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By Philip S. Morse

THE Australian lead-smelting plants began to use charges carrying high zinc percentages somewhat earlier than was common with American plants. When lead smelting first started in Australia the immense deposits of oxidized lead at Broken Hill were available but later these oxidized ores became exhausted and were replaced by sulfides. This was before the days of flotation and these sulfides when concentrated carried about 1 per cent. of zinc to 6 per cent. of lead. The works of the Sulphide Corpn. at Cockle Creek was perhaps the pioneer in high-zinc slags but the Port Pirie plant of the Proprietary Co. was a close and very able second and has continued the work to the present time. The Cockle Creek lead furnaces remained in operation until shortly after the war when most of the Broken Hill companies combined and took over the Port Pirie plant to treat their concentrates. As it was the practice both at Cockle Creek and Port Pirie to carry 20 per cent. or more of lead on the charge, it was found that under these conditions of large amounts of zinc in the charge, good roasting was absolutely necessary and matte production was unwise. The Hunting-ton-Heberlein system of roasting was introduced and later the Dwight & Lloyd process. In this way, by roasting the sulfide portions of the charge as thoroughly as possible and making no matte, a method of smelting was developed where the slag over long periods carried as high as 20 per cent. ZnO without serious furnace troubles, and slags carrying even up to 33 per cent. ZnO have been reported. The zinc slags were not very different in appearance from the ordinary slags produced in American practice except that they gave off more smoke and fume on tapping. The slag usually ran hot and freely, coming from the tap in a full stream. Normally there was little crust on the sides of the furnace and the tuyeres gave no trouble though they were always rather dark. At the works of the Sulphide Corpn. it was the custom, on account of the labor situation, to shut down the furnaces during the Christmas holidays, thus giving a campaign of about 12 months. The furnaces at the end of the run usually showed no crust on the sides, though crusts always occurred at the back and front ends. A furnace campaign of 22 to 23 months has been made at this plant where both sides of the

Jan 1, 1929

By David B. Reger

The expansion of the previously discovered gas pools and an intensified search for additional pools in the Oriskany and deeper sands were the principal petroleum activities in West Virginia during 1941. One small oil pool was discovered and another was considerably extended. One small gas pool was discovered, several isolated well discoveries were expanded into definite pools, and various recognized pools were substantially increased. The proved oil territory of the state was increased about 600 acres and the proved gas territory about 45,000 acres. The new discoveries of oil did not equal withdrawals but gas reserves added were greater than gas withdrawals. Oil activity, as in the past several years, was slight because of unfavorable crude prices. Most operators prefer to leave oil in the ground rather than to drill for it without a better return. Gas activity increased greatly because of better demand, even though the price of gas did not improve. The account of operations, as gathered from trade journals and other reporting services, shows that 838 new wells were drilled, resulting in 114 new oil wells with 2606 bbl. of daily new production; 558 new gas wells with 949,226,000 cu. ft. of daily open flow; and 166 dry holes. Also, 86 old wells were drilled to deeper sands with 9 bbl. and 56,030,000 cu. ft. of added production. On the new wells the oil average was 22.86 bbl. per well per day; and the gas average was 1,701,000 cu. ft. per well per day. On new wells the ratio of dry holes to completions was 13.61 per cent. On deeper drilling to other sands the ratio of failures was 15.12 per cent. From an exploratory standpoint one strictly new oil pool (Higginbotham Run) was opened in Kanawha County and one strictly new gas pool (Lost Run) in Taylor County. One entirely isolated wildcat gave commercial Oriskany-sand gas production and may open a pool. Various other wildcats greatly extended the boundaries of known Oriskany-sand gas pools and various others may have opened new pools in the shallow sands. On the other hand, various Oriskany tests in Harrison, Monongalia, Roane and Wood Counties were dry and all five tests to the White Clinton sand (Sil.) in Boone, Harrison, Kanawha and Wood Counties failed to find commercial production. The principal oil wells completed, by counties, were: Calhoun, 24; Clay, 7; Gilmer, 6; Hancock, 9; Kanawha, 9; Pleasants, 10; and Ritchie, 14. Production for the year was estimated by the Oil Weekly as 3,421,000 bbl., compared with U. S. Bureau of Mines final figures of 3,444,000 bbl. in 1940. The leading counties in gas-well completions were: Boone, 32; Braxton, 19; Cabell, 16; Calhoun, 46; Clay, 20; Gilmer, 37; Jackson, 94; Kanawha, 82; Lincoln, 17; Putnam, 46; Ritchie, 33; Upshur, 20; and Wayne, 33. Production for the year is estimated by the author as 210,000,000,000 cu. ft., as compared to the U. S. Bureau of Mines' final figures of 188,751,000,000 cu. ft.* in 1940.

Jan 1, 1942

By J. P. Hirth, C. S. Hartley

A simple graphical technique is presented for rapidly determining the ratio of resolved shear stress on slip systems in single crystals to the applied stress (Schmid factor) for various simple states of stress. Master plots are presented which, when used in conjunction with an appropriate stereo-graphic projection, allow one to determine the Schmid factor for all slip systems in a crystal of given orientation. It is shown that one such plot suffices for simple tension or compression, flex-ural bending, and biaxial compression, while a combination of two different plots must be used for torsion and simple shear. STUDIES of the deformation behavior of single crystals are most valuable when the applied stresses are resolved onto the various slip systems of the crystal. A careful study of the available slip systems and proper selection of the state of stress used and the specimen orientation can then yield quantitative information about the probability of specific dislocation reactions, the strength of barriers to plastic flow, and the mechanisms of yielding and flow in general. It is the purpose of this work to analyze some common states of stress used in deformation studies and to present a simplified way of determining for these cases the ratio of the resolved shear stress on the slip systems to the applied stress (Schmid factor). I) CALCULATIONS We first define two orthogonal coordinate systems: one based on the specimen geometry (a right circular cylinder of radius, R, is considered here) and one based on the particular slip system of interest. The unit vectors and angles specifying the two coordinate systems and the relationship between them are listed in Table I. The relationships among the various angles and unit vectors are shown on a stereographic projection in Fig. 1. The transformation matrix between the (XI X2 X3) and (x'1 x'2 x'3) system is x1 x2 x3 X'1 a11 al2 a13 x'2 a21 a22 a23 x'9 a31 a32 a33 where in this case the direction cosines aij are given by a11 a12 a13 aij = a21 a22 a23 a31 a32 a33 sin 0 cos F cos 0 sin F cos 9 = -cos 0 cos F sin 0 sin F sin 6 [1] 0 -sin F cos (p In terms of Eq. [I.], the stresses sij, referred to the slip system, are determined from oij, referred to the specimen axes, by1,2

Jan 1, 1965

By K. C. Gilbart, Edgar Stansfield

When plants decay in a peat bog the woody parts form a brown pasty mass, or peat muck, largely soluble in alkalis. This brown matter has been termed "ulmin." The same material, but commonly black in color, is found in coal, and there is evidence of the similarity between the material forming the main bulk of the coal and the bulk of the more recently decayed material in peat bogs. The more recent or low-rank coals, such as lignite, little removed from the peat stage, contain notable percentages of alkali-soluble ulmins, but the percentage decreases with increased degree of coalification and is negligible in bituminous or higher rank coals. The determination of the alkali-soluble ulmins in any coal gives, therefore, an indication of its degree of coalification or rank. Coals which contain few or no ulmins soluble in alkalis do contain ulmins which can be rendered soluble by oxidation. The higher the rank of the coal, the more difficult it is to oxidize the insoluble ulmins and make them soluble. High-rank coals can be differentiated by oxidation tests on the insoluble ulmins; but low-rank coals can be characterized by both their soluble and insoluble ulmins. This paper deals with the determination and significance of the alkali-soluble ulmins present as such in the coal. The chemical nature and composition of ulmins are not discussed. Review of Literature The history of the study of ulmin is well given by Stopes and Wheeler.' The action of potash on coal has long been known, as Braconnot in 1819 distinguished between lignites and bituminous coals by stating that the former gave colored solutions with potash. Later the intensity of color was used to give a fuller differentiation. Hoffman2 distinguished between lignites and lignitic coals by the darker color given by the

Jan 1, 1932

By Prof John E. Church

It is a well-known fact that under similar conditions a ton of pig iron can be made from any ore with less fuel when charcoal is used than when coke or anthracite is employed for heating. The cause of this superiority is entirely undiscovered, and no explanation has yet been offered which has won even temporary acceptance. Such as they are the hypotheses heretofore presented are of two general kinds, and they come from those two divisions of the working force which are so often antagonistic in all professions, the scientific and the practical men. The theory of the scientific men is drawn from the chemical reactions which are known to go on in the furnace, and it is well expressed in a recent paper by Prof. Akerman, of the Stockholm (Sweden) School of Mines. It makes the superiority of charcoal as a fuel in the blast furnace to depend upon its quick and thorough reduction of carbonic acid. This property belongs to charcoal in virtue of its porous structure. Its cells have a diameter of only one twenty-four hundredth of an inch, and one grain of charcoal has been computed to have a surface of two and four-tenths square feet. According to the theory in question, carbonic acid is formed by the first impact of the air upon the fuel; but in charcoal furnaces the acid is immediately reduced to oxide by taking the necessary amount of carbon into combination, and the gas reaches its highest reducing power even in the near vicinity of the tuyeres. Coke, being harder, does not produce so strong a reducing gas in that part of the furnace. Carbonic acid is formed as in the case of charcoal, and remains longer before its reduction to oxide is completed. Anthracite is the

Jan 1, 1879

By Zay Jeffries

The object of the present paper is to enlarge somewhat on the general principles advanced in my discussion1 of Mathewson and Phillips' article on The Recrystallization of Cold-Worked Alpha Brass on Anneal-- ing.2 It will also serve as an acknowledgment of Prof. Howe's most important remarks on my contribution. In this paper the writer has adopted Prof. Howe's suggestion to substitute the term "germinative temperature'' for "critical temperature for grain growth." Instead of being an exact or certain temperature it should be considered that the germinative temperature phenomenon exists throughout a small temperature range. v Factors Influencing Fast Growth Phenomena The development of grains of macroscopic size at the germinative temperature should be considered the extreme condition of a general rule. When considered in this light it is not strange that the development of these large grains should be the exception and not the rule. The principal factors influencing the operation of the laws of fast growth temperature are as follows: . 1. Rate of heating. In the original paper,' the germinative temperature was defined as "the minimum temperature at which two adjacent grains can coalesce to form one larger grain, provided that this larger grain will have sufficiently increased its power of attack, to enable it to absorb adjacent grains which cannot coalesce with each other. Time is always to be understood as a factor governing the first stage of grain growth." If the time of heating is short, the germinative temperature is raised. The formation of large grains in metals may occur at relatively high temperatures when the rate of heating is rapid. It is to be understood that in such cases, grain growth

Jan 1, 1917

By H. Rush Spedden, Arvid Thunaes

Pilot plant test work in 1942 and 1943 showed that by a combination of desliming, fine-size classification, and Sullivan deck concentration it is possible to recover heavy minerals such as cassiterite at least as fine as 10 microns in size. This appreciable improvement in gravity concentration practice has been substantiated by several full-sized plants.

Jan 8, 1950

By M. G. Cheney

THE production record of the Sinclair-Moren pool, in southeast Young County, Texas, demonstrates that under efficient operating methods a single well may obtain normal oil recovery from an area of 100 acres or more. This record is the more surprising in view of relatively adverse reservoir conditions such as lack of water drive, moderate initial reservoir pressures and a consolidated sandstone reservoir with original permeability greatly reduced by processes of lithification. This case history is considered worthy of special study in view of the ever present problem of proper spacing of wells. Cupidity, abetted by the unrestrained law of capture, has in too many instances guided development and production methods without regard for sound economic and engineering principles. Largely as a result of ill advised spacing of wells, many oil fields have brought financial losses instead of deserved profit to those using capital, time and energy in this important business of adequately meeting the petroleum requirements of what is known as our modern civilization. In March 1923, the Sinclair Oil and Gas Co. obtained initial daily production of about 12,000,000 cu. ft. of gas and 1100 bbl. of oil in its first well near the center of a 372-acre lease on the L. P. Moren land, James Rose survey, Abstract 245. This exploratory test was drilled as a geological prospect of average promise, on a plunging anticline with possibly 10 ft. of closure as mapped on the outcropping limestone of upper Canyon (Pennsylvanian) age. In subsurface, the top of the producing res-ervoir is 16 ft. lower in this well than in the highest wells but probably 25 ft. above lowest closing contour. Wells No. 2 and 3 were drilled about 1/4 mile west and southwest near a normal fault with some 30 ft. of downthrow to the southwest. The producing sand was reached at a depth of 2512 ft. and drilled to 2529 ft. in the first well. This sandstone reservoir is of Millsap Lake (middle Strawn, upper Cherokee) age. It was absent in the second and third wells, which were abandoned at the depths of 3725 or more. In April 1925, a fourth well was drilled 600 ft. east and 24 ft. lower for top of sand than No. I. Production of about 100 bbl. daily was reported from 2521 to 2562 after an 80-quart shot. This well was drilled to 4560 ft., plugged back to 2575 and shot again; but was abandoned soon thereafter because of small production.

Jan 1, 1940

By J. G. Thompson

THE methods employed for the determination of oxides and oxygen in ferrous materials may be roughly classed in two groups, "wet" methods and "hot" methods, the first group including the iodine, electrolytic, mercuric chloride, hydrochloric acid, nitric acid, and chlorine methods; the second group including the vacuum-fusion and hydrogen-reduction methods. The wet methods depend upon preferential solubility in a selected medium to separate the metallic portion of the sample from the oxygen-containing constituents. Subsequent analysis of the insoluble residue permits the isolation and separate determination of individual oxides and compounds. The hot methods depend upon the reduction of the oxide constituents of the sample by means of carbon or hydrogen at elevated temperatures. With the exception of the recently developed fractional vacuum-fusion method, the hot methods do not identify individual oxides and compounds but yield only a single value represent-ing the sum of the oxygen contents of several or all of the oxide con-stituents present. With such diversity in the principles and. aims of the different groups, it is not surprising that concordance of results by differ-ent methods has usually been difficult to obtain. The present cooperative attempt to define more rigorously than has been possible heretofore the accuracy and limits of usefulness of the vari-ous methods, originated in correspondence between Dr. John Johnston, Director of Research of the United States Steel Corporation, and other interested metallurgists. The plan was, briefly, to submit identical samples to a number of laboratories for analysis by different methods and to collate the results of these analyses. The project was endorsed by the Iron and Steel Division of the American Institute of Mining and Metal-lurgical Engineers at the annual meeting in February, 1933, and has been conducted under the joint sponsorship of the Iron and Steel Division and the National Bureau of Standards. The latter organization undertook

Jan 1, 1936

By J. M. Oblak, R. F. Hehemann, R. H. Goodenow

STUDIES of surface relief and growth kinetics have lead to the concept that widmanstatten ferrite along with upper and lower bainite constitute a continuous series of decomposition products.1-4 Current models4 propose that these products form as plates with a coherent or semicoherent leading edge which propagates at a rate controlled by diffusion of carbon into the surrounding austenite. There are, however, important crystallographic and morphological differences between these products—particularly between upper and lower bainite. For example, upper bainite appears to exhibit a (11lIy orientation habit, whereas lower bainite develops with a more irrational habit near {2251y.5-7 Many of the morphological features of these decomposition products are not yet well-documented. Recent studiess have demonstrated that low-carbon martensites form as sheets of closely spaced needles on {lllly planes while higher-carbon martensites form as plates with {225}? or other orientation habits. The similarity in the crystallography of these two modifications of martensite with upper and lower bainite is striking. Therefore, a study of the morphology of bainite in a series of hypoeutec-toid alloy steels has been initiated to explore these relationships further. The question of immediate interest is whether upper and lower bainite form as plates or needles. A two-surface (approximately perpendicular) metallographic method was employed to study the morphology of bainite in a variety of low and medium alloy steels. Compositions of these steels have been reported elewhere. The behavior of 4340 and 4370 was typical and will be described here. Austenitizing treatments involved 20 min at 2350°F for 4340 and at 2000°F for 4370. Isothermal transformation was conducted in molten-salt baths. Upper bainite was produced at 925°F in the 4340 steel and lower bainite at 575°F in 4370 with transformation times adjusted to produce 10 to 15 pct of the decomposition product. Many of the morphological features of upper bainite have been catalogued in the recent literature.'' The two principal variants observed in the present investigation are illustrated in Fig. l(a). One form appears as long, thin plates or needles and the other as small, frequently irregularly shaped particles. Both variants may occur as isolated forms but more frequently appear in groups as demonstrated in Fig. l(a). Two-surface analysis reveals that these two variants constitute different sections through a single morphological form. To demonstrate this, a number of sections perpendicular to the plane of Fig. l(a) were prepared at various positions along the length of the elongated particles. A section taken at position 1 in Fig. l(a) is presented in Fig. l(b). Here, the dark line represents the edge of the sample and the left-hand portion of this photomicrograph is that from the surface perpendicular to the original plane of polish. Since it was necessary to repolish the original surface after each sectioning, the shape of the bainite particles on this surface, right hand side of Fig. l(b), changes with each sectioning. The disappearance of plate A, Fig. l(a), in Fig. l(b) emphasizes the small cross section of these structures. The group of particles in the lower left-hand

Jan 1, 1964

By Eugene McAuliffe

THE mining press, as well as certain federal and state bulletins, refer from tine to time to. the relative hazards that attach to loading bituminous coal by hand when compared with the so-called "mechanical loading" process. Much of the coal coming under the head. of hand-loaded coal is won in part by the use of machinery; the coal-cutting machine is in general use, the electric power drill employed to a lesser extent. Therefore it may be said that the principal difference in the process employed, mechanical loading versus hand loading, lies in the fact that some type of loading machine is employed in the mechanical loading process to lift the coal from the face of the room, place or entry, after it is mined, placing it in the pit cars for transport to the tipple. It is a common practice to compute accident records on the basis of tons mined per fatal and per nonfatal accident, disregarding the fact that it is possible to produce by the aid of coal-loading machines the same daily, monthly and annual tonnage with a much smaller force than is required where the coal is all shoveled by hand. Inasmuch as the men who are released by the substitution of machinery for hand labor must find employment elsewhere, suffering some measure of hazard in their new occupation, we are of the opinion that the true relative hazard that attaches to the processes of mechanical loading and hand loading can be determined only by using as the basis of comparison "man shifts worked" or "hours of exposure" experienced per accident. The Union Pacific Coal Co., beginning with the year 1929, undertook to maintain a true record of man shifts worked per compensable accident, giving equal weight to fatal and nonfatal accidents. Accidents lacking sufficient severity to come under the compensable terms of the Workmen's Compensation Act were not included in the compilation, the Act providing that "no compensation, except the expense of medical attention, shall be allowed for the first seven (7) days of disability, unless the incapacity runs beyond the period of twenty-one (21) days,' in which case the compensation shall run from the time of the injury."

Jan 1, 1931

By U. K. Custred, E. W. Long, V. R. Degner

In 1973, the United States production of marketable phosphate rock set a record in excess of 42 million tons. This production rate is expected to continue to increase, due to the growing international requirement for fertilizer, at a rate exceeding 5% per year well into 1977. One approach towards increasing plant production capacity to meet the growing demand is through large-capacity flotation cells, provided they achieve metallurgical performance comparable to existing smaller cells. A 9-month evaluation test program recently completed at the Haynsworth mine at Bradley, Fla., demonstrated the feasibility of achieving economically acceptable concentrate grade and recovery levels using large, high-capacity flotation cells. The composition of the feed to the Haynsworth beneficiation plant is a typical Florida pebble phosphate matrix composed of phosphorite pebbles ranging in size from approximately 1-1/2 in. down to 150 mesh and intimately associated with a mixture of clay and sand (essentially silica). The feed contains approximately 22 to 28% phosphate reporting as tricalcium phosphate, Ca3 (PO,) 2, or "bone phosphate of lime" (BPL). The flotation section utilizes the double-float procedure typical of Florida plants. The phosphate is first floated away from the silica in the rougher circuit, using crude fatty acid, ammonia, and fuel oil or kerosene. Rougher conditioning is accomplished at 60 to 70% pulp solids with sufficient ammonia added to raise the pH to 9 to 9.5. Following coarse and fine rougher flotation, the concentrate (overflow) streams are joined and conditioned (sulfuric acid cleaned and washed) prior to entering the cleaner circuit where an amine float (cationic reagent and kerosene added in the feed box; pH 7.3 to 7.8) is employed to float the silica. The feed to the coarse rougher circuit averages 29% +35 mesh while the fine rougher feed averages 10%+35 mesh. Primary attention was directed toward the large rougher cell performance (recovery and grade) on coarse feed during the Haynsworth evaluation program. Flotation Cell Test Program A row of three No. 120 size (300 cu ft) WEMCO flotation cells was installed in parallel with an existing air-cell row. The total installed volume of the large cell circuit was 900 cu ft and required a floor space of 306 sq ft. This compared to the air-cell total volume of 200 cu ft and 152 sq ft floor space. (Both floor areas include feed and tails hoppers but exclude walkways.) Fig. 1 is a schematic cross section of the large flotation cell showing the relative location of key mechanism elements. In operation, the rotor generates a fluid vortex extending up along the walls of the standpipe and creating a sufficient vacuum within its core to ingest air into the standpipe/rotor cavity through the air inlet duct. The ingested air mixes with the pulp, which has been recirculated through the false bottom and draft tube, in the rotor. Further mixing occurs as the air and pulp move radially outward from the rotor, finally passing through the disperser into the flotation cell. Flotation is accomplished outside the disperser, where phosphorite laden air bubbles rise and the remaining pulp recirculates down along the cell wall to the false bottom and draft tube. Large-flotation-cell performance is influenced by the ability of the mechanism to (1) circulate, or suspend, the solids in the pulp; (2) ingest air into the rotor cavity; and (3) mix the air and pulp effectively. The proper balance between pulp circulation and air ingestion is a key consideration in achieving good recovery in a course feed application. Large-flotation-cell pulp circulation and air transfer characteristics are significantly influenced by rotor speed and rotor submergence; therefore, these two operational parameters can be used to "optimize" a particular mill application. Fig. 2 maps the hydraulic performance of the WEMCO No. 120 size flotation cell. This map can be used to relate the cell operational parameters which influence metallurgical performance. At a given rotor speed, power intensity (i.e., pulp circulation) is seen to increase, and airflow decrease, as rotor submergence is increased. The inverse relation between power and airflow is due to the two-phase air-liquid mixture density reduction accompanying the increased airflow rate. For any fixed rotor submergence, the power intensity (i.e., fluid circulation) and airflow both increase as rotor speed is increased. The selection of these two mutually related operating conditions (i.e., rotor speed and submergence) was a key consideration in the Haynsworth evaluation program.

Jan 1, 1976

By W. H. Emmons

Most mineral deposits change as they are followed downward on their dips. Some of these changes are due to primary arrangement; different ores were precipitated at different depths when the deposits were formed. Other changes are due to weathering or secondary enrichment. The chief changes resulting from weathering, in the main, are understood and standard changes are recognized. The processes are relatively simple. They take place at ordinary temperatures and pressures and can be duplicated in the laboratories. Moreover, there are thousands of deposits available for study, because the processes take place near the surface where the development of mines is begun. The changes due to primary arrangement of the deposits of the metals are not so well understood. Deposition has taken place at higher temperatures and our knowledge of the chemistry of the processes leaves much to he desired. Very few experimental data are available. The deposits, moreover, offer fewer examples because many mines are not developed to depths where the changes can be studied and a change to unprofitable material usually results in stopping work. Most students of ore deposits now accept, as confirmed, the hypothesis that nearly all lodes and related deposits were formed by solutions originating in intrusive igneous masses. Outward from these masses, the deposits at many places are grouped in zones and the arrangement noted from the intrusions outward are commonly the reverse of the changes noted from the surface downward in a single lode. A study of the changes in groups of deposits, from the parent intrusion outward, will throw light on the changes to be expected in a single lode downward. Recause the changes in series of deposits from the intrusive outward may all be observed near the surface, where more data are available, it is possible to increase the number of examples many fold and to apply the statisttical method of study with greater confidence of avoiding error. It is not everywhere possible to identify the parent igneous body to which a group of ore deposits are related. Several kinds of criteria are available; certain groups are superior to others. By applying the

Jan 1, 1924

By George Watkin Evans

The need for mechanization in coal mining wherever it can be successfully introduced is evident when we take into account the fact that during recent years the coal-mine employee's wages have increased and his hours have been shortened. Coal is no longer King, and a brief study of statistics covering the production of coal, petroleum and natural gas and the development of water power will convince anyone that coal has had very powerful competitors during the past 10 years. Petroleum production in the United States between 1918 and 1936 increased from 100 per cent to 309 per cent. Water power increased from 100 per cent in 1918 to 270 per cent in 1936. Bituminous coal slipped from 100 per cent in 1918 to 75 per cent in 1936. The anthracite industry slipped from 100 per cent in 1918 to 50 per cent in 1932, but climbed to 55 per cent in 1936. In 1918, the State of Washington produced a little over four million tons of coal and the production of California oil, at that time, was a little less than one hundred million barrels per year. By 1929 the production of California oil had increased to a little over 292,000,000 bbl. or nearly 300 per cent as compared with 1918. By 1934 the production of coal in the state of Washington had dropped to about 1 1/3 millions of tons per year. Our neighbors in British Columbia had their coal production reduced from a little over 2 1/2 million tons in 1920 to less than 1 1/3 million in 1933. The North western Improvement Co., a subsidiary of the Northern Pacific Railroad Co., owns coal properties in various parts of Washington and Montana. The Northern Pacific is one of the very few railroads using any considerable quantity of coal in its operations. Practically all of the American railroads in the Pacific Northwest, except the Northern Pacific, are using cheap California fuel oil or electricity. This problem, of course, is not a new one in coal mining, and all of the progressive coal companies in the country have tried to meet competition from an overproduction of petroleum and an overproduction of natural gas as well as enlarged developments of hydroelectric plants.

Jan 1, 1938

By George Watkin Evans

The need for mechanization in coal mining wherever it can be successfully introduced is evident when we take into account the fact that during recent years the coal-mine employee's wages have increased and his hours have been shortened. Coal is no longer King, and a brief study of statistics covering the production of coal, petroleum and natural gas and the development of water power will convince anyone that coal has had very powerful competitors during the past 10 years. Petroleum production in the United States between 1918 and 1936 increased from 100 per cent to 309 per cent. Water power increased from 100 per cent in 1918 to 270 per cent in 1936. Bituminous coal slipped from 100 per cent in 1918 to 75 per cent in 1936. The anthracite industry slipped from 100 per cent in 1918 to 50 per cent in 1932, but climbed to 55 per cent in 1936. In 1918, the State of Washington produced a little over four million tons of coal and the production of California oil, at that time, was a little less than one hundred million barrels per year. By 1929 the production of California oil had increased to a little over 292,000,000 bbl. or nearly 300 per cent as compared with 1918. By 1934 the production of coal in the state of Washington had dropped to about 1 1/3 millions of tons per year. Our neighbors in British Columbia had their coal production reduced from a little over 2 1/2 million tons in 1920 to less than 1 1/3 million in 1933. The North western Improvement Co., a subsidiary of the Northern Pacific Railroad Co., owns coal properties in various parts of Washington and Montana. The Northern Pacific is one of the very few railroads using any considerable quantity of coal in its operations. Practically all of the American railroads in the Pacific Northwest, except the Northern Pacific, are using cheap California fuel oil or electricity. This problem, of course, is not a new one in coal mining, and all of the progressive coal companies in the country have tried to meet competition from an overproduction of petroleum and an overproduction of natural gas as well as enlarged developments of hydroelectric plants.

Jan 1, 1938

By T. A. Rickard

INTRODUCTORY. THE presentation to the Institute, eight years ago, of the paper of Pošepny on " The Genesis of Ore-Deposits " has borne fruit in much fresh: investigation, as is evidenced, for example, by the group of very valuable papers, by distinguished members" of the United States Geological Survey, read at the Washington meeting-discussions of general principles particularly suggestive to those who are engaged in mining. Pošepny, in the discussion of his famous treatise, said that the present writer seemed to look at every new conception in ore-deposition" from the sole standpoint of its immediate usefulness in mining."* Protesting mildly against " sole " and "immediate," I accept the impeachment. It calls for no defence. THE DEVELOPMENT OF RECENT THEORIES. Given the idea of an underground water-circulation as the chief factor in the deposition of ore, the next step in the inquiry as to the genesis of such deposits is, the endeavor to determine which particular part of the general water-circulation is responsible for the results. Around this question have centered the controversies of a generation, and to these controversies we owe the gradual clarification of our ideas upon the processes of ore-formation. It is unnecessary to sketch here their progress from Werner to Le Conte, who combated in 1883 the extreme views of the lateral-seeretionists, and in 1893 opposed the narrow interpretation of the ascensionist-theory. The generally accepted opinions of to-day are a well-deserved tribute to his philosophic discrimination. Thanks to Prof. Van Hise and Mr. Slichter, whose work he utilizes, we have now arrived at a comprehensive conception

Jan 1, 1902

By Hiroshi Oikawa, R. G. Blake, A. G. Guy

An equatzon has been derivedfor conveniently calculatzng the couvse of homogenzzation in a three-corviDonent solid solutiorz. The necessary assumptions are that the initial distributions of concentration are sinusoidal and that the four interdiffusion coefficients are constant. Employed in the deriuation were the Laplace transform and the fouter Fourier sine transfovwz. The final equation is shown to be in good agveetnent with the experimental results of Kirkaldyet al. on Cu-Sn-Zn alloys. COMMON boundary conditions for representing physical problems are those of the finite solid and of the infinite solid. Many metallurgical phenomena, however, have the geometrical form of a finite pattern reproduced throughout an infinite solid. Precipitation within a uniform matrix and segregation during solidification are examples. The purpose of this treatment is to show that a convenient and useful mathematical analysis is possible in those cases in which the finite pattern can be approximated by a sine function. The particular topic to be considered here is the elimination of segregation by diffusion, but the mathematical model has applicability in many other areas. It should be recalled that the mathematical solution of a typical problem involving a finite solid, such as diffusion into a thin layer, is quite involved.' Various types of solutions are used depending on the degree of advancement of the diffusion process and on the initial conditions. A step function is the simplest initial condition, but even in this case the general solution has the form of an infinite series. Kirkaldy et a1.2 have

Jan 1, 1968

By D. W. Frommer, M. M. Fine

Early in 1957 St. Joseph Lead Co. announced discovery of three new centers of iron ore deposition in east central Missouri.1 The discovery resulted from exploratory drilling in the vicinity of a magnetic anomaly or high. A deep hole, drilled into the Pre-Cambrian porphyry to determine the cause of anomaly, penetrated a magnetite-rich deposit.2 The magnetic surveys that revealed the anomalies were begun by the Missouri Geological Survey in 1929 and were continued into the 1930's 3. At that time an area in Crawford County known as the Bourbon magnetic high was located. A second anomaly, similar in size and intensity, was discovered about six miles to the northeast in Franklin County in the vicinity of Sullivan. This area was not studied in detail until the early 1940's.

Jan 3, 1959

By G. St. J. Perrott

ONE of the important hazards in coal mining is the danger of ignition of explosive mixtures of methane and air or coal dust and air, or both, by the explosives used in blasting the coal. It has long been recognized that certain explosives are more dangerous than others in this respect. In America and abroad, government testing stations have been established for officially passing on the suitability of explosives for use in coal mines. In this country the Federal government is given no power to enforce the use of the approved explosives but merely publishes from time to time, through the Bureau of Mines, those explosives which have passed the tests necessary to place them on the list for use in coal mines. In spite of this lack of police power, the increase in the use of permissible explosives since the promulgation of the first list in 1909 has been rapid. In 1912, only 8 per cent. of the explosives used in coal mines were permissible; in 1925, this figure had increased to 25 per cent. While the past record of permissible explosives has been most gratifying, it is very desirable that we pave the way for further improvement in explosives and blasting methods by learning more about the mechanism of ignition of gas and coal dust by explosives. To this end a considerable amount of investigative work already has been carried out and a large amount yet remains to be done. It is the purpose of this paper to discuss briefly the effect of the characteristics of explosives and method of loading in the borehole on the liability of a blown-out shot to ignite explosive mixtures of gas or dust. For an account of the methods by which an explosive is tested for permissibility for use in coal mines, the reader is referred to Schedule 17-A of the U. S. Bureau of Mines.

Jan 10, 1926

By R. G. Ward

The temperature gradient in the subhearth metal or "salamandern of the iron bhst furnace results in the establishment of gradients in the concentrations of silicon, manganese, carbon, and sulfur. The temperature and compositional variations observed in three blast furnaces are analyzed according to irreversible thermodynamics and the systems appear to be close to the steady state condition. Apparent heats of transport, Q, for silicon, manganese, carbon, and sulfur are found to be respectively -17.5, -5, -2.1, and+22k cal per g mol. In conclusion the significance of thermal diffusion in extraction metallurgy is briefly discussed. INCREASING interest has been shown in recent years in the application of irreversible thermodynamics to metallurgical problems. In particular studies have been made of the transport of matter in thermal gradients1-' and under chemical gradients imposed by a binary solvent However, no detailed example in extraction metallurgy has been reported although gradients are the essence of many extractive processes. The case of the distribution of elements in molten blast furnace iron under a thermal gradient is discussed here. DATA In blast furnace operation the hearth bottom is often extensively destroyed by molten metal, and the metal may penetrate perhaps 10 ft into the furnace foundations forming a "bear" or "salamander". Several hundred tons of molten metal may thus exist beneath the level of the conventional tap hole and remain relatively undisturbed for several years under a thermal gradient. This system is subject to little convective stirring because the temperature decreases from top to bottom, and mechanical stirring due to movements in the stack and to tapping operations is unlikely to penetrate far into the metal. The system may thus be regarded as static

Jan 1, 1963