upon Coal Trimmers, concluded that among such workers there was an excess of deaths from bronchitis and pneumonia but not from pulmonary tuberculosis. They

Jan 1, 1935

Jan 1, 1935

By J. R. Thoenen

This circular is part 2 of the third subject (entitled "Excavation") of a series summarizing; the technical problems involved in the production and preparation of sand and gravel. Part 1 discussed the use of power shovels, draglines, and excavator cranes. This paper discusses the use of the power scraper, slackline cableway excavator, and hydraulic monitor, and part 3 will discuss the use of various types of dredges. Subsequent papers in the series will discuss the use of haulage equipment, the application of both excavating and haulage equipment to various types of deposits, and operating costs. THE POWER SCRAPER The power scraper is a younger member of the various forms of gravel excavators. It is a mechanized enlargement of the slip scraper and other scrapers which depend upon animals for power and has a greater range of operation from a single set-up than any other excavation unit except the slackline cableway excavator.

Jan 1, 1935

By H. F. Walther

Basic electric-are furnace steel production mainly involves the use of two separate types of slags. The first, known as the "melt down" or oxidizing slag, which is in most cases removed from the furnace mechanically, and the heat finished under the second or deoxidizing slag, which is commonly known as the "finishing slag.'' The melt down slag is formed by the addition of lime or limestone to the charge, which combines with the oxides formed during the melting period and the product of any bottom erosion that may take place.

Jan 1, 1935

By C. J. Wilhelm

The disposal of brines produced with crude petroleum and natural gas has been a long-continuing problem to oil and gas operators as well as to farmers and stock-raisers in the vicinity of producing fields. An impartial appraisal of conditions pertaining to the problem of brine disposal leads to the conclusion that study of the technical consideration, with proper weight given to the economic and social factors, is the most desirable approach to this problem. Brine disposal is a problem of such magnitude in certain areas in the State of Kansas that in August 1934 a cooperative agreement was made between the Kansas State Board of Health and the U. S. Bureau of Mines for a cooperative technical study of methods of brine disposal.

Jan 1, 1935

By Oliver B. Hopkins

The Peruvian production increased over 3 million barrels from 1933 to 1934—from approximately 13¼ million barrels to over 16¼ million barrels—bringing the cumulative production of the country up to 171 million barrels. Most of this production, as well as most of the increase in 1934, came from La Brea-Parinas Estate, the property of the International Petroleum Co., Limited. In 1932 Peru stood eleventh among the oil-producing countries of the world, but in 1933 her production exceeded that of Trinidad, Argentine and Colombia, which placed her in eighth position. In 1934 Peru's production was exceeded by that of Colombia by about one million barrels, and by that of the Argentine by about 1½ million barrels, thus placing her in tenth position. After several years of relative inactivity in drilling and exploration there was a noticeable increase during 1934 in both of these lines of activity. Oil Fields La Brea-Parinas Estate.—Production on the La Brea-Parinas Estate. reached a significant total of 85,080 bbl. as early as 1891. It increased to over one million barrels in 1912, and to over 10 million barrels in 1929, and in 1934 it reached an all-time high of over 14 million barrels. The total production from 1890 to 1934 was 133,784,609 barrels. Practically all the drilling on the property has been done with cable tools, but during 1934 three strings of rotary tools were introduced. One was a heavy outfit for drilling a deep test and the other two were lighter outfits for deepening wells in the newer section of the field, where the gas pressure was too high to permit safe drilling with standard tools. During 1934 a total of 28,127 ft. was drilled, 66 wells were deepened, and 6 new wells were completed. At the end of the year 2844 wells had been drilled on the Estate, of which 1814 were still productive. The remaining 1030 wells represent abandoned producers or dry holes. The total area that has been productive up to the present time is estimated at 13,369 acres. An interesting article on the various phases of operations of the International Petroleum Co. was written by Arthur Iddings and published in The Oil and Gas Journal (Dec. 27, 1934).

Jan 1, 1935

Jan 1, 1935

By J. C. Reed

CINNABAR was discovered in southwestern Arkansas on Little Missouri River in sec. 1, T.7S., R.26W., in April, 1930, and near Antoine Creek in sec. 28, T.6S., R.23W., some 15 miles farther east in May of the same year. It was not, however, until June, 1931, that cinnabar was identified as such in a specimen from the original discovery area sent to W. M. Weigel1 by Walter F. Hintze of Murfreesboro. Almost simultaneously2, in July, 1931, Moritz Norden of Hot Springs identified specimens from the Antoine Creek area as cinnabar. Immediate interest in the district followed the identification of cinnabar and by January, 1932, the district was known to extend as a mineralized belt about one mile wide trending east-northeast from sec. 13, T.7S., R.27W., in Howard County-across central Pike County and into Clark County to sec. 19, T.6S., R.23W., thence extending southeast into sections 33 and 34 of the same township. Since then, cinnabar has been found in sec. 6, T.7S., R.22W., thus giving a total east-west length to the district of approximately 30 miles. Interest focused mainly on the two discovery areas, with the result that mining development has progressed most rapidly in those localities. In the Antoine Creek area the Arkansas Quicksilver Co. has done con-siderable exploration work and has retorted the high-grade ore so .obtained. In the Little Missouri area the Southwestern Quicksilver Co. has had a 12-ton rotary furnace in more or less continuous operation since April, 1932, and has been the largest producer in the district.

Jan 1, 1935

By J. R. Bradfield

THOSE familiar with the development of the Horne mine can readily appreciate that more and more accommodation bas been required for underground labour as the mine has grown. A permanent fire-proof change house, 30ft. by 75 ft., was built in 1927 to accommodate 194 men. This was extended ro 30 ft. by 92 ft. in 1928 to accommodate 296 men, and to 30ft. by 110 ft. in 1930 to accommodate 398 men. By 1933 this building was again overcrowded and tentative plans for a new change house were drawn up. However, it was realized that future operations would be centred around No. 4 shaft and a proposed new shaft, and the decision as to the location of the new change house had to be deferred until the area which seemed most suitable for the new shaft had been thoroughly explored underground. In the spring of 1934, the basic idea was accepted of drying the wet clothes in open mesh compartments or baskets located between rows of standard steel street-clothes lockers and built so that the covers or lids would serve as seats or benches.

Jan 1, 1935

By R. S. James, E. J. Gleim

Not long after electrically driven equipment was introduced into coal mines it became apparent that the spark-producing parts, such as controllers and motors, required safeguards to prevent the ignition of mine gas that might come into their vicinity. Many of the early designs attempted to provide protective enclosures having ventila¬tion and relief for pressures if ignition should occur within. The principal feature of the Davy safety lamp, namely, the wire gauze, was employed widely for this purpose. Other devices were developed to reduce the temperature of products of combustion escaping through the protected openings to a value below that which would cause ignition of surrounding explosive atmospheres. Although many such devices performed their intended function satisfactorily under laboratory conditions they were not so satisfac¬tory when subjected to the rigorous conditions encountered under¬ground. Corrosion, mishandling, and accumulations of grease and dirt reduced or destroyed their protective qualities after a period of service in the mines. In the United States this has led to abandon¬ment of special devices in favor of what is called " total enclosure " which means that no regular provision is made for ventilation and release of pressure but rather that the housings or enclosures are built strong enough to withstand the explosion pressures without rupture. As a further protection the joints usually are made of broad, closely fitting surfaces. It is impractical to make such joints absolutely gastight in ordinary machine practice when provision must be made for partial or complete disassembly to facilitate ad¬justments and repairs. Therefore, when an explosion occurs within such enclosures flames may escape through the joints. If the latter are broad enough and not separated too widely, however, the flames will be cooled by contact with the metal surfaces (flanges) of the joints, by rapid expansion, or by both cooling and expansion, with the result that an explosive atmosphere surrounding the enclosure will not be ignited. This is termed " flange protection." In testing parts of cutting machines and other equipment for coal mines, with the ultimate object of approving the equipment for use

Jan 1, 1935

By W. J. Wright

Summary Statement The following notes on the geology of the Grand Lake coalfield are intended to be introductory to a second paper being read at this meeting, which paper will describe the earlier and the more modern mining methods. The coal industry of the Grand Lake coalfield is centred chiefly within a three-mile radius of Minto, but minor operations are dotted over an area of approximately 50 square miles extending easterly to the vicinity of Chipman and Coal Creek (see Figure 1). The coal comes from one seam of Pennsylvanian age. The seam varies in thickness from 16 to 30 inches and lies almost horizontal at depths of 0 to 125 feet. It has been mined and prospected over an area of approximately 150 square miles, but in a portion of this area the commercial possibilities have been destroyed by erosion. The industry is the oldest of its kind in North America, but it did not at tract particular publicity until about 1914. Since that date, mining methods have improved and the output has rapidly increased until, in 1934, it amounted to 271,335 long tons, and furnished employment for about 1,000 men (1). Approximately 73 percent of this amount was produced by the Minto Coal Company, the Miramichi Lumber Company, the Avon Coal Company, and Welton and Henderson, and 25 per cent by the Rothwell Coal Company, Harvey Welton Limited, G. H. King, the Reade Construction Company, and the Newcastle Coal Company. The remainder was produced by J. W. Carter, G. D. Crossman, T. H. Swift, C. S. Yeamans, and several other small operators. The coal is won by underground mining, except in the case of the Reade Construction Company, and a minor operation by Ashfield and Pieton, who have employed open stripping. It is mined only as required to fill definite orders, and is loaded directly into cars for shipment. In 1934, the larger mines did not operate full time, and the production could easily have been increased if markets had been available. The coal is sold in four grades: screened or lump, run of mine, slack, and stripping. The chief market is with the railways and commercial plants, with a fair amount for domestic purposes.

Jan 1, 1935

Jan 1, 1935

By T. R. Stanley

Introduction The purpose of this paper is to interest mining men in the economic possibilities of sand deposits suitable for modern foundry work. Many members of the profession are constantly travelling over the country and it is felt that some knowledge of the necessary properties of foundry sands will enable these men t0 recognize such deposits. It is the experience of the writer that good sands suitable for the varied work of a foundry, such as that of the Consolidated Mining and Smelting Company, at Trail, are almost impossible to obtain from western Canadian sources. It is hoped that the following discussion may arouse some interest in the search for such sands. Sands are used in foundries for two purposes. The main use is for making moulds suitable for receiving hot metal. The mould must retain the? required shape until the metal has solidified. The second use of sand in the foundry is as an abrasive in sand blasting. This is a relatively minor use, and consequently will not be dealt with in detail. Any coarse sand with a high content of quartz will serve this purpose, but round-grained sands are superior to angular types, because they have not the same tendency to shatter on impact with the casting. Sand plays an extremely important part in the successful production of sound castings. This is more evident today than ever before, due to the greater variety of castings and alloys, each of which requires special sand characteristics. Poor sand is responsible for a great many foundry troubles which formerly were attributed to bad? metal; in fact, one investigator goes so far as to say that ninety per cent of bad castings can be traced directly to the sand. Very little of the vast amount of sand distributed over the earth's surface is suitable for moulding. It is the purpose of this paper to describe briefly the properties which are essential in good moulding sand. Sand for this work must be able to withstand the wash and hydrostatic pressure of molten metal, and yet be sufficiently porous to allow the gases generated in the mould to escape.

Jan 1, 1935