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By H. A. Koch, R. L. Slobod

This paper discusses a new oil recovery process called the "miscible slug process." This process involves the injection of propane or LPG into the reservoir prior to gas injection. The operating conditions are maintained so that the slug is miscible with both the reservoir oil and the injected gas phase. Thus, a miscible phase displacement is achieved, and high recoveries are obtained from the area of the reservoir contacted. The most striking discovery of the laboratory study which included displacements from cores up to 123 ft in length was that relatively small slugs of LPG are effective over reservoir distances in the miscible displacement of oil. This makes possible the commercial application of the process. The important factors controlling the size of the slug are: (I) reservoir length, (2) reservoir fluid composition, and (3) reservoir pressure at the displacement front. Of lesser importance are the effects of injection rate and porous medium type. Questions which have not been completely answered deal with the effects of gravity and reservoir inhomogeneities on the process. INTRODUCTION One of the major problems facing the oil industry today is recovery of the large fraction of the discovered oil which will remain unrecovered unless some new processes are found. Water flooding has been one successful method used to increase recovery over natural depletion. But even successful water floods may leave 25 to 40 per cent of the pore space filled with residual oil. Recently a process which involves the use of thermal energy has been reported1,'*' which may prove useful in increasing recovery from shallow reservoirs containing highly viscous crudes. This paper deals with a new oil recovery process involving use of miscible phases to displace the oil from the reservoir. Miscible phase displacement oil has been an intriguing idea because the elimination of capillary effects in the reservoir leads to 100 per cent recovery in the areas contacted by the miscible displacing phase. The big deterrent in the past to the practice of miscible phase displacement has been the high cost involved in using large volumes of solvent in the process. The use of high pressure gas to achieve a miscible phase displacement of reservoir oil has been reported4,5 as one economically feasible method. However, this process calls for the maintenance of pressures above 3,000 psi at the dis-placement front. The process described in this paper is not restricted to high reservoir pressures; the only qualification being that the slug of material which is injected into the reservoir must be miscible with both the displaced oil 2nd the displacing phase. Two such cases are the use of an alcohol slug followed by water to achieve a mis-cable water flood, and the use of a low boiling hydrocarbon slug such as propane followed by gas to achieve a miscible gas drive. This paper will deal specifically with the propane dug process. This process will obtain a miscible phase displacement at pressures as low as about 1,200 psi at a reservoir temperature 01 150°F. The process is very simple. The propane displaces oil completely at one front because it is miscible with the oil, and gas displaces the propane completely at a second or trailing front because it is miscible with the propane. A small band of propane should thus remain wedged between the gas and oil phases. This idea has been called the "miscible slug process."6 Unfortunately, the propane slug will become diluted as it flows through the reservoir. This results from a mixing action since the fluids flow through a complex reservoir porous medium rather than simple capillaries. Fig. 1 diagrams a miscible slug displacement. The effects of some of

Jan 1, 1958

By H. E. Lee, P. C. Feddersen, D. R. Gittinger, G. W. Dunn, J. B. Schuettenhelm

The new Bunker Hill slag-treatment plant, designed ior, a capacity of 300 to 400 tons of hot slag per day, was "blown in" April 5, 1943. In the ensuing I5-months period, 157,530 tons of slag was processed, with an average recovery of over go per cent of the zinc and practically all of the lead contained. In addition to this high metal recovery, utilization of the waste heat in the gas and fume venting, the process has enabled the generation of 231,376 tons of steam at 250-lb, gauge. Over the first six months opcration the volume of slag treated averaged somewhat under 300 tons per day. Reclaimed dump slag made up only about 1 5 per cent of the plant feed. In October 1943, preparations for the smelting of additional tonnages of dump slag were completed and the plant capacity was increased to an average of about 420 tons of slag per day. During the nine-months interval since that date, monthly averages of 450 toils per operating day have been maintained several times. The new plant (Fig. I) is constructed in close proximity to blast-furnace operations. The fuming furnace and other necessary equipment are housed in an eastward extension of the existing blast-furnace building. Beyond this housed extension the dust-laden gas is conveyed about the perimeter of a large rectangle formed by the flues, cooling towers and baghouses. The course of a 10-ft. balloon flue, which transports the fuming furnace gas, describes the west and south perimeters. This flue connects with a set of cooling towers located at the southeast comer. The flue and cooling-tower system serving the deleading kiln constitute the north side and the two baghouses, serving the kiln and furnace operations, -border the east side. From these baghouses the several discharge gas flows are come biped and conveyed in to the rectangle, being vented to atmosphere by means of a fan through a centrally located zoo-ft. brick stack. In general, the plant design and operation follow quite closely that dictated by experience gained in years of slag-fuming practice by the Anaconda Copper Mining Go., at East Helena, Mont., and the Consolidated Mining and Smelting Co. of Canada, Ltd., at Trail, B.C., and more recently by the International Smelting and Refining Co. at Toocle, Utah. : Fuming operations at the East Helena and the Tooele plants are more or less identical. Trail practice differs chiefly in the methods employed for the storage of the hot feed slag and in the methods utilized for the handling and cooling of the fuming furnace gas. The new Bunker Hill fuming plant closely follows Trail procedure in the treatment of the furnace discharge gas while East Hclcna methods have been adopted for the storage of feed slag.

Jan 1, 1944

By S. Maemura

Miike Colliery of Mitsui Coal Mining Company, the biggest and oldest coal mine in Japan, is producing a quarter of the national coal production, about 5.2 million tons of clean coal annually and almost a half of which is now being mined under the "slicing Mining System". The slicing system is a mining method to mine a thick coal seam dividing it into two faces, upper and lower. Its history started nearly 20 years ago. However, the all-around modernization of this system has made little progress up to recent years, while mining methods for single longwall faces has made a remarkable progress together with the improvements in mining machineries, self advancing supports and so on. The reason was that the tremendous difference in adaptabilities of mechanized face equipments existing between the upper and lower faces has made it very difficult to increase the total production capacity of slicing system. After our persistent study for seventeen years, we have recently realized successfully the quite satisfactory slicing system, applying the combination of shield type self advancing supports and double ranging drum cutter at both faces. We are now fully convinced of that the high efficient, quite safe and improved slicing system has been basically established for the present. This paper intends to brief the transition on the combination of self advancing supports and mining machines, its results and further to detail the development of shield type self advancing support for upper face and artificial roof material which shall be the key point to be successful in full mechanization of slicing faces.

Jan 1, 1976

By F. T. Selleck, H. H. Reamer, B. H. Sage

An experimental investigation was made of the effect of temperature upon the three-phase pressure associated with the propane-water and propene-water systems when hydrates were present. In addition, the characteristics of the propane-propene-water system were established over a limited range of ternperatureo under conditions such that hydrate was formed. The hydrate phase for this system may he a solid solution and the distribution of propane and propene in it is similar to that found in the coexisting hvdrocarhon liquid phase. INTRODUCTION A knowledge of the characteristics of hydrates of the hydrocarborrs encountered in industrial practice is of importance in connection with the design of process equipment. Villardl.1,2 carried out early studies of hydrates, and de Forcrand1 con-sidered the more probable compositions of the hydrates of hydrocarbons. Hammerschnid1 presented information about the propane-water and the isobutane-water systems. Scheffer5 studied the hydrate of hydrogen sulfide in detail, and de For-crand reported on the hydrates of krypton, argon, and xenon.1 Roberts and co-workers1,2 determined the nature of the hydrates formed in the methane-water and ethane-water systems. Carson and Katz10 studied the methane-propane-water, methane-pentane-water, and the methane-hexane-water systems in the four-phase region. The results of this rather extensive investigation indicated that the paraffinic hydrates formed solid solutions. The experimental evidence now available does not Support the existence of hydrates of the pentanes-antl-heavier hydrocarhons but it cannot be stated with certainty that such hydrates are not formed. Stackelherg. 11,12,13 made extensive studies of the crystal structure of paraffinic hydrate; by means of x-ray techniques and found that hydrates poses; a definite structure and composition. The existence of such a Structure does not preclude the firmation of Solid solutions of hydrates in aqueous systems containing two or more hydro-carbon~. Wilcox, Carson and Katz" reviewrd the information on the hydrates of importance in the processing of natural gas and presented data concerning their formation from natural gas. Kobayashi and Katz1' made studies at high pressure of the Hydrate of methane. and Unruh and Katz"' investigated hy-drates in mixtures of carbon rlioxide and methane. Frost and Deaton contributed to the knowledge of the composition of the paraffinic hydrates The irregularities in the experimental results were several times the expected uncertainties. This experience confirms the behavior encountered by other investigators indicating that hydrates tend to occlude water during their formation, thus rendering difficult the direct measoremeut of their composition. Miller and Strong2 investigated a number. of paraffinic hydrates from the standpoint of their possible application to (, the industrial storage of gas. Powel1 studied the effect of solutes upon the decomposition temperature of paraffin hydrates. Marked lowering of the decomposition temperature at a given pressure may he obtained by the use of such additive agents as ethylene glycol, urea. and sodium chloride. APPARATUS AND METHODS Two method* were here employed to study the behavior of hydrates. The first involved a glass capillary within which the hydrocarbons and water were confined over mercury. The second made use of a double-ended weighing bomb technique." The glass capillary equipment has been described elsewhere.'" A schematic drawing of it is presented in Fig. 1, where the arrangement of the agitator and mercury reservoir is shown in some detail. The lower part of the glass capillary, D, was enlarged to afford space within which the fluids used in the investigation could he stored at low pressures after their introduction through the valve. G. The temperature of the capillary was controlled by the circulation of a hydrocarbon oil of low viscosity from the agitated bath, B, through the vacuum jacketed column. C. The pump, A, was employed for the circulation of this oil. A relatively clear view of the capillary tube, D, was obtained through the vacuum jacket. Mercury was introduced into the lower part of the vessel, E, from

Jan 1, 1952

By John Chipman

IN the manufacture of rimming steel-which constitutes the bulk of the world's production of mild steel-the factors that determine the quality of the product are very closely associated with the pouring and solidification of the steel in the ingot mold. The behavior of the metal in the mold is, on the one hand, the resultant of the complex processes through which the liquid metal has passed, and, on the other, it is an indication of the probable behavior of the ingot during subsequent rolling and finishing operations. A detailed study of the mechanism of solidifica-tion of rimming ingots ought to yield information that will be useful iii controlling the structure of the ingot and the quality of the ultimate product. The first step in such a study is to determine the rate at which the solid shell of the ingot forms from the liquid metal in the mold. A knowledge of the rate of solidification will make it possible to correlate observations of rimming action and gas evolution with studies of the structure, porosity, and segregation within the ingot. Thus, if the metal in the mold is observed to fall, let us say one minute after pouring, the portion of the structure associated with this fall will lie located in the part of the ingot that is solidifying at that particular moment. The knowledge that the ingot solidifies to a depth of ¾ in. in the first minute enables us to locate in the ingot the structural features corresponding to the observed fall. Conversely, the blowhole condition associated with a rising or growing ingot will be found in the part of the ingot that is solidifying at the time the phenomenon occurs. The time required for the complete solidification of an ingot has long been a matter of speculation. It is of considerable practical importance in connection with charging and heating in the soaking pits. Too rapid handling of the ingot through heating and rolling processes has been thought to be associated-with excessive pipe and other internal defects, so that a further object of this investigation was to attempt to estimate the time required for complete solidification, or the minimum practical time within which the subsequent operations can be performed with the minimum hazard.

Jan 1, 1937

By Walter S. McKee

When mixed with common cast steel in quantities ranging from 11 to 131/2 per cent. and properly treated, manganese increases the ductility of the metal and adds greatly to its toughness and resistance to abrasive action, which properties comprise the distinctive characteristics that make manganese steel so valuable for many purposes at the present time.. * At present the manganese-steel foundries of this country have an annual capacity of about 60,000 tons and most of the growth has occurred within the past 10 years. In the early days of the industry it was impracticable to make manganese castings weighing over a few thousand pounds, but at present crusher heads, rolling-mill pinions, and similar castings weighing up to 30,000 Ib. each are produced, and it does not appear that the limit of weight has been reached by a considerable margin. Manganese steel is similar in analysis to ordinary first-class converter metal except that it is high in carbon and contains from 11 to 13.5 per cent. of manganese. From one standpoint manganese steel is similar to malleable iron in that the casting as it comes out of the sand is hard and brittle and must be made ductile by a heat-treating process. The heat treatment is an essential part of the process of making manganese-steel castings and must be properly carried out to secure satisfactory results. The necessity for heat treatment limits the thickness of sections which may be made of manganese steel. Originally the annealing depth was comparatively small, but researches carried on during the past few years have resulted in an increase in the thickness of section up to 51/2 in., which it is possible to treat successfully. Large castings are cored out to a minimum thickness of 51/2 in., thus not only eliminating some of the internal stresses which are invariably set up in a very thick casting, but also reducing the weight and inertia of the piece, an important consideration if the casting is to be a moving part in a machine. At the same time, the thickness of 51/2 in. is sufficient to permit the use of manganese steel for the heaviest classes of machinery.

Jan 1, 1916

By Hans Lundberg

By electrical prospecting, orebodies that do not otherwise manifest themselves at the surface may be located. Conditions favorable to success with the methods are: Favorable geological conditions, such a proportion of minerals of good electrical conductivity in the orebody as will render the latter materially a better conductor than the enclosing rock, situation of the orebody within the range of influence of the electrical currents used and in proportion to this range a sufficient area of horizontal cross section of the orebody. The result is to permit of spotting drill holes accurately and to save the expense of drilling barren ground. THE art of prospecting, like other branches of mining, has developed rapidly during the last ten years, mainly because of the advancement of mining geology, but also because of the development of "geophysical methods," which are based on the different physical characters of minerals and rocks, e. g., specific gravity, elasticity, and magnetic and electric properties. These methods have proved of great value, especially in countries where the rock is covered by soil and direct geologic investigation is out of the question. In prospecting for orebodies, the methods based on studying differences in electrical conductivity have proved most successful; for which reason, the methods of electrical prospecting have been subject to the most energetic and systematic work, especially in Sweden. This paper gives a brief description of the methods of electrical prospecting now in use, especially the new electromagnetic methods, which have not been described before. The great differences in the electrical properties, especially in conductivity, between ore minerals and rock minerals are fundamental to all methods of electrical prospecting, for which reason, the electrical conductivity of ore minerals and rock minerals has been carefully studied in connection with and previous to the development of the various methods of prospecting with electricity. Ore minerals with a metallic luster, such as chalcopyrite, iron pyrite, galena, specular iron, magnetite, etc., also graphite and a number of cows, have considerably higher conductivity than the surrounding rock and soil (see Table 1). The figures of the table denote the specific resistance W, expressed in ohms for a cube with an edge of 1 centimeter.

Jan 7, 1925

By W. F. Boericke, T. H. Garnett

The Wisconsin zinc district, or the Upper Mississippi lead and zinc district as it is also termed, lies in the southwestern corner of Wisconsin, and embraces adjacent portions of Illinois and Iowa. It includes Iowa, Grant, and Lafayette counties in Wisconsin, and Jo Davies country in Illinois. In Iowa, Dubuque formerly produced considerable lead, but there has been little mining there in recent years. The map, Fig. 1, shows the entire district, withroads, railways, streams, and the various towns, or "camps," around which the mines are clustered. The hatchwork indicates the areas in which lead and zinc have been mined. The district is about 60 mi. (96 km.) north and south and about 40 mi. (64 km.) east and west. Not all of the territory is mineral bearing, and there are considerable areas that are believed to be barren. The grouping of the mines is patchy and irregular, though certain broad zoncs of mineralization extend almost the full width of the district, as from Mineral Point west through Mifflin and Livingston, and from Shullsburg west through New Diggings and Hazel Green. It is worth noting that the best mines of the district have, to date, been found within 10 mi. ease or west of the fourth principal meridian line, thus lying within a long, narrow, north-and-south belt extending the length of the district. In a field as large as the Wisconsin, which has only within comparatively recent time been worked intensively for zinc, the chances are good for opening new and important orebodies in parts of the district not yet, or insufficiently, prospected. However; the prospecting has been most successful around, or adjacent to, the old lead diggings of nearly a century ago, and the camps that were well known then are still centers of activity. In their order of importance they are: New Diggings, Ben-ton, Mifflin-Livingston, Galena, Linden, Hazel Green, Shullsburg, and Highland. The district is one of the best farming districts in Wisconsin, with deep fertile soil. The farms are large and well improved, and the towns are modern and prosperous. Railroad facilities are good and proximity to Chicago is an asset. Mining is usually done on a leasing system of 10

Jan 1, 1920

By E. V. d’Invilliers

The position of these magnetic ore-mines, with reference to the county-seat, is shown in Fig. 1. They are situated on the south margin of the Great Valley, five miles south of Lebanon, and about midway between Reading on the Schuylkill River and Harrisburg on the Susquehanna River, in three prominent, contiguous hills, standing in front of the Mesozoic red shale arid sandstone hill country of northern Lancaster and southern Lebanon counties, and overlooking the great limestone plain to the north. The three hills, named respectively Big, Middle, and Grassy Hills, and separated from each other by two branches of Furnace Creek, range in a nearly east and west direction for a distance of about one mile. Their summits are respectively 870, 715, and 700 feet above tide. The railroad line opposite the base of Middle Hill is 575 feet above tide at Cornwall and 471 feet at Lebauon. These features are all distinctly illustrated in the contour-line map accompanying this paper, but are made still more clear in the relief. map, Fig. 2, comprising, as it does, about six square miles of territory contiguous to the ore-mines. This is a photographic plate of a model made by Mr. A. E. Lehman, from surveys of my own and Mr. W. F. Shunk. The model was built in layers of cardboard, each layer representing one 10-foot contour-carve line. The scale was the same as the original map, 400 feet= 1 inch, without any vertical exaggeration. The lowest contour-line is 530 feet above ocean level; the highest, 1075 feet. The center of the model was made the focusing-point of the view, which was taken—according to scale—51/2 miles north from and 24 miles above the focusing-point, looking southward. When first mined in the last century these hills exhibited smoothlyrounded surfaces, composed of soft weathered ore of great parity, beneath which lay the great mass of hard ore, constituting the whole

Jan 1, 1886

By Michael A. Toole, O&apos

INTRODUCTION The tremendous capital investment required to produce a low grade ore deposit demands a reliable answer to the question: "How much does it cost to drill a well to produce the uranium that geologists have indicated is there in the ground?" However, you will find the answers given will be many and varied, depending on whether they come from the operating company, the drilling contractor, a geologist, a reservoir engineer, purchasing agent, or whoever. Each generally considers only a limited area of the total operation. The operating company usually depends upon the drilling contractors, service companies, and consultants to supply expertise. Because it is often difficult to see the "whole picture" or even to agree upon what the "whole picture" is, planning a well program and its costs is often done piecemeal. Frequently, costs "saved" in one area of the program are needlessly spent in another, because the effect of one area upon the other was overlooked. Since the drilling fluid is such an influential part of the drilling program, it should be given utmost consideration when planning the overall program. As W. D. Lacabanne wrote in 1954: "The drilling fluid system is understandably called the heart of the rotary oil drilling rig. Any other type of rotary rig.... should benefit by the incorporation of mud fluids in the drilling scheme." And G. R. Gray mentions that "The driller recognizes the drilling fluid as one of the useful tools available to solve drilling problems." However, in minerals drilling, only in recent years has the drilling fluid been considered as more than a tool to get through special problem areas. Although there are many similarities between drilling for oil and gas and drilling for minerals, the differences in the drilling equipment used justifies designing specific fluids for the minerals drilling industry. NL Baroid/NL Industries, Inc. has been a leader in introducing such fluids and in providing technical know-how to the minerals drilling industry. The purpose of this paper is: (1) to discuss the selection of drilling fluids to meet specific drilling conditions during both exploration and production and (2) to show the interrelationship among factors present in the exploration and production phases that influence total well costs. DRILLING FLUIDS FOR DRILLING PROBLEMS The drilling fluid is a tool that can be used to improve drilling performance by improving hole cutting, cleaning, stability, and formation productivity. Properly formulated and maintained drilling fluids enable the drilling operation to be carried out with increased efficiency and lower total (overall) costs. However, it should be noted that not all drilling problems can be solved by even the most carefully prepared and maintained drilling fluids. Of the many possible drilling problems encountered in a well before reaching target depth, this paper will discuss only those most likely to be present in the shallow [61 to 610 m (200 to 2000 ft)] drilling operations in South Texas. LOST CIRCULATION Loss of circulation is the most common problem encountered in drilling. Because the losses occur under varied conditions, it is often difficult to determine the exact causes. "Lost circulation" or "lost returns" means the partial or complete loss of drilling fluid to voids in the formation. "Loss of water" while drilling with water may take place into any permeable section and should be distinguished from "water loss" or filtration of fluid through the filter cake of mud solids laid down on a permeable formation. "Loss of water" can frequently be stopped by the addition of colloidal sized clay particles such as high yield bentonites, whereas "water loss" may be controlled with organic polymers. Subsurface conditions that lead to loss of circulation can be classified as: (1) natural fractures, (2) induced fractures, (3) unconsolidated or highly permeable formations (loose gravel), and (4) cavernous formations (crevices and channels). Loss of circulation may occur whenever the borehole pressure exceeds the formation pressure. The greater the differential pressure, the more likely it is that circulation may be lost. To stop loss of whole mud, voids must be bridged so that a filter cake can be laid down on the permeable section. The plugging material must be of the proper size and shape to offer greater resistance to the fluid flow around it than the flow up the annulus. A plugging composition that satisfies these requirements may not be able to be handled by the small rig pump available.

Jan 1, 1979

By C. G. Dunn

Many investigations have been made concerning the nature of plastic deformation and recrystallization of metals either in the form of polycrystalline materials or in the form of single crystals. However, similar work on strip materials composed of large grains as thick as the strip and having a high degree of preferred crystal oricntation has not been carried out extensively. Such materials are ideal not only for studying changes in single crystals under conditions where neighboring grains exert their influences but also for obtaining the complete change in orientation of a grain or group of grains during the course of plastic deformation and subsequent recrystallization. It is well known that first-order twins in the form of Neumann bands may be produced during the plastic deformation of ferrite crystals, particularly silicon ferrite crystals.l--3 Furthermore, it is believed that high-stress regions exist in the vicinity of these bands4. and it has been said that these banded regions would be active in recrystallization processes.5 Evidence to that effect in silicon ferrite had already been presented with photomicrographs showing recrystallization among Neumann bands during the early stages of recrystallizati~n.5,6 Similar evidence has been published for nonferrous metals5 Merging of fine parallel deformation bands during annealing to form twin bands of ordinary appearance in alpha brass has been offered not only as evidence of an active role being played by mechanical twins but also as evidence that such twins cxisted prior to recrystalli~ation.5 Proof that such new structures are actually first-order twins, or even twins at all, must be considered inadequate except for those cases where X-ray or optical data have been obtained to confirm the necessary oricntation relationship.7,8 A. B. Greninger has obtained excellent iliustrations of annealing twins in alpha iron.9 Since his material was previously deformed by sharp hammering, a process that generally induces Neumann bands, the existence of twins following annealing might suggest that they grew from mechanical twins. In connection with transformation twins in alpha iron, Greninger reported that grains containing three twin orientations occurred rarely and none occurred with three sets of well-developed bands.9 The work at the Pittsfield Works Laboratory on silicon ferrite in the form of large-grained strip steel deformed a small amount and annealed to partially recrystallize the grains indicates that the deformation and recrystallization processes that lead to annealing twins involvc more complex processes than the formation of Neumann bands and the growth of such bands. Some groups of annealing twins are obtained which contain not only three well-developed twin structures, but also contain more than one order of twins. It is also shown, in one case, that an interrelated group of twins did not arise within one single parent grain and, furthermore, orientations of grains in the group

Jan 1, 1944

By H. C. George

The Wisconsin Zinc District, or the Upper Mississippi Lead and Zinc District as it is often called, lies in the southwestern corner of Wisconsin, in Grant, Iowa and Lafayette Counties, and it includes adjoining parts of Illinois and Iowa. The district is about 70 miles long, north and south, and about 40 miles wide, east and west. It lies wholly within what is geologically known as the non-glaciated area of the Upper Mississippi Valley. HISTORY OF THE DISTRICT The district was first opened up as a lead producer in 1822. From this time until 1860, about 205,000 tons of cog lead (galena) and washed lead (galena) was produced from shallow crevices and openings. From 1860 to 1900, about 74,500 tons was produced, and since that time, from 5000 to 7000 tons has been produced annually. Since 1900, most of the lead concentrate produced has been as a byproduct of the zinc mines. The first zinc ores were mined about 1862. These were the carbonate ores, locally known as "drybone." Very little zinc blende was mined in the district, previous to 1875. The zinc blende ores mined from 1875 to 1900 were mostly of the high-grade, hand-cobbed, sheet-ore class, which usually contained from 45 to 60 per cent. metallic zinc Such mines as the "Sallie Waters," "Quinlin," 'Lead Mine," "Benton Blende," and "Ida Blende," located near Benton, Wis., were mines which produced ores of this type, during this period. The mines located at Highland, the "Coker Mine" located at Livingston, Wis., and the "Opencut Mine" located at Shullsburg, Wis., were mines that were heavy zinc carbonate producers, previous to 1900. The production of zinc ores in the district from 1862 to 1890 was about 283,500 tons, mostly zinc carbonate, with a probable average metallic zinc content of 30 per cent. From 1890 to 1903, the production

Jan 1, 1918

By Charles R. Keyes

I. Introductory,.......... 185 II. Hypotheses oF the Origin of OzaRk Ores..... 186 1. General Considerations........ 186 2. Schmidt-Leonhard and Gage View...... 187 3. Jenney Opinion.......... 187 4. Posepny Idea,.......... 188 5. Winslow-Robertson Hypothesis....... 188 6. Branner Proposition......... 189 7. Keyes Statement.......... 189 8. Van Hise-Bain Theory........ 190 III. Requirements of an Adequate WoRking-Hypothesis,... 190 IV. GeneRal Geotectonics of the OzaRk Region.... 192 1. Salient Aspects.......... 192 2. Geologic Formations......... 192 3. Character of Faulting...192 4. Extent of Flexing......... 193 5. Unconformity Inequalities....195 6. Warping of Strata...195 V. Classes of Ore-Deposits... 196 VI. Vadose ORe-ConcentRation,........ 197 VII. GeogRaphic DistRibution of the Ore-Bodies,... 199 VIII. Relation of ORe-Deposit to Geologic Structure... 201 1. General Occurrence of Ore-Bodies in Basins.... 201 2. Deposits of the Central Missouri District..... 203 3. Deposits of the Southwestern Missouri District.... 203 4. Deposits of the Northern Arkansas District... 305 5. Deposits of the Southeastern Missouri District.... 206 6. Synclinal Ore-Deposits of Other Districts.....207 7. Significance of Ore-Troughs in Prospecting... 209 8. Origin of the so-called Synclines,...210 9. Significance of the Cross-Bars of Joplin..... 213 10. Relation of Ore-Run to Ancient Relief-Features,... 215 IX. Direction of GRound-Water Circulation..... 216 X. VeRtical Range of Workable Ore-Bodies,... 218 XI. Oscillation of Ground-WateR Level...... 219 XII. Relations of Ore-Bodies to Lithoclasic Features,.. 220 XIII. PRimaRy Source of Ore-Materials,...... 220 XIV. Zone of Ore-Enrichment,......... 222

Jan 1, 1910

By E. M. Wise

THe properties required of gold alloys for jewelry are not well standardized, due in part to problems peculiar to certain branches of the jewelry industry, in part to the individual preference of the fabricator and to his willingness to cope with certain difficulties in manufacture, which arise with the use of certain alloys. General Requirements In general, the properties desired may be classed as follows: 1. Color should conform to the dictates of good taste and smart style. 2. Corrosion resistance and tarnish resistance should he good. This is to a considerable extent determined by the carat. Resistance to such corrosive agents as mercuric chloride as well as certain depi1atories is unreasonable to expect and difficult to meet. 3. Strength and hardness must be adequate to maintain the delicate contours of finely modeled jewelry. 4. Wear resistance must be great enough to resist abnormal wear, such as is encountered by a wedding ring in a lifetime of wear. 5. Ductility must be sufficient to permit the fabrication of drawn shells, tubes and difficult shapes. Material having a yield point of not less than 60,000 lb. per sq. in., an ultimate strength of 100,000 Ib. per sq. in., and an elongation of 40 per cent. is desirable. 6. Melting point should be between 800" and 1200" C. Colored Golds The popular green and yellow golds are based on the gold-silver-copper alloys; in some cases modified by the introduction of zinc to improve the casting properties and to alter the color, and nickel to increase the strength. The properties of the Au-Ag-Cu system have been the subject of a very thorough investigation by Jänecke,l Sterner-Rainer12 and Carter."

Jan 1, 1929

An informal discussion on the application of physical chemistry to steelmaking was held during the Annual Meeting of the Institute in February, 1929. Alexander L. Feild presided. In opening the session, Mr. Feild said: We are all familiar with the cooperative mining and metallurgical studies that were begun in 1920 by the U. S. Bureau of Mines, the Carnegie Institute of Technology, and the Mining and Metallurgical Advisory Boards, and in particular with the work on the physical chemistry of steelmaking which was launched under the technical direction of Dr. C. H. Herty, Jr., in May, 1926. It was this work at Pittsburgh more than anything else that was the immediate cause of the formation within the Institute of a committee on the physical chemistry of steelmaking. During the latter part of 1927 a small group of Institute members interested in. the general subject of the physical chemistry of steelmaking undertook the organization of a subcommittee within the Iron and Steel Committee, to foster an active interest in this comparatively new field among the Institute membership and to obtain papers for publication in the Transactions, covering the various phases of the general subject. This plan was conceived by C. E. Meissner, to whose active efforts at the outset as well as during the past year is largely due whatever measure of success the plan has thus far attained. The subcommittee, now a committee of the Iron and Steel Division, was recognized and formally made a part of the Institute's organization at the February, 1928, meeting. As originally organized and as const,it,uted during the past year the committee has been made up as follows: C. H. Herty, Jr., C. D. King, A. B. Kinzel, John Johnston, C. E. Meissner, L. F. Reinartz, R. B. Sosman, and A. L. Feild, Chairman. Dr. C. H. Herty, Jr. has just been elected chairman for the coming year and C. E. Meissner has been reelected as secretary. From the outset it has been the settled policy of the committee to make membership an annual rather than a permanent matter and to reconstitute in part the membership of the committee each year by dropping a certain number of members and adding new members. In view of the fact that the work of the committee is still in a

Jan 1, 1929

By H. W. Weart, D. J. Mack

SINCE the first recognition of eutectic solidification as the simultaneous formation of 2 solids from one liquid,1 many complex structures thus produced have been observed. Despite many attempts to ascertain it, however, the detailed mechanism by which these structures develop remains obscure. In an attempt to clarify the origin of eutectic structures, the study described in this paper was undertaken. The broad objective of the study was to investigate the effect of different solidification conditions on the structure of single eutectic grains. It was expected that the eutectic structure would thereby be isolated for study, but preliminary experiments revealed another structure within each grain. When a literature surveye revealed only 1 previous mention of the subgrain structure,' it was decided to determine the origin of the structure and to study its response to various growth conditions. Before presenting the details of the investigation, it is apropos to distinguish carefully among the 3 structures produced during eutectic solidification. This is especially desirable in view of the apparent confusion existing in the literature concerning the structures in a eutectic specimen. The confusion is due largely to the existence of the subgrain structure noted above which is easily mistaken for the grain structure. In the following paragraphs, an effort is made to distinguish the 3 structures by briefly describing their origin during solidification, even though the results are thereby anticipated slightly. The 3 structures produced during eutectic solidification are the grain structure, the colony structure, and the eutectic structure, each one contained by the one preceding it. The grain structure is analogous to the polycrystalline structure of a metal or inle-phase alloy in that each grain grows from a single nucleus. A somewhat broader interpretation is needed here, however, because of the presence of 2 phases in each grain. Since in most eutec-tics particles of 1 phase are dispersed in a matrix of the other, a grain may be taken to be the region in which the matrix phase is monocrystalline.*

Jan 1, 1959

By B. H. Bergstrom, J. J. Gilvarry

Previously the authors showed that the Gilvarry equation correctly describes the distribution of fragment size in single fracture, provided the exoclastic particles showing original surface of the specimen are removed from the distribution. In the present work this conclusion has been strengthened in two respects. First, it has been shown that the existence of two peaks in the differential distribution for the endoclastic particles, corresponding to the effect of surface and volume flaws in the interior of the specimen, can be demonstrated from the average of data for a large number of specimens. Second, it has been shown by means of a Coulter counter that data obtained from specimens fractured in gelatin display the behavior at fragment sizes approaching 1 p which is demanded by the limiting form of the Gilvarry equation in this case. In previous work, a rigorous derivation of the proper distribution function for fragment size in single fracture of a brittle solid has been given by Gilvarry,' based on a closely defined physical model and deduced strictly by the laws of probability. Experimental work has been reported by Gilvarry and Berg-str~m,~ confirming the theory in its broad outlines. Subsequently, Gilvarry and Bergstrom extended the theoretical discussion to include comminution and presented experimental data bearing on this point. They have described further experimental results for the case of single fracture recently. The experimental evidence regarding single fracture was rather convincing. However, it was based on only five specimens for which fragment sizes were determined by sieve analyses and three for which measurements in the finer sizes were made on a Coulter counter. The purpose of the present paper is to extend the experimental results as obtained by means of both sieve analyses and the Coulter technique. In the former case, sufficient specimens are included so that the average data should vield ac- curately the detailed behavior of the distribution function for the coarser fragment sizes. In the latter case, measurements for the finer sizes are reported which correspond to single fracture more closely than prior results and fill a lacuna left in the experimental verification. In addition, an extension of the theory given recently bGilvarry for the case of fracture of a two-dimensional solid will be outlined, and experimental results obtained by him will be discussed.6 THREE-DIMENSIONAL CASE Gilvarry' has shown that the Schuhmann size modulus is a measure, in a sense specified later, of the number of activated edge flaws in a specimen undergoing single fracture. Single fracture is defined as that resulting from a single instantaneous application of energy, such as the blow of a hammer whose motion is halted when fracture begins. Plural fracture consists of a short sequence of single fractures, as in a jaw or gyratory crusher; multiple fracture obtains when many applications of energy are made, as in a ball mill. The Griffith flaws associated with fracture of a specimen are flaws occurring within the volume of the body, on the new surfaces created within its interior and on the new edges (intersections of two surfaces) within the body. Fracture proceeds by activation of flaws in the volume of the specimen, in the fracture surfaces throughout its interior, and in the edges produced by intersection of fracture surfaces. If all the flaws and all groups of flaws are distributed at random, independently of other flaws or groups thereof, it has been shown by Gilvarry that the distribution function for fragment size has the form of a Poisson distribution. The fraction y, by weight or volume, passing a sieve of mesh size x is given by where k is an average spacing of activated edge flaws, j2 is an average amount of surface containing one activated surface flaw and i3 is an average volume corresponding to an activated volume flaw. The averages in question are referred to the mean dimension x of a fragment. On the basis of the theoretical

Jan 1, 1962

By W. D. Haselton, J. B. Newsom

SAFER, cheaper, and faster sinking of mine openings seems to have been realized with the completion of a borehole 5 ½ ft. in diameter and 1208 ft. deep, in Minnesota, during 1938. Moreover, as the opening is to be used solely for ventilation, its circular cross section, smooth walls and freedom from fire hazard recommend it in comparison with the usual timbered shafts of rectilinear cross section. It should be pointed out that a drill hole sunk without the use of explosives frequently will stand open without support, whereas a shaft sunk by standard procedure using dynamite usually must be timbered because of the wall-shattering effect of explosives. The saving in maintenance resulting from the elimination of timber is obvious. The work was done by Pickands Mather & Co. at its Zenith mine, Ely, Minn. This company wanted a ventilation opening capable of delivering 50,000 cu. ft. of air per minute to the fourteenth level, 1200 ft. below the surface. While several general articles1-3 have described the method used, detailed time and performance records have not been presented before. Moreover, with a method as new as this, it is important to compare the results attained under widely varying conditions. Among the new conditions faced at Ely were some extremely hard rock, a series of vertical fractures, seepage water, and some long stretches of sound rock which, combined with excellent equipment, gave a chance to operate without unusual delays. Developments in boring large holes have generally taken the obvious course of increasing the size of the equipment, a line of attack that has resulted in putting down 3-ft. diameter holes at damsites for studying the foundations4 and in drilling ventilation openings between levels at Butte.5 Such drills operate from the collar of the hole, and the power from the drill is transmitted to the cutting tool through drill rods or pipes. In order to keep down the volume of rock that must be ground to sludge, the cores in large-diameter drilling are made as large in diameter as possible. Their large diameter increases their weight per foot of length, which

Jan 1, 1939

By Joseph S. Malesky

The discovery and development of explosives mark one of the most important findings in the history of civilization. Without explosives our vast economic enterprise concerning the mining of coal, copper, iron, aluminum, and various other ores could not function. Explosives are used in all kinds of construction works, in the razing of old buildings, blasting of trenches, driving of tunnels, and in many other instances common to our everyday life. For these reasons explosives are rightfully referred to as the forerunner of progress. An explosive may be defined as a substance (usually a mixture) that, when flame or shock is applied, yields readily to rapid combustion or oxidation, accompanied by the formation of such relatively large quantities of gases as to produce much violence and pressure which, in turn, react against their surroundings and cause what is termed an explosion. By their very nature the action of explosives is destructive and disruptive of adjacent materials. Decomposition of explosives can occur through deflagration, which is rapid burning or combustion, as in the case of black powder, or through detonation, which is an almost instantaneous disruption, as in the case of dynamites and blasting agents. HISTORY OF BLASTING WITH EXPLOSIVES At one time workmen obtained stone blocks for building by grooving the rock with crude picks, driving wooden wedges into niches in the rock, and pouring water on the wedges; the swelling of the wood forced out the blocks. As late as the 17th century, fires were placed against the face of rock to crack it, and water was sometimes dashed on the heated rock to shatter it by sudden cooling. The progress of our country is synonymous with advancement of the improved manufacture and extended use of explosives. Coal had been

Jan 1, 1981

By Ancel St. John

Defects in the interior of metal objects are troublesome to both manufacturer and user. For the former, they frequently increase manufacturing cost through the rejection of material when defects appear after considerable work has been done. For the latter, they often cause damage to equipment, personal injury, or loss of life when a part, which has passed all inspections and has been put in service, gives way because of a hidden flaw. Methods of testing that locate such flaws without subjecting the specimen to possible, if not actual, destl-uction are few; x-ray examination, whether fluoroscopic or radiographic, is one. Hitherto, however, x-ray examination has been restricted to objects of nearly uniform thickness and regular outline; the inspection of such articles as those shown in Fig. 1 has been inconvenient and unsatisfactory. This figure represents a group of 5/16-in. hexagonal-head machine bolts,

Jan 1, 1923