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By Alan Stanley

THE MacIntyre Development of National Lead Co. is located at Tahawus, N. Y., in the heart of the Adirondack Mountains. Operations involve the mining and concentrating of a titaniferous iron ore to produce ilmenite and magnetite concentrates. A general description of the operation and metallurgy has been given by Frank R. Milliken.' Pigment plant production demands that the MacIntyre mill produce a 44.7 pct TiO, ilmenite concentrate. To achieve the required ilmenite grade and tonnage it is important that the table concentrate grade be closely controlled. Unfortunately, however, the titaniferous orebody which feeds the MacIntyre mill is not uniform. Ore dressing characteristics vary from one end of the orebody to the other, and from • one level to the next. The changeable nature of the mill feed precludes a single adjustment of the equipment for long periods of time. Thus the operators must constantly watch the equipment to insure a uniform concentrate from the fine and coarse tables and Wetherills, or dry magnetic separators. Chemical assaying of mill products requires about 4 hr from the time the sample is taken until assay results are obtained, and this is available only on a two-shift basis. The ore may change rapidly, even several times during a shift, so that assay results lose most of their control value by the time they are reported to the mill operating crew. Members of the crew have therefore tried to evaluate the table and Wetherill concentrate by visual inspection, since through long experience the shift operators, under most circumstances, can gage closely the grade of the mill products. However, there are times when the physical nature of the ore is radically different from normal. Under these conditions visual inspection is of no value, and at such times final ilmenite as low as 43 pct TiO, has been produced and shipped before the assay results have been received. The specific gravity method of assaying for TiO, has been attempted to eliminate the shipping of ilmenite below normal grade as well as to help control day to day and hour to hour mill production. Table I shows the minerals found in the MacIntyre ore along with their average weight proportions and specific gravities. The first two products considered for the specific gravity method were fine and coarse table concentrates. It was reasoned that these products were essentially ilmenite with the higher specific gravity gangue minerals. Since they were always produced the same way, and the desired grade of TiO, was always constant, the specific gravity of these materials would increase or decrease as the amount of ilmenite increased or decreased. Thus for table concentrates which assayed 40 pct TiOz a constant gravity would invariably be obtained, and as the TiO, value changed the specific gravity would change in direct proportion. The third product considered was Wetherill ilmenite. It was assumed that a desired grade of 44.7 pct Ti02 would also always contain the same amount and type of gangue minerals along with the ilmenite, and thus would always have the same specific gravity. As the TiO, value of the ilmenite concentrate changed so would its specific gravity. Dr. Kenneth Vincent, chief metallurgist of the Baroid Division of National Lead Co. at Magnet Grove, Ark., ran specific gravity tests on 17 samples of the desired products. The lowest specific gravity reading assayed the lowest in TiO, and as the specific gravity increased the trend was for the TiO, assay to increase, see Fig. 1. Since these results warranted further investigation, a 500-g capacity Torsion balance and 250 ml Le Chatelier specific gravity bottles were obtained. Shift samples of fine table concentrate, coarse table concentrate, and final ilmenite were tested. Each sample was split and 85 g weighed on the Torsion balance. The Le Chatelier bottle was filled with water to a zero mark. To avoid wetting the neck of the bottle it was found necessary to do this

Jan 1, 1953

By S. Ramachandran, R. A. Walsh

Many investigations have shown that the manganese enhances the deoxidation power of silicon. Here it is suggested that this phenomenon could be explained in terms of the formation of impure silica. Data of Hilty and Crafts on the Fe-Mn-Si-O System has been evaluated on the basis of the reaction S_i + 20 = (SiO2) where (SiO2) denotes silica of variable activity. The activity of silica in this system is a function of aMn/aSi and the temperature, and can be described by the equation 12700 l°gaSiOz = -6.85+ - - 0.5 log aMn /asi PRACTICAL melting experience has shown that it is helpful to maintain a certain range of Mn/Si ratio in deoxidizing quality alloy steels. Herty,1 as early as 1932, reported a strong association between manganese and silicon as did schenck2 and Korber and Oelsen3 in later work. More recently, Hilty and crafts4 have studied the solubility of oxygen in the Fe-Si-O system, both with and without manganese. Their study confirmed the marked ability of manganese to increase the deoxidizing power of silicon. This phenomenon has remained unexplained in the liter,ature5 since it has been shown that manganese has virtually no influence on the activity coefficients of silicon or oxygen.= In this paper, an explanation for the role of manganese is suggested and equations are devised for quantitatively describing this influence. DISCUSSION Hilty and crafts4 equilibrated their melts under an argon atmosphere and the system established equilibrium with a self-generated slag which was not always the oxide of lowest free energy. Drawing on the early work of Korber and Oelsen,3 it was reasoned that the formation of complex Fe-Mn-silicates

Jan 1, 1963

By Paul M. Tyler

YEAR after year, the kaolin industry of the United States has been setting new production records and making better products. High-grade paper, pottery, and rubber clays are produced in this country mostly in the South. Georgia alone contributes over 70 pct and South Carolina almost 20 pct of the total domestic output. Residual kaolin is mined in North Carolina, highly plastic but naturally sandy Tertiary (Eocene) potting clays are worked in north central Florida, and good white clays are produced in several other states, but the main sources of kaolin or china clay have been numerous deposits in the Tuscaloosa (Upper Cretaceous) formation. This formation of generally sandy sediments is called the Middendorf member in older geologic reports and corresponds in age with some of the New Jersey clays. As shown in fig. 1, it crops out almost continuously in a generally southwesterly direction across South Carolina and Georgia and into Alabama. Clay is mined from this formation in all three states but the principal producing centers lie within about 10 miles of a straight line drawn between Aiken, S. C., and a point about 10 miles south of Macon, Ga. The white kaolins of the South were recognized and used prior to the Civil War but suitable treatment processes were not introduced until World War I when imports, chiefly from England, were curtailed. Although imports of high-grade clays were resumed after 1918, the domestic industry managed to treble its prewar production record during the early 1920's and has continued to grow. Whereas the 1909 to 1913 average total production in the United States was only 132,104 short tons valued at $705,352 f.o.b. mines, the output in 1948 was 1,568,848 tons worth $19,756,738.

Jan 6, 1950

By W. TRINKS

RAPID progress has been made in the automatic control of open-hearth furnaces in the past few years and many firms today\supply such control apparatus. It is somewhat surprising that so little was heard about open-hearth control up to about, 1928, and that thereafter the practice of automatically controlling open-hearth furnaces spread very rapidly. Before discussing the reasons for this it may be advisable to list the quantities that can be controlled. One of the easiest quantities to be controlled in the open-hearth furnace is pressure. The reasons for controlling it are plain. If there is excess pressure in the furnace, products of combustion leak out around .the .door and through all the cracks in the brick-work. The stability of the piers between the doors is seriously endangered, and front wall repairs become frequent. Furthermore, hot gases are lost that might be usefully employed in heating the checkerwork. If there is a slight vacuum in the furnace, cold air entering through the doors and cracks cools the interior, slowing down the reactions and making it impossible to secure the highest degree of preheat from the checkerwork.

Jan 1, 1931

By F. S., Mc Nicholas

A practical discussion of the theory of A block caving is presented which applies particularly to the physical conditions of the Climax orebody although the conditions are sufficiently characteristic of caving ore-bodies to provide valuable information applicable elsewhere.

Jan 1, 1950

By Charles White Merrill

Mankind's progress is measured in minerals. Man's emergence from prehistory is marked by passage through a Stone Age and a Bronze Age and into the present era, sometimes called the Iron Age or the Age of Metals. With the evolution of civilization and the development of a modem industrial economy, minerals become more and more important. Structures, roads, and machines are built largely of minerals; the energy to heat the structures and to drive the machines is mostly mineral; agricultural fertility is maintained by mineral fertilizers and water; and military strength is provided by fortresses, armaments, and munitions, largely of mineral origin. Thus in the material world, in the productivity of the economy, access to minerals has paramount importance. Every evidence indicates increasing dependence on minerals in the modem economy, particularly on the mineral fuels as energy sources to provide the power base for advancing industrialization. Both the total and the per capita consumption of almost every mineral is increasing in the industrialized nations. Moreover, nations with predominantly agrarian economies call themselves underdeveloped and universally strive to industrialize. Most mineral consumption trends in the more advanced economies have been greatly exceeding population growth-which itself has been advancing at an accelerating rate-and sometimes have surpassed the growth in real income. Some minerals have only recently been adopted or grown to importance in use. Titanium metal did not appear as a commercial product until 1948, and even coal seriously displaced wood as a source of heat less than two centuries ago. On the other hand, minerals have always played an important role in construction. The prehistoric megaliths that form the dolmens of Salisbury Plain are stone; the pyramids are andesite faced with limestone; and many other ancient structures are built of mineral materials. In modem times the whole course of architecture has been redirected by new building materials, mostly mineral. Most conspicuous is the sky-

Jan 1, 1964

By E. P. JENNINQS

(Cleveland meeting, October, 1912.) LARGE deposits of titaniferous iron-ore occur at Caribou, an old silver-mining camp in Boulder county, Colo., 17 miles west by south of Boulder, and a few miles northwest of the tungsten-mines. Professor Regis Chauvenet 1 published a part analysis of the ore many years ago, but gave no description of the wall-rock. Caribou hill, which contains both the silver-bearing veins and the iron-ore deposits, is a low dome of gabbro surrounded by the Archaean schists and gneisses of the Front range of the Rocky mountains, the peaks of which, a few miles west of Caribou, attain an elevation exceeding 12,000 ft. The gabbro stock is roughly elliptical in outline, with approximate diameters of 1 and 3 miles. The crest of the dome is 10,500 ft. above sea-level, and the town and ore-deposits are 500 ft. lower. Outcrops of the iron-ore occur in the town and extend NW. for 2,000 ft., where they disappear under the swampy meadows of Caribou park. Portions of the deposit are covered by drift, but one continuous outcrop is 900 ft. long and from 200 to 250 ft. wide. A second deposit is 0.25 mile south of the town along the eastern slope of the hill. It is not as well defined as the north bed, but is approximately 1,000 ft. long and from 100 to 200 ft. wide. The easily disintegrated ore does not form prominent outcrops, but the outlines of the deposits are readily traced by the large amount of ore fragments that cover the ground. Trenches and pits sunk on the outcrop expose a roughly banded magnetic iron-ore, with pyroxene as the principal gangue-mineral. The Gabbro. This rock was classified in the field as a gabbro from the presence of pyroxene and striated feldspars, and for convenience the field-name will be retained. 1 Chauvenet, Regis, Biennial Report of State School of Mines, Golden, Colo., p. 16 (1886).

Oct 1, 1912

By C. J. Rodgers

The present day success of gravel packs to prevent or retard the migration of unconsolidated sands into the well bore is due to: (I) the use of a saline or non-aqueous, nonsolids drill fluid, (2) proper preparation of the well bore prior to gravel packing, and (3) pressure placement of the gravel. The experience gained from the "pressure pack" method of gravel packing indicates that sand-free fluid production can be maintained for a length of time sufficient to make the operation economically attractive. Data pertaining to the first 15 wells so completed by Gulf indicate that for each dollar spent to effect the completion, there will be a return of more than $2.92. The pressure pack technique of gravel packing is essentially the placing of gravel in and adjacent to the producing formations. This is done with fluid pressure and by the use of a drill fluid that will permit partial or complete loss of returns to the formation during placement. This technique was first intentionally used by Gulf in May, 1950, and since that time has been applied in more than 90 wells. Other advantages claimed for this type of completion are that the pressure placement of the gravel has a scouring effect on the casing perforations, that additional drainage channels to the well bore are created, and that the possibility of shifting of the formations adjacent to the casing is minimized and possibly prevented. During the past few years, the use of gravel to prevent or retard the migration of unconsolidated sands into the well bore has met with a favorable degree of success. Numerous methods and techniques of "gravel packing" have been used, each having its own relative merits, and with varying results. M. L. Cashion1 in 1939 ably reviewed the history of gravel packing to that time. As stated in his paper, ". .. the idea of gravel packing wells is not new." During the period 1939 to 1949, very little if any progress or change in technique in this type of completion was made. However, it was noted in some cases that during the placement of gravel, if there was a loss of drill fluid to the formation, there was a corresponding loss of gravel to the formation. Also, it was noted that in those gravel-packed completions (opposite casing perforations) that "sanded up," there was found to be an absence of gravel in the annular space between the liner and casing, although gravel had previously been placed in this space and no gravel had been removed from the well at the surface. These findings resulted in the placement of gravel with fluid pressure and by the use of a drill fluid that would permit partial or complete loss of returns to the formation during placement. Pressure placement of gravel became an accepted practice in late 1949 and early 1950. Another fact brought to light that has contributed to the current success of gravel pack completions is that drilling fluids containing solids will to some extent cause plugging of the screening medium or blocking of the producing section. The removal of these solids by chemical action, mechanical action, or a combination of the

Jan 1, 1955

The earliest record of production in this county is for drilling a salt well in 1809. Some scattered data are shown in the table; the total figures are estimated. Little coal could be shipped in this period on account of lack of transportation. [ ]

Jan 1, 1942

By N. J. Grant, B. C. Giessen, M. Morris

The slvuclures of alloys in the system In-Bi have been investigated after (levy vapid queuching from the mell (splat cooling) to -190°C. Tuo-phase fields could be suppressed over most of the tota1 concentvalion range; five melastable phases a1, a2, ?, ?1. and ß exisl, of which four have simple elementtike structures. For example, ß has the A5 struclure of white till. Crystal-tographic data and coordination numbers for these phases aye given, as well as addilional information on the equilibrium diagram, where a new phase In5Bi3 teas found. THE phase diagrams of binary combinations of B elements from the groups B2, B3, B4, and B5 are usually of a simple type and show considerably fewer intermediate phases than combinations of these elements with A metals, transition metals, or the B1 noble metals. Aside from phases such as the typical B3-B5 compounds with the ZnS-B3 structure type, few stoichiometric phases are known; among them are In2Bi and 1nBi.l Nonstoichiometric phases include ß (In-Sn), a1, (In-Pb), and the tin-rich ? phases in the In-Sn, Cd-Sn, and Hg-Sn systems.' The first two phases have a close relationship to indium, while the latter group are known to be structurally related to a Sn. Thus, there are generally no immediate experimental data for the correlation of the crystal structures of B metals and B metal combinations with certain monotonously varying parameters, such as the valence electron concentration (VEC), or the average atomic size. Such parameters have been recognized as structure determining, e.g., for the transition 4 Sn — y phase,2,3 where nonintegral valence electron concentrations are encountered. It should be possible to extend such correlations to other binary systems, if nonequilibrium single-phase alloys could be produced over broad valence electron concentration ranges, and if their crystal structures could be regarded as being imposed by their electronic states. It has been shown in the case of the tin-rich 7 phases3 that alloy phases with typical crystal structures can be produced in B metal alloys rapidly quenched from the liquid to -190°C by the splat cooling technique due to Duwez,3-8 and reviewed in Refs. 5 and 6. The In-Bi system was selected because it extends over a valence electron concentration range in which several metastable, nonstoichiometrir phases could be expected to occur. Further, the low melting points of the known intermediate phases, In2Bi and InBi, Fig. 1(a), indicated low binding energies and thus possibly low driving forces for the formation Of the equilibrium structures. EXPERIMENTAL TECHNIQUES AND RESULTS The preparation of the quenched foils followed the practice described in Ref. 3. Master alloys were produced by melting of indium (99.97+) and bismuth (99.99+) in evacuated Vycor capsules or in an inert gas arc furnace; quantities of 20 mg were splat-cooled onto copper and silver substrates held at - 190°C; and crystal structures and lattice parameters were determined on a GE XRD-5 diffractometer using Cu Ka, radiation at -190°C and at room temperature. The duplication of each run with both substrates permitted the elimination of overlap of the substrate diffraction pattern and that of the investigated substance. The XRD patterns were usually taken from sin2 " = 0.03 to 0.35; the substrate was used as a means of internal calibration. The fractional accuracy of the lattice parameters of metastable phases is approximately 10-3 In the following, all percentages are in atomic percent. The stable and metastable phases found after rapid quenching to -190°C are listed in Table I, together with estimated concentration ranges and crystallographic data. The investigated alloys and phases present in them are given in Table 11. Except for the region between indium with 33 and 50 pct Bi, where a revision of the equilibrium phase diagram became necessary to include a new stoichiometric phase In5Bi3, the diffraction patterns taken after heating to room temperature agreed with those expected from the phase diagram, Fig. l(a). This suggests that the new nonstoichiometric phases are not stable at room temperature, thus following the observations made for the y phases based on tin.3 Results concerning the equilibrium phases In2Bi and In5Bi3 and the revision of the equilibrium phase diagram which is made necessary by the inclusion of In5Bi3 will be treated first. The Crystal Structure of In2Bi. Makarov7 had identified In2Bi as belonging to the AlB2-C32 type ; however, in a later paper the structure was revised.8 In2Bio was found to be of the Ni21n-B8ß type,21 with a = 5.496A, c = 6.57.9A, and N = 6 atoms per unit cell.9 This crystal structure was confirmed in the present work; definite evidence for the doubling of the c axis, as compared to the A1B2-C32 type, and for the proposed order structure, was found in the powder pattern. The observed lattice parameters agree well with those of Ref. 8; those measured at -190°C are given- in Table I. The Crystal Structure of In5Bi3. A new, equilibrium, intermediate phase was identified in slow-cooled, as-cast alloys; it was identified as In5Bi3. The structure has been worked out by Giessen and Grant;" lattice parameters at -190°C are given in Table I. This phase is probably identical with "In3Bi2", produced by vapor deposition techniques, but not recognized as an equilibrium phase by Palatnik et a1.11 After completion of the present work, the existence of In5Bi3 has also been demonstrated by superconductivity measurements on In-Bi alloys.20

Jan 1, 1968

By W. F. Wheeler

A discussion of the paper of W. F. Wheeler, presented at the Toronto Meeting, July, 1907 (Trans., xxxviii., 621 to 632). A. BEMENT, Chicago, Ill. (communication to the Secretary*):¬Formerly it was the general practice of engineers to designate coal that is free from moisture and ash as " combustible,", not-withstanding that it contains oxygen and nitrogen. The origin of this practice was more particularly due to the requirements in connection with boiler-testing, which demanded a consideration of that portion of the fuel which took part in the combustion-process because results based on a unit of either moist or dry coal were not comparable, since both moisture and ash were recognized as variable quantities. Thus, a pound of " combustible " became a standard of value, and was treated as a constant before employing measurements of heating-power and calculating therefrom the percentage of efficiency. The recognition of this term ." combustible" was an advance to be credited to the engineer .rather than to the chemist, because the latter, not having to do with the interpretation of analysis in practice outside the laboratory, usually saw no reason for reporting results in terms other than those of the moist-coal composition. Some years ago I needed a table of fuel-composition in terms of moist, dry, moisture-free and ash-free coal, and of the combustible components. This table required the use of the word combustible in its proper sense, for the purpose of designating carbon, hydrogen, and sulphur, instead of including these three elements with oxygen and nitrogen, to which aggregate the term combustible was formerly applied. To make such a tabulation involved either the use of the inconvenient and cumbersome term, "ash and moisture-free coal," or of some other representative term, and for this purpose I adopted the expression " pure coal," which is short, simple, convenient, and technically correct. It is also harmonious, because it agrees

Sep 1, 1908

By E. H. Sellards

ON Oct. 9, 1929, a sink formed in the Sour Lake salt dome oil field in Texas, and on Oct. 12 a second smaller sink formed at the north margin of the first. The purpose of this paper is to give such observations as it has been possible to make on the earth movement incident to this subsidence. Sour Lake salt dome is typical of the salt domes of the Gulf Coastal Plain of Texas. Structurally the dome is a plug of salt which rises to within 900 ft. or less of the surface. Above the salt is a cap rock consisting of anhydrite with more or less calcium carbonate. The salt plug, as contoured on the cap rock, is circular in outline with, however, some appreciable irregularities. Overlying the cap rock are relatively uncompacted sediments consisting of sand, clay and gumbo.. At the crest of the dome these deposits are no more than 700 or 800 ft. thick. However, the sides of the dome are steep, and the sediments thicken rapidly away from the crest. The sink formed about 1500 ft. northeast of the crest of the dome where the sediments overlying the cap rock are from 1000 to 1200 ft. thick. The cavity permitting the subsidence was quite certainly either in the cap rock or in the salt below the cap rock, so that the sink was formed by the caving of as much as 1000 or 1200 ft. of earth.

Jan 1, 1930

By I. A. Ettlinger

DEPRECIATION allowances have become firmly rooted in our income tax structure both by legislation and by court decisions. Secretary of the Treasury Morgenthau has recently stated before the Ways and Means Committee of the House: A taxpayer who did not provide for depreciation of assets used in his business could not long remain in business and the income tax should be levied on the assumption that he will provide for such depreciation. The 1934 Revenue Act has now been enacted, the depreciation provisions of the 1932 Revenue Act having been carried forward without change. However, there has arisen, in connection with the preparation of this new Revenue Act, a determination by the Treasury Department to make certain changes in the future administration of the depreciation allowances that will affect all corporations, and mining companies in particular.

Jan 1, 1934

By Harry M. Mikami

Chromite is the only ore mineral of metallic chromium and chromium compounds and chemicals. Because of this fact, chromite and chrome ore are used synonymously in trade literature. In commercial market quotations, chrome ore is the term commonly used. Chromite per se, because of properties imparted by its chromium content, is used in refractories and in special purpose molding sands for metal casting. There are many other minerals containing some, generally minor, amounts of chromium, but none are commercial sources of the element (Thayer, 1956). Chromium and chromite have many diverse uses that, directly and indirectly, critically affect vast segments of our modern industrial system. Most important are probably the metallurgical applications wherein chromium is a component of heat-, abrasion-, corrosion-and oxidation-resistant and high-strength alloys of many types. Stainless steels are the largest volume category of chrome-bearing alloys. Chromium chemicals are used in leather tanning, in pigments, dyes and mordants, printing, chemical process industries, photography, pharmaceuticals, metal plating, pure chromium metal production, and for many other purposes. Chromite is a necessary constituent in basic refractories indispensable for the production of steel, copper, cement, and glass. Under present conditions, the US and North America, with the possible exception of Cuba, have no commercial ore reserves. There are chromite deposits, as will be described, but they would be used only under highly abnormal conditions if all outside sources were cut off for an extended period. All chromite used in the US is imported from the eastern hemisphere in which are contained the principal world reserves. The main suppliers in 1980 were the Republic of South Africa (43%), the USSR (21% ), the Philippines (12%), Albania (11 %), Turkey (8%), and others (5%). The strategic nature of chromite is obvious. End Uses-Grades and Specifications As noted before, the three principal uses for chromite are metallurgical, refractories, and chemical with a fourth minor use as foundry molding sand. For metallurgical applications chrome ore is first reduced in electric carbon arc furnaces to various types of ferrochromium alloys. There are high, medium, and low carbon ferrochromiums with carbon ranging from 0.01 up to 10%. Chromium itself ranges from 50 to 73 %. Ferrosilicon chromium and ferrochromium-silicon grades have chromium from 33 to 67% and silicon from 3 to about 48%. Since iron is reduced with chromium, the Cr:Fe ratio of the ore will determine the ultimate grade of the ferrochromium whereas carbon and silicon can be controlled during processing. MgO, A12O3, CaO, and excess SiO2, are removed in slag. A small amount of pure chromium metal is prepared by alumino-thermic and electrolytic processes from essentially iron-free chrome components that have been made via the chemical route. The higher grades of ferrochromium with chromium in the 66 to 73% range can only be made from ores with not only high chromium content, but low iron, i.e., high Cr:Fe ratio. These ores, conventionally termed metallurgical grade, have Cr2O3 contents of 45 to 56% with Cr: Fe ratios of 2.5 to 4.3. A standard composition is generally 48% Cr2O3 and 3:1 Cr:Fe ratio. Very high grade ores are often blended with lower grades even with the high iron chemical grade. For some ferrochromiums, additions of high alumina refractory grade are used as slag conditioners to facilitate smelting while still contributing chromium values. A lower grade ferrochromium, the high carbon charge chrome, has become the predominant grade in use today for making chromium-bearing steel alloys. This

Jan 1, 1983

By Walter P. Jenkey

[ ] I. THE REDUCING ACTION OF CARBON AND OF HYDROCARBONS. Carbon has long been recognized as one of the most powerful reducing agents in the deposition of ores. Investigations, made by myself, of the zinc- and lead-deposits in Southwest Missouri, in the region centering about Joplin, where the formation of the metallic sulphides has been due to the action of bitumen, carbonaceous shales and bituminous coal, Lace afforded abundant evidence that the solid oxygenated hydrocarbons, particularly, when in fine powder and in suspension in the waters circulating through the ore-bodies, are the most energetic and powerful reducing agents known. Bitumen, liberated by the decomposition of the ore-bearing limestone, is found in the Joplin mines in all degrees of fluidity and hardness, dependent on the amount of oxidation it has undergone. From semi-fluid maltha it grades into partly oxidized mineral-pitch, which, by further oxidation, changes to hard asphalt, finally breaking up, from continued absorption of oxygen, into a fine powder resembling in appearance powdered coal. In this condition oxidized bitumen, from its light gravity, is transported readily in suspension in the underground circulating-waters. Bituminous coal and black carbonaceous clays and shales occur as surface formations, often in intimate association with

Jan 1, 1913

By Raymond D. Daniels, Frank E. Rizzo, James D. Gerber

ThIS discussion describes a method for the addition of small amounts of oxygen to columbium (niobium) in an accurate and reproducible manner. The method is based on the complete reduction by columbium of a carefully weighed amount of another metal oxide. The equilibrium Pq associated with Cb-CbO mixtures is extremely low, e.g., 10"25 atm at 100O°C, and the pressures over Cb-0 solutions are even lower. The equilibrium Pq associated with a given metal-metal oxide mixture can be easily obtained, with the aid of a Richardson-Jeffes chart.' Although columbium should effectively reduce almost any metal-metal oxide combination, the proper choice of a metal-metal oxide system is complicated by the low rate of oxygen transport in the gas phase at low oxygen pressures and the difficulty in reducing any columbium suboxide formed during the reduction of the oxygen source material. Thermodynamically, oxide formation on columbium will be avoided so long as the oxygen partial pressure over the columbium is below the equilibrium pressure associated with the mixture Cb-CbO. The logical choice of a source for oxygen would appear to be a mixture of Cb-CbO, since oxide formation would be precluded by nucleation difficulty. But calculations using the kinetic theory of gasses indicate that, for a temperature of 900°C, the reaction would proceed too JAMES D. GERBER, formerly Research Assistant, University of Oklahoma, Norman, Okla., is Research Metallurgist, Air Force Weapons Test Laboratory, Kirtland Air Force Base, N. Mex. FRANK E. RIZZO, Junior Member AIME, formerly Assistant Professor of Metallurgy, University of Oklahoma, is Associate Professor of Metallurgy, University of Texas at El Paso, El Paso, Tex. RAYMOND D. DANIELS, Member AIME, Professor of Metallurgical Engineering, University of Oklahoma, is an NSF Fellow, Institute de MBtallurgie Structurale, Universite de euch:tel, Neuchitel, Switzerland. Manuscript submitted October 28, 1968. IMD

Jan 1, 1970

C. A. HANSEN (communicated appendix*).-Since the above paper was written, tests have been conducted with a view to securing a sounder basis for discussing the effects of temperature on the behavior of the zinc cell. The following data, while making no pretense to great accuracy, are still reasonably close. Cells were operated with the same feed solutions, but at varying temperatures, the latter being controlled by means of immersed steam coils. Current efficiencies obtained indicate that the corrosion rate

Jan 11, 1918

By D. M. McFarland

IN mining, quarrying, and construction, drilling and blasting have an important influence on the operations that follow. If the fragmentation of material being disrupted is inadequate, loading and transportation equipment will not operate at or near full capacity. Any operator faced with this difficulty should not be satisfied until he is convinced by a careful study of his methods of drilling and blasting that no improvement can be made. Rock in a certain quarry in Ohio seemed to defy any grade of explosive or means of detonation that the explosives industry had to offer. The average result of a blast was that a great part of the burden would be pushed out from the face in a number of large sections that would jokingly be referred to as "boxcars." These were no credit to the explosives man and a costly problem for the quarry company. Such blocks retard shovel operation as they have to be uncovered and subjected to secondary drilling and blasting which, if extensive, is an expensive operation. It was an attempt to improve the fragmentation obtained in primary blasts that led to the development of milli-second-delay electric blasting caps. The reasoning that prompted the trial was that even with wide spacing of the drill holes it seemed that the burden was separated too quickly from the face by the cutting action of the explosives from hole to hole. If the time of firing of the holes could be regulated so that

Jan 1, 1948

By W. H. Bassett

IN the commercial annealing of cartridge brass there are four points regarding which definite data are essential. They have to do with the correct interpretation of grain count in its relation to annealing temperature and, incidentally, to Brinell hardness. These points are: 1. The comparison of the grain sizes of two cartridge-brass mixtures: 69 copper, 31 zinc, 0.376-in. (9.5-min.) gage; and 68 copper, 32 zinc, 0.130-in. (3.3-mm.) gage. 2. The comparison of the grain sizes of annealed metal that had previously been reduced by rolling varying amounts; for instance, 20.0, 36.6, 50.9, and 59.1 per cent. 3. The determination of standards for grain sizes on annealed brass of the composition 68 per cent. copper, 32 per cent. zinc and 69 copper, 31 zinc. 4. The comparison of grain size with Brinell hardness on identical samples of annealed metal. In their comprehensive and thorough investigation of the recrystallization of cold-worked alpha brass on annealing,1 Mathewson and Phillips have discussed the relations between temperature of anneal, degree of deformation, and structural alteration in alpha brass. They have also shown certain comparisons between the ordinary physical properties and the grain size of annealed brass. The purpose of the present investigation is mainly concerned with the grain size of cartridge brass, its relation to Brinell hardness, and the publication of sufficient data to enable those engaged in the inspection of such material to have a correct foundation upon which to work.

Jan 1, 1919

By David J. Mack

A survey and critical appraisal of published information about Young's modulus was originally made by the writer because of a complete lack of information about this very important quantity in works on. mechanics, physical metallurgy, physics, and other sciences. It was felt that a comprehensive summary of such information about Young's modulus might be of general interest and may suggest new problems or lines of attack on other problems that involve E. Hence this paper has been prepared even though it is only a review, with no new ideas or experimental data. The references are only those used in assembling the paper. No attempt was made to compile a complete bibliography on the subject of Young's modulus. CalculatioX oP YouNg's Modulus from Theoretical or Empirical CoNsidera-tions Many attempts have been made to compute E from theoretical considerations. The earliest calculations were probably those of Tomlenson (1883) and Souther-land (1891), but Fess'enden4',~ made extensive calculations a few years later and arrived at the relationship: £ = 78.TOw(i)* where V is the atomic volume. In 1923, Peczalski, working from the same standpoint but with more information available on atomic structure, arrived at an identical relationship, which he expressed as: where B is a constant of value about 8 . 107, p is density and mis atomic weight; the atomic volume, of course, being ml p. Portevind4 immediately pointcd out that while the equations of Fessenden and Peczalski were true of the common metals, they gave low values for the refractory metals with high moduli (Fig. I). He showed (Fig. 2) that much better concordance was obtained by means of an empirical equation of the form: F- KT" where K is a constant; T the absolute melting point; V, atomic volume, and a and b constants of value approximately I and 2 respectively. This constant K in the Portevin equation is not necessarily the same for all elements, as shown by Thompson. Other equations for E based upon theoretical considerations have been derived by Honda and Yamada49 and Lasareff.50 The most recent calculations of elastic moduli based upon quantum mechanics are probably those of Fuchs He extended the method of Wigner and Seitz for calculating the lattice energy and compressibility of monovalent metals and computed the elastic constants of lithium, 18

Jan 1, 1946