Search Documents

By J. Earl Frazier, Howard A. Meyerhoff

IT is not known when silica sand was first noticed along the north coast of Puerto Rico, but the first mention of its occurrence was made in 1922, by N. L. Britton,1 who described its presence in isolated patches extending from Loiza westward beyond Manati. Further observations were made in 1925 and 1926 by Meyerhoff,2 who extended the known occurrences still farther westward to the low hill belt in the Quebradillas limestone immediately south of Hatillo. The extraordinary purity of the sands, which in most localities exhibit no contamination from the nonsiliceous materials surrounding them, was quickly appreciated, and the feasibility of utilizing them for the manufacture of glass was investigated, initially by the Committee on Mineral Resources3 and later (1936) by the Puerto Rico Reconstruction Administration and by H. C. Ray, mining engineer of the Insular Bureau of Mines. In 1934 samples submitted to the Hazel Atlas Glass Co., of Washington, Pennsylvania, were reported to have the composition as shown in the table on column two. Appreciation of the quality of the sand prompted geological and quantitative studies of the deposits, as well as commercial investigations to determine the feasibility of utilizing it locally or on the mainland for the manufacture of glass containers. [ ] DISTRIBUTION OF THE SANDS The quartz sands consistently lie within the outcrop area of the Quebradillas limestone, the youngest of the Miocene formations in the Tertiary coastal plain that fringes the northern coast of the Island. Many of the deposits are closely associated with limestone outcrops, but some appear to be embedded in lagoonal sediments at some distance from rock exposures, and at least one deposit, near Dorado, has been reworked by waves and littoral currents. With this single known exception, the deposits consist of irregular, patternless patches of white sand, which have sharply defined contacts with the surrounding material. Although patches of sand are present in a 90-km. belt that is not more than 5 km. wide, extending from Loiza to Hatillo, they attain maximum size, purity and number in the north central coastal area between Dorado and Barceloneta. Fifty separate deposits have been mapped in

Jan 1, 1945

Samuel T. Wellman, Cleveland pioneer steel man, who was often referred to as the "father of the open-hearth process of the United States," died suddenly on July 11, 1919, of heart disease, at Stratton, Me. For more than half a century, he was closely identified with the improvement of equipment used in the making of steel and contributed a number of inventions that virtually revolutionized the industry. Mr. Wellman was born Feb. 5, 1847, at Wareham, Mass., his father at the time being superintendent of the Nashua Iron Co., Nashua, N. H. After attending public school and a year at Norwich University, he served in the Civil War as a corporal of the first New Hampshire Heavy Artillery. He went to Pittsburgh in 1867 and assisted in starting the first crucible steel melting furnace built in America at the works of Anderson, Cook & Co. It melted a ton of steel with an average of 1000 Ib. of nut coal, which cost less than $1, while the melting of a ton of steel in crucibles in the old fashioned coke furnace took three tons of the very best coke, costing from $2 to $3 per ton. This furnace was a great success and in a very few years had driven the coke furnace out of use. From Anderson, Cook & Co., Mr. Wellman went to the Singer, Nimick & Co. works, Pittsburgh, where he built two crucible steel melting furnaces of the same type. After that he spent some time in the office of the Siemens agents in Boston and also at steel works in different parts of the country, starting crucible steel furnaces. He then went to the Bay State Iron Works in South Boston, Mass., where he built the first open-hearth furnace that was a commercial success in the United States. It made steel of a much better quality than had previously been made in this country. The principal use to which it was put in those days was the manufacture of locomotive fire-boxes. From South Boston, he went hack to the old works in New Hampshire where his father was still superintendent, and built for it an open-hearth furnace, a plate mill, and a bar mill. In 1873, Mr. Wellman went to Cleveland to design and build the plant of the Otis Steel Co. He remained with this company for 16 years as engineer and superintendent. During this time he developed the open-hearth charging machine and introduced the electromagnet for handling pig iron and scrap steel. The first charging machine was operated by hydraulic power, and although it was not entirely satisfactory it performed the work fairly well and encouraged its inventor to build another one, which was driven by electric motors. This proved

Jan 1, 1920

By F. W. Gordon

Since the waste gases of the blast-furnace came to be generally utilized in heating the blast and raising steam, the gradual improvement in the economy of fuel, mainly through the nse of higher temperature in the blast, has impoverished the gases. The increased output per unit of measurement of the furnace, and the increased height of the furnace, have markedly increased the resistance to the blast, thus enormously increasing the duty required from the gases. In other words, a gas reduced in heating power by a further dilution of CO, is required to raise the temperature of the blast to 1800' Fahr., where formerly 600' was a good temperature, and at the same time to raise steam enough to drive the air into the furnace at a pressure of from four to eight pounds in coke practice, and from eight to twelve pounds in anthracite practice, and also pump at least double the water formerly used at furnaces. Hence the necessity for the employment of the best scheme for thoroughly consuming these gases with the least dilution of air, and the use of the best device for absorbing the heat prodnced for the purposes above mentioned. In a former paper before this Society the writer called attention to such improvements as had been made by his firm, by which it was claimed 1400' Fahr. could be maintained in the blast by a less consumption of gas than was required to maintain 900' when using pipe-ovens; and it would not be too much to say that 1600' Fahr. might now be written in place of the 1-400. The object of this paper is to give the practice of our firm in the

Jan 1, 1884

By Christopher C. Barton

Each variable known to affect laboratory measurement of fracture-energy and fracture-toughness is reviewed. Specific examples are cited where each of the variables have been isolated.

Jan 1, 1982

By Eugene C. Robertson

INTRODUCTION A direct proportionality between the observed displacement of a fault and its thickness of breccia and gouge has been proposed recently (Robertson, in press). To validate this finding, an explanation of the mechanics of continuous breccia formation is needed and is offered in this paper. A summary of evidence for the finding will show why an explanation is needed. The correlation between fault displacement [d] and accompanying breccia- plus-gouge thickness [t] seems to be linear and reasonably well established over 6 orders of magnitude, with a range in [d] from 1 mm to 1 km, on a trend of [d/t]= 100, shown in Figure 1. Most of the points are for faults observed underground in mines. The [d] – [t] relation is limited to normal and reverse faults, that have a flat to steep dip and a displacement less than 5 km. It is not applied to large strike-slip and low-angle overthrust faults, whose displacements and breccia thicknesses are widely variable and uncertain. Undisplaced jointed rock is not included in the thickness measurement. A complete description of sources and analysis of the data is given in Robertson (in press). One would intuitively expect that continued movement on a fault would grind up the previously formed breccia and gouge and not produce any more, but the evidence (Fig. 1) indicates otherwise. A physical model to explain continuous formation of gouge and breccia from the wall rocks can be obtained from laboratory experiments on friction.

Jan 1, 1982

By Leon T. Eleiel

Ten years ago a broad knowledge of aerial mapping, coupled with a smattering of geology, qualified one to speak on the subject of the application of aerial mapping to geology. Today, with aerial maps a common tool in the hands of expert geologists on every continent throughout the world, it would be nothing short of presumptuous for the author of this paper, who is not a geologist, to give any geological statements on his own authority. Relatively, today we are only purveyors of general geological gossip, with a definite case here and there by way of illustration. But we can present a story of the really marvellous strides that have been made in the evolution of aerial mapping, built around a skeleton of geological tidbits, from which some useful conclusions may be drawn. The average geologist goes about reading his aerial maps much as one would approach the problem of deciphering a cryptogram. To begin with, typical key expressions appear in recurring sequences and under certain conditions. If once the meaning of these isolated bits of information can be ascertained, the message begins to take meaning. In a similar fashion, the geologist works out his key from aerial maps of territory with which he has some familiarity. He learns that a certain type of thin, white line may mean a vein of quartz. He sees that a certain change in the photographic tone of vegetation on the ground reflects two kinds of soils on opposite sides of a contact. He sees that a certain type of alignment of topographical features often means a fault. He learns that by the erosion pattern he can frequently distinguish soft formations from harder ones. And so, bit by bit, he ties together the information of the picture with his experience on the ground until he develops a reasonably creditable capacity of interpretation. Through the complete gamut of surface conditions, ranging all the way from flat, arid, exposed desert terrain to dense jungle, or rugged mountains, the evidence from which the geologist must make his interpretation varies with bewildering profusion. The quality of photographs which are obtainable may range from perfect pictures in the desert to almost useless smudges in the steaming jungles. One thing he has learned with certainty—the airplane carrying its mapping camera is a superb reconnaissance tool, only awaiting his ingenuity in correlating the pictures with the ground to simplify most exploratory problems.

Jan 1, 1937

By Andrew A. Blair

The increased importance and value of chemical analysis in connection with metallurgical operations is largely, if not entirely, due to the increased accuracy of the analytical methods used for the quantitative determination of the foreign elements always associated with the metal operated upon. This applies especially in the working of iron and steel, and to the determination of the amounts of such elements as phosphorus, carbon, and silicon. The influence of greater or smaller amounts of these elements upon the physical properties of iron and steel will be better understood when the proper experiments shall have been made upon samples whose chemical composition is known with almost absolute certainty. From the present standpoint of analytical chemistry, it is easy to see that at least one reason for the failure of many attempts to solve this problem, is the inaccuracy of the analytical methods used. Even at the present time the frequent want of agreement (over and above the unavoidable error due to manipulation) between chemists working on the same sample, leads one to think that there is still at least a choice in the methods used. It is true that very frequently a faulty method in the hands of a skilful analyst may be made to give corroborative results

By John Gross

A SURVEY of the status of ore dressing in 19231 placed particular stress on the need of research in the crushing and grinding of ore, especially on the need for a method of measuring the surface of the products obtained in crushing and grinding, and for fundamental data on the law of crushing, in order that intelligent conclusions may be drawn from actual crushing or grinding experiments. There has been no satisfactory means of determining the surface of crushed products. The results have been judged entirely by the amount of the various sizes produced, based on sieve sizing for particles above 74 microns in size and on microscopic measurement or elutriation for particles below 74 microns, a method which could give only a general idea of what had been accomplished. The fact that the long controversy between the followers of Kick and of Rittinger has resulted in no accepted conclusion is evidence of the need for fundamental data on the crushing law.

Jan 1, 1928

Electrical requirements in surface mining can be divided into three categories: main substation, plant power, and pit distribution. A main substation may vary from a 500-kva transformer supplying 480-v power to motor-driven pumps and conveyors, to a 50,000-kva substation serving a large beneficiation plant or a large strip mining operation. Regard- less of size, it should be designed with the realization that a failure of the main substation will totally shut down the operation. Location of a main substation usually is a compromise between expense of running the incoming high-voltage transmission lines and the voltage drop of long secondary runs. Based on a geological survey for immediate and future areas of excavation, the main substation should be located as near to the center of load as possible.

Jan 10, 1967

By Bennett R. Bates

Nowhere in the world has cone classification in closed-circuit grinding with tube mills reached as high a state of development as on the Wit-watersrand. In the development of the Far East section the necessity of fine grinding to obtain satisfactory residues gave rise to a situation with which the cone could cope only at a great sacrifice in efficiency of tube-mill grinding. H. A. White1 recognized the limitation of the cone in his study of the theory of tube milling as early as 1915, but it was not until Ewing, Davis and Willey2 carried out their tests at Springs Mines during 1920 that the advantages of mechanical classifiers were demonstrated. During the fall of 1924 the writer supervised a series of tests with Dorr classifiers undertaken by Mr. White, Consulting Metallurgist, at the mill of the Geduld Proprietary Mines, Ltd., Dersley, Transvaal (Far East Rand). The importance of classification to obtain efficient tube-mill grinding was thoroughly demonstrated. The installation of classifiers of the above type that followed the test confirmed the results of the experimental work. Tests with Cones, Straight Type and Bowl Classifiers The test at the Geduld mill was made to determine the relative grinding efficiency of a tube mill when grinding in closed circuit with cones, straight type Dorr classifier and Dorr bowl classifier. The efficiency of a tube mill, as expressed in this article, is based on the tons of minus 200-mesh material produced by the mill. The efficiency is also expressed in terms of tons of minus 90-mesh material produced by the mills to correspond to the standard practice on the Witwatersrand. The results given for the performance of the tube mills grinding in closed circuit with cones (Fig. 1) were taken from previous tests carried

Jan 1, 1926

By Frank Antisell

CERTAIN physical and chemical properties of copper are so intimately related that a change in variation of the physical properties indicates a certain chemical change. The standard specifications of copper of the American Society for Testing Materials are based upon physical characteristics with one exception, namely, the copper contents. The physical standard includes electrical properties, defects in the "set or casting," variation in dimensions, weight, etc. Paragraph 4 of the specifications states, " Wire bars, cakes, slabs and billets shall be substantially free from ;shrink holes, cold sets, pits, sloppy edges, concave tops, and similar defects in set or casting." Shrink holes and concave tops indicate both physical and metallurgical defects; cold sets, sloppy edges, etc., indicate physical defects only; small pit holes may be indicative of either or both physical and metallurgical defects, depending on conditions under which they originated. To the refiner, a copper casting, no matter how made, is known as a "shape," irrespective of whether it is wire bar, ingot, cake, slab, billet, etc. As practically all shapes are cast in an open mold, that is a mold without cope, the surface of the shape cools in contact with the atmosphere and has a coating of oxide. Certain phenomena of the surface indicate the adaptability of the metal for forging or rolling. The writer believes that it is much simpler to produce shapes that are metallurgically correct than those that are mechanically satisfactory. When copper is to be rolled into thin sheets or drawn into very fine wire, the slightest physical defect becomes evident. It is, therefore, of the utmost importance to, consider every characteristic of the shape and ascertain the physical and chemical relationship. Pitch and Set.-The appearance of the surface of the copper when cooled is considered as to its "pitch," or the general contour of the surface of the shape (which may vary from a concave to a convex); and the "set," or the detail appearance of the surface of the shape (the wave-like struc-

Jan 1, 1920

By J. E. Schiller, S. E. Khalafalla

Due to its unique surface properties, magnesium oxide (MgO) is an excellent medium to filter asbestos and other suspended solids from water. MgO operates up to twice as long as a sand filter before backwashing is required while flow rate and filtrate clarity are as good or better with MgO.

Jan 1, 1984

By William P. Blake

The mineral, garnet, is a common associate of copper-ore in the southwestern portion of the United States. This association may be observed on a large scale in southwestern Arizona, in southern New Mexico and in Sonora, Old Mexico, especially at El Cananea, and at Nacozari. At other localities in Mexico the general occurrence of garnet " as a contact metamorphic mineral" in the copper-deposits of the Cretaceous limestone is noted by José G. Aguilera.1 It is usually found at the contact of this limestone with diorites, granites, etc., at numerous mines. The same authority also cites the occurrence of garnet in metamorphosed Cretaceous limestone alongside of diorite dikes in association with iron-ore. Other foreign examples are found in the Banat and Servia, at Rezbanya in Hungary, and Offenbanya in Transylvania, and at Bogoslovsk in the Urals. In New South Wales, at Broken Hill, the gangue in the Proprietary mine is chiefly garnet, with quartz, opal and rhodonite.2 Also, in a recent paper by George Smith, entitled, " The Garnet-Formations of the Chillagoe Copper-Field, North Queensland, Australia,"3 it is shown that in the copper-field of Chillagoe, Australia, where there are many lode-formations, about one-half of the number are garnetiferous, and many of this garnet-type are associated with magnetite, which is regarded as of analogous origin. The two minerals are found merging imperceptibly into each other. These examples suffice to show the very general and wide distribution of garnet as an associate of copper-ore. In addition to the localities already mentioned as known in Arizona may be mentioned the copper-mines and occurrences

Jan 1, 1904

By E. H. Crabtree, T. C. King

THE ferrosilicon grinding unit at the Central Mill of the Eagle-Picher Mining & Smelting Co. near Picher, Okla., was completed in March 1947. The object of the plant was to grind pigs of ferrosilicon, having a size of approximately 1 ½ by 4 by 12 in. and an analysis of 85 pct Fe and 15 pct Si, to approximately 100 mesh by crushing and wet grinding in a ball-mill classifier circuit. The minus-loo mesh ferrosilicon had formerly been purchased, and was used as medium in the heavy media process for treatment of lead-zinc ores. From the standpoint of dollars and cents, the cost of minus-100 mesh ferrosilicon was roughly $40.00 per ton more than pigs of the corresponding alloy delivered to the mill. Estimated wet grinding costs were considerably below this figure. The possible saving in cost of make-up medium for the cone plant was particularly attractive since, at that time, the plant losses averaged over four tons of minus-100 mesh ferrosilicon per day. Aside from the probable saving on the grinding charge, the need for such a unit was twofold. First, periodic fluctuations in the differential between the top and bottom densities of the cone were thought to be detrimental to metallurgy. There was little doubt that an intermediate differential existed at which the heavy media separation was most efficient, representing a compromise between concentrate grade and tailing loss. Furthermore, if a finer, but considerably cleaner, medium could be obtained, there was the possibility that the differential could be decreased without increasing the viscosity, or conversely, the viscosity of the medium decreased without increasing the differential. Preliminary to experimental work aimed at pegging the cone differential and circulating medium viscosity at whatever values were found to be most efficient, it was essential to have control over both the non-magnetic content of the medium and the particle size of the contained ferrosilicon. The latter was possible by means of a grinding unit at the mill. Second, whereas the ferrosilicon alloys are made by a number of manufacturers, only two, to our knowledge, grind it in any quantity for use in heavy media plants. For all practical purposes, the Central Mill was limited to one source of supply, a particularly vulnerable position. In case the supply was cut off, it was thought that pigs of the 85 pct Fe, 15 pct Si alloy could be obtained elsewhere, providing means of grinding them was available. There was no published information available covering wet grinding of ferrosilicon. Dry grinding in batch mills and in continuous mills with air classification was being practiced, but the cost of grinding was excessive and the dust condition objectionable. It appeared that primary and secondary crushing was no particular problem, providing heavy duty equipment was used;

Jan 1, 1947

By Henry Morris

AS STATED last year, in a similar review by David White and the author, any review of the petroleum industry purporting to cover such a wide field can only mention the principal facts. This incompleteness is necessitated not only by the limitations of space, but by the delay in receiving detailed information. The principal feature of the year, in Europe, was a material increase in the consumption of petroleum products, and a notable decline in prices. Although there we relative increases in production in Roumania and Poland, the total did not by any means keep pace with the increase in consumption, which, as usual, was supplied "from America and both the Near and Far East. The interest in Asiatic production, as usual, centers around the Persian fields, which, according to the annual report of the Anglo-Persian Oil Co. published at the close of last year, it was estimated would amount to 3,775,000 tons by the close of the fiscal year, March 1, 1924. Russia also showed an increase in production. In Africa there was nothing of outstanding interest in production, although Egypt showed a decrease and the goverment refinery at Port Said was closed.

Jan 3, 1924

The housing of labor and sanitation at mines in India are difficult problems to solve because-no more than two or three castes will accept the same conditions, and conditions suitable to one coal-field are not applicable to other fields. It is also necessary to consider the financial standing of the different companies. The European companies, which pay 30 per cent. and more dividends, can erect more suitable houses than the Indian companies, which are just able to keep their heads above water. The Santhal will not live in a bucca-roofed house as a permanent dwelling, and both the Santhal and Koras have an aversion to living in a line of attached huts. They have forsaken a whole, line of houses in one of which a case of sickness or death has occurred, and those houses were afterward considered unfit by all other classes of natives. The Santhals, Koras, and Douri castes will not take drinking water from a stand pipe; wells must be furnished. When well water is not available, these people will take water from the nearest pool or tank regardless of whether or not the water is stagnant. The well tops should not he completely enclosed, nor should there be a drain around the top. The ground should slope away from the well. In the Girieih coal fields, the miners have a great objection to pucca floors; they prefer earth which is lapped, easily cleaned, and renewed. As it is customary for the miner to build his own house, the company supplying the roofing material, he takes a special interest in it, keeps it in order, and hesitates to leave it. Each house is surrounded by its own bit of land, which the inmate cultivates.

Jan 12, 1918

By I. J. Lin

Surfactants are classified according to the size and strength of the hydrophilic and lipophilic groups of the molecule. The balance of these two opposing groups is known as the hydrophile-lipophile balance or HLB. According to this definition, a lipophilic surface-active agent is assigned a low HLB number and a hydrophilic one-a high one. The HLB value is obtained as follows, on the basis of known group values defined empirically by Davies' and listed in [Table 1:]

Jan 1, 1972

By Koehler S. Stout

At today's mineral prices, unproductive or low productive work in any underground mine must be kept at a minimum to insure a profit. Improper level and raise spacing can be one of the contributing factors to high production costs, and little can be done to reduce these costs after the spacing interval has been chosen. The objective in selecting level spacing is to find the most desirable interval which produces ore at the least cost per ton while still operating within the highest margins of safety and efficiency to the workmen. In addition, maximum possible recovery of ore under the conditions must be attained.

Jan 11, 1962

By K. R. Y. Simha, W. L. Fourney, D. C. Holloway

An experimental investigation was performed to evaluate the role of stress waves in the pre-splitting operation. 3D birefringent Plexiglas models and the dynamic photoelastic technique were used to visualize the stress waves generated by the detonation. Simultaneous as well as sequential detonation of the explosive charges were investigated. The development of fractures and stress waves were recorded using a high speed multiple spark gap camera of the Cranz-Shardin type. The experimental data was analyzed and displayed-on a Lagrangian diagram to present an overall picture of the entire dynamic event. It was repeatedly observed in the tests that the time required for the completion of the pre-splitting operation as practiced in the field is of the same order as that for the transit time for the stress waves between the blastholes thereby revealing the highly elasto-dynamic nature of the event.

Jan 1, 1982

By C. E. Shoenfelt

The most important development in an otherwise colorless year in Colorado oil fields was the completion, late in 1933, of a well on Iles dome on the western slope of Colorado, with an initial production of 1100 bbl. of oil. No great amount of activity beyond the drilling of necessary offset wells is to be expected as a result of the completion of a well of this size because the acreage on Iles dome is closely held; there is no pipe line outlet other than to the Texas Company's small refinery at Craig, 24 miles distant; and the market for the oil is limited to the demands of sparsely settled communities in the high mountains. The Iles field is located on a large dome developed in Mancos shale of Cretaceous age, and having a closure of approximately 400 ft. The structure is highly faulted on the southern end. The first commercial oil well on this dome was completed by the Midwest Refining Co. on the south side of sec. 22-4N.-92W. Oil of 37" gravity was developed in Nancos shale at 2560 ft. and water in the Dakota sandstone at 2630 ft., but a considerable amount of additional oil was found in the shale immediately overlying the Dakota. From 2630 ft., the well produced in 16 hr. 750 bbl. of fluid, 33 per cent of which was water. Production in the Sundance sand of Jurassic age was found in the Midwest Refining Company's No. 4 Parkinson, in the NE.-SW.-SE. of sec. 22-4N.-92W., and completed on the last day of the year 1926, for an initial production of 450 bbl. of oil at a total depth of 3242 ft. The well completed in 1933 is also a Sundance sand producer and was finished at a depth of 3447 ft. It extends the productive area of the field about a quarter of a mile cast. The Iles field is said to have a potential production of 5000 bbl. of oil a day from its present wells, but for the past year has been held at about 600 bbl. a day. The most important test, stratigraphically, ever drilled on the western slope of Colorado is the California Company's No. 1 Raven, NW.-SE. of sec. 30-2N.-102W., which had an initial production of 138 bbl. of oil of 32" gravity, in the Weber formation (Pennsylvanian) between 5750 to 6315 ft. It mas drilled to 7137 ft., probably near the base of the Weber, and then plugged back to 6315 ft. It was shot quite heavily with nitro-glycerin, but failed to respond. While the well can hardly be classified

Jan 1, 1934