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By J. H. Frye, J. W. Caum, R. M. Treco

IT has been suggested that: "Insofar as the hardening due to a solute depends upon the increase of lattice parameter produced by it, it is reasonable to suppose that this hardening might be related to the resistance which the pure solvent would offer to increase in its parameter."' It was further suggested that this hypothesis might be examined by comparing the hardnesses of analogous silver and copper alloys, since the stress necessary to produce a given lattice expansion is quite different in the two metals. Suitable data2,3,4 are now available on these alloys, and we shall proceed to an examination of the hypothesis quoted above. Hardness, Lattice Parameter and Ionic Overlap Increase in ultimate Meyer hardness has been plotted against increase in lattice parameter in Figs. I and 2. It is believed that most of the values are accurate within the limits indicated by the rectangles. These data are also presented in Table I. Ultimate Meyer hardness, P u, is defined by the equation: where L = load, D = diametei of an impression having the same diameter as the testing ball, which in this case is 4 mm. Increase in lattice parameter is defined as the difference between the lattice parameter of the solid solution and that of the pure solvent. The curves in Figs. I and 2 are based on equal solute concentration and an equal degree of plastic deformation pro duced by the testing ball. Hardnesses are corrected to a constant grain size for copper and silver alloys, respectively, and these two grain sizes are approximately equal. Furthermore, all solutes are from the same period of the B subgroup of the periodic table as their solvent. The question arises as to whether Or not lattice parameter is the only factor controlling the hardness of these alloys. There

Jan 1, 1943

By H. Siebert, G. Raitt

With the advent of the Interstate Highway Pro- gram, many problems have been encountered in the application of highway design standards to topography, particularly rock cut design. A rigid application of slope ratios with little respect to rock type, dip, foliation, structure and height of cut face is a problem. Generally a slope ratio of ½ : 1 or 63º for shallow cuts and 1/3: 1 or 71º in deeper cuts are used in Connecticut. The deepest cut face constructed recently was greater than 185 ft. With cuts of this size, rock fall and stability become a problem, and a way to reduce the problem is to construct a stable face initially. A search of the literature indicates that adequate information on the construction of stable rock slopes is not available. A major highway contract was awarded in 1962 to Savin Brothers, Inc., in which line drilling on 6-in. centers was required in many portions of the contract where the cut was greater than 60 ft and one or more benches were to be constructed. From the start of the project many variations were attempted regarding slope hole spacing and distribution of explosives in the holes. Rock ranged from a competent granitic gneiss to an incompetent soft graphitic schist. Generally, the roadway alignment was roughly normal to the strike of the foliation having a dip of ± 60º. An important factor affecting construction of rock slopes was the existence of intersecting joints and faults. The spacing used in less competent rock was about one ft on center. Loading of holes was purposely varied. As competency of the rock increased, hole spacing was also increased. Thus, on a different project in similar rock, spacing was kept at 4 ft.

Jan 4, 1966

By H. G. Turner

The coals mined in the area known as the anthracite fields of Pennsylvania have always been recognized commercially as anthracites. In the literature, however, some of these anthracites have been called semi-anthracites by various writers. The coals mined in Sullivan County, especially those from the Bernice field, have been recognized commercially both as anthracites and semi-anthracites. In the literature they have almost always been referred to as typical semianthracites, although Franklin Platt,1 in his report to the Pennsylvania Geological Survey, uses the terms semibituminous, semianthracite, and anthracite in describing them. The purpose of this paper is to endeavor to dispel the confusion of names used to describe these coals and to supply further information that will permit a logical and definite classification. Most of the confusion of the past has been due to the impossibility of securing enough fresh face samples from which to draw sound conclusions; some of it was due, no doubt, to lack of standard methods of analysis, and of course, to the ever-present lack of definition of boundaries from the standpoint of classification. Map Showing Lines of Equal Volatile Matter and Lines of Equal Specific Gravity As a foundation for this work the writer constructed a map showing lines of equal volatile matter and lines of equal specific gravity throughout the anthracite and semianthracite regions. The points on these lines were determined from a study of analyses of 214 face samples from 28 mines and composite analyses from 18 different breakers. These samples were collected through the joint efforts of the U. S. Bureau of Mines and the Anthracite Institute. The Bureau of Mines standard method of sampling was used in all cases. All analyses were made by the Bureau of Mines and are used here with its permission. The

Jan 1, 1934

By J. H. Frye, R. M. Treco, J. W. Caum

IT has been suggested that: "Insofar as the hardening due to a solute depends upon the increase of lattice parameter produced by it, it is reasonable to suppose that this hardening might be related to the resistance which the pure solvent would offer to increase in its parameter."' It was further suggested that this hypothesis might be examined by comparing the hardnesses of analogous silver and copper alloys, since the stress necessary to produce a given lattice expansion is quite different in the two metals. Suitable data2,3,4 are now available on these alloys, and we shall proceed to an examination of the hypothesis quoted above. Hardness, Lattice Parameter and Ionic Overlap Increase in ultimate Meyer hardness has been plotted against increase in lattice parameter in Figs. I and 2. It is believed that most of the values are accurate within the limits indicated by the rectangles. These data are also presented in Table I. Ultimate Meyer hardness, P u, is defined by the equation: where L = load, D = diametei of an impression having the same diameter as the testing ball, which in this case is 4 mm. Increase in lattice parameter is defined as the difference between the lattice parameter of the solid solution and that of the pure solvent. The curves in Figs. I and 2 are based on equal solute concentration and an equal degree of plastic deformation pro duced by the testing ball. Hardnesses are corrected to a constant grain size for copper and silver alloys, respectively, and these two grain sizes are approximately equal. Furthermore, all solutes are from the same period of the B subgroup of the periodic table as their solvent. The question arises as to whether Or not lattice parameter is the only factor controlling the hardness of these alloys. There

Jan 1, 1943

By A. S. Yue

It was deemed desirable to obtain an understanding of the vacuum desulfurization process. McKechnie1 has reported that the sulfur content of nickel- and cobalt-base alloys is reduced in vacuo. Keverian and Taylor2 have observed that vacuum melting causes desulfurization of iron-carbon-silicon alloys. Garnyk and samarin3 have desulfurized transformer steel by vacuum treatment. Experiments were conducted in order to investigate the desulfurization of liquid iron under reduced pressures, and to establish the effect of some alloying elements, and various crucible materials. A vacuum-induction furnace of 50-lb capacity was used. The charge was Armco iron. Silicon was added as 90 pct ferrosilicon, carbon as electrode graphite, and aluminum as high-purity aluminum metal. Magnesia and silica crucibles were used, their inside diameters were 5 1/2 and 5 3/8 in., respectively. The temperature was measured with an optical pyrometer and it was held at 1600 1 15°C. Samples were withdrawn with quartz tubes of 6 mm ID, without disturbing the furnace atmosphere. Pressures were measured with an alphatron gage. The experimental results are shown in Fig. 1. They indicate that: 1) Sulfur can be removed from liquid iron alloys by vacuum treatment; 2) The desulfurization is enhanced by the presence of silicon, carbon, and aluminum, all these elements increase the activity of sulfur dissolved in liquid iron;4 3) The pronounced effect of silicon indicates that probably a volatile silicon sulfide is formed, Alcock and Richardson5 have observed a similar phenomenon; 4) The same rate of desulfurization was obtained when the metal was contained in either magnesia or silica crucibles. Dr. J. Keverian has contributed many discussions and recommendations. M. S. Sutliff has helped in conducting the heats. The permission of General Electric Co. for this publication is gratefully acknowledged.

Jan 1, 1960

By M. W. Strong

The technique of handling drilling muds varies somewhat, partly because of personal factors but mainly because of differences in formation, the type of problems, and the general drilling conditions in different localities. The much greater depths to which bore holes are now carried have made necessary closer attention to and great modifications of all aspects of drilling-mud technique. Increased depth means smaller hole, smaller drill pipe, smaller clearances, higher pumping pressures, higher differential pressures between shows and the mud column, less accurate control of the weight of the mud column, delayed receipt of formation data, and poorer samples. It means longer delays and greater hazards in rectifying mistakes or dealing with accidental occurrences. Equipment on a larger scale is necessary and more pains must be taken with layout. Lastly, the budget costs of raw materials have risen to high figures and economy of time and of direct monetary expenditure have come to mean much more than formerly. A mud laboratory is now part of the essential establishment of a modern oil field and to it current problems can be submitted for the most thorough investigation. The detailed chemical properties of all materials purchased or quarried have to be investigated. Detailed data on the physical properties have to be ascertained and research on improvement of material and its most efficient use has to be carried out. In this paper will be discussed the main mud problems of Iran, some of which are peculiar to local conditions while others are of the general type common to all workers in this subject. Underground Conditions In deep wells in Iran the normal overburden may consist of: (1) up to several thousand feet of marls with interbedded sandstones and limestones of varying porosity and permeability; (2) beneath this a chemical series of rock salt and anhydrites, containing various marls and thin limestones,

Jan 1, 1939

From the cold Pacific waters in June rolls a blanket of white clouds that tucks up around the mountains at around 8000 or 9000 ft. This is the way it happens in southern Peru and so the mining operations and daily living at Toquepala have an ethereal quality not often encountered. Besides looking down on the clouds from the brightly sunlit mountain tops, one can discern the trace of a different era in the brown barren mountain slopes. This trace is like a delicate net laid over the surface of the earth-a criss-crossing of innumerable trails that are so omnipresent, yet faint, that the local people have long since ceased to notice them. It is difficult at first to ask about them because no one understands what you are talking about. It finally comes out though, that the markings are indeed trails, but fossil trails made by animals in times when they were in abundance in a countryside that was green in some bygone century. In a way Toquepala is still pristine, it is the way the engineers planned it-from the ground up. There are no additions or expansions- those tackings-on that spoil the symmetry of design while increasing the profit. This does not deny that annual production has gone up over the years. Daily mill throughput has been increased from 30,000 to 42,000 tpd. Initial design of the concentrator was for 30,000 tpd but in 1964-65 milling capacity was increased to 36,000 tpd at a cost of $3 million.

Jan 11, 1969

By Hsun Hu

The formation of annealing textures in high-purity silver, from the various rolling textures obtanled in the course of texture transition, was studied. It was found that from a brass-type rolling texture the recrystallization texture is mainly (120) [211] type, which is quite different from the recrystallization texture of brass. From a predominantly copper-type rolling texture, the reclystallization texture is mainly (100) [001]. The recrystallization texture of silver- varies also with the degree of purity. In each case, however, the reorientation can be expressed as [Ill] rotations of 30° to 40°, which is consistent with the oriented growth theory of the formation of annealing textures. ThE recrystallization textures of rolled silver were studied long ago by Glocker and co-workers (1924-27) and were reported to be (113) [iil] upon annealing at low temperatures.1 Since that time, no further study of the recrystallization textures of silver, particularly with the modern techniques of quantitative texture determinations, has been reported in the literature. In a previous study2y3 it was found that the rolling texture of high-purity silver (99.999 +pct pure) is changed gradually from the common silver- or brass-type to the copper-type by raising the temperature of rolling from 0" to 200°C. The formation of annealing textures from the various rolling textures in the same material is, therefore, of considerable interest. The present paper constitutes the results of such a study. MATERIAL AND METHOD Specimens were taken from the same strips of high-purity silver* that were used previously for

Jan 1, 1962

By George J. Bancroft

INTRODUCTION. IT is unnecessary to repeat here the contents of many valuable contributions to this subject which have appeared in the Transactions and in the publications of the U. S. Geological Survey. As a basis for the further suggestions of this paper, the following are the most important: 1. The investigation of J. R. Don,1 showing the gold of certain Australasian veins to have been deposited by ascending solutions, and not by lateral secretion. 2. The theory of Prof. Posepny,2 distinguishing the vadose from the deep circulation, and ascribing the origin of certain classes of ore-deposits to ascending solutions of the latter class. 3. The theory of Prof. Van Hise,3 as to the underground circulation and the primary enrichment of veins thereby. 4. The paper of Prof. J. F. Kemp,4 showing that ore-deposits are largely the products of " expiring vulcanism." Many of Prof. Kemp's, ideas have been widely adopted by mining men. 5. The theory of secondary enrichment, so lucidly expounded by Mr. S. F. Emmons.5 This theory, dealing with, the rearrangement of ore-bodies after primary mineralization, has been generally adopted, and seems to me to have been as completely proved as the nature of the case permits. There are two facts which I think should be constantly borne in mind in formulating a theory of the genesis of ore-

Jan 1, 1913

By O. C. Wheeler

In past years the exploration of the oil possibilities of Colombia has been confined to parts of three distinct physiographic provinces; namely, the coastal plains area near the Caribbean Sea, the Magdalena Valley and the upper reaches of the Maracaibo Basin near the Venezuelan border. During 1935, little exploratory work and no drilling was carried on on the coast, but there was considerable activity in the other two areas. In the Magdalena Valley, the Tropical Oil Co. continued its producing and development operations on the De Mares Concession. The Socony-Vacuum exercised the option it acquired in 1934 on Sr. Luciano Restrepo's concession adjacent to the Tropical property and north of the Sogamoso River. No wells have been started on the Socony's lands although, according to the terms of the lease, drilling must be started within the next two years. West of the Carare River and adjacent to the Tropical's southwestern boundary, the Sociedad Nacional del Carare denounced the lands formerly held by the Union Colombiana, whose lease automatically lapsed during the year owing to the company's failure to comply with its drilling obligations. In the same area, the concessions held by Callejas et al. and the Société Européene des Pétroles are also understood to have lapsed for the same reason. Holdings of other interests in the Magdalena Valley were inactive during the year. Near the upper part of the Maracaibo Basin, the Gulf, through its subsidiary the Colombian Petroleum Co., continued active exploration and development on its Barco concession. Colombian Petroleum Co.—The following information and that presented in the accompanying tables relating to the activities of the Colombian Petroleum Co. was supplied through the courtesy of Mr. E. S. Bleecker, chief geologist of that company. Four wells were completed during the year on the north Petrolea dome, where an attempt is being made to define the limits of the field. On the south end of the Petrolea anticline, one well, Petrolea No. 3, which might be classed as a wildcat, encountered a heavy flow of salt water immediately below the oil zone and had to be abandoned. A second location has been made 1 miles south of No. 3 and somewhat higher on

Jan 1, 1936

By George W. Sheary

Situated 45 miles west of Philadelphia and 50 miles southwest of Bethlehem Steel Company's Bethlehem plant, the integrated Grace mine facilities produce 4000 tpd of high-quality iron ore pellets. Startup of the Grace mill was in November 1958, and iron concentrates were shipped until March 1960, when the pellet plant went into operation. The underground mine, when fully developed, will hoist about 9000 tpd, including development rock. The crude ore, which has an iron content of approximately 42%, is magnetically cobbed and crushed in closed circuit with 3/4-in. slotted vibrating screens. The ore is washed and screened in the mill and the plus 1/4 in. screen product is again cobbed prior to feeding to the rod mills. Grinding is done in rod mills, and in ball mills that are in closed circuit with 30 in, cyclones, to 1% on 100 mesh and 65% minus 325 mesh. The ground ore is magnetically concentrated by three-drum permanent type finisher magnets to 67% Fe. The magnetite concentrate is pumped from the mill to a 50 ft thickener in the pellet plant. The thickened magnetite concentrate is relayed to the filters through a two-stage pump arrangement. The filter cake is fed by belt from filter concentrate bins to mixer-muller belts where it is intimately mixed with bentonite and a slight amount of water for moisture control. The fluffed concentrate then drops into balling cones. The green pellets from the balling cones are fed in a prescribed feed pattern to shaft furnaces through the use of shuttle car mechanisms. The green pellets are dried, heated to 2500°F and cooled to 1200°F as they descend through the furnace and into pellet coolers where the pellets are further reduced in temperature to 250°F. Heat is recovered in the cooling process through the use of air-to-air heat exchangers. The cooled pellets discharge on a rubber conveyor belt and are transferred to 6000-ton pellet railroad loading bin. The final pellet product consists of 90% plus 1/4 in. material (after tumble testing1) and contains 66% Fe plus 3% silica.

Jan 5, 1962

By O. Hall

DIAMOND drilling has become a very important factor in mining. It is the most satisfactory method of obtaining proof of the existence of an orebody and of determining the character and extent of the body, in measures where a core can be made. Large investments are based on the information obtained. The method of development, the mine and reduction plants, and subsidiary essentials as railways are often built without other information. The Mond Nickel Co. has drilled about 50,000 ft. (15,240 m.) per yr. for several years and has given considerable study to the question of improving the methods and of overcoming the limitations of this means of securing information. One of the main limitations of the diamond drill has been its inability to drill a straight hole. To depths of 1000 ft. (304 in.) the deflection is often not large but all holes tend to curve and take somewhat erratic courses. A hole running at a small angle to a fissure plane tends to run, along the fissure. If the hole is at a large angle, the tendency is to penetrate the fissure plane at right angles. The face of the bit having one side in solid formation beyond the fissure, the other in the selvage of the fissure tends to turn, the rods curving to the extent of their clearance in the hole. Usually rock measures have somewhat regular fissuring or strata and holes take somewhat similar courses, usually at right angles to the fissuring or strata. Excessive pressure or short or worn core barrels increase curvature. Slow speeds, correct feeds, sharp hits, and core barrels the full size of the hit, tend to decrease curvature but do not prevent it Curvature once started increases rapidly. The disappointments from crooked holes have been numerous. Discoveries have later been found to be on the properties of others. One Canadian company had a hole, supposedly discovering ore 300 ft. (91 m.) from old workings, unexpectedly turn in 8 ft. (2.4 m.) of wooden core from a timber in the old workings.

Jan 9, 1919

By S. W. Hurlbut

12.4 Application of Research Findings. After the findings of research have been evaluated and approved, there remains the problem of translating them into practical usage. It frequently happens that this is the more difficult phase of the research project. Hitherto, the problems have been largely associated with material objects and scientific laws. When the findings of research are implemented in the field, the human factor becomes the most important element bearing on success or failure. From this point on, the attitudes and reactions of people of all kinds are involved, and just how they are involved and their relation to successful implementation is the subject of the remainder of this section. 12.41. Management Attitudes. To engage in research at all implies management backing to a degree. But this could be dictated by overall company policy or by just some executives in the hierarchy of management. The existence of research per se does not necessarily mean that there is a solid, unanimous echelon of management executives who sincerely believe in the fruits of research, who have an earnest desire to make breakthroughs, and who have a willingness to take calculated risks. Under the ideal condition of complete management backing, translating the results of research into practice is greatly facilitated. If management accepts the results of research as valid, the order is given, or it has been established by precedent that those results will be implemented. The rest of the organization will have grown to accept the fact that this is so, and that the results must be given a fair trial in the field. However, this ideal condition probably exists but rarely, and it is against a background of incomplete, or partial, management backing that most results of research must be implemented. At the present time, the climate for research in the mining field is less than perfect but is improving rapidly as the realization grows within the industry that the way toward taking its proper place in the Space Age is by applying to mining the philosophy and techniques of research that made the Space Age possible.

Jan 1, 1968

By David N. French

In a recent paper, Miyoshi, Hara, and sugimotoL have shown that hardness increases and crack resistance decreases with polishing time in tungsten car-bide-cobalt alloys. They attribute the changes in hardness and crack resistance to cold working in these alloys. More recently Exner2 explains the decrease in crack resistance with the amount of material removed (polishing time) by suggesting that polishing removes a high compressive residual surface stress due to the initial grinding operation. He cites previous work on steel to show grinding can induce surface compressive stresses but offers no direct experimental measurements to support this in cemented tungsten carbides. In recent work we have observed changes in residual stress in the W C phase as measured by X-ray diffraction techniques with changes in polishing conditions.3 As a result of the work of Miyoshi et al.,L a brief study was undertaken to investigate the effects of polishing and grinding on the residual stress in the WC phase and have been reported.4 A single composition of tungsten carbide —10 wt pct Co was used. Two initial conditions were studied: an annealed condition with about -30,000 psi residual stress from the differences in thermal coefficients of expansion of WC and cobalt and, on the same specimen, a surface ground with a 150 grit diamond wheel. Stress was measured in the WC phase using X-ray diffractometry as a function of the amount of material removed by metallographic polishing with 6 diamond paste. The results are shown in Fig. 1. Two things are noted, 1) polishing with 6 p diamond paste has little effect on the annealed sample and 2) the magnitude of the grinding stress is markedly reduced as material is removed. By the time 0.1 mil is removed the surface has a metallographic polish satisfactory for light microscopy examination. Thus the surface, even though polished, can still retain most of the stress due to grinding. Since WC is itself slightly ductile, it seems reasonable that high compressive stresses can be generated in the surface by the plastic deformation accompanying grinding. Exner2 suggests, by analogy with steel, that as a result of grinding both WC and cobalt in the

Jan 1, 1970

By L. W. Jones, B. H. Bennetts

The removal and disposition of large quantities of slag from blast-furnaces is a question of great importance in the design of works, and various methods have been devised, from time to time, in order to take the best advantage of local conditions. With blast-furnaces treating copper-ores or lead-ores, it is necessary to use a fore-hearth, or matte-settler, in order to collect, if possible, every particle of valuable matte which, otherwise, would be carried away with the out-flowing slag. In all of these cases, the slag overflowing from the fore-hearth is caught in pots and then conveyed to the dump. If the slag is of no value and the necessary water-supply, grade and dumping-space be available, the disposal of the slag by granulation is by far the cheapest and best method. It involves a minimum of labor, both at the furnace and at the dump; and it permits a continuous outflow of slag from the furnace or settling-pot, thereby avoiding frequent tapping and plugging. When the conditions of water-supply, grade and dump-area will not permit slag-granulation, there are three other methods in common use. Large steel or cast-iron pots, or ladles, supported by trunnions on heavy cars which are moved by steam-, air-, or electric locomotives; some type of mechanical conveyor; and small pots or buggies moved by hand. The pots on the slag-cars are generally circular or oval in shape, and each one contains from 15 to 40 or more cu. ft. of molten material. The mechanism for tipping them is more or less elaborate; and, as a general rule, the slag is dumped alongside, and quite close to, the track. They are more or less costly to construct and to keep in repair, and, in order to use them to best advantage, it is necessary to have a good elevation of track above the dumping-ground ; furthermore, the rails must be of heavy weight, and well-supported on heavy ties. Other disadvantages of the slag-pots are—1, that the slag cannot be removed continuously

Jan 1, 1906

By William Newnam

LEAD mining has been carried on in several localities of the Province of Ontario in a desultory fashion for the past 60 years, but up to 1916 the results have not been of much commercial importance. The most ambitious attempt was made by an English company which built a lead smelter at Kingston, Ont., in, 1880 to treat the- concentrates from the . Frontenac mines. After 2 years' operation, the -mines and smelter were abandoned. Up to the present there has not been a sufficient tonnage of concentrates to support an efficient blast-furnace plant and as most of the small properties could not stand the heavy freight and duty charges into the United States, development work has not been carried on in a, systematic manner. As a result the industry has languished. At, Galetta, in southeastern Ontario, considerable prospecting and development work has been carried on in the last few years and very promising deposits of galena have been found in the Chats Island group by the James Robertson Co., Ltd., of Montreal. The chief deposit is that of the Galetta or Kingdon lead mine, located on Chats Island in. the Ottawa River about 5 miles east of the town of Arnprior. The rocks' in the vicinity of -the mines consist of an interbedded series of crystalline limestone and biotite gneisses of pre-Cambrian age. This part of the Ottawa River' basin has been severely faulted and the overlying Paleozoic limestones may be seen in normal fault contact with the pre-Cambrian. The vein filling is of a very well-marked fault fissure type and although the amount of displacement is not determined at this point, similar faults to the east show a displacement of from 1,500 to 1,800 ft. which would indicate mineralized fault fissures of considerable depth. The ore occurs in a highly crystalline calcite with some barite and fluorite, and the galena occurs more or less richly disseminated in clusters and crystal aggregates. In some cases these masses weigh several hundred pounds. Small amounts of sphalerite are occasionally encountered.

Jan 4, 1917

By E. L. Davis

There have been many attempts to devise formulas for flowing efficiency and flow friction of oil-gas mixtures in oil-well flow tubes. Actually, however, flowing efficiency is rarely any real concern of the oil producer and flow-friction formulas contain so many unknown variables as to be of little, if any value. The production engineer is generally concerned with producing as much oil as possible with a minimum expense per barrel, and with the lowest possible net gas-oil ratio. These ends frequently are opposed to each other and the gas-oil ratio usually is sacrificed. In competitive operations, such as in town-lot fields, high current production is the sole interest. In conservative operation the greatest possible amount of oil obviously should be produced by natural flow unless the net formation gas-oil ratio can be improved by circulating gas. In practice this condition frequently exists. It would be a great advantage if the flowing condition of a well could be analyzed to determine the best possible producing status. Anticipating the death of a well so that gas-lift could be started immediately after the death, or preferably before, would save both production and expense. Frequently it happens that circulating gas fails to help a flowing well, or will not flow it after it has stopped flowing naturally. A knowledge of the laws governing flow would save considerable expense in testing such cases. A predetermination of probable pressures and amounts of circulating gas needed to flow wells and give best possible producing conditions would help in designing compressor installations. The optimum producing status of an oil well generally may be obtained by the conditions that subject the producing formations to the least possible back-pressure. This pressure is made up of the weight of the fluid column, frictional resistance to flow and the reaction from the acceleration of the fluid mass. A mathematical calculation of these components to arrive at a condition giving a minimum summation is impractical. Formulas would be complex and the results untrustworthy because it is impossible to assign proper values to the many variables involved.

Jan 1, 1931

By J. Campbell

Long freezing range casting alloys are particularly susceptible to a type of porosity which is observed to form in layers parallel to the supposed position of the isotherms in the solidifying casting. Under favorable conditions (which appear to be typified by low-temperature gradients in the casting giving rise to a wide and more or less uniform pasty zone, and which arise from several factors, particularly: a) wide freezing range alloy, b) high thermal conductivity of metal, c) low thermal conductivity of mold, and d) high mold temperature3) layer porosity has been observed in many different casting alloys: copper,' aluminum, magnesium,' steels, and high-temperature alloys.3 Baker4,5 and later cibula6 argue that layer porosity occurs because of thermal contraction, in a manner analogous to hot tearing. In outline, the theory consists of the establishment of a coherent dendrite network by the impinging of dendrite tips. Subsequent shrinkage imposes tensile stresses on the network which tears perpendicularly to the stress, i.e., parallel to the isotherms. If these tears are not filled by the inflow of residual liquid then layers of porosity result. Baker7 attempted to test whether the porosity was the result of thermal contraction by casting test pieces in a mold designed to accentuate hot tearing. However, no significant increase in porosity was observed. This negative result of Baker's critical experiment appears to be substantiated by numerous observations, particularly the experiments by Lagowski and Meier8 on Mg-Zn alloys covering the range of zinc contents up to 30 pct Zn. These clearly reveal that the maxima for the incidence of hot tearing and layer porosity are well-separated, occurring at 1 and 6 pct Zn, respectively. Furthermore, the thermal contraction maximum occurred at 1 pct Zn, indicating that hot tearing is associated with contraction in the solid state, and not with porosity. These observations are further substantiated by the elementary consideration that the thermal contraction of the casting is likely to produce (if anything, since the temperature difference across casting of high thermal conductivity, such as aluminum and copper, is likely to be negligible) a compressive stress on the

Jan 1, 1969

By J. F. Wolff

The iron formation of the Gogebic Range in northeastern Wisconsin and the northwestern part of the Upper Peninsula of Michigan, resembles that of the Mesabi Range in Minnesota very closely in lithologic character and the subdivisions and horizons that can be recognized. It contains numerous interbedded slaty layers and considerable intraformational conglomerate in certain horizons. In contrast to the flat dip of the Mesabi formation, the Gogebic dips steeply to the northwest at an average angle of about 70". It has a quartzite and siliceous slate foot wall and a hanging wall of conglomerate, graywacke and slate. The black and gray Tyler slate has been designated the hanging wall of the Gogebic iron formation in U. S. Geologicial Survey monographs, but between the true Tyler slate and the commercially important Gogebic iron formation, and apparently unconformably upon the latter, is a series 600 ft. or more thick of conglomerate, slate, graywacke, and cherty iron formation, the latter being of no commercial importance on the Gogebic Range as far as now known. This series is probably that described as the "Capps" on the eastern Gogebic by the Michigan Geological Survey. The Gogebic iron formation proper can be subdivided into three main horizons, a lower cherty and an upper cherty with a banded or slaty horizon between them, corresponding to the three lower horizons of the Mesabi. Several minor subdivisions can be made of these major ones. Orebodies occur in all three horizons of the Gogebic series and in some places ore is developed across practically the entire series. Dikes and Sills The Gogebic iron formation has been intruded most intricately by basic dikes and sills, most of the former pitching east but some pitching west. One very extensive sill is intruded near the base of the lower slaty or banded horizon, in the formation known locally as the Yale slates. One extensive bedding or strike fault is associated with this sill and a great many transverse faults occur at different places along the Range. The combination, or association, of steep dip, faults, dikes and sills has produced conditions very favorable for the development of orebodies through the leaching, oxidation, and consequent concentration effected

Jan 1, 1925

By William Blauvelt

THE type of gas producer in which the ashes are fluxed and run off as slag was among the very earliest made. Ebelmen built the first one in 1840 at Audincourt, France, only a year after the installation of the first gas producer of which we have record. Charcoal was used as the fuel, with blast-furnace slag and clay is flux. My interest in this type of producer began when as a boy I saw the fluxing producer at Chester, N. J., which was invented by W. J.. Taylor, and described by him in 1881.1 This producer was invented independently by Mr. Taylor to meet the difficulties he experienced in making producer gas for roasting sulphurous iron ores. It will be of interest to review briefly his description of his producer. It was built like a small blast furnace, having a hearth 24 in. in diameter and 24 in. high. The bosh angle was 25° from the vertical; the diameter at the bosh 4 ft. and at the top 3 ft.; the total height 12 ft. The producer contained one water-cooled tuyere 12 in. above the bottom, with a 1.5-in. nozzle.. Depth of the coal above the tuyere; 6 ft. Mr. Taylor mixed the coal with from 30 to 40 per cent. of basic blast-furnace slag to flux the ash. Occasionally some limestone was also used, but never limestone alone, as the use of the furnace cinder gave a larger volume of slag and made it easier to maintain a proper fluidity. . The producer was blown with a small Weimer blowing engine, delivering 300 ft. of air per minute, at from 1 to 1.5 lb. pressure. The slag was tapped every 2 hr. and was black and glassy in appearance. Broken or egg size anthracite was used. The fine sizes of anthracite could not he made to work. Mr. Taylor expressed the belief that bituminous coal could be used if not too fine, but no experiments were made with this coal. Runs were made of four weeks' duration, with no stops or changes. Mr. Taylor reported the following advantages:

Jan 12, 1913