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By M. C. Udy, P. C. Rosenthal

The use of minute boron additions to steel has been given considerable attention in recent years. Comparisons made between boron-free and boron-containing heats of otherwise identical analysis have indicated, beyond a doubt, the potent effect of boron for increasing hardenability. The actual hardenability increase has been expressed as a multiplying factor, or in terms of the percentage of other alloying elements boron might replace. The present study presents the results of a systematic survey of the use of boron as an addition to two types of alloyed steels and as a replacement for various percentages of molybdenum in these steels. Both cast and wrought steels of the two basic compositions were prepared. Molybdenum, because of its scarcity at the time the investigation was started, was selected as the element to be replaced by boron. Attention was also given to the effects of boron on other properties of the steels, particularly their notched-bar toughness, to investigate other advantages or limitations of this element as an alloy addition. Experimental Work Steels Investigated The two basic compositions used in this survey of boron as a replacement for molybdenum are given in Table I. The cast steels were higher than the wrought steels in silicon content to improve the casting quality. Table i.—Nominal Composition of the Two Base Alloy Steels composition. Per Cent. steel Mn Si Ni Cr Xi-Cr-Mo Wrought 0.28-0.70-0.15-o.45—o.45-0.32 0.90 0.25 0.55 0.55 Cast 0.28-0.70-0.35-0.45-o.45- 0.32 0.90 0.45 0.55 0.55 hln-&lo Wrought 0.28-I .go-o.0.15-0.32 1.70 0.15 Cast o. 28- I.40- 0.35- 0.31 1.70 0.45 a Sulphur was 0.040 per cent maximum and phosphorus 0.030 per cent maximum. Each of these base steels, both cast and wrought, was made with molybdenum contents of o, 0.10, 0.20, 0.30, or 0.40 per cent, the total comprising 20 steels. In addition, each of these 20 compositions was prepared with boron additions in amounts of o.oo15, 0.003, and 0.006 per cent as ferroboron; and in amounts of 0.002 and 0.005 per cent as two commercial intensifier alloys, designated alloys A and B. The boron-treated steels totaled 100, and the entire series 120. Test Procedure Each steel was melted as an individual heat in a 50-lb., magnesia-lined induction furnace. Ingot iron scrap or mixtures of ingot iron and steel. scrap were used for melting stock. Deoxidation was carried out in the furnace with 0.10 per cent aluminum. The aluminum addition was

Jan 1, 1948

INDEX OF CONTENTSIntroduction.Systems of classification of coals.RankClassification of Australian coals.Defects of systems in use in other countries.Indexing by Fuel Ratio.Classification by Ultimate Carbon/Ultimate Hydrogen.Relationship between Fuel Ratio and ultimate composition.Suggested convention for classification.Origin and Evolution.Notes on directions of change of composition on Carbon Hydrogen chart.Summary and conclusion.Acknowledgments.Bibliography.Appendix.

Jan 1, 1948

By P. E. Cavanagh

Introduction A comprehensive study of the economics of processes for smelting iron ores has been made by the Ontario Research Foundation on behalf of the Ontario Research Commission. This survey has included investigations of all processes in commercial use, and proposed processes which are still in the experimental stage. The two main objects of this work were to discover (l) whether any known processes would be particularly suited to present and future Canadian conditions, and (2) whether any new process would be of assistance in solving the present scrap shortage in Canada. The future prospects of the Canadian iron smelting industry have changed radically in the past ten years. For nearly twenty years before 1939 no iron ore was mined in Canada. The ore used was imported, mainly from the United States and Newfoundland. The economics of iron blast-furnace smelting always force the location of blast furnaces near the source of coal for making high-grade metallurgical coke, and near the market for iron and steel, rather than near the iron ore. Blast-furnace installations in Canada are confined to the north shores of the Great Lakes with ready access to United States coal and ore and the major Canadian markets, and to Nova Scotia near the coalfields of that Province. This distribution of primary smelting capacity naturally results in relatively high prices for iron and steel in the West, the North, and in Quebec.

Jan 1, 1948

By E. C. Wright

The following article is based on observation of college graduates entering the steel industry in technical work made during the Past 25 Years, the first five of which were spent as a college instructor in two engineering schools, and the last 20 in the employ of a large steel company that has hired hundreds of engineering graduates for steel-mill operations. The college graduates encountered during this period have come from many colleges representing schools in Eastern States, Midwestern Universities, many Southern colleges, and many smaller colleges and normal training schools mostly in western Pennsylvania and Ohio. The college training of these students for engineering work naturally has varied widely and the educational qualifications of the entrants have been in many ways different. It was found at an early date that graduates of standard engineering colleges were much more adaptable than graduates in science from nontechnical schools. The engineering students seemed to be more suited to actual work in steel plants and in general were better able to grasp a knowledge of the operations they observed. However, although the graduates of engineering schools have had somewhat better training in physics, mathematics, and engineering, it has been a general and continual observation that most of the students employed have had inadequate training in the fundamental sciences. Since this discussion relates entirely to metallurgical engineers it should be emphasized that students taking metallurgical engineering courses in college seem to be poorly trained in organic chemistry-physics, physical chemistry, thermodynamics, and any higher form of mathematics than simple calculus. It has been noted frequently that young engineers faced with problems in a mill that involve some mathematics generally flounder badly, and that they have little conception of physical chemistry. Another common deficiency lies in the young graduate's lack of knowledge of where to look for the more detailed literature on any subject. He reverts instinctively to some college textbook whose coverage is usually very elementary. It is recommended that such textbooks contain a bibliography of the source literature. and that students be taught to use the original data. Many of the students had had previous courses in college dealing with metallurgical work such as steel melting, metallograhy, etc.r but it was found that their grasp of these subjects was extremely sketchy. It was soon realized that an ordinary engineering graduate could be taught more about steel melting and manufacturing processes in a few weeks in a plant than he could learn in a college course on such subjects. A similar statement may be made regarding the ability of students to conduct laboratory work. Their lack of technique and skill in handling equipment and setting up experiments was soon apparent. It became neces-

Jan 1, 1948

By Donald F. Reed

The bauxite deposits of Tippah and Benton Counties in northeastern Mississippi were developed by drilling as a part of the investigation by the Bureau of Mines of the domestic sources of supply of aluminum. The primary purpose of investigations of this nature was to provide essential information to the war agencies of the United States Government and to assist owners and operators of mining properties in the production of minerals vital to the prosecution of the war. These reports are based upon the field work of the Bureau of Mines and upon data made available to the Department from other

Jan 1, 1948

By Ivor Jenkins

Processes employing 'controlled at-mospheres in the heat-treatment of metals and alloys are now well established on an industrial scale, and the general principles involved and the advantages to be gained in the use of the technique have received considerable publicity over a period of years. During this time the greatest emphasis has been on the establishment of the process in industry, the main effort being devoted to development work on various types of atmospheres, their useful fields of application and the design of suitable heat-treatment furnaces in which they are to be used. The various types of controlled atmospheres are fairly well standardized, but there still remains a considerable field for the investigation of related problems, in connection with both the gas-generating equipment and the surface chemistry of the heat-treatment of metals, especially in complex controlled atmospheres. This paper describes certain investigations of this nature that were carried out in England up to 1939. The development of processes employing controlled atmospheres has been asso-ciated to a very large extent with the heat-treatment of steels, both because of the major importance of steel in industry and the many diverse and dificult prob-lems of surface chemistry involved when steels of such a wide range of composition are heated in the presence of active gases. Controlled atmospheres such as disso-ciated and burnt ammonia or charcoal gas are used in the heat-treatment of low-carbon and high-carbon steels, but from certain points of view a suitable atmosphere generated by the partial combustion of city gas is to be preferred. Both the ammonia derivatives are comparatively expensive, and even if the burnt ammonia is regenerated, thereby reducing operating costs, the capital expenditure of the gas plant may make it prohibitive for the smaller type of furnace installation. Charcoal-gas generators are not without their operating difficulties especially those associated with the quality of the charcoal, clinker formation and the removal of carbon dust from the generated gas. City gas has the advantage of being comparatively cheap and "on tap" in most if not all industrial centers. The use of raw city gas as a protective atmosphere in the heat-treatment of steels has been described,' but it presents certain difficulties because of its complex composition and its explosive nature when mixed with air. These factors, together with the tendency toward sooting at elevated temperatures, arising mainly from the hydrocarbon gases present, all militate against its use as a protective atmosphere in industrial furnaces. The following analysis, based on the analyses of city gas in different localities in Great Britain, indicates the wide limits existing

Jan 1, 1948

By Pol Duwez, Howard E. Martens

INTRODUCTION THE high temperatures encountered in the operation of jet engines have imposed most drastic requirements upon the materials used in their construction. There are two different approaches to the materials problem connected with the design of parts in contact with high temperature gases. The first approach is to use a material which will perform satisfactorily at a temperature comparable to that of the gas. The second approach is to use a cooling system so that the material is maintained at a temperature appreciably lower than that of the gas. Besides the conventional method .of cooling by means of a liquid in contact with the material exposed to a high rate of heat transfer, a less orthodox method consists of making the part to be cooled of a porous material, so that the cooling fluid can be forced through the pores. In this scheme, the temperature of the coolant moving in a direction opposite to that of the heat flow increases gradually while passing through the porous material, and the coolant forms a protective layer on the surface exposed to heat. This method, referred to as "sweat cooling," was proposed at the jet Propulsion Laboratory in September 1944, and the experimental work on the preparation of porous metals was started early in 1945. The sweat cooling method opens new lines of research in powder metallurgy by extending the field of application of porous metals. The porous metals available at the present time are used mostly as bearings or filters, and a rather limited number of alloys are made for these applications. In addition, the fabrication of bearings or filters does not require a very dose control of the permeability, while in the case of sweat cooling such a control is of primary importance. In designing a sweat cooled part it is imperative to assure a given rate of flow of coolant under certain conditions of pressure drop. Generally, the proper pressure drop and the rate of flow of coolant are deduced from heat transfer and design considerations, and consequently the permeability of the porous metal to be used is also determined. It is therefore necessary for the designer to have available a continuous series of porous metals covering a range of permeability as wide as possible. Contrary to the requirements established in the fabrication of filters, the actual pore size of a porous metal intended for sweat cooling is of little consequence, except for its effect on permeability. The tensile strength is likely to be of great importance for some applications. Since the tensile strength of a porous alloy decreases with increasing porosity, an important problem is to develop porous alloys having the maximum permeability with minimum porosity.

Jan 1, 1948

Jan 1, 1948

Stope filling practice on the Great Boulder Mine was described in -a paper published in Aus.I.M.M., Proceedings No. 137, in 1945. When the paper was presented the process had emerged from the experimental stage, most of the initial operating difficulties had been overcome, and it had been established that this method of filling was suitable for the working of ore bodies in the Kalgoorlie field: Since 1945, it has fulfilled its early promise, -and during 1947, the tonnage of fill placed was sufficient to cover current operating requirements as called for by the mine ore breaking programme. The object of this paper is to outline current operations. In so doing it will refer' to some ground covered by the previous paper, but will omit details of the initial experimental work. It will include, however, a description of further experimental work on the use of hydraulic filling for worked-out shrinkage stopes, arid will provide more accurate data on costs than were available previously.ESTIMATE OF TONNAGE OF FILL REQUIRED.Early in 1946, the mine ore reserves were analysed in order to estimate the relative tonnages to be mined per four-weekly period by shrinkage stope methods -and by cut and fill stope methods respectively. This analysis was extended beyond the blocks already prepared for stoping, and inclqded the majority of the major ore blocks in the mine ore reserves. It gave the following results:-For a mill tonnage of 28,000 tons per period, 6,933 tons were required from cut and fill stopes, and a possible future maximum programme of 35,000 tons per period would require...

Jan 1, 1948

By M. C. Dow

Belt conveyors generally are conceded to be the most economical method yet devised for the transportation of large quantities of bulk materials within plants. Belts are coming into greater use for transportation over long distances and are replacing other forms of long-haul conveyance. It is not the intent of the writer to comment on the design of belt conveyors, but to offer some suggestions for improvement in the operation of conveying belts, based on many years experience with belts in several stone-crushing plants. It is the contention of this writer that opportunities for improvement not fully realized by most operators exist in many plants and that a study of the individual conveyors can result in lower unit belt costs. General Reliability It is the fool-proof nature and general reliability of the belt conveyor that is responsible for its neglect. Even when abused, a belt will carry large tonnages and last a long time, often outlasting the personnel responsible for its care. Some operators look upon the purchase of a new belt as an expensive outlay every so many years, rather than a constant and steady cost amounting in belt wear alone to several dollars every operating day. This belt wear for all conveyors in one stone-crushing plant known by the writer costs 1 /12 cents per ton or $12 to $15 per hour, based on the present cost of belt replacements. The fact that these replacement costs are double those of prewar quality emphasizes the necessity of improving the conditions that make belts wear out. Some of those conditions are the responsibility of the conveyor designer, and if a serious original error has been made, this handicap cannot be overcome by the operator. If the belt is too narrow, too steep, or too fast for good loading, the operator finds that he has an inherently expensive belt. The other factors that decrease the life of a belt are more or less under his control. The two factors of most importance are the loading conditions and the alignment. Most of the cover wear and carcass cutting occurs at the loading point and if the alignment is not good under all conditions, edge wear or damage may result, Fig I. Loading the Belt It is difficult to load a belt in an ideal manner; that is, to flow the material on the moving belt at a steady rate, without impact, without turbulence, and with a velocity equal to and in the same direction as the belt. An inclined belt is especially difficult to load and particularly when its speed is over 300 or 350 fpm. Inclined conveyors require longer skirt plates to prevent spillage until the load settles. It does not seem reasonable to expect an inclined the to carry the same load as a horizontal belt of the same width and speed, because of the difficulty in loading

Jan 1, 1948

By J. W. Galpin, V. L. Minear, F. C. Sturges, B. H. Mott, R. H. Allen, W. W. Weigel, Wm. D. Owsley, R. E. Moeller

By definition the word "grout" means a thin mortar, or a kind of plaster or ce¬ment, and "grouting" means to fill up or finish with grout. The words "cement," "plaster" and "mortar" mean a substance that is used in a soft state which subsequently hardens. Thus, grouting is the filling of void space with a substance that hardens. Construction cements are the most common substances used, either by themselves or in mixtures, but the term grouting is applied quite correctly when other substances such as plastics and certain chemicals are used. Also, the use of the term grouting to cover the filling of voids with materials that do not actually become hard, such as the-flotation tailings used in grouting in the southeast Missouri lead district, should be considered correct, as some stiffening does take place and, anyway, it is a better descriptive term than any substitute. Engineers are interested in grouting because some of the materials with which they must work contain voids, and certain conditions can be improved if these voids can be filled with something solid and permanent. Grouting is done to accomplish several purposes: I. To stop the passage of fluids and gases, 2. To cement materials together to make them stronger, and 3. To prevent consolidation of materials by filling void space with something solid as a replacement for the air and water that could be forced out under load. The construction industry uses grouting extensively for all three purposes. Grouting is used to stop water percolation under and around dams. It is used to control water flow in tunnel driving and in shaft sinking. It is used to improve foundation conditions under civil engineering structures by permanently filling void space and thereby reducing settlement, or by cementing broken rock together and increasing its supporting strength. The oil and gas industry does a lot of grouting, primarily to stop the passage of gases and fluids. The search for oil at increasingly greater depths has meant greater investment per well, and the oil industry has spent large sums on development of improved drilling methods. This

Jan 1, 1948

By B. M. Larsen, T. E. Brower

In an earlier paper1 we discussed a simple, rapid method of taking samples of liquid steel and analyzing them for oxygen, which, though possibly not absolutely accurate (as is likewise true of all other methods), certainly yields results that are satisfactorily consistent. Accordingly, samples from hundreds of heats ill different shops were analyzed for oxygen, with results sufficient in number to be handled statistically and permit estimation of some general trends. Measurements were made in acid as well as in basic open hearths, throughout the refining period, to learn how stirring, blocking, adding ore or lime or sand, affects the oxygen content of the bath; we also followed the changes brought about by tapping, teeming, and deoxidizing. Some of these results, discussed in an earlier paper,2 bring out the dominant role of the carbon-oxygen reaction in regulating degree of oxidation both of metal and of slag, also the marked variability of concentration of dissolved oxygen [0] in excess of that which would be in equilibrium with carbon and with carbon monoxide at a partial pressure of one atmosphere. As a logical beginning on this complex problem, we take up in the present paper the variability of this excess oxygen, A[O], when other factors are as constant as they ever are in open-hearth operation; namely, toward the end of the refining period, when the bath may be regarded as in the comparatively steady state it approaches in absence of disturbing factors. This condition was chosen because by that time the significant reactions, except carbon oxidation, between slag and metal have come to substantial equilibrium; this facilitates interpretation of the complex situation and thus perinits more definite conclusions to be drawn. This excess concentration of oxygen, A[O], in the metal is needed, of course, to make the steelmaking process go at a reasonable rate; alternatively it may be regarded as a measure of the virtual pressure increment above one atmosphere, or of the degree of supersaturation, of carbon monoxide in the metal. According to our measurements, the excess concentration A[0] in liquid steel varies from about 0.009 to 0,035 per cent oxygen by weight. It is quite sensitive to change of conditions, being altered temporarily by operations such as stirring with green poles, additions of ore, lime, or sand; but as the disturbance works itself out, it resumes a level within the intermediate range characteristic of the steady state. The conditions most common in average furnace practice are covered by the following: i[O] Usual Per Cent Oxygen by Conditions Weight 1. Vigorous lime boil........... o.oog-0.01s 2. Steady state................ o.or;-0.025 3. Working of ore.............. o.023-0.035 Thus when the bath can be regarded as in a reasonably steady state—that is, when it is boiling normally, is at proper temperature with a well-shaped slag, and has been free from disturbing effects during the preceding half hour—A[0] returns from

Jan 1, 1948

By M. C. Malamphy

A general description of the activities and results of bauxite investigation by the Bureau of Mines at its bauxite project in Saline and Pulaski Counties, Ark., has been given in Report of Investigations 4251. The factual data obtained during the project are reported in a series of Reports of Investigations beginning with No. 4251, of which this is the fifteenth. The data are accompanied by maps showing the location of holes drilled and the deposits developed. Each area upon which work was done is reported by halt townships. Each bauxite deposit investigated was assigned a name and a number for ready reference and identification and its location and name are shown on the appropriate half-township map. The description of each half township is followed by a description of each deposit developed in that half township. The 14 halt-township maps and 77 detail maps of the bauxite deposits in this series of reports give the locations and numbers of all the holes drilled on the project except the deep holes drilled to test the geophysical anomalies. The locations of those holes show on figure 13 in volume 1. The Descriptions of the deposits developed are followed by complete detailed logs of the drill holes. Many of the widely spaced exploratory holes did not discover bauxite of minable thickness and grade. The pertinent information obtained from the widely spaced exploratory drill holes has been summarized and tabulated, and a table for each halt township is given with the discussion covering that area.

Jan 1, 1948

By Henry Lepp

Introduction A shaft sinking operation carried out at the Viking Yellowknife mine in the spring of 1947 presents certain features, especially as regards speed of sinking and low cost, that may be of interest to Institute members, and especially to those who are not familiar with conditions and costs in the Northwest Territories. After collaring, the inclined, two-compartment shaft was sunk 130 feet by four miners in twenty-eight days at a direct cost of only $53.19 per foot. All things considered, this is a remarkable performance, even if it does not actually establish a record. The property is at Morris lake, some forty-five miles north of Yellowknife. Formerly owned by Athona Mines (1937), Limited, it was acquired by the then newly incorporated Viking Yellowknife Gold Mines, Limited, in 1947. Surface work and diamond drilling in 1946 disclosed a number of veins and masses of quartz in a sill of diorite which lies conformably within sedimentary rocks. The sill strikes N.30°E. and dips at 70° to 85° southeast, and has a mean width of 40 feet over its explored length of 3,000 feet . Both the quartz and the diorite carry gold and are mineralized with pyrrhotite and lesser amounts of galena, sphalerite, chalcopyrite, and arsenopyrite. Of thirty-five holes drilled in the mineralized zone, the core from twenty showed visible gold. Sampling of drill cores indicated several ore shoots in the north and central parts of the sill. Assays, however, were somewhat erratic, possibly due to the fairly widespread presence of visible gold, and it was decided that the deposit could best be explored by underground sampling. Accordingly, late in 1946, plans were laid for the sinking of a shaft.

Jan 1, 1948

By John R. Shattuck

The Shasta and California Iron-ore deposits are 14 miles northeast of Redding, Shasta County, Calif.; and since 1907 have produced more than 300,000 short tons of exceptionally pure iron ore. Although some ore was mined and smelted from 1907 through the First. World War, most of it has been produced from 1942 through 1945 for use in making heavy ship ballast and concrete anchorages for mines. Irregular masses of magnetite, ranging from lumps of a few tons to pods containing about 25,000 tons, occur associated with skarn near the contact between the McCloud limestone and a younger granitic intrusive. Some of the deposits are low-grade, whereas others are nearly pure magnetite. Selective mining and hand sorting are necessary to produce a high-grade product. Investigation of these deposits by the Bureau of Mines included 2,910 feet of diamond drilling, some surface sampling of the principal mineralized zone and beneficiation tests. Resulting factual data are given in the body of this report.

Jan 1, 1948

By Sage B. H., G. W. Billman, Lacey W. N.

The composition of the coexisting phases in the methane-ethane-n-pentane system was determined at 100°F. This was accomplished by withdrawing samples of the coexisting phases under isobaric-isothermal conditions. The relative amount of each of the components present in the liquid and gas phases was determined by conventional analytical fractionation methods. The phase behavior of this system approximates that estimated from generalized correlations which take into account the influence of the nature and amount of each of the components present upon the equilibrium. It was found that for particular pressures and temperatures the equilibrium constant of each of the components was influenced significantly by the composition of the system and this effect was more pronounced at the lower pressures for methane than for the components of greater molecular weight. However, at the higher pressures approaching the maximum two-phase pressure for the system at this temperature the composition markedly influences the equilibrium constants of all the components at a particular pressure and temperature. The results of this study are presented in graphical and tabular form. Introduction The phase behavior of many of the binary systems containing parafin hydrocarbon components from methane through n-pentane has been investigated during recent years. In addition the compositions of the coexisting phases in mixtures of crude oil and natural gas have been studied.' However, these results do not establish the influence of the nature and amount of the other substances making up a multi-component system upon the gas-liquid equilibrium constant of any one component. A preliminary correlation on the basis of values for binary systems was made2 utilizing such experimental information as was available. However, there is need for much additional information regarding behavior in systems containing more than two components. Study of the phase behavior of ternary systems offers a feasible attack upon the determination of the influence of composition as well as of pressure and temperature upon the several equilibrium constants concerned. An investigation of the phase behavior of the methane-propane-n-pentane system at 100°, 160°, and 220°F was reported.".' This work served to illustrate the marked influence of concentration of the other components upon the equilibrium constants. Variations of as much as 50 pct in the equilibrium constants for methane for fixed temperature and pressure were observed in regions remote from the critical state. Likewise there was a marked variation in the equilibrium constants of propane and n-pentane as a result of changes in the composition. These results indicated the desirability of investigating additional ternary systems. The present paper deals with a study of the methane-ethane-n- pen-tane system at 100°F, which is similar in many respects to the work upon the meth-ane-propane-n-pentane system cited above.

Jan 1, 1948

By L. F. Marek, G. W. King, A. Bogrow

The purpose of this paper is to present the data and some interpretation of the results of a laboratory study of the reduction of iron ore and the deposition of carbon from the reducing gas mixtures in such reductions. One major object of the study was to determine the effect of gas pressures on these chemical processes. Effort was made to approximate the conditions of temperature, gas composition, linear and mass gas velocities, pressure range, and extent of reduction prevailing in commercial blast furnaces. The results show that the reduction of Fe203 proceeds by two steps, largely consecutive under the conditions used herein: reduction of Fe203 to FeO, and reduction of FeO to Fe. Unless the gas has a CO!CO, ratio greater than 2.1 only the first step occurs under these conditions (850°C) but the following generalizations apply to either step or to the combination. The rate of reduction of relatively fine ore particles .at any time is proportional to the mass rate of supply of CO (provided some of it is thermodynamically available): the rate therefore is proportional to the linear velocity at constant pressure, or to the pressure at constant linear velocity. Thus, the rate of reduction may be increased without increase in linear velocity of the reducing gas by increasing the mass velocity of the gas and increasing the pressure correspondingly to avoid any increase in the linear velocity. The rate "constants"—i.e., the efficiency of conversion of the "available" CO supplied— is not actually constant but decreases as the reduction proceeds, and is a function only of the state of the ore; i.e., of the amount of reduction already accomplished and hence of the amount of CO passed. The particle size of ore used in nearly all the experiments was relatively small (8 to 14-mesh). The rate of reduction in run 16 with 3 to 8-mesh ore particles is within experimental error the same as with the finer ore. Although this would indicate an absence of effect due to particle size in this range of ore particles, it is desirable to have more data on other ore sizes and on ore of different densities before arriving at any generalizations on this point. Although it is possible to extend the analysis of these results to consideration of the more detailed kinetics and mechanism of iron oxide reduction, such extension is beyond the scope of the present paper. From the experiments on carbon deposition, it was evident that if carbon deposition is increased at all by the application of pressures up to 10 psi ga., such increase appears to be less than the experimental and analytical error. It appears safe to conclude that at top pressures on the order

Jan 1, 1948

By S. H. Lorain

The Minah silver-lead mine in the Wickes district, Jefferson County, Mont., produced substantial quantities of silver-lead ores in the 1890's. The mine has been abandoned since the "silver panic" of the early 1900's. As a part of the Bureau of Mines: program to develop new sources of lead to overcome the growing shortages of that metal, a development project was started at the Minh mine in April 1946 and continued until June 1947, during which 5,600 feet of angledozer trenching and. 1,093 feet of core drilling were completed on the main vein and nearby parallel veins: As a result of this work, interest in the property was stimulated and private operators are now engaged in reopening the mine. This report discusses the past history, geologic setting, and the recent and early operations of the mine.

Jan 1, 1948

By Leon W. Dupuy

A brief elemental discussion of the fundamental factors involved in diamond drilling often fills a need, particularly when a mine operator is contemplating for the first time an exploratory drilling campaign. Mr. James A. Barr, of the Mining Methods Committee of the Institute, has suggested that many engineers must undertake a drilling program of one kid or another and, in the case of diamond drilling, sometimes even are at a loss as to how to start correspondence. The Bureau of Mines has acquired much experience in managing exploratory diamond-drilling activities. Its activities in diamond drilling included exploring for potash in Texas, Utah and New Mexico1-' during the 1920's. The Strategic Minerals Exploration program was started in 1939 and was materially expanded during the war to include critical and essential minerals. At the peak of its war-time activity more than 200 engineers were employed, a majority of whom supervised diamond drilling. Many of them had little experience with such work prior to their employment with the Bureau, and it was necessary to instruct them in their duties. The purpose of this paper, therefore, is to present the fundamentals of exploratory diamond drilling from the viewpoint of management in such a way that they will Serve as a basis on which those beginning exploratory diamond drilling may build an experience and acquire ability to direct exploration as they gain that experience. Selection of Method of Drilling Selection of the method of drilling is governed by the type of material to be penetrated and by the type of sample needed to determine the quality and importance of a deposit. Types of drills that might be used for a given job include diamond drills, churn drills, hand auger drills, power auger drills, bucket drills, and rotary drills (sometimes called "seismograph rigs"). Each type has a specific field in which it is most useful. While the Bureau of Mines utilized all the types of drilling mentioned, diamond drilling was used on a majority of its exploratory projects. Factors Governing Selection of Diamond Drilling The prime consideration in selecting a method of drilling is first to determine what results are desired and then to choose a method that will furnish reliable data in the ground to be penetrated. Use of diamond drills permits recovery of a core as well as sludge at a comparatively low cost. The core provides an excellent means of studying the formation being drilled and furnishes much information that would be difficult to obtain otherwise. Diamond drills will recover a satis-

Jan 1, 1948

By Vaughn Moyer

A method for incorporating well drawdown effect into reservoir calculations is presented in detail, together with examples of its use for widely divergent conditions that could be normally encountered in oil reservoir sands. Tentative conclusions as to the effect such factors as permeability, producing interval, well spacing, or well damage caused by completion or repair practice could have upon economic ultimate recovery are reached. It is carefully pointed out that the conclusions reached are subject to limitations indicated in the text, and placed upon all calculations made in the paper. Introduction Papers have been presentedl-3 in which theoretical depletion histories for reservoirs under equilibrium conditions and no appreciable well-bore drawdown pressure are determined. However, except for a limited number of cases, appreciable drawdown Pressures in a well bore exist, and Pressure and saturation gradients consequently vary throughout a reservoir. This Paper is an attempt to incorporate well-pressure drawdown into reservoir history, and to analyze certain factors, such as those involving recovery, well spacing, and productivity index, from the standpoint of permeability and drainage radius. BY incorporation of drawdown into reservoir history, it is believed that theoretical considerations will more closely approxi- mate actual reservoir behavior experienced in an oil field. For purposes of simplification, a solution gas-drive type field1 without primary gas cap, has been selected. Basic Data and Assumptions Details of equilibrium saturation conditions for no drawdown production for various pressures in a reservoir are deter-minable by methods described by several are permitting the construction of a curve of oil saturation vs Pressure for any selected combination of initial interstitial water and hydrocarbon saturation (Fig I). This curve is then a description of equilibrium saturation conditions at any given pressure in a reservoir. Developing the above, details of saturation and flow permeability may thus be determined for any increment or portion of a well drainage area or reservoir. In this manner the effect of pressure differential (drawdown) may be incorporated into reservoir and well drainage considerations. It is pointed out that this method thus makes use of no-drawdown equilibrium production data, superimposing a draw-hwn effect upon them. It also assumes that net flow conditions in any considered increment of reservoir are not materially altered by the entrance of fluids from other increments into them, but approach equilibrium for the existing pressure and saturation (i.e., each increment behaves in more or less independent fashion, dependent largely upon the equilibrium considerations mentioned above)

Jan 1, 1948