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By J. J. Scott, L. Adler3

L. Adler (Assoc. Professor, Department of Mining Engineering, Virginia Polytechnic Institute, Blacks-burg, Va.) - Dr. Scott is to be commended for undertaking the arduous and specialized task of applying three-dimensional photoelastic techniques to a mining problem. However, 1 feel his analysis suffers seriously from a lack of clarification on one important matter, among several others; and that the paper as a whole lacks balance and thus tends to confuse the reader. 1) The major technical criticism refers to the fact that nowhere are the boundary conditions for his mod-

Jan 1, 1964

By C. W. Hill

IN a previous article preliminary experiments were described, indicating the possibilities of a quantitative spectroscopic method for the determination of small amounts of lead in copper, which would be accurate and rapid, and could be carried out in the refining plant by one not skilled in chemical analysis. The present paper deals with the development of the method in the factory, giving the details of apparatus and its standardization, and presenting a comparison of the accuracy of the method with that of the standard electrolytic determination. (For variations and other applications of the method, the reader is referred to the first article.) FIG. 1.-STEPS IN THE ELIMINATION OF LEAD. (The lead line, at point 105.8 in the violet portion of the spectrum, is seen between the two copper Lines,-102.29 and -106.29, lying close to the latter. The crowded faint lines are due to the carbon are.) 1. OUTLINE OF METHOD A carefully weighed sample (0.4 gm.) of the copper to be tested is placed in a cavity in a graphite positive electrode. An arc capable of

Jan 10, 1918

Jan 1, 1944

By Raul Ramirez

Jan 1, 1983

By Fred M. Phillips

Jan 1, 1985

Jan 1, 1946

Jan 1, 1947

By C. A. Crawford

NICKEL and the nickel-copper alloy, the latter generally referred to as morel metal, are available in a variety of wrought and fabricated forums, of which the following are regular commercial products: Form Monel Metal Pure Nickel Roc Hot-rolled; round, hexagon, Same as morel metal square, and flat shapes Cold drawn; round, hexagon, square, and flat shapes Hot-rolled wire rod Cold-drawn wire rod Plates Hot-rolled Same as morel metal Sheets Hot-rolled annealed Same as morel metal Hot-rolled annealed, pickled Full-finished Full-finished, No. 3 grind one side Full-finished, No. 4 grind one side Cold-rolled (annealed) Cold-rolled, No. 5 polished finish Strip Hot-rolled (flat rods) Same as morel metal Cold-rolled (annealed) Cold-rolled (unannealed) Tubes and pipe Gas-welded tube Seamless tube Seamless tube in I. P. S. Gas-welded tube Forgings Bolts, rivets Same as morel metal Nuts and washers Forging to order Castings Sand castings Same as morel metal Centrifugal castings Electrolytic Cathodes of high purity Anodes Cast anodes Rolled anodes Shot and block for 25 to 50-1b. pigs 5, 25 and 50-1b. pigs melting. Shot Shot

Jan 1, 1927

By E. J. Schmitz

This section was obtained last year during an examination of the iron-ore resources of the Rich Patch Mountain region and along Craig's creek valley. The geological members below the Oriskany and Lower Helderberg are exposed along the gap in a beautiful arch, while the higher formations appear in a more or less disturbed state on both sides of this arch, and are partly covered by dèbris. I have thought it of interest to the Institute to reproduce the drawing of this section at the gap which I made in my note-book at the time of my examination; those parts of the section, which lie at both sides of the arch, are only approximated. I give also a number of notes and measurements, referring to the Clinton formation and especially to the characteristics of the fossiliferous ore-seam opened in the various tunnels along the arch (see section). I. In Tunnel C: For the first 110 to 120 feet to second shute, we find the ore only here and there in small deposits, and interchanging with, or changing into, either a very siliceous limestone or a sandstone. About 10 feet beyond shute we have : Sandstone roof. Clay-slate, 211/2 inches Brown lean ore, 1 inch. Sandy clay, 3 to 31/4 inches. 1. Dark .brown ore, 3 inches. 2. Fossil-ore, changing into sandstone or very siliceous limestone, 2 inches. 3. Brown lean ore, 6 inches. Clay and slate below, 1 foot. 194 feet from entrance : Sandstone roof. Clay-slate, 4 inches. Clay 15 inches. Fossil-ore, 63 to 7 inches. Clay and ore, If inches. Lean brown ore, 2 inchea. Clay to bottom, 2 feet.

Jan 1, 1896

The world's production of petroleum in 1926 amounted to nearly 150 million long tons, of which India contributed 0.72 per cent. In 1927, this figure jumped to some 172 million long tons, of which the Indian proportion, on a practically stationary production, fell to 0.64 per cent. In 1928, there was another substantial rise in the world's production, which reached the figure of over 181 million tons. In 1929, there was another jump to over 202 million tons, but in 1930 the world's production fell to about 193% million tons, in 1931 to about 187 million tons, and in 1932 to about 183 million tons, while in 1933 the production rose again to about 202 million tons, in 1934 to about 215 million tons, and in 1935 to 233 million tons1. Decreases were shown by Poland, Sarawak, Egypt, Rumania and France. All other important producers showed an increase in production, by far the largest being due to Iraq, as a result of the opening of the pipe line to the Mediterranean. The United States contributed 60.9 per cent of the world's supply in 1935, Russia 10.7 per cent, Venezuela 9.4 per cent, Rumania 3.9 per cent and Iran 3.1 per cent. In 1928, India contributed 0.64 per cent, which fell to 0.60 per cent in 1929 and rose to 0.62 per cent in 1930, 0.63 per cent in 1931, and 0.64 per cent in 1932, and fell again to 0.62 per cent in 1933, to 0.60 per cent in 1934 and to 0.50 per cent in 1935; her position on the list of petroleum-producing countries fell from eleventh in 1929 to twelfth in 1930 to 1933, her place being taken by Trinidad and to thirteenth in 1934 and 1935, owing to the production by Iraq. The production of petroleum in India (including Burma2) increased slightly from 322,025,280 gal.3 in 1934 to 322,662,336 gal. in 1935, the highest figure in the history of the industry. The increase in 1935 is due to an increase of some 4 million gallons in Assam, almost offset by a decrease of 31/2 million gallons in Burma. This increase in output in 1935 was accompanied by an increase in estimated value amounting to Rs. 22,73,550 (£170,944).

Jan 1, 1937

By H. W. III Straley

SOME ten years ago the writer1 made a survey of college catalogues to determine what sort of training geologists were receiving in basic sciences. In the light of this compilation and subsequent experience, he made the statement at the 1939 meeting of the Institute that apparently only in schools offering a curriculum in geological engineering or in the geological option of mining engineering curricula could geologists hope to receive the training advocated by Hubbert.2 In the former study, schools of engineering were excluded because the preparation was known beforehand. The present study aims to consider engineering schools in an effort to determine not only what basic studies are required but what use is made of them in geological courses of the third and fourth years. The present study combined the method of consulting catalogues with a questionnaire. Letters were mailed to officials responsible for supervision of mineral industries curricula requesting information on: (I) the extent to which the engineering preparation of the first two years is actually used in the work of the last two; (2) the extent to which the engineering of the last two years is used in courses in geological engineering or geology; and (3) whether geologists or geological engineers teach descriptively or analytically. Both methods of securing information are open to criticism; the former on the basis of the incomplete information supplied by university catalogues concerning prerequisites and curricula and the latter on the ground that the questions may be phrased poorly or given insufficient consideration by replying officials. Fifty-six questionnaires were mailed and 39 (70 per cent) replies were received. Of the replies, 6 (11.3 per cent) were from colleges of liberal arts unconnected with engineering schools, 11 (20 per cent) were from schools having curricula in geological engineering and 22 (39 per cent) were from departments of mining engineering. The number of replies and their distribution were satisfactory in spite of the receipt of only six from liberal arts colleges. It should be understood that the universities of which the catalogues were examined were not necessarily the same in both compilations. No departments that are admittedly or known to be acting solely as service departments were recorded in the second study. Table I shows that all professional schools require mathematics through calculus, whereas only 7 per cent of the liberal arts curricula expect the same level of preparation; only 73 per cent require trigonometry and 40 per cent college algebra. The proportion of geological engineering curricula requiring differential equations is higher than mining. All of the engineering schools require general and analytical chemistry, whereas only 77 per cent of liberal arts curricula require general and 18 per cent analytical. Twenty-two per cent of the mining and 40 per cent of the geological engineering

Jan 1, 1941

By Andrew S. M’Creath

THE treatment which a steel receives, and the uses to which it may be applied, are frequently determined by the percentage of carbon which it contains; and especially is this the case in the different steel works in this country. The part which this element plays in the composition of steel is such an important one that a process for its accurate determination becomes an absolute necessity.

Jan 1, 1877

By John E. Miller

The Miller Number System is a well established method of measuring the relative abrasivity-friability of slurries, resulting in data that can be used in the selection of pump type and in forecasting wear-life of pumps and pipelines in slurry service. 1,2 Then after the pump type is selected, a Flow Analysis is determined by computer using pump design and operating parameters. This is used to determine pulsation control, suction requirements and stabilization, etc.

Jan 1, 1977

By Ward W. Minkler

Since 1978, the titanium metals industry, throughout the non-socialist world, has experienced a period of growth and prosperity unparalleled since the late 1950s. Sponge producers, melters and mill product manufacturers have operated at capacity, record shipments have been attained, new producers have entered the industry and established producers have implemented expansion plans. However, there is now mounting evidence that the underlying elements which generated this vigorous surge have abated, at least temporarily. It now appears that in 1982, the industry will encounter overcapacity, excessive inventory accumulations and the probability of declining prices. Therefore, it does seem appropriate that we now take inventory of the present and future markets for titanium with the hope we can identify both near term opportunities as well as challenges the industry now faces. If we view the development of titanium markets as a function of time, they fit rather neatly into three sectors.

Jan 1, 1982

By W. E. Ruder

IT has been pointed out by Stead 1 that grains of considerable coarseness may be developed in steels containing from 3 to 5 per cent. of silicon, and in a previous paper 2 the present author has shown that under the proper conditions of annealing single grains having an area of 50 sq. cm. may be obtained. It is the purpose of this paper to discuss in more detail the conditions, promoting the growth of these grains, in the hope that the experiments described may throw some additional light upon the general problem of grain growth in metals. These silicon steels lend themselves particularly well to such experiments because of the ease with which the change in structure may be followed and because of the fact that the effect of the carbon present is largely obliterated by the high percentage of silicon. This forms a solid solution with the iron, which acts very much like a pure metal. This alloy has been found to have but one critical point, viz., Are. This point, determined by Roberts-Austen for Hadfield's 4 per cent. Si alloy, was found to lie at 703° C. Vigouroux3, in working with pure Fe-Si alloys, finds this point to rise from 750° C. for 0.5 per cent. Si to 860° for 6 per cent alloy, with a flat region in the curve from 3 to 4 per cent. Si. No accurate determination of this point has been undertaken by the present author, but it has been roughly determined to lie between 730° and 750°.

Jan 12, 1913

By Bernard Moore

THE last few decades have witnessed the introduction of many new nonmetallic mineral products and changes in the use of many of those already well known. Among these is diatomite, formerly employed as a mild abrasive and, at one time, as the absorbent material in dynamite. Now nearly 100,000 tons a year are mined and milled into such things as filter aids, cement admixtures, insulants, fillers, absorbents, cosmetics, cleansers, etc. Pumice, commonly regarded as only an abrasive, is now also employed as an insulant, as light-weight aggregate and as a concrete admixture. With increasing use of insulants, light-weight aggregates, and acoustic stuccos and plasters in the building trades, both these mate-rials should find increased application. Very large deposits occur in eastern Oregon and have been studied by the U. S. Geological Survey in cooperation with the Oregon State Mining Board.

Jan 1, 1934

By A. G. H. Andersen

A FEW years ago, while the writers worked on the constitution of ternary and quaternary alloys consisting mainly of iron, chromium and silicon1,2 some information on microstructures and hardness, not incor-porated in the published work, was obtained. It has not been possible to do any further work on the properties of the alloys. The information possessed is hereby presented for the interest it. may have in connection with the constitution of the alloys.

Jan 1, 1937

By Fred Beasley

METALLURGISTS have, in the past ten years, overcome many difficulties of high zinc in lead blast-furnace slags. This problem was brought to the front at the close of the late war, by the price obtained for lead and the high cost of labor, fuel, and flux. The Port Pirie plant of the Broken Hill Associated Smelters, Australia, early in 1919 had increased the zinc oxide in its blast-furnace slags from 13.5 to 20 per cent., at the same time reducing the iron oxide in the slag from 33.5 to 25.6 per cent. These results were obtained by the following proceduret the addition of granulated slag to the roaster charge, 10 to 12 per cent., improved conditions of the crushing and mixing and roasting of the constituents of the sinter. By experiments and improve-ments the practice at this plant has developed a normal slag that carries 22 per cent. zinc oxide, and at times runs as high as 33 per cent. zinc oxide, with only slight furnace trouble. The granulated slag is used not, only as a diluent to the sulfur in the roaster charge, but also on account of its value as a slag-forming material and on account of the physical properties it imparts to the finished sinter. The ore is mixed with flux and given a double roast. All the first roasting is by sintering with the Dwight & Lloyd machines. The final roasting is performed partly by Dwight & Lloyd machines and partly by H. & H. pots. The charge to the blast furnaces consists chiefly of the final sinter, slag shells, siliceous and non-bearing sulfur, lead ores. High blast and ore columns are the practice. The greatest care is taken to obtain in the final sinter as low a sulfur content as possible.

Jan 2, 1925

By J. D. Price, W. M. Bertholf

In preparing a paper on coal washing in Colorado and New Mexico, it is difficult to refrain from entering into a discussion of the historical aspects of this subject, for the story of coal washing in these states goes hack well into the last century. This phase of the subject could well make a complete paper in itself, and of necessity this present discussion must be limited to current operations. Therefore, we are taking into consideration only those washing plants which have operated for some period during the years of 1947 and 1948. Summary Of the eight million tons of coal mined in the two states in 1947. ap- proximately two million tons were washed in wet washing plants, using concentrating tables or jigs. The one table plant accounted for 70 pct of the output of washed coal, and two large Baum jig plants accounted for an additional 26 pct, leaving only a small residual tonnage to be accounted for by other types of jigs The necessity for washing coal is occasioned by the desire or necessity of reducing the ash content of the coals— sulphur is not a problem in this area. All washeries, except the table plant, are at or near the tipple, hence wash only one kind of coal. At the table plant a large number of different coals are washed. Only at the table plant is there any occasion for drying any considerable quantity of fine coal— other plants size and/or dewater on shaking screens. The results of washing at the smaller plants are judged by the number (or lack) of complaints about the quality of the washed coal. This is probably as good a system as can he devised for small, intermittent operations. The efficiency of the Baum jig ap-pears to be quite high. This is to be expected as long as the automatic control of the refuse gate operates properly. The efficiency of the concentrating table is not as high as that of the Baum jig, especially when the "difficulty" of washing is taken into consideration. When dealing with coals in which the "bone" is larger than the "coal," the table appears to be at a definite disadvantage, because of its sizing action.

Jan 1, 1950

By K. G. Davis, P. Fryzuk

VALUES for the equilibrium distribution coefficient, ko, are required for solidification studies. The procedure generally adopted1-3 is to progressively solidify alloy rods over a range of growth rates, under conditions where a high degree of convective mixing is present in the melt. The measured effective distribution coefficients are plotted as a function of growth rate, and the extrapolated value at zero growth rate is taken to be the equilibrium ko. The method is limited by the experimental difficulty in obtaining steady growth rates less than approximately 10-4 cm per sec. Extrapolation from rates greater than this can lead to inaccuracy. In the present investigation, an alternative method for determining ko, previously used by the authors for the Ag-Sn system,' was applied to alloy of thallium in tin. Specimens were grown under conditions where convective mixing was absent, and experimental concentration-distance curves in the region of the initial transient were compared with curves calculated for trial values of ko. The ko which gave the best fit was taken as the correct value. To obtain the calculated curves, a value for the diffusion constant in the liquid near to the melting point was needed. This was determined by the capillary-reservoir method. Diffusion Constants. Details of the experimental procedure used by the authors in the capillary-reservoir technique have been described in previous papers,5'6 the only variation being in the use of Tl204, a ß emitter, as tracer, in contrast to previous work where ? emitters were used. The activity of a ß-emitting sample, as measured in a Geiger counter, is proportional to the surface area. To measure the concentration of thallium along the capillary after diffusion had taken place, the solidified capillary (1 mm diam) was cut into 2.5-mm lengths and each length compressed between parallel steel plates to form a disc approximately 5 mm in diam. The discs were placed in a flat-bottomed dish, covered by a thin lead shield with a central aperture, and counted in a 0 counter with fixed geometry. Each disc was etched lightly in a dilute solution of nitric and hydrochloric acids a short time before counting, to eliminate sur-

Jan 1, 1968