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By F. W. McNair

WITHIN the last twenty-five or thirty years the actual operations of the great mining industry have passed almost wholly under the charge of men trained in the technical colleges. It follows that the industry is profoundly influenced for good or ill by the character of the training which the college graduate receives, and the relations existing between the industry and the colleges. This fact seems to be generally recognized, as evidenced, for example, by the existence of a Committee on Technical Education created some two or three years ago by the Mining and Metallurgical Society of America. In 1921 this committee rendered a very able and. extremely well poised reports of technical education as applied to the prospective mining engineer. It deserves the attention of every one interested in the effectiveness of engineering training. That the importance of the relation between the mining industry and the engineering colleges is recog-nized is evidenced also by the mass of criticism, usually adverse, which is proffered to and often hurled at the colleges by those in the industry. The man inn the field sometimes goes so far as to say that engineering educa-tion is hopelessly inefficient and its product worthless, while the college worker sometimes complains that the demands of the industrialist are too numerous and conflicting to be met, and adds that they would' best be ignored. Between these extremes, there seems to be a general consensus of opinion that the training of the would-be engineer can be, and. ought to be, made much better than it now is.

Jan 4, 1923

By James B. Vance, Parviz Mottahed

An extensive research program has been carried out at PCS Mining for some time into the use of high frequency microseismic emissions in the range of 30-200 kHz for roof fall warning in the mines. A laboratory investigation on loaded samples of potash has established a close correlation between acoustic emissions and the applied load. The tests also indicated the occurrence of the Kaiser effect. The positive and encouraging response from underground testing and controlled laboratory testing has lead to the extension of the investigation into correlation of the high frequency microseismic emissions and the change in stress distribution due to mining. Hydraulic borehole pressure cells were installed at different depths ahead of the advancing boring machine. The output due to the stress change and the microseismic event count was monitored by a continuous chart recorder. This paper discusses the results of this instrumentation. The results confirm the strong correlation between the two measured parameters and outlines future areas of research for the use of the high frequency microseismic emission techniques in quantifying the changes in stress distribution.

Jan 1, 1984

By Alan Morris

IN a previous paper1 the results of cutting tests on free-cutting brass rod were reported. Investigation was made of the effects of variation in lead content, microstructure and cold drawing. The author's reply to the discussion of that paper includes a study of the directional cutting properties of drawn and annealed rod. The present paper records the results of tests made on series of samples in which the tin, iron and copper contents have been varied. The apparatus, used and method of testing are described in detail in the previous paper. The machine is of the pendulum-operated milling type used and described by Airey and Oxford.2 Angular readings of the height to which the pendulum rises after falling from a fixed position, both when a cut is made and when the pendulum swings freely, give the basis for calculation of the energy consumed in making a cut. Careful weighing of the sample before and after cutting gives a measure of the amount of metal removed. The results are expressed in foot-pounds per cubic inch of metal removed, and have been called "unit cutting energy." In the course of the discussion of the author's earlier paper, W. B. Price reported large-scale tests involving some 50,000 lb. of material. These tests indicated that the addition of as much as 0.6 per cent of iron and 0.25 per cent of tin had apparently no adverse effect on the high-speed cutting characteristics of the rod. The rod also contained a small amount of nickel. The test results reported here tend to confirm his observations.

Jan 1, 1933

By D. G. Hartley, P. C. Hayward, K. R. Weller, U. J. Sterns

The major copper loss at Mount Lyell is in the coarsest particles presented to flotation. An analysis of data collected from the five Primary and six secondary ball mill circuits showed that grinding was limited by low breakage rates in secondary mills, possibly due to oversize balk. For five months, the make-up ball size for one secondary mill was reduced from 50 to 30 mm (2 to 1.1 in.). Frequent steady-state tests indicated that overall average breakage rates could be increased by about 70% using smaller balk. A mathematical simulation of the whole circuit with increased breakage rates showed that the resultant finer grind was likely to improve copper recoveries by about 2%.

Jan 1, 1984

By L. H. de Wald, J. Walter Scott

The removal of lead by fire refining methods from copper of electrolytic quality is growing in importance. Particularly is this true of the refining of secondary copper and copper cathodes obtained from electrolytic cells where lead is used as the anode material, as in the electrolysis of ore-leaching solutions and foul electrolyte. When investigating the removal of small amounts of lead from molten copper in a reverberatory furnace during the refining of secondary copper of otherwise electrolytic copper quality,' it was found necessary first to know something about the distribution of the lead throughout the bath. The authors believe that it is not generally known how small amounts of lead as an impurity are distributed in a molten copper bath; that is, whether the lead is concentrated at the bottom or at the top, or whether it occurs more or less uniformly throughout the bath. The data contained in this report may help, therefore, in the development of a satisfactory fire refining method for the removal of this obstinate element from a molten copper bath. The first step was the development of a method for taking samples from various locations in the bath, at the surface and at various depths. The sampling device used, shown in Fig. 1, consisted of a 10-gram fireclay assay crucible fitted into a ring on the end of a steel rod handle of suitable length. A fireclay scorifier, 2 in. dia., with a ½-in. hole bored in the

Jan 1, 1930

By Eric Jette

The nickel-chromium alloys form the base f for many industrial heating alloys, so that this system is of considerable practical importance. The literature on these alloys, however, contains much conflicting evi-dence, not only regarding the solubility limits of the terminal solid solu-tions at different temperatures but even regarding, the number of phases existing in the system. Part of the difficulty undoubtedly arises from the fact that chromium of sufficiently high purity has been available only during the last few years. A second and possibly even more impor-tant difficulty arises from the ease with which chromium reacts with silicon and carbon compounds and the atmosphere to form silicides, carbides, nitrides and oxides. Pilling and kihlgren1 in 1929 reviewed the existing scanty information. They did not consider the diagram by which they summarized the various bits of information to be entirely satisfactory. Matsunaga2 investigated the system by thermal analysis, microscopic examination and other means. Electrolytic nickel of 99.9 per cent purity and thermit chromium containing 0.30 per cent al, 0.40 per cent fe, 0.25 per cent si and 0.04 per cent c were used. A tammann furnace with hydrogen flowing through it was used for melting. Sekito and matsunaga3 reported an x-ray, investigation presumably on these same

Jan 1, 1934

The Library of the above-named Societies is open from 9 A.M. to 10 P.M. on all week-days, except holidays, from Sept. 1 to June 30, and from 9 A.M. to 6 P.M. during July and August. The 'Library contains about 55,000 volumes, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library can render valuable service through correspondence; letters requesting information will receive special attention. The Library is prepared to furnish references and copies of articles on mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general information as to the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape. The members of the Institute can be. of service to the Library by forwarding copies of mining reports, maps privately issued; and similar material, which will be classified, indexed, and made available to other members. Suggestions for additions to the Library, either by purchase or personal solicitation as gifts, will be welcomed. It is hoped that members, while in the city will use, the Library freely, and assurance is given that most careful service will be rendered to them.

Jan 12, 1915

By Clemens Jones

A FORM of apparatus for volumetric determinations which shall possess the features requisite for the constant use of potassium permanganate, is a very desirable fixture in a well-appointed laboratory. Expedients to economize time and insure accuracy are generously employed for various other reagents, while the permanganate seems to have been consigned to the use of an ordinary burette, and a black bottle of the standardized solution. But the introduction of new, methods dependent on the permanganate, and the urgency of technical requirements where it has long been indispensable, require a revision of practice more scientific and convenient. The apparatus designed by the writer for the laboratory of the Thomas Iron Company at Hokendauqua, Pa., is so simply contrived and works with such entire satisfaction that a description of it may be of use. It may be prefaced that the characteristics of a suitable device offer some mechanical difficulties when combined in a continuous appliance. The burette, B (50 C.C. to 1/10 c.c.), shown in Fig. 1, consists of the graduated tube proper and an arm, E, fused to it below the 50 c.c. mark. At its top are rubber connections with the blast-aspirator, shown in the cut (Fig. 2) of the front view. By means of an extra stopcock, D, connection through E is established with the reservoir F. The burette is clamped Securely to a slide, C, which is counterpoised and moves freely on guides between two parallel sides, L, suitably

Jan 1, 1887

By H. W. Hardinge

Disregarding for the present the economic side of a new device, let us turn to that feature of the conical pebble-mill which is of interest from a scientific point of view, and consider the device as a puzzle in which the theories of the cylindrical type of mill have been increased. Many articles have been written on the theory of the tube-mill, and explanations have been made which do not explain ; but these have evolved suggestions of practice which have resulted in changes in the tube as to length, diameter, feed, discharge, speed of rotation, rotation on hollow trunnions, rotation on rings, and changes in the operation as to quantity and size of pebbles, charge of load above or below the axis, crushing by causing the larger pieces of the material of the charge to act as grinders, whether crushing is abrasive or impactive, etc. The practical worker in crushing. is first interested in the endeavor to reach an econonlic means of accomplishing a desired end; but the improvements in crushing-practice have been largely left to the manufacturer of machinery, who, as a rule, has little, if any, knowledge of the specific requirements— such as granulation, sizing for concentration without pulverizing the metals, instead of pulverizing the rock or gangue; the metals being the more friable, while the rock is tough and not so easily disintegrated. A reversal of this practice is the aim of sliming direct for cyanidation or pulverizing for cement, etc. In the ordinary cylindrical mill, having a diameter of 4 or

Jan 1, 1909

By Oliver Bowles

THE inorganic non-metallic minerals, that is, the non-metallics exclusive of coal, oil, gas and related minerals, constitute the basic raw materials for a number of essential industries. It is estimated that the value of the raw materials in this group produced in 1919, together with certain of the primary products ordinarily manufactured at the mine, exceeded $800,000,000. They are employed chiefly in the building, agricultural, and chemical industries. It has been estimated, by the Bureau of Mines, that approximately 00,000,000 worth of non-metallic minerals and their products were used in the building trades during 1918; with the great increase in building since that date and the increased cost of materials, the value of non-metals used in such industries during 1920 probably exceeded $500,000,000. The chief of these materials are cement, building stone, crushed stone, sand and gravel, clay products, lime, gypsum, glass materials, slate, talc and soapstone. In many of the producing industries of this great group, the waste is so great that the expense of handling it is an important item in the production cost. The utilization of waste is receiving unusual attention in many of the non-metallic industries at present. The most obvious advantages of such utilization are: (1) Conservation of mineral resources, (2) the removal of waste heaps that in many places obstruct development, (3) manufacture of new and useful products, (4) reduced production costs through elimination of a large part of the item of waste-disposal expense. In many industries there is keen competition between producers of various products used for the same purpose, so that advantage will accrue to the manufacturer who is able to reduce his production costs.

Jan 1, 1921

J. S. UNGER,*Pittsburgh, Pit., (written discussion?).-From the subject of the paper it is natural to expect that the data presented must be results secured from an open-hearth furnace working under normal conditions, but such is not the case, as the conclusions are based on the results of laboratory tests, which do not approach service conditions. The early basic hearths were made of burnt lime, then followed burnt dolomite, bricks made of calcined dolomite and a 'binder, usually tar, and finally magnesite bricks covered with a layer of sintered magnesite. When this material became scarce, special dolomitic refractories were used. In the summary, it is claimed that magnesite low in lime, or of greatest purity, ranks first in the resistance to slaking and to corrosive slags. It is well known that neither pure lime nor magnesia has much value as a refractory. By the addition f fluxes, such as silica and iron oxide, lime is rendered inert to slaking in the same way as are the special dolomitic refractories. An example on a large scale is the ordinary basic open-hearth cinder, produced every clay, which does not slake. Pure magnesia, regardless of the lime content, is not any better fitted for a refractory than pure lime. The pure natural varieties, such as Grecian or Washington magnesites, must be burnt with sufficient silica and oxide of iron to produce a satisfactory material. Grain magnesite, either artificial or natural, is, not used in burning in a hearth in the state in which it is received. To make a satisfactory hearth, it must be made more impure by adding about 20 per cent. of basic open-hearth cinder, otherwise it will-not remain in place.

Jan 5, 1919

By M. S. King, B. N. P. Paulsson

Four vertical boreholes in the vicinity of an electrical heater simulating a canister of nuclear waste in a granitic rock mass have been logged with an acoustic borehole sonde before and after thirteen months' heating. Excellent control of the structural geology and fractures present in the rock mass was provided by the considerable amount of oriented core recovered from the four boreholes used for acoustic logging and the large number of others used for a variety of rock mechanics instrumentation. Compressional and shear-wave velocities were measured as a function of stress on some twenty core samples, water-saturated and dry, which were recovered from the four acoustic logging boreholes. Further control was provided by a cross- hole acoustic monitoring program conducted before, during and after heating between the same four boreholes, and by measurements of acoustic velocities in an isolated block of granite in the same heater drift, which was subjected to an increase in temperature and to changes in uniaxial stress. It is concluded from the acoustic logging tests, taken in conjunction with the acoustic cross-hole and heated block experiments, that acoustic techniques: 1. Provide a means for locating and delineating systems of weakly- bonded or open fractures within the rock mass; 2. Provide a sensitive means for monitoring a rock mass for changes in moisture content or structural damage to the rock fabric induced by thermal or mechanical loading; 3. Together with the rock bulk density yield the elastic constants of the rock mass.

Jan 1, 1982

By W. W. Tyler, A. C. Wilson, L. B. Nesbitt

INVESTIGATIONS of thermal conductivity and impact strength of the titanium alloy RC-130-B and 316 stainless steel were undertaken because of interest in strong, nonmagnetic, commercially available alloys of low thermal conductivity for use in low temperature experiments. Measurements of electrical resistivity and thermoelectric power were also made for some of the samples studied. The titanium alloy designated as RC-130-B is manufactured by Rem Cru Titanium Inc. It contains 0.14 pct C, 3.99 pct Al, and 4.7 pct Mn. A general discussion of properties of the two phase Ti-4Mn- 4A1 alloys is given by Finlay and Vordahl.' The alloy is machinable and has a yield strength greater than 130,000 lb per sq in. at 0.2 pct offset. The 316 stainless steel sample used for both conductivity and impact strength measurements was obtained from the Allegheny-Ludlum Steel Corp. and is designated as Allegheny metal 18-8M, Type 316, Grade 316. The sample had received 25 pct minimum final cold reduction and had a Brine11 hardness rating of 255. Several impact tests were made on a sample of 316 stainless which had not received the 25 pct cold reduction. Also several data points are reported giving thermal conductivity and electrical resistivity for a sample of 304 stainless steel taken from stock. Figs. 1 and 2 give thermal conductivity and electrical resistivity data for the titanium alloy and for

Jan 1, 1954

J. S. UNGER, ? Pittsburgh, Pa. (written discussion ?).-Firebricks intended for, the same purpose, but supplied by different manufacturers, may be of entirely different clays, contain different proportions of flint, calcined and plastic clays; the particles may vary widely in size; the water used to make the brick will vary; the pressure in molding will vary, depend-ing on whether the brick is hand made or power pressed; and the degree of burning in the same kiln will differ. These variables affect the melting point and the strength of the brick when heated. An important property, of a firebrick is its ability to resist heat and, at the same time, weight or load without serious deformation. The soft-ening point and the melting point of a firebrick may be several hundred degrees apart, and two bricks may show considerable difference in their softening points, but the melting points may be approximately the same. Bricks are not usually employed at temperatures close to their melting points. If they must withstand very high temperatures, the firebrick is discarded and a brick of more refractory material is used. Under these conditions' it is doubtful whether the determination of the melting point of a brick has much practical value. If the determination of the melting point is necessary, the test should he made on a portion of the original brick and not on a specially prepared sample. A small triangular pyramid with a base about 1 1/2 in. and 3 in. high can be sawed from the corner of the brick with a thin-bladed car-borundum wheel, without injuring or destroying the size of particles, the bond, or degree of burning of the original brick. This specimen can then he compared with standard Seger cones or tested by any other method desired.

Jan 12, 1919

By Bernard E. Fernow

About eight years ago a comprehensive study of American timbers was begun in the U. S. Division of Forestry with a twofold object. On the one hand, it was desired to deternliiie the working-qualities of our numerous economically important timbers, and to furnish reliable standards of strength. 011 the other hand, it was intended to get a clearer insight into the properties and behavior of wood in general, with a view of establishing more rational methods in its use, and to furnish data for physical inspectioil which would permit an intelligent application of the standards of strength, and place upon a rational foundation the so-called " factor of safety," which is at present a mere baseless guess. The first object, namely, the establishment of standards for any given species, requires a very large series of tests, since Wood is an exceedingly variable substance, so much so that in the same tree a variation of 50 per cent. in strength may be found; hence the greater need of rational data of inspection. So far, the insufficient appropriations and facilities at our disposal have permitted us to establish really reliable standards for five species of southern conifers only. These have been deduced from nearly 20,000 tests. Besides these, 10,000 other tests have furnished indicatious regarding some two dozen other species. This work is now entirely abandoned, waiting for more prosperous times. The study of wood in general, however, can be carried on with smaller means, and has this year yielded not only very interesting, but highly important results, which will soon be published in detail. It is the purpose of this paper to make to the Institute the

Jan 1, 1899

By G. H. Ashley

THE Pittsburgh coal bed stands today: as probably the largest contributor of wealth of any single mineral deposit in the world. If it is not, what other deposit is? To the present it has contributed more than 2,530,000,000 tons of high-grade coal from Pennsylvania alone, worth nearly $4,000,000,000. Since 1910 it has added more than $2,500,000,000 to the value of Pennsylvania's mineral output. There is estimated to be about three times as much coal still in this bed as has been mined. To realize the full value of this wonderful bed it must be remembered that the figures given are for one State only. To them should be added the figures for the same bed from West Virginia, Ohio and Maryland. Furthermore, as known by man, this great deposit is only a fraction of its original whole. Outliers in Somerset County, Pa., indicate that its original extent in Pennsylvania in an east and west direction was more than two times its present extent. Add to that the northward extension as indicated by outliers in northern Allegheny, Armstrong and Indiana counties,, and it seems safe to say that its original extent was not less than three times the area at present underlain by it. And as the subjacent beds of the Allegheny group are found still further eastward and northward, it is at least a possibility that it originally covered an area many times its present area.

Jan 10, 1926

COLUMBIA LOCAL SECTION Executive Committee F. A. THOMSON, Chairman GEORGE W. RODDEWIG, Vice-Chairman L. K. ARMSTRONG, Secretary- Treasurer, P. O. Drawer 2154, Spokane, Wash. R. S. MCCAFFERY S. H. RICHARDSON The quarterly meeting of the Columbia Local Section of the Institute Was held in Pullman, Wash., May 16-17, 1914, as a joint meeting with the Spokane Sections of the. American Institute of Electrical Engineers and the American Society of Civil Engineers, each holding separate sessions on the afternoon of the 16th With a joint meeting in the evening. The Section meeting was held in Science Hall, the Chairman, Prof. Francis A. Thomson, presiding. E. Jacobs, Secretary of the Western Branch of the Canadian Mining Institute, acted as Joint Secretary: About 35 members and guests Were present. H. C. Bellinger, formerly Metallurgical Manager of the Great Cobar Co., Ltd., N. S. W., Australia, described the Horwood process. Papers as follows were presented and discussed: A Smelting Furnace for Cyanide Precipitate, by P. S. Anderson. Mining Methods in Rossland, by C. H. Loux. Geological Notes on a Part of Central Idaho, by Prof. D. C. Livingston. Some Notes on the Ore Deposits of Republic, Wash., by A. M. Balfour. E. Steidl, of the U. S. Bureau of Mines Rescue Car, spoke on the mine rescue service of the Bureau, and E. Jacobs described what is being done along similar lines in British Columbia and elsewhere. The evening was occupied in joint session, J. B. Fisken presiding. Mr. Fisken read a short paper on the benefit to the young engineer of an association y membership in the local section of either of the societies represented in the meeting, and C. F. Uhden gave a stereopticon lecture on Power Development Along the Spokane River.

Jan 7, 1914

By J. J. Donos

IN the operation of a smelter, continuous and accurate determination of smoke losses is essential for purposes of metals inventories and as a check on the efficiency of smoke recovery apparatus. Previous to the development of a continuous and automatic smoke sampler by R. MacMichael, in 1924, two methods were in vogue, and still are in some smelters, for measuring solids passing out of a flue or stack. These are: (1) the so-called dust concentration method whereby the gas volume passing through the flue is first measured and then the total amount of solids carried in the smoke stream calculated from the weight of suspended matter filtered out of a measured volume of gas; (2) the balanced tube method is independent of gas volume flowing through the flue, and relies for its accuracy on the fact that a true smoke sample may be taken if the velocity of the gas in the sampling tube is constantly maintained at a known ratio of the average flue gas velocity. The total amount of solids passing through the flue is then proportional to the weight of filtered solids and to the ratio of the area of the flue to the area of the sampling tube, corrected for the velocity ratio. The limitations of the first method lie in the uncertainty of the varying volume of gas arising from metallurgical operations and the unreliability of ordinary gas meters to hold their accuracy under

Jan 1, 1951

By Frederic Benard

THE treatment of Balbach-Thum slimes at Copper Cliff by the Ontario Refining. Co. is of interest because it differs considerably from methods usually employed for the recovery of fine gold from parting-plant slimes. Owing to the comparatively high percentages of pal-ladium and platinum, wet methods are used to remove the greater proportion f these metals before electrolytic refining in the Wohlwill cells. THE PLANT The platinum-metals department, Wohlwill room, and gold-melting room extend along the north side f the silver refinery and are separated from the parting plant by a glass partition (Figs. 1 and 2). The platinum-metals department resembles a laboratory built on a large scale, with the various pieces of equipment laid out on terraces to facilitate handling. Because of the corrosive nature of the solutions, chemical stoneware is used throughout. Elevation of acids is accom-plished by means of Mariotte bottles. On the top level are three steam-jacketed stoneware kettles of 50-gal. capacity, also a packed tower. One kettle is used for digesting the slimes while the remaining kettles are used for precipitating the gold. The dissolver is equipped with a treated concrete hood, which is connected to the flue system. Gases are drawn off through the packed tower by means of a 6-in. stoneware exhaust fan. A 15 per cent solution of sodium carbonate is continually circulated through the tower. On the intermediate level are two suction filters, one for removing silver chloride and the other for the gold sand. The filter medium consists of an asbestos pad covered with a filter paper on which is a layer of twill.

Jan 1, 1938

By Harry J. Morgan

One of the greatest improvements in drilling equipment has been the development of hard facing metals which are welded by electricity or by acetylene to form a facing which protects the steel of the bit from abrasive wear. The main desirable characteristics of hard facing metals are resistance to abrasive wear, resistance to shock and perfect bond with underlying metal. Resistance to abrasion offered by various metals shows many anomalies. Compounds containing carbon, silicon and boron are the most important hard substances. Carbon, as diamond, silicon carbide and especially the carbides of iron, chromium and tungsten are the outstanding hard products in common use. Tungsten carbide is probably the most commonly used. It is made in the electric furnace and it is important to get the right amount of carbon and the correct crystalline structure in order to obtain the greatest hardness and greatest resistance to abrasion. It may be obtained in three main divisions: wrought, cast and casehardened. Insert hard metals are common. The method of application varies, but it is generally welded to the bit, placed in channels or in drilled holes and covered with a hard surfacing metal. Robinson' has given a very complete article on the use of inserts. Gregg and Küttner2 has discussed the metallography of tungsten carbides and given a good bibliography of the subject,. The time and expense of large-scale testing, together with variations in results, led to the development of a laboratory testing machine for determining the abrasive-resisting qualities of different metals. This machine consists of a motor-driven 40-grain, alumina-base corundum wheel, 8 in. dia., rotating at 30 r.p.m. It is run wet and dressed with

Jan 1, 1930