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By C. L. Monroe

It has been the custom in recent years to look upon Atlin as a worked-out placer camp. This is a conception, however, which is far from the real situation. The placer-gold deposits of Atlin are today, after thirty-one years of continuous working, a field well worth the attention of the mining world. It is true that the shallow diggings (the 'easy money') have been practically cleaned out, but although there have been perhaps ten millions, or more, in gold already taken from the district, there are still many more millions left in the creek beds . A conservative estimate of the gold still remaining in one creek alone, Spruce creek, for a long time known as the 'prospector's meal ticket', would place the amount at anywhere from fifteen to twenty million .dollars, and there are a number of other creeks that have never been thoroughly worked, and some only partially prospected. That the true situation is beginning to be recognized by those who are on the lookout for a profitable field for investment, is born out by the fact that, within the last few years, New York capital directed by Mr. Charles V. Bob, who is also responsible for the opening up of the Engineer mine, has installed on Pine creek, where the first discovery of gold in the district was made, one of the largest hydraulic mining plants on the continent, utilizing six miles of the old hydraulic ditch of the Discovery Mining and Power Company, and over two miles of pipe line. On Boulder creek, where already two millions have been taken out, the Consolidated Mining and Smelting Company are on their third year of development work in opening up the unworked ground, while on Otter creek a newly organized French company have started a plan of development which will involve an expenditure in the neighbourhood of $200,000, and two or three years' work, before they can hope to find gold in paying quantities. It is probably safe to prophesy that placer gold will be produced in the Atlin district for the next fifty years

Jan 1, 1929

By C. O. Rison

HIGH explosives, particularly nitroglycerin, have been used in torpedoes for the purpose of shooting oil and gas wells for more than 60 years. The early history of the oil industry in Pennsylvania is not clear as to who actually torpedoed the first well, although in 1865 the Roberts Torpedo Co. procured a patent covering the process. Gunpowder was first used, although nitroglycerin was substituted shortly afterwards. Wells are shot for the purpose of increasing the flow of oil and gas A shot-hole in the producing horizon, with its contributory fissures and fractures, increases the area of and stimulates drainage into the hole. The shot-hole also acts as a collecting basin from which the oil is pumped. As a rule, hard or close-grained sands or limes are shot, other more or less porous and soft formations usually do not require shooting. and might be injured by blasting. Shooting is also resorted to in mechanical trouble such as straightening crooked holes, sidetracking pipe or tools, and for severing frozen strings of casing or drill pipe. Explosives arc also used sometimes to extinguish oil or gas-well fires although that work, which involves unusual conditions and methods, does not properly come within the classification of oil-well shooting. Some Factors to Be Considered in Shooting Wells Although nitroglycerin has been used extensively for more than half a century in shooting oil and gas wells, there is still a great deal of uncertainty as to the proper method of shooting or the amount of explosive required to produce best results in a particular formation. The possibility of shooting unproductive or cavey formations above or below the productive horizons, shooting into lower water, destroying casing seats, and the splitting or collapsing of casing strings, are factors that require consideration. The engineering departments of a number of the larger oil companies are making a study of methods of shooting, and the amounts of liquid nitroglycerin or other explosives required in shooting various productive

Jan 1, 1929

By R. S. Dean

BLUE HEAT PHENOMENA IN constructing a theory of the flow and hardening of metals, we necessarily make use of such phenomena as seem to be, universally observed in metals. It is, therefore, a matter of. concern to the constructors of such mnemonic systems if one or two of the group classified as metals show anomalous behavior. Such egregious phenomena are observed in pure or nearly-pure iron in the reaction of its mechanical properties to low-temperature annealing after cold work and to increased temperature of testing. In short it has been generally observed that iron," as an outstanding exception among metals, increases its hardness and strength by low-temperature annealing. after cold work,1 and also by increase of testing temperature to the range of 150° to 300° C. The investigation here recorded was made then with the object of ascertaining if similar phenomena were observed in high purity iron and, if not, to the presence of which impurities these phenomena could be traced.

Jan 1, 1929

By H. V. Churchill

There are two distinct methods of combating corrosive conditions. The first and most popular method is to choose a surface or material which will give adequate service under the specific and general conditions which are present. The second is a control or modification of the corrosive conditions to the end that metals and materials which would be attacked and corroded without such control or modification may be used. Under the first method of attack of the corrosion problem may be grouped such devices as the selection of metals or alloys which offer great resistance or the use of protective coatings such as paints, lacquers or metallic coatings. Such procedures are exceedingly useful. It is undoubtedly true that most of the problems of corrosion will be solved by recourse to this first method of attack. However, it must be remembered that there are many conditions in which metals are used where the choice of the particular metal to be used must depend upon other factors than corrosion behavior. Some of the factors which may govern the selection of metals for specific use are the physical and mechanical properties of the metals. But there is another factor which is of prime importance and that is relative price. It is the pressure of these factors of mechanical properties, physical characteristics, and relative price that has acted as the stimulus for the second methhod of combating corrosion. The producer and user of various metals is confronted with the fact that because of mechanical properties, physical characteristics, or price, the use of a particular metal is desirable even though the corrosion conditions are adverse to the use of the metal. In many cases, the successful use of the metal may be made even though it is impossible to protect the metal by coatings. This is rendered possible by control or modification of the corrosive media. Use of Sodium Silicate to Prevent Attack by Alkali Solutions This idea of controlling or modifying corrosive media is well illustrated by some recent experiences with aluminum. For a number of years collapsible tubes have been made of aluminum. Due to the ease with which aluminum is attacked by even mild alkalies, the use of such tubes

Jan 1, 1929

By A. B. Coates

During the last three years the use of ethylene glycol dinitrate4 (E.G.D.) as at low-freeze (L.F.) agent in place of nitropolyglycerin has become common in the manufacture of explosives of the dynamite type. The usual proportion of D. G. D. in the explosive "oil" is 25 per cent; the remainder, 75 per cant, is regular nitroglycerin. These proportions were probably selected as a continuation of the practice of 25 per cent nitropolyglycerin and 75 per cent regular nitroglycerin.

Jan 1, 1929

The Institute is custodian of funds for support of numerous gold medals and prizes and has representatives on boards awarding still others. Details regarding the Institute Awards are given below. The Institute is represented on the boards of the John Fritz Medal, the Hoover Medal and the Washington Award, in connection with the three national societies of Civil, Mechanical and Electrical engineering; and, also, in the case of the Washington Award, with the Western Society of Engineers.

Jan 1, 1929

By W. S. Burbank, B. S. Butler

STUDY of the ore deposits of Colorado has disclosed, in numerous places, sharp changes in both mineralogy and metal content of the primary or hypogene deposits with change in depth. A clear understanding of the meaning of these changes is requisite to form intelligent conclusions that can be applied in the exploration of such ore deposits. This paper is an attempt to set forth some of the geologic and chemical relations of minerals that bear on this problem. The effect of the differing electrode potentials of elements on the order of oxidation and on the order of displacement of one metal by another metal in supergene sulfide deposits has been studied for many years by several investigators. The results all agree rather closely with the original Shurmann series of replaceability of metal sulfides, as Wells has shown.1 So far as the writers are aware there has been little attempt from the geologist's viewpoint to correlate the electrode potentials of the elements, other than those of the common metals, with the positions and mode of combination of the elements as found in ore deposits, and in particular in hypogene deposits. Wells2 discusses electrochemical activity between solutions and certain ore minerals and mentions the possibility of its effect in precipitation reactions. The senior writer for a number of years has emphasized the importance of oxidation-reduction reactions as a factor in the formation of certain hypogene ore minerals, and as the electrode potentials are a measure of the relative Oxidizing and reducing power of the elements and their ions, it seems possible that a study of them may offer some suggestions on certain problems. The data at present available for such a line of

Jan 1, 1929

By H. R. Hanley

IT is a well-known fact that the solubility of zinc compounds decreases when these compounds are roasted in contact with iron compounds, but descriptions of tests to quantitatively express the fact have not appeared in the literature. Possibly such an expression cannot be uniformly and exactly duplicated by different operators because of the variation in the personal equation. In a general way, however, the reactions between zinc compounds and iron compounds under roasting conditions will show a certain trend with changing conditions and the approximate quantitative expression of this trend appears reasonably well established by experimental work conducted for this purpose.

Jan 1, 1929

By James Aston

Three years ago the writer presented a paper on the trend of development in the wrought iron industry,' wherein was described a process in the development of which he has been a factor, which at that time had passed through several years of progressive experimental development but which had not then been put upon a commercial scale of operation. The present paper deals with two years of observation and experience in the commercial operation of a plant by the A. M. Byers Co. at Warren, Ohio. It will not enter into the controversial field of the relative merit of wrought iron and steel in various classes of service, nor will it elaborate upon the characteristic services or fields of utility to which wrought iron is particularly adapted. It is sufficient to state that the wrought iron industry is upon a substantial basis and that the material finds service in pipe, where its advantages are in superior corrosion, fatigue, welding and threading qualities; in bar iron for staybolts, engine bolts, and rivets, demanding maximum service against corrosion and fatigue; in plates for corrosion service; and in chains, because of welding and shock-resisting characteristics. In short, ability to withstand the stresses of shock and vibration, or the ravages of corrosion, to hold protective coatings, and to give maximum efficiency in welding, are its features of relative superiority. If these features were not well recognized, the wrought iron industry would have shrunk to insignificance in the face of high costs and acknowledged limitations in manufacture. To charge that this industry is built upon a structure of assumption, psychology, and improperly weighed evidence is an impeachment of the integrity or belittling of the powers of observation of users through many centuries of service experiences. In a history which extends to prehistoric time, and which is linked up with the earliest records of ferrous products, the dominant method of manufacture, as we have known it for little over a century, occupies a very small niche in the span of years that mark production and use of wrought iron. Puddling, the outstanding manufacturing method of

Jan 1, 1929

By T. D. Thomas

CONTENTS PAGE T. D. Thomas-Misfires in Anthracite Coal Mines 3 W. H. Forbes-Misfires in Bituminous Coal Mines 12 A. W. Worthington-Misfires in Non-metallic Mining (Limestone) 18 Misfires in Anthracite Coal Mines BY T. D. THOMAS,* LANSFORD, PA. (New York Meeting, February, 1929) IN THIS paper, major attention is given to misfires in mines where electric multiple shot-firing is the system used. Misfires are sometimes caused by one action or condition and at other times by a combination of two or more. They may be divided into two classes: (1) those caused by workers in the mines, (2) mechanical or manufacturer's causes. The second cause will be discussed first. MISFIRES CAUSED BY FAULTY DETONATORS The important part of an electric blasting cap, to the user where multiple shot-firing is done, ass in the steep-pitch, thick-vein, anthracite mines, is the bridge wire. In single shot-firing this factor is not apparent, but in mines where multiple firing is done any variation in the resistance of the bridge wire, where full or even rated battery capacity is required, will most likely cause a misfire The reason for this is obvious. If the resistance in the bridge wires is not the same, some of the detonators will fire because of their greater comparative resistance. Variance in resistance of bridge wires is caused by a slight difference in the diameter of the bridge wire, also to a difference in the composition of the bridge wires. Again, where the bridge wires have become rusted, there will be a variance in resistance. About the year 1922, one of the large coal companies was greatly alarmed by the number of serious and fatal accidents caused by misfires. The general manager issued an order that these accidents must be greatly reduced, and if possible, entirely prevented.

Jan 1, 1929

By T. D. Yensen

IF the question should be asked at this time: "Does pure iron have allotropic transformations?" the reply would necessarily be, "We do not know." And it is doubtful whether anybody, anywhere, is in a FIG. 1.-EFFECT OF CARBON ON HYSTERESIS LOSS OF IRON-SILICON ALLOYS. (ALL OTHER IMPURITIES AND EFFECT. OF GRAIN SIZE ELIMINATED.) position to make any other reply at this time, for the simple reason that pure iron has not yet been made and tested. The nearest approach to it contains either an appreciable amount of carbon or else an appreciable amount of oxygen (a few hundredths of a per cent.). But why be con-

Jan 1, 1929

By Paul M. Linebarger

This paper is one of a series of digests of foreign mining legislation and court decisions prepared in advance of a general report relative to the rights of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the laws of Mexico has been pro oared from the best information available in Washington but is released subject to correction and amplification, if necessary, by the proper American diplomatic and consular officers, to whom it has been referred through the courtesy of the Department of State. INTRODUCTION Present-day Mexican mining legislation involves, not only the latest minim enactment (August 1, 1026), but many other enactments and regulations, principal among which are the Constitution, the Civil Code, the Code of Commerce, the Foreign Law, the Mining Tax Law, and. the Civil Jurisprudence of Mexico--the last-mentioned being based in Dart on Supreme Court decisions. Ere Mexican Federal Government is supreme in mining legislation because, among other reasons, a large part of the revenue of the Government must come from the fiscal control of the mines. All circulars, decrees, and rulings that affect the mines not only have their origin in the Central Government but are administered thereby. The Department of Industry, Commerce, and Labor is in control of all mines. Attention may here be called, however,

Jan 1, 1929

By Charles H. Fettke

The Bradford field of northwestern Pennsylvania and adjacent portions of New York state has attracted world-wide attention in recent years on account of the remarkable success that has been attained in the application of water-flooding as a means of increasing the extraction of oil from a pool that had almost reached the economic limit by ordinary production methods. It is one of the few large oil fields in which artificially conducted water drives have thus far proved successful, although many attempts have been made to apply them elsewhere. As detailed a knowledge as possible of the character of the producing sand in this field is therefore of considerable interest, not only from a scientific but also from a practical standpoint. Outside the Bradford field, such knowledge should aid operators in determining whether or not their sands are amenable to flooding. In the Bradford field itself flooding operations are not uniformly successful over the approximately 85,000 acres of productive area, due in many instances primarily to variations in sand conditions. A knowledge of just what these variations are would often be a great aid in overcoming the difficulties, or else would save considerable sums of money which might otherwise be wasted in experimenting in areas where the chances of success are very small. Realizing that more precise information in regard to the nature of the reservoir rock was essential to improvements in the methods of oil recovery, the Northwestern Pennsylvania Oil Producers Assn., by private subscription of its members, took a core of the Bradford sand from a well 1/2 mile west of Custer City, Pa., during the spring of 1925. The Forest Oil Co. also took a core of the same sand from a well about 8 miles east of Bradford at that time. The cores were submitted to the United States Geological Survey for study and A. F. Melcherl has published the results of porosity determinations on the Custer City core.

Jan 1, 1929

By Research Staff ? Verde Copper Mines

FLOTATION is now commonly practiced in alkaline ore pulps, yet little is known regarding the action of the alkaline solutions on the ore particles beyond the fact that films of oxidized material form. We wish to chronicle our discovery of the presence of soluble reducing agents in alkaline ore pulps of the United Verde, and present some data on lime consumption. During the grinding and flotation of a pyritic ore containing small amounts of ferrous sulfate and other soluble salts, an excess of lime was added to precipitate the salts, and filtered samples of the solution were titrated with standard permanganate solution. Even in pulps of high causticity an appreciable permanganate titration was always obtained, in spite of the fact that the solutions were shown to contain little iron. Investigation of the cause brought about the discovery of several previously unsuspected compounds in flotation pulps made from pyritic ore. Not only the reducing agents present had to be identified, but also the amount of dissolved oxygen, and a survey was finally made of the free oxygen content and reducing agents of the mill pulp in the concentrating mill at Clarkdale. A great many compounds might form, caused by oxidation of pyrite or other metal sulfides or by reaction between a lime solution and pyrite. The most probable compounds considered were calcium sulfides; polysul-fides, thiosulfates, and polythionates. Later it was discovered in the literature that in alkaline pulp polythionates do not exist and if introduced. are decomposed into sulfites and thiosulfates.1 Any precipitated sulfur is changed by alkali into thiosulfate and polysulfide. Sulfites and sulfides react to form thiosulfate, so that in the end it is possible to have in an alkaline solution only thiosulfate and an excess either of sulfide or sulfite. Confirmatory tests were made and it was finally established that the alkaline mill pulps made from the United Verde ore contained

Jan 1, 1929

By W. F. Hazen

This paper describing the mining practices at a 100 per cent mechanized mine working the Pittsburgh or No. 8 coal bed in eastern Ohio is one of a series being prepared by the U. S. Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. The purpose of assembling this data is to place before those interested in the mining industry the methods employed and the cost data on the items involved in the winning of the coal and its removal to the railroad car at the tipple. Mining costs are governed by the mining method used, which is selected for its adaptability to local natural physical conditions such as the nature and thickness of the coal, its dip, the character of the roof and floor, and the thickness of the overlying strata.

Jan 1, 1929

By C. E. Reinhard

A USEFUL accelerated weathering test should be capable of placing any series of metals quantitatively in the same order of endurance as that noted under a particular set of actual exposure conditions. The development of such a test must necessarily depend to a considerable extent upon data obtained from a wide variety of exposures. This paper offers preliminary data from exposure tests on nine metals placed in 11 locations in the Lehigh Valley, within a radius of 20 miles from Palmerton. The exposure conditions vary from a severe industrial atmosphere to a pure rural atmosphere. The data are offered as evidence of the necessity for the identification and evaluation of the variables of corrosion and as illustration of some of the variations to be considered in the development of a useful accelerated test. It is quite clear, from this evidence, that a useful accelerated test must be versatile to the extent of showing the probable variations of corrosion resulting from differences in atmosphere as well as from differences in the metals. The paper is presented solely with the object of pointing out the wide variations in relative merits of several common metals in resisting corrosion and without any thought of initiating controversy regarding the, merits of particular metals. For this reason the metals are designated only by symbols in the tables and no key is given to these symbols.

Jan 1, 1929

1. Any society of undergraduates at a technical school, comprising students in any branch of engineering, metallurgy, chemistry, geology, etc., may be recognized by the Board of Directors in its discretion as an Affiliated Student Society, and its name, together with the names of its president and its secretary, may be published in Mining and Metallurgy or the Directory of the Institute. The members of such a society will not be named individually on the membership list of the Institute, but may at any time be proposed for election as Student Associates or Junior Members of the Institute, in the usual way. 2. Membership in an Affiliated Student Society, certified by the official representative thereof, and accompanied by suitable testimony as to character and qualifications, will have special weight with the Membership Committee of the Institute, in its consideration of the proposal of a candidate for membership. The Affiliated Student Societies receive the following privileges: 1. A copy of Mining and Metallurgy free; 2. The use of Employment Service; 3. The use of Mining and Metallurgy for publicity purposes, such as printing notices of their activities, etc.; 4. Assistance in obtaining speakers for their meetings, lists of moving-picture films, etc. To retain the privileges of the Affiliated Student Society, its officers must keep in touch with the Secretary of the Institute and advise him of its activities. The foregoing plan is not confined to students in mining engineering or metallurgy. Any undergraduate society of engineers may avail itself of the privileges offered. Societies desiring to be recognized as Affiliated Student Societies are requested to make application to the Secretary of the Institute, giving particulars as to the nature, membership and officers. The following list gives the names of the Affiliated Student Societies as of December 1, 1929, and their presidents and secretaries.

Jan 1, 1929

By C. L. Mantell

Although so common and well known a metal, tin is really a less abundant element than many of those less familiar and usually ranked with the scarce or rare elements, such as cerium, yttrium, lithium, beryllium, titanium, zirconium and vanadium. The color of tin is white, with a slightly bluish tinge. When it is compared with nickel, the latter metal is brown. When placed alongside of tin, chromium is definitely blue. Tin is whiter than silver or zinc. Exceedingly thin films of tin show various shades of brown by transmitted light. The metal has a brilliant luster, and when mirror-polished, has high light reflectivity. The luster depends to a large extent upon the pouring temperature at which the metal is cast. If the temperature be too high, iridescent colors may show on the surface. These are the result of oxide film formation. If the pouring temperature be too low, the surface is dull. Small amounts of foreign metals, such as lead, arsenic, antimony and iron, decrease the luster of tin and impart a yellowish tinge to the metal. The structure is decidedly crystalline. The cast metal is a mass of crystals. When a bar of tin is bent, it emits a characteristic creaking sound. This is called the "cry" of tin, resulting from the grinding of the crystals one against the other during the bending of the metal. Tin metal may lose its crystalline structure by cold working, but grain growth occurs rapidly under the influence of heat. Metal which has been cast at a low temperature may become amorphous as the result of mechanical work. If such material be heated to temperatures well below the melting point, say at 110° C. for a half hour or for a few minutes at 150" C. recrystallization occurs. If the surface of tinned plate, tin foil, or tin meta1 in cast form be etched with hydrochloric acid containing a little free chlorine, attack occurs at the intererystalline faces. The surface shows patterns resembling the frost flowers on window panes in winter. The etched appearance is called moire metallique. Fine dendritic surface crystals of tin may be obtained by casting the metal on a surface of polished steel. In commercial tin plate, the intercrystalline boundaries are shown by fine grooves or channels, .which result from the method

Jan 1, 1929

By James S. Wroth

The Act of Congress approved June 25, 1926 (Public Act 424, 69th Congress), authorized joint investigations by the U. S. Geological Survey and the U. S. Bureau of Mines to determine "the location, extent, and mode of occurrence of potash deposits in the United States." The particular deposits selected for exploration were the extensive rock-salt formations underlying large areas in western Texas and southeastern New Mexico, from which potash salts had been identified in the cuttings and sludges from oil wells drilled with cable tools. The evidence of these sludge samples was qualitative only and beyond definitely proving the presence of potash salts in the salt beds, gave little clue to the possible size, richness, or extent of the potash occurrences.

Jan 1, 1929

Allen & Garcia American Mining Congress American Steel and Wire Company Blue Blaze Coal Company Bogue Supply Company Brandenberger, L. Burke Company, J. J

Jan 1, 1929