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By Paul M. Tyler

Magnesite is of importance primarily as a refractory material for lining steel furnaces , although substantial amounts are used in the production of flooring compositions and other building materials and for certain chemicals , notably epsom salts . Since consumption for all of these purposes is largely in the eastern United States and domestic deposits are situated in California and Washington , this country's magnesite mining industry , which was created largely by war- time conditions , has subsequently been sustained by tariff protection .

May 1, 1931

By PALMER LARSEN

INDEX TO GEOPHYSICAL ABSTRACTS

May 1, 1931

By R. R. Sayers

That the maintenance of proper air conditions is a most important factor in the control of occupational hazards is shown by the large amount of material presented each year through the technical journal's on the effects on workers of injurious dusts, gases, and variations in temperature and humidity.. SUMMARY OF RECENT LITERATURE ON EFFECTS ON WORKERS OF EXPOSURE TO DUSTS The subject of the control of dust and dust diseases continues to be a matter of serious concern in most of the industrial countries of the world, as indicated by the following summary of reports published in a number of foreign countries as well as in the United States. Australia. The Workmen's Compensation Act of 1920 for New South Wales3 provided for the promulgation of schemes for the compensation of workers dis- abled by silica or other dust. In 1924 the prevalence of silicosis and tuberculosis among Sydney stonemasons, quarrymen, sewer miners and rockchoppers was investigated by a Technical Committee of Inquiry, appointed upon the recommendation of the New South Wales Board of Trade. The findings of this committee were published by the Government in 1925. No scheme was promulgated by the Government and in 1926 the Act was amended limiting its scope to workmen disabled by disease caused by silica-dust. This was promulgated and gazetted on September 16, 1927, and applies to men working in sandstone as stonemasons, quarrymen, rockchoppers, and sewer miners in the County of Cumberland.

Feb 1, 1931

By T. W. Quayle

This paper describing mining practices at the United Verde copper mine, Jerome, Ariz., is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various mining districts f the United States. At present mining operations are being conducted both underground and by electric shovels in an open pit. The open-pit work has been described by E. M. J. Alenius in a previous publication of the Bureau of Minos;3 the present paper will be confined to a description of the underground mine. The underground methods comprise horizontal cut-and-fill, shrinkage with delayed filling, horizontal square-set, inclined square-set, and top slice. The normal daily production of the underground mine is 3,000 tons of copper ore per day, requiring the employment of 900 men underground.

Jan 1, 1931

By IRENE AITKENS

The Mining Law of 1910 , with amendments of 1914 and 1928 , is at present in force in the Dominican Republic . The first and basic mining law of the Republic was passed in 1876 , and although numerous changes and amendments have been made from time to time , the new laws and amendments thereto have not changed the original or basic law materially . However , these enactments have materially changed the legal methods governing the exploitation of the mineral resources of this country and have added new regulations and requirements to those concerning certain specific minerals , etc. The original or basic law still exists as it was first promulgated to protect the rights of the Dominican Republic itself , the rights of the landowner , and the rights of prospectors in general . The Mining Law of 1876 remained in force , without amendment , until it was superseded by the law of May 25 , 1904 , an enactment modeled after the Mexican mining law and designed especially to encourage the investment of

May 1, 1931

By E. P. Youngman

Before the World War the use of zirconium and its compounds was largely experimental and confined almost wholly to Germany and Austria . Occasionally small lots of zirconium ore had been produced in the United States ( 1,000 pounds in 1869 , 26 tons in 1883 , and 3,000 pounds in 1903 ) and used (with monazite ) in the manufacture of various lighting devices , especially incandescent gas mantles ; but it was not until 1906 that the discovery of the natural zirconium oxide in large quantities near Sao Paulo , Brazil , first gave promise that a zirconium industry eventually might be developed . Edward Rietz , who worked the Brazilian deposits , interested German chemists in extending the use of zirconium , and by 1911 trade journals were listing German firms as manufacturers of compounds or products derived therefrom . For a time zirconia was one of the various oxides used in the Nernst lamp . It was used also for crucibles and hearths as refractory material ; in the manufacture of chemical utensils ; in enamels ; in the place of bismuth subnitrate for defining Röntgenray pictures of the stomach ; as a pigment ; in medicine ; and in a number of other ways . The Germans were credited also with producing a remarkable zirconium steel , which , it was claimed , was much superior to other alloy steels . During the World War the United States Government investigated the possibilities of zirconium , as well as those of other steel -hardening elements , and a large automobile manufacturer actually purchased a substantial quantity of ore with the purpose of employing zirconium in automobile steels . Immediately after the armistice the Government ceased its investigations ; but despite the difficulties experienced by various investigators in reaching concordant results , interest in the use of zirconium as a steel -hardening agent , as well as in other uses of the element and its compounds , continued . In 1918 the Foote Mineral Co. , which had been interested in zirconium for several years , was exploiting the deposit in Brazil formerly worked by the Germans and was supplying zirconia in the form of ore , brick , and cement for refractory and other purposes . About the same time the Electro Metallurgical Co. , which before the entrance of the United States into the war was experimenting with zirconium alloys , supplied in tonnage quantities the demand for these alloys . In 1919 it was reported that American manufacturers , after several years of research, were producing in commercial quantities pure zirconium oxide , which was finding a place in the manufacture of small refractory articles , scorifying dishes , crucibles , tubes , and one- piece furnace linings . In 1920 the lowering of the price of zirconium metal powder ( because of improved metallurgical methods ) promised the production of the metal on a semicommercial scale . In 1924 the Titanium Alloy Manufacturing Co. introduced a new opacifying agent , " Opax , " made from zircon . A year or two later some of the large pottery manufacturers became interested in the use of zirconium oxide as an opacifying agent , the increased production of titanium pigments having resulted in the production of zirconium as a by-product at a price that could compete with tin oxide . In 1928 it was reported that the industrial use of zirconium oxide was increasing steadily in the manufacture of brick , crucibles , and other refractory products , such as high- temperature cements . However , the reluctance of producers to install additional and more suitable

Jun 1, 1931

By E. P. Youngman

Zirconium, formerly distinctly a rare element, is rapidly becom- ing of rather extensive commercial importance. Economic features of the zirconium industry, together with general information regarding the metal and its compounds, are discussed in a separate paper, to which this paper is a supplement. In addition to giving a brief discussion of the four or five de- posits that so far have proved to be commercial sources of the element, this circular summarizes available data (including some hitherto unpub lished material from the files of the Bureau of Mines) upon other occur- rences, including many of scientific interest only, of the two commercial. minerals, zircon and baddeleyite, and also data upon some of the minor minerals, such as eudyalite and cyrtolite, which have attracted addition- al interest in recent years because they are frequently richer in hafnium than the more common zirconium minerals.

Jun 1, 1931

By I. AITKENS

The basic mining law of Cuba is contained in the basic Spanish mining decree having the effect of law December 29 , 1868. This legislation has remained substantially unchanged , with the exception of a few minor administrative changes made by the present Government . These changes provide for the register of mines , oil wells , and operations of such nature , and also provide for the keeping of records showing the value of minerals taken out . By Royal decree of April 17 , 1883 , the law of mines enacted for the Peninsula ( Spain ) on July 6 , 1859 , and the General Bases of December 29 , 1868 , were declared in force in Cuba . In order to encourage the mining of iron org , in 1883 the Crow of Spain issued a royal decree to the following effect.

Jul 1, 1931

By IRENE AITKENS

The emerald is the most costly of all gems , due to the scarcity of flawless stones . This fact gave rise to the ancient axiom , " As rare as an emerald without a flaw . The finer gems not only command the highest prices at all times , but when flawless are considered the most highly prized of all gem stones . George F. Kunz divides emeralds into two distinct classes : " Exceptional specimens , " which bring as much as $ 6,000 a carat ; and " fine- quality specimens , " which bring about $ 1,000 a carat .

Jul 1, 1931

By H. B. Brunot, L. C. IlsLey

The chief object of the Electrical Section of the United States Bureau of Mines is the study of causes and means of preventing accidents resulting from the use of electricity in mines . A large part of this work for the last 20 years has been the inspection and testing of mining equipment under the provisions of schedules which give the minimum requirements considered essential for the safety of equipment intended for use at or near the working faces of dusty or gassy mines . During the first few years of this work , particular attention was paid to the explosionproof features of the various accessories such as motors , controllers , and other parts . The knowledge of the essentials necessary for safe designs of enclosures has since been augmented by field experience and by data obtained in testing a large number and variety of designs . With our present knowledge it would seem that a disproportionate stress was placed on making the various enclosures explosionproof , but not enough thought was given to the danger from wiring and connections outside of explosionproof enclosures . The list of equipment that has met minimum requirements for safety and has been approved as permissible by the Bureau of Mines includes storage - battery locomotives , power trucks , drills , loading machines , conveyors , cutting machines , room hoists , pumps , concrete mixers , and rock-dusting machines . The wiring on some of the machines is comparatively simple and sometimes , except for the trailing cable , may be entirely within the explosionproof enclosures . In general , there is outside wiring between enclosures , and on the larger machines the wiring may be extensive and complicated . In considering the safety of wiring for mining machinery , attention must be given the severe service and unfavorable surroundings imposed by mining conditions . Some of the matters that require consideration are : ground . The lack of care of the exterior wiring to be expected in the average mine . The lack of adequate periodic inspection of the wiring . The absence of adequate facilities for satisfactory inspection and repairs under- The severe conditions of moisture , dirt , mechanical injury , and low voltage encountered in mining service .

Apr 1, 1931

By E. P. Youngman

From a scientific point of view , the zircon is by far the most remarkable of the gem stones , and a satisfactory solution of the problems offered by its characters and constitution has not yet been made . 3 Three distinct forms have been recognized , differing in specific gravity , hardness , optical properties , behavior when heated , and color.4 ( See section of this paper entitled "Description and Properties . " ) Zircon as a gem stone has not been as well known as its properties warrant . It is one of the most brilliant of the precious stones (having a high refractive index) . The colorless zircon rivals the diamond in brilliance and fire play to such an extent that a judgment based entirely upon optical inspection might be erroneous . In the opinion of gem authorities , the colored stones likewise have much merit . The blue zircon ( " Starlite" ) was so named by Kunz because of its resemblance to a " star twinkling in the night . " Another gem authority describes the leaf- green stone as one possessing a restful beauty , the red stone as having a certain ( though somber) grandeur , and the golden-yellow stone as being unsurpassed in magnificence . The slowness with which the zircon , a stone frequently mentioned in ancient literature , has come into use in modern jewelery may be owing to the fact that authorities differ as to whether the colorless and the blue zircons are found as such in nature or are treated stones . Any treated stone , although the material of which it is composed may be essentially genuine , has been considered a deception . However , according to Kunz , " Starlite is now sold over the entire world ; never has anything been so well introduced. "7 Dr. Foshag, mineral curator of the United States National Museum, states that the first allotment of zircons to enter the United States was obtained in 1921 from Siam ( through France ) for scientific or museum purposes and that four or five years later the stones were adopted by the jewelers of this country . Retail jewelers are displaying the colorless type and the blue stones , especially , in finger rings , necklaces , and like ornaments . Fine crystals have been used somewhat extensively in jewelling watches and as supports for the edges of fine balances . At one time zircons were though to be appropriate in mourning jewelery .

Jul 1, 1931

By Paul M. Tyler

Bismuth is a useful metal and rather an uncommon one . The element probably constitutes much less than one-millionth part of the earth's crust , but the potential supply - to no small extent as a by-product of the production of lead and copper with which it is associated in nature has tended for many decades to exceed the demand. A single mine in Bolivia could readily flood the world's markets , and considerable quantities of bismuth are allowed to escape recovery at many smelting plants .

Jul 1, 1931

By D. Harrington

Along with other phases of mining , the ventilation of metal mines has been affected by the business depression of 1930. As might be expected , some of the results are favorable , and some are distinctly disadvantageous to progress . Probably the worst effect of the recession of mining activity is that , as usual , one of the first departments of almost any industrial establishment ( and this is especially true of mining ) to be curtailed is that which concerns what might be called welfare work , such as safety , health , etc. , and ventilation : in consequence , a number of men who were employed mainly on ventilation work in metal mines are now out of employment and their former duties either are being handled by others as only part of a crowded routine or are being allowed to lapse . On the bright side of the picture is the following paragraph from a letter by the ventilation and sarety engineer of the United Verde Copper Co. , Jerome , Ariz . , indicating that money and effort expended on ventilation during " flush " times give results which aid in money savings when depression comes : The desirability of absolute control over the ventilation system has again been demonstrated at this mine . Under full operation we have been using approximately 500 hp . to drive our big fan . Under curtailed operations we naturally do not require as much air , so by sending the air only where needed and airing out all other places periodically to keep timber , etc. , in good condition we have been able to economize in the quantity of air required . The fan speed has been reduced and the power dropped to 300 hp . , thus effecting a material saving in the power bill , and still maintaining an efficient ventilating system . "

Jul 1, 1931

By J. D. Tolman

In view of present interest in a revival of gold mining enterprises, papers dealing with the development of small gold properties are apropos. The present paper deals with the operation of a small gold property in the exploration and development stage, mining and milling 25 tons of ore daily, and indicates what may he expected in the way of mining costs under northern climatic conditions, by practicing rigid economy, at a property where disproportionate overhead costs are unavoidable bacause of the small rate of production. The output of this prospect is treated in a small amalgamation plant which has been described in a previous circular.. HISTORY Prospecting in the district was begun in 1909, and by 1911 the adjoining mines, Hollinger and McIntyre, were in operation. Actual work was begun on the Rochester claim in July, 1922, and carried on through 1924. The property was closed until 1928 when the present company took it over, together with the other holdings of the Canadel Mining Co. A small mill was started as a pilot plant on March 24, 1929, and is still in operation.

Jan 1, 1931

By R. M. Santmyers

Except for optical purposes and a few other special uses quartz and quartzite are to a considerable degree interchangeable. This also may be said with respect to pulverized quartz and ground silica sand, which are discussed in a separate paper of this series. All these materials, except perhaps quartz crystals of optical grade, are abundantly available in many parts of the United States. In the form of ordinary crushed stone much of it is sold at $1 a ton or less, and ordinarily

Aug 1, 1931

By Paul M. Tyler

Masurium and rhenium are two elements known only to a few scientists and known to them for scarcely more than five years . The existence of two members of the manganese family was long suspected , and places were left for them in the orderly table of the periodic systemas developed by Mendeljeeff . The empty spaces left in this table some 60 years ago were for elements numbered 43 and 75 , respectively , and since it was evident these were related to manganese they were sought for in research laboratories under the names of ekamanganese and dvimanganese . This nomenclature is in harmony with that usually employed in describing hypothetical elements , and the prefixes are taken descriptively from ancient Sanskrit wherein the word " eka " means one and " dvi " ( also spelled dui or dwi ) means two . Ekamanganese or element 43 was once removed and dvimanganese or element 75 was twice removed from manganese . It was further possible to predict that these elusive elements would not only be related to manganese but would have a great deal in common with certain other elements . It was reasonable to suppose that element 43 , merely because it stood in numerical sequence between element 42 and element 44 , would likewise prove to be intermediate in many other respects . Since its next neighbors were molybdenum ( No. 42 ) on the one hand and ruthenium (No. 44) on the other , ekamanganese could be given in advance what would correspond among persons to a social and economic rating . Similarly , the properties of dvimanganese were likely to be in simple harmony with those of tungsten and with those of osmium , which latter , like ruthenium , is a member of the platinum group of metals . Another inference , although one which could not be stated with scientific certainty , is that these new elements because they have odd instead of even atomic numbers , would be even more sparingly distributed than their near neighbors , none of which is abundant in nature . This inference has been amply supported by available evidence . These elements eluded discovery until 1925 and never have been found except as minute traces in complex association with relatively rare minerals . In 1930 , for the first time , rhenium became available in quantities which give promise of commercial possibilities , but masurium still stands on the border of the unknown , like some distant star speck photographed and identified by vigilant astronomers but invisible without the aid of the powerful tools of science . The telltale flame of element 43 has been charted by its spectrum lines ; but beyond that , little more can be said except perhaps to repeat the forecasts made for ekamanganese before the Noddacks captured it and gave it a definite name . Certain rare - mineral dealers will furnish molybdenite samples from Norway which are said to contain masurium as well as rhenium , but except for a few highly technical statements as to its behavior in the spectrograph , nothing in the way of concrete information on masurium has come to the notice of the present writer . The literature of rhenium is a little less meager and a brief résumé of the data available in the files of the Bureau of Mines may be of interest not merely because of the novelty of the metal but because its unique properties and increasing availability afford a prospect of its finding employment in industry .

Jul 1, 1931

By H. S. Martin

This paper, describing the concentrating practices at the plants of the Utah Copper Co., is one of a series being prepared by the United States Bureau of Mines in which the data are given in as nearly uniform c manner as possible. The Magna mill is 19 miles west of Salt Lake City on the routes of the Lincoln and Victory highways, and the Arthur plant is 1 mile west of the Magna mill. Both are on the main road west of the town of Magna and east of the town of Garfield.

Jan 1, 1931

By E. B. Kester

Of the many angles from which coal can be studied it is evident that some have a direct and others have only an indirect bearing on its physical or chemical nature . The more drastic the treatment employed in an investigation , the more inferential become the conclusions permissible from the experimental evidence obtained . Thus , ultimate and proximate analyses tell something concerning age , behavior on carbonization , and possible industrial usefulness , but nothing regarding structure or composition in the larger sense . Strong oxidation reveals the fact that benzenoid , pyrrol , and furane rings are prevalent in the chemical substances present , and milder oxidation indicates that the mass of coal , as in the case of the peats and lignites , is humic in character . But beyond such points of information , very little additional can be gained by the use of these more or less vigorous measures . To gain wider knowledge of the actual constituents of coal substance as found investigators have worked out systems of separation by means of solvents , of which a large number have been employed at various times both singly and in combination . The list of solvents includes petroleum ether , benzene , toluene , xylene , ethyl ether , alcohol , acetone , carbon bisulphide , pyridine , quinoline , aniline , phenol , tetralin , glycol ethyl ether glycol ethylether acetate , glycol methyl ether , glycol diethyl ether , pine oil , mesityl oxide furfural , benzaldehyde , ethylene oxide , rosin , caustic potash in solvents , amyl alcohol plus pyridine , chloroform , carbon tetrachloride , acetylene tetrachloride , naphthalene , and others . Once a coal has been extracted it has become common practice to subdivide the extract by means of partial solution in other and weaker solvents . Thus , we find the oily and solid bitumens of Fischer ( 1 ) , 3 Bone ( 2 ) and others ; the alpha , beta and gamma constituents of Wheeler ( 3 ) ; the classification of Novak and Hubacek ( 4 ) embracing oils , resins A , resins B , bitumens An , bitumens Bn , and bitumens Cn ; Crussard's ( 5 ) malthenes , asphaltenes , and carbenes , borrowed from asphalt terminology; and the 40 or more subdivisions of the phenol extract of coal worked out by Frazer and Hoffman ( 6 ) . Perhaps the primary object of interest in these many researches has been to find the coking principle of coal , and to study it and to learn why certain coals form hard , wellfused cokes , and others merely fall to pieces during carbonization . The origin of the various constituents of the gas and tar , the temperature at which each forms , and something of the mechanism of their synthesis have also been sought , as well as new bases for adjudging rank .

May 1, 1931

By L. D. Stewart

The main reasons for developing an induction system for signaling from the cage are, first, to increase safety, and second, to effect economies in the operation of cage and ship hoists, especially when work is being done in the shaft. To-day nearly all mines which employ safe methods have installed safety gates on cages, at the different levels, and at the collar of the shaft. Under the old system in some instances signals could only be Given from the station outside the cage, and in other cases, after the signal was given the only method whereby those riding on the cage could control its movements consisted of pulling the bell-rope hanging in the shaft, an uncertain and somewhat hazardous procedure at best. With the system herein described, however, it is possible, without opening the gates, to signal to the engineer from any place in the shaft whether or not the cage is moving, and finder the same conditions it is possible to converse with the engineer by using the telephone. In short, the cage tender has at all times an opportunity either to signal or talk to the engineer without leaving the cage.

Jan 1, 1931

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