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By AIME

Lewis E. Young, who will formally assume his duties as President of the AIME at the Annual Meeting in San Francisco in February 1949, was born in Topeka, Kansas, Oct. 1, 1878. Dr. Young received his engineering education at the Pennsylvania State College, where he received the degree of B.S. in Mining Engineering in 1900. In 1904 he received his E.M. degree from Iowa State College, and in 1915 a Ph.D. from the University of Illinois. In 1947, the University of Missouri conferred on Dr. Young honoris causa the degree of Doctor of Engineering. His active career began in the educational field as instructor at Iowa State College, and following that, as professor of mining at the Colorado School of Mines, 1903-1907. While he was at Golden he launched hi: career as consulting mining engineer for various Western companies. Leaving the Colorado School of Mines, Dr. Young returned to Missouri, serving the University of Missouri as director of the School of Mines and Metallurgy at Rolla, 1907-1914. Leaving Missouri he went to the University of Illinois as assistant professor of business organization, 1915-1918, during which period he wrote exhaustive treatises on mine subsidence and mine taxation, which won for him the degree of Ph.D. before mentioned.

Jan 1, 1949

By Subhash C. Malhotra

This paper discusses the historical background on major sources of obsolete electronic scrap and spent catalytic converter scrap. The paper discusses the principal changes taking place that will affect the future supply of these scraps. The author projects from this background the future opportunities for reclaimers and refiners in these two important segments of the precious metals scrap reclamation industry.

Jan 1, 1984

(Read at the Amenia Meeting, October, 1877.) THE Committee on a Standard Gauge have been constantly engaged, since their appointment, in the duties assigned to them.§ They have corresponded with different persons interested in the manufacture and use of gauges in this country, and have received from several of them important information. They have also entered into correspondence with the governments of England, France, Germany, and Russia through their Consuls, and with Austria directly. The Consuls of Germany and France * Transactions, Vol. V, p. 575. t Transactions, Vol. III, p. 43. + Transactions, Vol. II, p. 224. §See Transactions, Vol. V, p.,48.

Jan 1, 1878

By Georges Fleming

The new burden preparation plant of ARBED Luxembourg, Belval- Works, which comprises 2 large sinter strands, is equipped with a process computer connected to a comprehensive process control system. The main jobs done by the computer are the control of the raw mix composition, and thus the monitoring of the stacking of the piles at the bed-blending plant, and the optimization of the sintering process. Among the optimization criteria, quality is considered as the most important. The sinter quality, characterized by the mechanical strength and the state of oxidation, is controlled automatically. The control system which we have dev loped is highly reliable; as a result, the standard deviation of Fe++, for the control of bivalent iron, has been narrowed to 0,5 % and the standard deviation of the IS0 + 6, 3 mm index, for the control of the mechanical strength, has been kept within 1 %. Thanks to these results, the combined savings in fuel consumption at the sinter plant and at the blast furnaces have covered the total costs of the optimization project in 2 years. By applying automatic control, the optimum driving range of the sinter plant has been defined and these new guidelines are used for monitoring the sinter production.

Jan 1, 1977

By Rossiter W. Raymond

By the courtesy of Mr. Charles W. Jenks, of Boston, one of the owners of this interesting mine, I am enabled to lay before the Institute a suite of specimehs, illustrating its peculiar formation and the paragenesis of mineral species which it presents; and a recent brief visit and rapid reconnoissance of the locality permit me to supplement this exhibition with a general description, based upon personal observation. The mine is situated upon the Culsagee Fork of the Tennessee River, in Macon County, North Carolina, a few miles from Franklin. The most practicable route by which it can at present be visited is by wagon (or preferably on horseback) from Seneca City, S. C., a station on the Charlotte and Atlanta Air Line Railroad. The itinerary is as follows: to Walhalla,* nine miles; Walhalla to Highlands, twenty-nine miles; Highlands to the Culsagee, fourteen miles. By passing the night at or near Highlands, the mine can be reached and examined and the return to Highlands made on the second day; and the round trip, if performed in the saddle, can be completed in three days from Seneca City. It is not easy, with due regard to steed and rider, to do it in less time. The rough and precipitous mountain roads do not permit rapid travel; and the journey is at best a fatiguing one. But its slight hardships are overpaid by the stimulating effect of the climate and the great beauty of the scenery, both of which are destined to become more widely known than at present, to seekers for health and pleasure. Indeed the town of Highlands, already named, is almost entirely made up of northern immigrants, attracted by these advantages and by the inducement of cheap land for agriculture and stock-raising. The Culsagee or Sugartown fork of the Tennessee traverses the belt of ancient crystalline schists on the west flank of the Blue Ridge. This belt abounds in valuable minerals. Among those of the nonmetallic class may be mentioned graphite, soapstone, serpentine, asbes-

Jan 1, 1879

By Pedro L. Lizaur

INTRODUCTION The degree of success of an association between parties in establishing a new venture ultimately depends on three factors: a. the venture's underlying economic strength, which is based on the complementarity of the comparative advantages brought by each party to the negotiating table; b. the ability to reach an agreement which satisfies each party's objectives and constraints; and, c. the capacity to design and implement a funding structure which is consistent with the project economics. A thorough assessment of the venture's profitability and associated risks under alternative technical and economic scenarios is the basis for a sound "go" or "no go" decision. In-depth evaluation of the risks and rewards to each of the parties involved under alternative legal and financial structure must be the foundation for a long lasting "how to go" decision. The allocation of risks and rewards should be consistent with the objectives and constraints of all parties and the sharing mechanisms, established in the contract, should be flexible to assure the long-term stability of the agreement. Rapidly changing economic conditions during the last decade have had a dramatic impact on the envisaged allocation of risks and rewards between host countries and private investors. The effects of these changes, and the fact that the relative strengths of the parties involved may shift during the life of a project (e.g. before and after major capital investments have been made), have forced the renegotiation of a multitude of contracts. Therefore, the present and future stability of an economic agreement would depend not only on the originally designed provisions, but also on provisions which allow for the automatic adjustment of rewards to project sponsors under a variety of future economic situations. A pre-condition for the allocation and quantification of risks and rewards is the definition of standards of measurement used by each of the parties. This is critical in international negotiations when one of the parties represents the national interests of a country. The understanding and use of different standards for the measurement of rewards for risk taken between a government and private enterprise facilitate the negotiation of a satisfactory agreement. This is possible because certain trade-offs between the negotiating parties may have different relative values. STANDARDS OF MEASUREMENT OF REWARDS FOR RISK TAKEN The negotiating process takes a step forward when the parties are able to focus on their interests, explore different alternative solutions and then base results on a set of objective standards. Unfortunately, the parties frequently put more effort into "staking out" and defending positions, than into understanding their intrinsic interests. Moreover, when one party, such as a governemnt owned corporation, represents a country's national interests, the negotiation process increases in complexity. Private firms focus on commercial profitability, using discounted cash flow techniques such as NPV, IRR, or ROE. In contrast, the government is also concerned with the project's impact on the local socio-economic environment. Without entering into a discussion of alternative economic development theories and approaches, there exist several possible measures that could be pragmatically utilized by each party in evaluating the socio-economic impact of a project. The more complete measure is the National Profitability (NP). The NP is a discounted cash flow procedure similar in structure to IRR or NPV but in which the project's financial cash inflows and outflows and discount rates are adjusted to take into consideration the local conditions. The NP is calculated on an unlevered basis and all taxes and duties are removed from the project

Jan 1, 1985

By E. Topuz, G. Faulkner, M. Karmis, C. Haycocks

The Appalachian coal region of Virginia, southern West Virginia and Kentucky and the extreme eastern portion of Tennessee constitutes a unique area of surface coal mining activities. The area contains a number of contiguously placed coal seams, up to a total of fourteen in some places, which vary in thickness from a few centimeters to 2,5 meters. Much of this coal is of high quality, some being the highest grade metallurgical coal found anywhere in the world. The region may be broadly characterized physiologically as a dissected plateau with a relief above the valley floors of up to 500 meters and a dendritic drainage pattern. Up to six seams may outcrop in the hillsides above drainage, many of which have been subjected to contour stripping operations. Prior to the passage of the surface mining reclamation act, little effort was made to reclaim stripped areas. The passage of the strip mining act, including the controversial requirement for returning the land to its approximate original contour, has forced intensive recla¬mation efforts from the mining industry. The wisdom of this original contour requirement has been the subject of considerable debate and litigation, mainly because of its cost, inconvenience, and value of the land after it has been reclaimed. Regardless of whether recla¬mation is carried out, under current practices slope failures do occur. This in effect circumvents the intent of the law and can expose large unvegetated spoil areas, and contribute to hillside erosion and stream silting. Such failures must be eliminated if further costly reclamation efforts are to be avoided.

Jan 1, 1983

By Edward Sayre

IN shaft sinking for coal mines, the cost item greatly influences the method adopted. This holds true especially when soft material must be traversed. The average life of a coal mine is short. This is clue either to the limited area of the coal basin or to the great expense of maintenance and haulage underground when the entries are extended a considerable distance from the hoisting shaft. Therefore, the engineer in opening a coal mine is confronted with the fact that the cost must be kept within certain bounds else the venture will prove unprofitable. For this reason he may be prohibited from adopting certain safe, but expensive, methods that are used in sinking caissons for foundations, driving transportation tunnels, or other work of permanent construction. A common method of sinking through difficult ground employs the aid of a steel shoe pushed ahead of the shaft timbers. Another is the drop-shaft method. These two methods were used in sinking the main shaft and the air shaft of the Eagle No. 3 mine, at Des Moines, Ia., and the following data show the relative success and cost of the two methods of sinking under the same conditions. A drill log of the material to be penetrated was as follows (see Plate 1, Fig. .1)

Jan 9, 1916

By W. F. Tanner

A river delivers a given load of sand, and hence heavy materials, into the sea. The load is fixed by drainage basin characteristics and processes. Wave energy available for redistributing that load is fixed in an entirely different way. An equilibrium diagram of these two parameters (load vs energy) pennits a tentative prediction of what will happen to the heavy minerals. Alluvial rivers transport a mechanical load which consists essentially of wash load (finer than about 0.05 mm in particle diam), bed load (coarser than about 0.10 mm) and the transition sizes in between. A few rivers carry no appreciable mechanical load, and are excluded from this discussion. An example of the latter is the Suwannee River of Florida, which empties across an oyster bar into the Gulf of Mexico and does not build a delta despite the absence of significant waves or currents in that part of the Gulf. An alluvial river may deliver its load into a protected sediment trap (such as an estuary, sound or lagoon), onto a low-energy coast (where it builds a delta) or onto a high-energy coast (from which spot the river load is swept away). The nature and disposition of the load depends, obviously, on three sets of factors: 1) drainage basin characteristics and processes, which determine quantity and make-up of the load; 2) coastal structure and geomorphology, which determine the kind of river-sea coupling which

Jan 1, 1962

By Clyde E. Williams

The purpose of this report is to supply the Coal Classification Committee' with information for use in the formulation of a system of classification of coals according to their uses. Consideration is given here only to the nonferrous metallurgical operations that consume relatively large amounts of coal or coke; i. e., the smelting of copper, lead, zinc and aluminum. For all of these uses, coal of certain definite qualities is desired. Geographical location, however, often determines whether these qualities can be specified. In some instances the preferred qualities must be specified, regardless of cost. In others, quality may be sacrificed for lower cost, although the best quality consistent with cost is usually the determining factor. These considerations will be outlined in the following discussion under the various uses, which, however, will illustrate the impracticability of preparing definite specifications for coal used in the majority of the nonferrous industries. Coal and Coke in Copper Metallurgy From the standpoint of coal consumption, copper smelting and refining operations are the most important of the nonferrous metallurgical uses of coal. As nickel ores treated in the United States and Canada are associated with copper, the first step in their recovery is really a copper-smelting operation; accordingly, the following considerations under copper smelting apply equally to nickel. Copper Smelting in Reverberatory Furnaces.—For a long time, rever-beratory copper-smelting furnaces were fired with lump coal burned on grates in a fire box. Later, lump coal was displaced by pulverized coal or oil burned directly in the smelting chamber. Recently, natural gas has been used in several plants, although producer gas was used for this purpose at Great Falls as early as 1903.2 Requirements for coal used in

Jan 1, 1932

By T. V. Moore

IN many of the important problems of the petroleum engineer, it is necessary to know accurately the laws governing the flow of gas and liquid mixtures in vertical' pipes. Although much work has been done along these lines, no satisfactory solution to the problem has been found. A good theoretical discussion of the energy balance in a gas¬lift has been published-by Versluys.1 One of the most important factors affecting the efficiency of the flow of oil and gas mixtures is slippage, and in most of the experimental work that has been done no provision has been made for the measurement of this quantity. As Versluys pointed out, since there is no method now known to estimate it from the data usually taken; slippage must be determined empirically. This paper presents the results of some work carried on to, measure slippage in short experimental gas-lifts. As shown herein, slippage can be easily calculated in a vertical pipe carrying a mixture of oil and gas if the fractions of the pipe occupied by liquid and gas respectively are known. In this work, the fraction of the pipe occupied by the liquid was measured under a wide variety of conditions and the relationship between this fraction and other quantities, which are easily measured in ordinary work, was determined. It was hoped that the quantitative relationship obtained from this work could be used-for making accurate calculations in flowing or gas-lift wells, but unfortunately it did not check satisfactorily when applied to actual wells. Apparently flow in long flow pipes is mote efficient than in the short ones used for the experimental work. Nevertheless, it is felt that the data themselves are of interest; that the method of attack may be of value in future work and that the relationship derived between slip and the relative velocities is a contribution toward the solution of the gas-lift problem.

Jan 1, 1931

By James E. Lonergan, Young C. Kim

Over the past two and one-half years, various emission control strategies for a coal-fired power plant have been jointly developed by the University of Arizona and the Homer City Owners. The objective of this work was to assist the Homer City management in their efforts to comply with SO2 emission regulations while continuing to use the relatively high sulfur coal from their captive mines as the primary source of plant fuel. One of the operational strategies studied was to have the captive mines minimize the sulfur variability of the run-of-mine coal on a short term basis. A mine production scheduling program called COMPF2 was developed to perform this task. This paper describes the application of this mine planning program at an underground coal mine. A comparison of the planning results with actual production figures showed the ability of this program to schedule production so as to minimize both the sulfur content and the sulfur variability of run-of-mine coal.

Jan 1, 1983

By L. Casagrande, C. O. Brawner, D. L. Pentz, B. Kennedy, E. Hoek, H. Q. Golder, K. Barron

H. L. HAMMERSLEY, B. C. Dept. of Mines. I would like to ask Mr. Brawner if the direction that he measured in the boreholes with the camera was referenced to magnetic north? MR. BRAWNER. Yes, it was. However, there is one problem that you may encounter if the ore body is magnetic; the borehole compass will give erroneous results. Three procedures are available to overcome this. The first one involves the use of a gyro compass instead of a magnetic compass. The second technique developed by Christiansen in Salt Lake City, is to orient the core with the use of scribing knives. The third method is to remove the compass needle and place a steel ball in the compass case. The hole must be drilled at a slight angle off the vertical. The location of the steel ball, which will roll to the underside of the hole is photographed. A borehole directional survey is then made, from which the bearing of the steel ball relative to the axis of the compass can be determined. The joint orientation is then related to this bearing at all depths. J. ROBINSON, B. C. Dept. of Mines. It was stated this morning that there have been some recent developments that give us the ability to drill horizontal drainage holes and install drainage pipes more cheaply than in the past. Would Mr. Brawner tell us some of the new developments and methods of installing these horizontal drain holes? MR. BRAWNER There are two zones in which you may be concerned about installing drains; the first is in the overburden soil, the second is in the rock. Each area requires a different installation method. If the rock is fairly massive and the holes will remain open, the simplest procedure is to use standard air track equipment or a percussion drill. At one of the mines in the Highland Valley, drains up to 300 ft. long have been installed with a percussion drill at a rate of one drain per day. The costs were in the order of $2.30 and $2.40 per foot. If the rock is quite soft, such as in a serpentine, it will be necessary to install a casing in the hole. The least expensive casing that will not deteriorate within the life required should be used. Plastic pipe or black iron pipe are commonly used. In soft rock, it may be necessary to drill with a casing to prevent the col-

Jan 1, 1971

By Henry B. Kaeding

This paper presents the results of experiments in the treatnient of the gold-bearing ores of the Pis Pis district, near the Atlantic coast of Nicaragua, C. A. Up to the present time, the methods in use in this section of the country for the extraction of the values from the ores have been of the crudest, and the waste has been criminal in its enormity. The transportation of heavy machinery being difficult and costly, recourse has been had to flimsy and inadequate installations, involving great wastes in operation. In some places $15 ore is considered the lowest workable grade. One mine that came under my observation had a 7-ft. vein of $23 ore when examined for purchase; it has been running for years and is now deeply in debt. The future metallurgy of these ores must depend upon chemical, mechanical, and economical considerations—the last being, of course, a resultant of the two former, discussed in the light of prevailing or realizable commercial and industrial conditions. I. Chemical. The ores consist principally of quartz, carrying galena, pyrite, marcasite, and chalcopyrite, and occasionally magnetite, hematite, pyromorphite, and sphalerite, in which minerals the gold lies. The quartz veins occur between malls of andesite, " porphyry," or dioritic rocks, occasionally limestone and dacite. Often the dacite itself is heavily ribbed and filled with auriferous quartz, and is mined as ore. Owing to the excessive rainfall of the country, the ores above water-level have been oxidized and leached of their sulphides, and have become in that operation highly acid and free from

Jan 1, 1912

By L. F. Reinartz

ANOTHER year has rolled by. We are twelve months further away from the start of the depression and. therefore that much nearer to recovery. The accumulated needs and wants 'of our lame, virile population are ready to burst their bonds as soon as confidence returns and credit is stabilized. The steel industry has been harassed by uncertainty of the Government's attitude toward organized labor's de¬mands, and irregularity in volume of production. Steel labor, if left to its own devices, would in most instances, march shoulder to shoulder with the management of steel plants in their effort to pull the industry nut of the ?red.? Cooperation between management and men has improved considerably during; the year.

Jan 1, 1935

By G. G. Gunther, C. L. Boeke

THE zinc deleading processes at the Parral and Santa Barbara mills are described separately to provide a basis for comparison. Although the two procedures are fundamentally alike, there are some differences in application to meet specific conditions. The Asarco mill at Parral in the State of Chihuahua is a flotation plant treating 1450 metric tons per day of complex sulphide copper-lead-zinc ores. In general, the procedure used for selective separation of the minerals into a copper, a lead, and a zinc concentrate follows the usual practice. First, a bulk copper-lead concentrate is floated and then separated into a final copper and a final lead concentrate by the sulphurous acid process. A small tonnage of high grade gravity lead concentrate is tabled from the bulk copper-lead cleaner tailing before it is reground so as to avoid undesirable over-grinding and sliming of this portion of the lead mineral. Next, a zinc concentrate is floated from the lead rougher tailing and, as described later, is separated into a final lead product and a final zinc concentrate. Finally, the zinc rougher tailing receives a strong scavenger float to remove all recoverable middling values for regrinding and return to the flotation circuits. The slime is separated from the scavenger flotation product, and only the sand portion goes to the regrind section. The minerals in the separated slime are extremely resistant to all methods of selective separation and pose one of the major problems awaiting solution. Nevertheless, the slime shows a profit when mixed with either the lead or the zinc concentrate, except when metal prices are very low, so it is accepted as a final product for lack of a more profitable method of handling it. In contrast, the minerals in the reground sands of the

Jan 1, 1953

By W. L. Freyberger, H. Alter, K. L. Woodruff, E. L. Michaels

Laboratory and pilot scale tests have been made to determine the utility of heavymedia separation, particularly a cone-type separator, as a means of recovering aluminum and other values from shredded municipal solid waste. The effect of the method of shredding on the behavior of aluminum in a heavy-media system was determined. Two-stage pilot-scale heavy-media separations were made with size fractions of shredded refuse. Recoveries of aluminum, as well as other components of the refuse, were measured and medium losses determined. The experimental results indicate that with certain reservations a heavy-media cone system can be utilized for aluminum separation and recovery from shredded and air-classified municipal solid waste. Observations made using two-stage heavy-media separation in a drum unit are included. Qualitatively, the results from the two types of separators are similar.

Jan 1, 1976

By AIME AIME

WILBER JUDSON is one of that fairly large group of mining engineers that graduated at an Eastern college, worked his way up in various jobs in the West and in the Latin-American countries, and finally came to New York as an administrative officer of a large mining company. Since coming to New York he has been a loyal friend and counselor of the A.I.M.E., and is now serving a second term as one of its Directors, his first term covering the period 1935-1938. Mr. Judson was born in the capital city of Michigan on July 26, 1880. Probably it was his roving spirit rather than professorial urging that was responsible for the fact that four colleges were responsible for his education: Northwestern, University of Michigan, Harvard (S.B., 1901), and the Michigan College of Mines (graduate study). In his first ten years of professional work he might have been found serving as mine foreman at Catamarca in the Argentine, as superintendent of the Inter Ocean mine at Sunshine, Colo.. as foreman for the Cerro Prieto, Magdalena, Sonora, as superintendent of the Hudson Iron Co. in New York, or as manager of the Dolores mine in Chihuahua for the Mines Co. of America, or in Spain, or in Panama.

Jan 1, 1942

H. M. HOWE, Bedford Hills, N. Y.-One wonders, whether it might not be well to check, by a rather simple and direct way, the inferences that would be drawn from this investigation. Suppose we quench, in these various liquids cylinders of steel, selecting material that is not likely to split in hardening, and then examine their cross-sections micro-scopically. If the cylinder is of any size, you will find a series of concentric bands, a very hard band, a softer band, and a hard band-but it seems that here would be a way of checking the inferences from the cooling curves by comparing these waves of hardness obtained in similar speci-mens quenched in different liquids. One would think that there would be great promise in that way. One's first thought is to quench similar pieces of steel, similarly heated, in different liquids and determine their hardness. I suppose many of us have tried that. We then meet the-difficulty that it is not the most rapid cooling that gives the greatest hardness. There is an intermediate rate of cooling that gives maximum hardness so that you can not by any simple method as that check this cooling method. But it seems possible

Jan 12, 1919

By Goldye Leeds, Marian Balicki

A SURVEY of literature reveals the scarcity of experimental evidence relating to work hardening and reannealing of silver.'-'" With the exception of the well-known X-ray investigation of silver and other metals by W. A. Wood? the effect of progressive cold working has not been studied. The determination of thermal stability of silver in the work-hardened state by means of isochronal or isothermal annealing has been confined apparently to very high reductions only. In the survey made, no study was encountered which endeavored to produce a complete picture of the changes in various properties due to cold working and subsequent reannealing. To fill these gaps and to assemble data that could be used for the determination of activation energies and of frequency coefficients of primary recrystallization, a systematic experimental approach, which was developed by one of the authors, has been applied to pure silver. Material and Processing The silver used was Handy and Harman fine silver, with a spectroscopic analysis at the testing stage of Cu, 0.0001 to 0.001 pct; Te, 0.0001; Pb, Si, Ca, Mg, and Mn, traces. The material was supplied in the form of a rod 0.406 in. diam and was converted into test samples according to the procedure condensed in Table I. It should be mentioned that air annealing was adopted to simulate industrial practice, though it was realized that annealing in a neutral gas or in a vacuum would be preferred. The usual precautions have been taken to eliminate any structural changes and property changes resulting from the storage of the samples prior to annealing or testing. Thus the wires were kept at the fully annealed stage, and the final wire drawing, which produced the desired degree of work hardening, was done just prior to the final annealing or testing. During the short waiting period, the samples were kept in a thermosflask filled with ice. Even with these precautions some strain-age-hardening or self-annealing could occur. To test such a possibility, wires of different reductions were prepared in the manner adopted and portions of them were immediately tested. The remaining portions were similiarly tested after different periods of storage, both at room and melting-ice temperature. Within experimental error, all samples obtained from a wire of a given percentage of reduction yielded identical values. This result qualified the material for further tests and interpretations, because it showed that either strain-age-hardening and self-annealing were absent, or that these effects fully balanced each other. The final annealing was carried out in an electric resistance furnace automatically controlled to within a 10°F. It was realized that the temperature fluctuations were greater than desired for this type of work. TO diminish the errors due to fluctuations of temperature, the hot junction of the thermocouple was placed as close to the samples as possible; the time of soaking was reduced to 15 min; and the number of samples annealed at different temperatures was increased. It will be seen from Table I that some tests were performed on the same material at rising temperature. These will be discussed elsewhere. Room temperature testing was limited to the determination of some of the mechanical properties that are known to be additive in a degree sufficient to be used for indirect study of the kinetics of the reannealing process, Tensile tests, carried out on a manually operated J. Camillon machine, accurate to within permitted the determination of the ultimate stress (U.S.1 and of the 2 in. elongation, (A,). The proof stress (d,e) has been determined from a series of bend tests carried out on a Tinius Olsen Stiffness Tester by using the offset method. This involved accurate determination for each sample of load-angular deflection curves, finding a

Jan 1, 1952