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By G. C. McCartney, S. J. Kidder

The Helen Mine, of the Algoma Steel Corporation, in the Michipicoten district, Ontario, Canada, has produced more than 6,240,290 tons of iron ore. Prior to and during World War I, 2,823,369 gross tons of brown ore were shipped, and from 1939 to the end of the 1944 season, 3,416,921 gross tons of siderite ore were produced from open-pit operations. Brief descriptions are given of the nature of the ore, the mining methods employed and the manner of treatment of the ore. Shipment of the finished product, known as Algoma sinter, is made to blast furnaces in both Canada and the United States. The iron-ore bodies—i.e., the oxide ores of the Old Helen and the siderite of the New Helen—are a part of a tabular shaped area of iron formation that extends over a length of more than 100,000 ft. and has a maximum width of 1000 ft. The ores are considered to be a product of introduction of iron-bearing material accompanied by replacement of the rocks already present. It is shown that introduction took place subsequent to the development of the major folded structures. It is believed the iron-bearing material emanated from an igneous source. Introduction The Michipicoten mining district derives its name from the Indian word1 meaning "place of bold promontories" or "region of big places," and anyone who has visited this part of Canada will agree that the district is well named. In 1897, there was active prospecting for gold in the district and the Ontario Bureau of Mines2 opened a recording office at the Hudson's Bay post at Michipicoten River. In the summer of 1897, Ben Boyer, probably searching for gold, discovered an outcrop of brown iron ore at the east end of a small lake, less than 8 miles, in an air line, northeast of the nearest point on Michipicoten Harbour. In the following year, extensive surface exploration and diamond drilling disclosed a commercial body of nonbessemer brown ore, possibly 700 ft. long and 200 ft. wide, of about the following analysis:3 Fe (natural), 57.15 per cent; S, dried at 212°F.. 0.113; SiO2, dried at 212°F., 4.00; P, dried at 212°F., 0.125. The property (Figs. 1-3) was taken over by E. V. Clergue and ultimately was transferred to the Algoma Steel Corporation. The Algoma Central Railway shortly afterward built its line from Michipicoten Harbour to the mine, together with an ore dock at the Harbour. Thus, within three years of its discovery, the mine had adequate shipping facilities and a market for its ore. Production of Brown Ore and Pyrite The first shipment of brown ore was made in July 1930. By 1939, the mine was shipping at the rate of 170,000 long tons

Jan 1, 1949

By S. J. Kidder, G. C. McCartney

The Helen Mine, of the Algoma Steel Corporation, in the Michipicoten district, Ontario, Canada, has produced more than 6,240,290 tons of iron ore. Prior to and during World War I, 2,823,369 gross tons of brown ore were shipped, and from 1939 to the end of the 1944 season, 3,416,921 gross tons of siderite ore were produced from open-pit operations. Brief descriptions are given of the nature of the ore, the mining methods employed and the manner of treatment of the ore. Shipment of the finished product, known as Algoma sinter, is made to blast furnaces in both Canada and the United States. The iron-ore bodies—i.e., the oxide ores of the Old Helen and the siderite of the New Helen—are a part of a tabular shaped area of iron formation that extends over a length of more than 100,000 ft. and has a maximum width of 1000 ft. The ores are considered to be a product of introduction of iron-bearing material accompanied by replacement of the rocks already present. It is shown that introduction took place subsequent to the development of the major folded structures. It is believed the iron-bearing material emanated from an igneous source. Introduction The Michipicoten mining district derives its name from the Indian word1 meaning "place of bold promontories" or "region of big places," and anyone who has visited this part of Canada will agree that the district is well named. In 1897, there was active prospecting for gold in the district and the Ontario Bureau of Mines2 opened a recording office at the Hudson's Bay post at Michipicoten River. In the summer of 1897, Ben Boyer, probably searching for gold, discovered an outcrop of brown iron ore at the east end of a small lake, less than 8 miles, in an air line, northeast of the nearest point on Michipicoten Harbour. In the following year, extensive surface exploration and diamond drilling disclosed a commercial body of nonbessemer brown ore, possibly 700 ft. long and 200 ft. wide, of about the following analysis:3 Fe (natural), 57.15 per cent; S, dried at 212°F.. 0.113; SiO2, dried at 212°F., 4.00; P, dried at 212°F., 0.125. The property (Figs. 1-3) was taken over by E. V. Clergue and ultimately was transferred to the Algoma Steel Corporation. The Algoma Central Railway shortly afterward built its line from Michipicoten Harbour to the mine, together with an ore dock at the Harbour. Thus, within three years of its discovery, the mine had adequate shipping facilities and a market for its ore. Production of Brown Ore and Pyrite The first shipment of brown ore was made in July 1930. By 1939, the mine was shipping at the rate of 170,000 long tons

Jan 1, 1949

By George J. Clark

One of the major problems of operation in the anthracite industry is the disposal and handling of refuse—not because of its complexity but because of the quantity and type of material involved. It is the purpose of this paper to describe the kinds of refuse, methods of disposal, quantities of material to be handled and equipment used, together with present day application at specific operations in the Northern, Eastern Middle, Western Middle and Southern anthracite fields. For the purpose of this paper, refuse is considered to be any material that has no present or foreseeable future value and that must be handled and disposed of in the process of mining and preparing anthracite for market. Included in this classification are tunnel rock, mine rock, cleaner plant refuse, breaker refuse, old timber, ashes and silt. Disposal Methods Old timber is disposed of either by burning or by depositing on the refuse bank. Burning is preferred because timber on the refuse bank is a potential fire hazard. Ashes are deposited on a separate bank, mixed with other refuse, or flushed into old mine workings. In many places, the latter practice has caused considerable difficulty in preparation of coal mined from these areas. In depositing ashes on the surface, it is wise to refrain from mixing them with material containing coal as such contamination may prevent reclamation of the coal in future years. Tunnel work, mine rock, cleaner plant and breaker refuse compose the bulk of the material to be disposed of and handled, and are referred to collectively as "refuse" in this paper. Waste material in or adjacent to the coal beds may be removed at the working face wherever possible. This can be done in flat or lightly pitching beds, and in the Northern field represents a sizable percentage of this type of refuse handled. In the other three coal fields, this method of disposal cannot often be used. Refuse not removed at the working face is taken to the surface and generally is deposited on banks; occasionally it is crushed and flushed into old mine workings. Breaker refuse often is used for constructing berms for silt-retention basins. Disposal Problems The problem of handling refuse is different for each operation, owing to topographical conditions, quantity of material to be handled, anticipated requirements and types of equipment in use elsewhere at the operation. Preparation plants with limited refuse-disposal areas, excessive grades to reach the required elevation and long hauls to disposal areas not readily accessible require the selection of equipment to best meet the conditions. The quantity of refuse to be handled from a given amount of raw material varies considerably throughout the four fields. In mine coal, this varies from a low

Jan 1, 1949

By Lloyd R. Jackson

IN the past 15 years there has been a great deal of interest in the fundamentals of plastic flow and rupture in metals and a number of papers have presented substantial advances toward a fundamental insight into the mechanism of these two processes. This paper is an appraisal of the present position with respect to the following: I. The relative importance of shear and hydrostatic stresses in controlling the plastic flow of metals. 2. The relative importance of shear and hydrostatic stresses in determining the amount of flow before rupture in metals. 3. The use of generalid strains in determining the effect of plastic flow on the work-hardening of metals. FUNDAMENTALS INVOLVED IN PLASTIC FLOW In attempting to devise a quantitative description of plastic flow in metals, it has been customary to assume that metals are homogeneous and isotropic. The fact that neither of these assumptions is correct complicates the experimental appraisal of relations developed. Never- the less, as will be shown, metals are close enough to being isotropic and homogeneous so that considerable insight into the mechanism of plastic flow can be obtained. The assumptions of .isotropy and homogeneity allow both the elastic and plastic behavior of metals to be described in terms of 12 variables-six being stress variables, and six being strain variables. ) From this viewpoint, it should be possible to represent the stress-strain relations in the plastic range for metals by a surface in 12 dimensions. One boundary of this surface would be the surface of transition from elastic to plastic behavior; the other would be the surface of rupture. These two surfaces would be joined by the surface of plastic flow. The shape of this composite surface would depend on the test temperature and speed of straining. This paper is concerned only with results obtained at constant temperature and constant speed of straining. While such a representation is conceivable, the demonstration of such a surface would present almost insurmountable obstacles. The most fruitful simplification of this concept has been the recognition that the behavior of metals in the plastic region is primarily a result of shear stresses and strains. Based on this viewpoint, it is possible to utilize stress and strain invariants that are independent of hydrostatic components to define an effective stress and strain. In effect, this amounts to reducing the task of representing stresses and strains in 12 dimensions to one of representation in two dimensions. The two invariants (one for stresses . and one for strains) that have received most attention are the following: [ ]

Jan 1, 1946

By Brian F. Dyson

The surface tensions at 1550°C of some Fe-S alloys (in the range 0.008 to 0.052 wt pct S), Fe-Sn alloys (0.31 to 48.4 wt pct Sn), Fe-P alloys (0.038 to 2.38 wt pct P), Fe-Cu alloys (2.15 to 22.8 wt pct Cu), and Fe-1 pct C-S alloys (0.005 to 0.076 wt pct S) along with the surface tension of the base iron have been measured by the sessile-drop method. A mean value of 1754 dynes per cm was found for the surface tension of the base iron. Sulfur was found to be highly surface-active, the surface-tension results being in quantitative agreement with existing data. Tin and copper were found to be less surface-active than sulfur while phosphoms was completely nonsurface-active. The surface tensions of Fe-1 pct C-S alloys were found to be lower than those of the Fe-S alloys containing the same sulfur content. This was shown to be a mmzifestation of the increase in the thermodynamic activity of suZfur by carbon. It is only in recent years that attempts have been made to measure the surface tension of liquid iron of known high purity.1-3 Earlier measurements4-7 were made on liquid iron containing variable amounts of what are now known to be surface -active solutes. The exact value of the surface tension of liquid iron is still, however, open to some doubt. Halden and Kingery' reported a value of 1720k 34 dynes per cm at 1570°C, Kozakevitch and Urbain8 gave 1790k 25 dynes per cm at 1550°C, while Van-Tszin-Tan et al. obtained a value of 1865k 37 dynes per cm at 1550°C. The first systematic investigation into the effect of controlled solute additions on the surface tension of iron was made by Halden and Kingery.' They showed that sulfur and oxygen were highly surface-active, whereas nitrogen was only slightly active, and carbon inactive. A subsequent investigation by Kingery indicated that two other group-6B elements, selenium and tellurium, were also surface-active. This highly surface-active nature of sulfur and oxygen has recently been substantiated by Kozakevitch and Urbainla and Van-Tszin-Tan et al. l1 Kozakevitch and Urbainl2 have also conducted an experimental survey of the effects of a number of metals on the surface tension of liquid iron. Their surface-active nature was, in all cases, less than that of the group 6B elements. The present investigation was undertaken to study in more detail the surface tensions of dilute Fe-S alloys and to measure the surface tensions of binary alloys of iron containing phosphorus, copper, and tin. The effect of sulfur additions on the surface tension of Fe-1 pct C alloys was also determined. EXPERIMENTAL PROCEDURE The sessile-drop method was employed in the present investigation. An apparatus was built similar in principle to that described by Humenik and Kingery.lS It consisted of a horizontal silica tube, which could be evacuated to pressures less than 10-5 torr, with its central portion surrounded by a water jacket within which was a high-frequency coil. This generated heat in a tantalum susceptor placed inside the silica tube, which in turn radiated heat to the specimen mounted on a recrystallized alumina plaque. Temperatures were measured by an optical pyrometer and photographs of the molten drop were taken on a fixed-focus plate camera giving a magnification of X2. Surface-tension values were determined from the resultant drop using the method described by Baes and Kellogg.l4 The high vapor pressure of molten iron made it necessary to conduct all the experiments under a 1/4 atm of argon (greater than 99.995 pct purity). The analysis of the base iron used in the investigation is given in Table I. Each sample was approximately 3 g in weight and had a hemispherical base to ensure a uniform advancing contact angle on melting. The iron alloys were prepared individually in the sessile-drop apparatus by drilling a hole in the top of each sample and adding the required amount of solute, the drops being analyzed after the experiment. This method of preparation had the advantage of ensuring a consistent minimal contamination by oxygen due to refractory attack and also allowed surface tension to be measured at the same time. Every precaution was taken to ensure that the specimen was not contaminated by grease when it was introduced into the apparatus, the samples being cleaned in acid, dried in alcohol, and rinsed in petroleum ether. All handling was done with tweezers. Once the specimen had been placed inside the susceptor, the furnace was evacuated and the Sample leveled. The furnace was then degassed at approximately 1000"C before the argon was introduced. In every case the surface tension was determined at 1550" C.

Jan 1, 1963

By C. E. Sims, H. M. Banta, S. L. Hoyt

Over the past few years, metallic arc welding has been extended to steels of the hardenable type. As compared with other methods of fabrication, production has been facilitated, service performance frequently has been improved, and the overall results have been so favorable that engineers and production men have placed great emphasis on this application of welding. The metallurgist and welding engineer, however, have been confronted with new problems, since, for one reason, the harder steels are more apt to crack and special precautions must be taken if sound joints are to be procured. Some of the factors that are pertinent to this problem are metallurgical, and it is an object of this contribution to discuss steel manufacture and processing methods and to show how their control assists in reducing the hazard of cracking. By this time, the problem of cracking— specifically underbead cracking, or "hard cracks," or parent-metal cracks-—is well known, and a large amount of work has been published, both here and abroad, dealing with this subject.' The tests described are made under restraint to facilitate cracking and arc so designed that a semiquantitative, or at least a relative, value of the cracking tendency is obtained. As one would expect, it has been reported that the incidence of cracking increases with the carbon and alloy content of the steel. More specifically, the cracking tendency is said to increase with the hardenability of the steel, though it is now recognized that the situation is not so simple. The phenomenon itself, on the other hand, has been but loosely described, and it is in only broad generalizations that this cracking has been related to steel metallurgy. Thus, while it has been abundantly demonstrated that the hardenable aircraft steel, S.A.E. 4130, must tend to crack when are-welded, the problem still remains of why two lots of the same composition and the same hardenability can vary so greatly in cracking tendency, or what it is about the prior metallurgical history that so strongly affects the results. Further, while the efficacy of preheating and postheating in preventing cracking is recognized and utilized in production, the mechanism by which they function seems not to have been described. These points are thought to be significant in the production of steel for fabrication by metallic arc welding and, hence, of interest to mill and process metallurgists and welding engineers. Consequently, it is another object of this paper to discuss the mechanism of parent-metal cracking, including the influence of the condition of the steel and the control of cracking by manipulation of the time-temperature conditions during and after welding. A new method of rating the cracking tendency is also discussed, and the results of the test are related to steel composition and structure or prior history. The work to be described was the outgrowth of work in 1940-41 at Battelle Memorial Institutc on two projects, one

Jan 1, 1945

LIMA, PERU Established May, 1952 (Official year begins in June) Luncheon meetings third Wednesday monthly Ernesto A Baertl, Chairman Arthur C Hall, Chairman-Elect Raymond R Beard, First Vice-Chairman Edgardo Portaro, Second Vice-Chairman Walter E King, Secretary-Treasurer Av Santa Cruz 331 San Isidro, Lima, Peru Alberto E Brazzini, Asst Treasurer Daniel M Rodriguez, Asst Secretary, '58, Section Delegate '58, Alternate Section Delegate

Jan 1, 1956

By C. Dirksen

This study investigates whether oxygen consumption during segregated forward combustion may be affected by natural convection. Linear theory indicates that thermal instability occurs in a horizontal porous medium when the modified Rayleigh number N 'Ra exceeds a critical value of about 40. Most experimental results, including those described here, indicate this value to be about an order of magnitude smaller. N ', is derived from "differential similarity" and the proper time scale factor is also obtained. The critical value of N'ra for a horizontal, water-saturated porous medium at atmospheric pressure subjected to a uertical temperature gradient was found to be about 3.0. The ambiguity in the value of N'R, arising when fluid properties cannot be assumed constant is indicated. Natural convection was observed for oblique systems below N 'Ra , while simultaneous horizontal flow did not affect N Racrit. The expected range of values for the various parameters pertaining to segregated forward combustion is indicated and the corresponding values of N 'Ra calculated. Only under very favorable conditions, such as high permeability, high pressure and low top temperature, can the critical value of N 'R, be exceeded. Thickness of the convection layer should not become too large, since the time required to obtain significant mixing is proportional to the square of the thickness. For an oblique combustion frant the conditions for significant mixing may be less strenuous. LNTRODUCTION Laboratory1,2 and field314 experiments have shown that a markedly upgraded oil can be produced by in situ forward combustion. Under certain conditions injected air may move through a high permeability, gas-saturated channel over the oil-saturated layer, while combustion takes place, exclusively, at the horizontal interface (Fig. 1). Such a channel may be a natural gas cap, or it may result from a forward combustion process in which injected air and combustion gases fingered through the top of the formation, causing a premature breakthrough at the production well. In this particular case of segregated forward combustion, the air stream moves parallel to the combustion front. Molecular diffusion and transverse mechanical dispersion will be insufficient to cause all the oxygen in the air stream to reach the combustion front. When the oxygen in the air stream is not completely consumed in the combustion process, it will reach the production well and create a serious fire hazard. In addition, the reduced efficiency may make the process economically unprofitable while also serious corrosion problems may be experienced in the production we11.3 This undesirable situation should, therefore, be prevented. However, in a situation as depicted in Fig. 1, an unstable temperature gradient exists in the gas phase. The combustion is taking place at the lower boundary at a nearly constant temperature that may be anywhere from 600 to 1,200F, depending on the conditions. The upper boundary of the gas phase is overlying, impermeable rock; its temperature might be around 100F, but may increase to 300F or higher due to conduction and convection as the combustion process continues. This represents a steep temperature gradient and it is conceivable that under those conditions free or natural convection will take place in the gas

Jan 1, 1967

By Y. A. Rocher, J. E. Dorn, L. A. Shepard

Creep activation energies for single aluminum crystals favorably oriented for shear by (010) [101] glide were detemined over the temperature range from 78" to 900°K. Observations of slip bands on the specimen surface were made in conjunction with the investigation. From 78" to 780°K, the activation energies obtained in this imestigation agreed closely with those previously found for creep by (111) [101] slip. Between 78" and 140°K, the activation energy was identified with the Peierls process, while between 260°and 780°K the activation energy was close to that for cross-slip. The coarse wavy slip bands nominally parallel to the (010) plane observed above 260°K were attributed to fine cross-slip. From 800" to 900°K, unusually high apparent activation energies ranging from 28,000 to 54,000 cal per mole were obtained. These apparent activation energies were attributed to re crystallization. AS illustrated in Fig. 1, a recent investigation1 has shown that creep of aluminum single crystals by the (111) [i01] mechanism is controlled by three unique processes, each of which is characterized by a single activation energy which is independent of the applied stress and the creep strain. A comparison of the observed activation energies with theoretically calculated values permits a fairly clear identification of the three operative creep processes. Below 450°K, where the activation energy for creep is 3,400 cal per mole, the deformation is controlled by the Peierls process, the activation energy for creep agreeing well with that calculated by seeger2 for the energy required to nucleate the motion of a dislocation loop against the atomic forces of the lattice. Between 590° and 750°K, the observed activation energy for creep of about 28,000 cal per mole agrees well with the energy necessary to induce cross-slip. Seeger and schoeck3 estimate that the activation energy is about 24,000 cal per mole whereas Friedel4 recently calculated this activation energy to be 28,000 cal per mole. Above 800°K the activation energy of 35,500 cal per mole that was observed for creep agrees well with that estimated for self-diffusion in aluminum.= In this range the operative rate-controlling slip process has been clearly identified as that arising from the climb of edge dislocations. The objective of this investigation is to ascertain whether a single crystal of aluminum favorably oriented for simple shear in the [loll direction on the (010) plane might exhibit uniquely different activation energies for creep from those obtained previously for (111) [101] slip. Whereas the exis- tence of such unique activation energies would constitute incontrover table evidence for new mechanisms of slip, the absence of any new activation energies might suggest that slip of aluminum is confined to the (111) [loll mechanism. Several factors prompted the selection of the (010) [101] orientation for study. First, there are more reported observations of (010) [loll slip than of any other nonoctahe-dral mechanism.8-10Secondly, Chalmers and Martius1l have concluded from considerations of the energies of dislocations that (010) slip is the second most favored mechanism in face-centered-cubic metals. Finally, favorable orientations for simple shear by the (010) [loll mechanism provide the least favored orientation for slip by the (111) [101] mechanism. EXPE-RIMENTAL PRO-CEDURE The high-purity aluminum stock, specimen preparation, shear fixture, extensometry, and experimental technique used in this investigation were the same as those previously reported.' Single-crystal spheres grown from the melt of 99.995 pct pure Al* were _ *The high-purity aluminum used in this investigation was graciously given by the Aluminum Company of America. oriented, carefully machined into dumbbell-shaped shear specimens, annealed, and chemically polished. The finished specimen had a central reduced section 0.190 in. wide and 0.590 in. in diam and 1/4-in. grip sections at both sides, 0.690 in. in diameter. The specimen was oriented in the stainless steel grips of the shear fixture with the (010) plane perpendicular to the dumbbell axis and the [loll direction parallel to the stress axis within 2 deg. Creep activation energies were calculated in the previously described manner1 from determinations of the instantaneous change in shear strain rate produced by an abrupt 15 to 20 deg increase or decrease in test temperature. If is the instantaneous strain rate at strain y and temperature T1, and ?2 the instantaneous rate at y and T2,

Jan 1, 1960

By J. A. Cahill, A. D. Kirshenbaum

Using an alumina or zirconia crucible with an alumina sinker or a molybdenum sinker coated with zirconium dioxide, the density of liquid iron was determined by the immersed-sinker method over the temperature range of 1800" to 2500°K. The density, with respect to temperature, is ex-Dressed by the equation Dg/cm = 8.523 - 8.358 X 10 T'K The molar Volumes and thermal coefficients of expansion were calculated. Iron, upon me1ting, was found to expand 3.5 pct. A basic knowledge of the physical properties of materials at high temperatures is becoming increasingly important. A check of the literature shows, that in spite of the importance of iron, very few measurements have been made of its physical properties in the liquid state. Density measurements have been made by Benedicks and his collaborators1g using the method of balanced columns, by Desch and smith4 using the immersed sinker method with an alumina sinker, by Lucas using the maximum bubble method5 and by Stott and endall' who used an alumina pyknometer. In the method of balanced columns, the difference in level of molten iron in two arms of a U-tube, together with the corresponding difference of pressure had to be measured. The formation of gas bubbles in one or both arms was a great source of error. These values are very erratic. They vary from 6.83 to 7.45 g per cm3 at the melting point (1805"~) and from 6.45 to 7.15 g per cm3 at 1890°K. Stott and Rendall determined the density at 1837"K, with a reproducibility of *0.2 pct. They used an alumina pyknometer fired to 1973°K. The vessel was filled in a vacuum furnace by immersion in the liquid metal. When thermal equilibrium was attained, the pyknometer was withdrawn, cooled, the ingot removed and then weighed. The chief disadvantage of the method was the difficulty of inserting the pyknometer without cracking it. The authors have been able to determine the density of liquid iron from its melting point up to 2500°K, by using the immersed-sinker method, with A1203 or ZrOz crucibles and A1203 or molybdenum sinkers coated with Zr02, Fig. 1. EXPERIMENTAL Apparatus. In these studies the source of heat was the carbon tube resistance furnace with an argon atmosphere described previously.7 Experimental runs were made using either Ala3 or ZrOz crucibles. The sinkers used were 1) pure A1a3 and 2) molybdenum coated with ZrOz. The crucible, 2 1/8 in. in diam and 3 in. high, was centered in the furnace on an Ala3 of Zr02 pedestal. The sinker, 1/2 in. in diam and 1 1/2 in. long, together with a counter weight, was suspended from an analytical balance into the melt by a molybdenum wire. Procedure. The procedure, as described previously,' consisted in measuring the weight loss of the sinker in the liquid iron while determining simultaneously the liquid iron temperature by means

Jan 1, 1962

By Eugene A. Stephenson

The writer apologizes for presenting this very elementary analysis of one aspect of proration, but a search of the literature failed to disclose any concrete illustrations of the effect of various proration formulas upon the allowable oil produced by tracts of different sizes. Many engineers have doubtless made somewhat similar calculations and are fully acquainted with the results. The various allocation formulas that are in use are based on one or more of the following factors: (1) wide-open well potential, (2) potential through an orifice, (3) uniform well allowable, (4) acreage, (5) sand thickness, (6) bottom-hole pressure, (7) productivity index, and (8) volumetric displacement. Of these, the unrestricted potential formula, or open-flow test, and the uniform well allowable are commonly regarded by engineers as those least likely to give each producer his proportionate share of the oil or gas, as represented either by acreage or by sand thickness, or both, except when the wells are located on tracts of large size. Unless the mechanical equipment that may be used during the potential test and the method of taking the test are both specified, the net result of the potential formula is to practically force the operators to use special equipment and adopt special procedures prior to and during the potential test, so as to secure the largest possible allowables. Much ingenuity and skill have been devoted to this,problem, but the general effect is to permit excessive allowables for very small tracts, and stimulate unnecessary drilling. It is interesting to compare some of the high yields from the Wilcox horizon at Oklahoma City with each other, as an illustration of the effect of an allocation factor based solely on potential (Table 5). One of the glaring instances is a well on a ½-acre lease, which had produced, as of September 1936, at the rate of almost 3,000,000 bbl. per acre. This is at least twice as many barrels as could have been present under the property if the reservoir had consisted of a tank of oil 200 ft, deep and 56 acre in area. Numerous combinations of acreage, potential, bottom-hole pressure, sand thickness, etc., have been proposed and are in use in various fields.

Jan 1, 1937

By Charles E. Lundin

Pressure-temperature-composition data were obtainedfor the Er-H system. Measurements werecar-ried out in the temperature range of 473° to 1223°K, the composition range of erbium to ErH,, and the pressure range of 10-5 to 760 Torr. Solubility relationships were established from these data throughout the system. Three solid-solution phases were delineated: metal solid solution, dihydride phase, and trihydride phase. The trihydride Phase decomposes at about 656°K and 1 atm pressure. The dihydride phase is stable to about 1023°K, but becomes more deficient in hydrogen above this temperature. The equilibrium decomposition pressure-temperature relationships in the two-phase regions, erbium solid solution plus dihydride and dihydride plus trihydride, were deter- The differential heats of reaction in these two regions are AH = - 52.6 * 0.3 and - 19.8 i 0.2 kcal per mole of Hz, respectively. The differential entropies of reaction are AS = - 35.2 * 0.3 and - 30.1 * 0.4 cal per mole HZ.deg, respectively. Relative partial molal and integral thermodynamic quuntities were calculated in the system to the dihydride phase. RARE earth metal-hydrogen systems have been the subject of general survey,1"4 and all have been found to form hydride phases. The heavy rare earths, of which erbium is a member, form dihydride and trihydride phases with different crystal structures, whereas the light rare earths form only a single-phase dihydride which expands without structure change, as hydrogen is added, to the trihydride composition. These materials are of interest primarily because of their theoretical properties, such as bonding, defect structure, and thermodynamic and electronic characteristics. Erbium has been studied in several previous investigations.5, 6 It was deemed desirable to more thoroughly and accurately define the system, both for the phase equilibria and the thermodynamic properties. I) EXPERIMENTAL PROCEDURE A Sieverts&apos; apparatus was employed to conduct the experimental measurements. Briefly, it consisted of a source of pure hydrogen, a precision gas-measuring buret, a heated reaction chamber, a mercury manometer, and two McLeod gages (a CVC, GM 100A and CVC, GM 110). Pure hydrogen was obtained by passing hydrogen through a heated Pd-Ag thimble. The hydrogen was analyzed and found to have only a trace of oxygen and nitrogen. A 100-ml precision gas buret graduated to 0.1-ml divisions was used to measure and admit hydrogen to the reaction chamber. The reaction unit consisted of a quartz tube surrounded by a nichrome-wound furnace. The furnace temperature was controlled by a recorder-controller to ±1°K. An independent measurement of the sample temperature in the quartz tube was made by means of a chromel-alumel thermocouple situated outside, but adjacent to, the quartz tube near the specimen. Pressure in the manometer range was measured to ±0.5 Torr and in the McLeod range (10-4 to 10 Torr) to ±3 pct. The hydrogen compositions in erbium were calculated in terms of hydrogen-to-erbium atomic ratio. These compositions were estimated to be ±0.01 H/Er. The erbium metal was obtained from the Lunex Co. in the form of sponge. The metal was nuclear grade with a purity of 99.9 pct +. The oxygen content was reported to be 340 ppm and the nitrogen not detectable. Metallographically the structure was almost free of second phase (<1 vol pct). A quantity of sponge was arc-melted for use as charge material. The solid material was compared with the sponge in the pressure-temperature-composition relationships. They were found to be identical. Therefore, sponge material was used henceforth, so that equilibrium could be attained more rapidly. The specimen size was about 0.2 grain for each loading of the reaction chamber. The procedure employed to obtain the pressure-temperature-composition data was to develop experimentally a family of isothermal curves of composition vs pressure. First, a specimen of erbium was wrapped in a tungsten foil capsule to prevent contact with the quartz tube. After loading the specimen, the system was evacuated to less than l0-6 Torr, flushed several times with high-purity hydrogen, and evacuated again ready for the start of the experiment. The furnace was then brought to the desired temperature. A measured amount of hydrogen was admitted into the chamber. Equilibrium was allowed to be attained, the pressure read, and the process then repeated many times until 1 atm of gas pressure was finally reached. Other isotherms were then developed in the same manner. The partial pressure plateaus were determined by another manner. In the solid solution-dihydride region a composition of approximately 1.0 H/Er was selected on the plateau. The temperature was varied throughout the range of interest. At each temperature level, equilibrium was achieved, the pressure read, and the next temperature attained. The temperature was cycled both up and down. In the dihydride-trihy-dride region, the plateaus were determined in the 473" to 651°K range only by heating to the desired temperature and not by both heating and cooling. The data were much more reproducible in this manner. Equilibrium required long periods of time. Specimens were initially hydrided to 2.8 H/Er, so that at the higher

Jan 1, 1969

By Samuel Taylor

IT is customary for the president of an engineering society, in his annual address, to describe either some engineering problem with which he has beer connected or to review the work of the society during his administration. My first thought, this being the sesquicentennial year of our nation, was to review the advance in coal mining for the past fifty years, during which period I have been more or less intimately con-nected with the bituminous coal industry, and have personally witnessed most of the great changes which have occurred in methods and machinery used in the production of coal, but preparation of the requisite address would take more time than could be spared to prepare it, and its presentation would consume so much time that it .would not be suitable. The new arrangement providing for giving the presi-dent&apos;s address at the business meeting makes it more .appropriate to review the work of the Institute during the past year, together with some suggestions which appeal to me as being of advantage to the future wel-fare of the Institute, which I will try to do briefly. The work of the business office has been reviewed in the Secretary&apos;s report and it will not be necessary for me to dwell on it. Suffice it to say, it seems to be going along very well. Additional work could be done which would be to the advantage of the Institute, if we had the money with which to defray the necessary ex-pense incident to it, but I will refer to this again later. I would be derelict if I did not refer to the splendid work of the Secretary and the Assistant Secretary. Keeping in touch with all the sections, which number now about 26, and affiliated student societies which number 40, besides special committees, and represent-ing the Institute on various boards, provides work enough to occupy the Secretary&apos;s time almost exclu-sively. In addition to this the Secretary and the As-sistant Secretary have the work of editing and publishing the TRANSACTIONS of the Institute; the issuing of the magazine, MINING AND METALLURGY, in the splendid manner in which it goes out to the mem-bership is no light task and I think they should receive the commendation of the membership for this work.

Jan 3, 1927

By W. C. Knopf, I. M. LeBaron

In the Carlsbad area potash is dry-mined and wet-concentrated. Wet concentration involves recircu-lation of saturated brines, with resultant difficulties of brine disposal and inherent losses in recovery through solution of the KCl. A dry beneficiation process for potash minerals would offer many advantages over present methods. International Minerals & Chemical Corp. has been working on development of a dry process for some time. This article is a progress report. Potash ores available in this country are largely mixtures of halite and sylvite contaminated with slimes and often with many sulfate and magnesium minerals. Electrostatic concentration of KCl when the contaminating minerals are in low percentage has been accomplished. Continuous production of better than 60 pct K2O concentrate from high potassium sulfate ores has not been demonstrated at the present time. Laboratory Procedure: Laboratory work on electrostatic beneficiation of potash minerals has been carried out using both pure crystals and mined ore. Electrostatic separation of the two main components of potash ore, sylvite (KCl) and halite (NaCl), is accomplished by first heat-treating the ore to allow for electric charging of the particles. Preferential exchange of&apos; electrical charges between different mineral particles through surface contact is the principal mechanism involved. After proper conditioning of the particle surfaces, the oppositely charged minerals are dropped vertically into a horizontal electric field having a field gradient from about 5000 to 15,000 v per in. The particles are free-falling in the field. A suitable power supply is used to produce the proper total voltage for the electric field. Total required voltage is, of course, a function of electrode spacing. A typical electrode arrangement with power supply is shown in Fig. 1. In general, the total voltage on any system is 75,000 to 90,000 v. Power consumption is negligible, as leakage at insulators and corona discharge are the main losses in the system. Optimum preheat temperatures for pure material components generally are not the same as for mined minerals. Fig. 2 shows clearly that maximum recovery on a 50 pct pure KCl, 50 pct pure NaCl mixture occurs at a preheat temperature of about 600°F. In this test the preheat mixture was allowed to cool to about 225°F before dropping through the electric field. The optimum temperature for sep- aration is practically never the optimum temperature of preheat. Optimum separation for mined Carlsbad potash ores occurs when a preheat temperature closer to 900°F is used, as shown by Fig. 3, which plots percent sylvite (KCl) in the concentrate and tails as a function of preheat temperatures. Here again the ore was allowed to cool to about 225°F before separation. It should be noted that efficiency of separation increases continuously with increasing preheat temperatures until incipient fusion of the ore takes place at about 950°F. The increase in optimum preheat temperature for Carlsbad ores over the pure minerals can be traced to the effect of the clay slimes intimately associated with the mined potash. If the slimes associated with the ore are removed by washing with alcohol or other non-aqueous material, the necessity of preheating to the high temperature is removed. This temperature range has been proved critical within these limits during continuous pilot plant operation. Concentrate and tailings grade and optimum recovery also are functions of the temperature of the potash mineral particles during separation in the electric field. Fig. 4 presents data indicating that feed to the rougher pass should range between 150°F and 275°F for best results. It has been found by subsequent pilot plant work that these temperatures can be maintained in actual operation.

Jan 1, 1959

By George Comstock

Results are given of scleroscope and Brinell tests on specimens of cast 10-per cent. aluminum bronze, quenched and reheated at various low temperatures. The scleroscope was not found as reliable as the Brinell machine for measuring the hardness, for the size of the piece tested seemed to affect the scleroscope results. The maximum hardness was obtained by quenching and reheating to between 315° and 370° C. Softening was produced by reheating above 370° or 400° C. A series of polished and etched microsections showed a more reddish color in those that had been reheated above 400° C., and a change in microstructure above 500° C. IT HAS been known for many years that the alloy containing 90 per cent. copper and 10 per cent. aluminum can be hardened, like steel, by quenching from a suitable temperature, and that the hardened alloy can be softened again by annealing or drawing the temper. It does not seem to be generally appreciated, however, that the effect of the first slight reheating after quenching is actually increased hardness, the softening effect not taking place until a certain temperature of "drawing" has been exceeded. This paper gives the results of a few experiments on various specimens of cast 10-per cent. aluminum bronze, quenched for maximum hardness, and subsequently annealed at different temperatures. The hardness measurements were made with both a scleroscope and a standard Swedish Brinell machine; some peculiarities of the scleroscope test on this material are described. The author is not aware of many previous investigations of the hardness of this alloy when quenched and drawn, but two important papers on the subject should be mentioned. The earliest was by Portevin and Arnou,1 in which it was stated that tempering quenched 10-per cent. aluminum bronze at 400° C. increased the hardness as compared with the quenched untempered alloy and that reheating above that temperature was necessary to obtain any softening effect.

Jan 7, 1924

By W. I. Duvall, D. E. Stephenson. Discussion by R. G. K. Morrison

R.G.K. Morrison (Chairman, Dept. of Mining Engineering and Applied Geophysics, McGill University, Montreal, Que. Canada) - The authors have introduced a subject, the intensive study of which has awaited scientific developments. These are now such as to justify a thorough review of our thinking on the causes and control of rockbursts. The formulae developed in the paper, the comparison between rockbursts and earthquakes in figure 1 and the energy data relating to explosives serve as an effective foundation. In the paper this writer is quoted as suggesting that energy of the order of 10 x 10 11 ft. lb. may have been released in some of the heaviest rockbursts in the Kolar Gold Field. He now hastens to add that such an estimate has no scientific validity. It arises only from a casual comparison of surface and underground effects of the medium heavy bursts, referred to in the paper and estimated by Jones at 3.0 x 1010 ft.lbs., with those of obviously greater magnitude. In any case, we have the estimate by Jones above, that by a team of seismologists 1 on the Witwatersrand of 10 x 1010 ft.lbs., that by Coates of 3.8 x 10" ft.lbs., also referred to in the paper, that by Blan-chard2 for the catastrophic rockburst at Springhill, N.S., of only 7.4 X 107 ft. lbs., and finally the range covered by Cook, referred to in the paper. It is probable also that data for the heavy rockburst at Merkers3 in the WERRA potash area of Germany are available as it was recorded on seismographs from Moscow to Spain. It is the writer&apos;s impression that some standardization is present in the estimates above for 10 x 10 10, 3.8 x 1010 and 7.4 x 107 ft.lbs., respectively. The latter, for Springhill, represents a relatively low order of magnitude. It is obvious that any energy estimate must be related to the local geometry of openings at the time of the event. It is also obvious that any explanation of the causes of rockburst must be capable of providing a wide range of energy. However, we must remember that the energy release is an effect indicating magnitude. The cause lies with the mechanism initiating the primary failure, generating the seismic activity, to which much of the damage is probably due.

Jan 1, 1967

By C. L. Siebenthal

C. E. SIEBENTHAL, ? Washington, D. C.-From being one of the most maligned of metals-a veritable bugaboo-cadmium has almost overnight become respectable, though its slender claim to respectability rests almost wholly on the possibility of its substitution for tin. Preliminary to any campaign for such substitution, particularly for enforced substitution, the possible supply of cadmium should he determined as closely as possible; for that reason the statistical inquiry of which this paper embodies the results was undertaken. Production Cadmium is marketed in two forms, as metallic cadmium, in sticks or bars, and as cadmium sulfide, the pigment. The metal has found its greatest field of use in this country as a component of an easily fusible alloy that is used in automatic fire extinguishers. The sulfide is .used to some extent in paints but chiefly to give color and luster to glass and porcelain. The metal was first made in this country by the Grasselli Chemical

Jan 12, 1918

By Thomas Watson

INTRODUCTION THE users of barite in the United States derive their supply partly from the domestic production and partly from the imports from foreign countries. According to the Mineral Resource division of the U. S. Geological Survey, the domestic production of barite in 1913 was 45,298 short tons, valued at $156,275, or $3.45 a ton, and the imports of crude barite were 35,840 short tons, valued at $61,409, or $1.71 a ton. These figures clearly show a decided advantage in cost of the foreign over the domestic barite to users in the United States. The difference in cost is the only advantage to the consumer of foreign barite, for there are large reserves of the mineral in the United States of good grade. The production of many of the operating mines is capable of decided increase, and it is believed that the operating mines together with the large reserves of undeveloped deposits of barite are entirely adequate to meet the demands of the users in the United States. Deposits of barite are known in California, Idaho, Nevada, and Alaska, but most of them are undeveloped because there is, apparently, no market for the .material in that region. The domestic production is derived from Missouri and the Appalachian States, the greater part being obtained from Missouri. Following the outbreak of war in Europe many users of foreign barite in the United States have been forced to seek their supplies at home. It seems opportune at this time, therefore, that a general review be given of the barite industry in the Appalachian States, one of the two areas from which the domestic supply of the mineral is derived, and that attention be directed to the undeveloped deposits in the region. Briefly, then, this paper reviews the barite industry in the Appalachian States, and describes the occurrence, preparation, and uses of the mineral.

Jan 2, 1915

By O. B. Bucklen, P. G. Meikle

INTRODUCTION The trend in the coal industry for many years has been to make every- thing "bigger and faster." This also held true for loading and storage facilities. Where once a million ton per year mine was rare, three to five million ton per year mines are not uncommon today in the bituminous industry. This greatly increased production, made possible through mechanization, required greatly improved loading facilities just to get the coal away from the mine. Also, there is a trend toward combining production from more than one mine and cleaning it in a single preparation plant. In addition to increased loading capacity, this frequently necessitates raw coal storage and blending facilities. The development of the unit train with its attendant economics, more than any other factor, has contributed to the widespread construction of storage and high-speed loading facilities. In the export market, the construction of ever larger coal colliers has contributed to a need for faster and larger loading facilities. In this climate of rapidly changing technology, any written account is faced with the possibility of obsolescence before its appearance. Thus, this chapter seeks to define the common and current practice in coal loading and storage facilities with the full knowledge that this practice is an ever-moving target. FUNDAMENTALS OF COAL STORAGE Storage of coal is becoming an increasingly important part of coal handling systems at mines, particularly since the advent of the unit train concept in transportation. In order to take advantage of reduced transportation rates on trainload shipments of coal offered by unit train movement, operators have found that storage is an economic necessity. In unit train practice large predetermined quantities must be loaded in relatively short periods of time as opposed to conventional practice where coal is loaded at a speed dependent on the production capacity of the mine and/or the cleaning capacity of the preparation plant. Two surveys of storage practices at mines reveal several objectives for storage.1, 2 Raw and/or clean coal storage is generally practiced in order to accomplish one, or a combination, of the following objectives: 1. To improve plant efficiency by distributing plant feed over the entire operating time, or to allow a preparation rate different from the production rate. 2. To limit interruptions of supply, ie, allow mine and plant to function independently with delays in one not affecting the operation of the other.

Jan 1, 1968

By G. F. Loughlin

Nearly 55 years have elapsed since the U. S. Geological Survey was organized. During this period the mineral industries have grown from infancy or early childhood to well developed maturity, and some mining industries appear to be declining. Decline in mining is even more conspicuous in certain districts, or even states, than in any mining industry as a whole, and discoveries or developments of important new districts have been very few in recent years. Our reserves of most metals and nonmetals are adequate for many years of normal production, subject to changes in rate of exploitation that may be caused by foreign competition and by changes in technology and market conditions; but the declining production of many districts and the scarcity of important new discoveries to compensate for them is cause for some apprehension. It is likely that future production will depend to a considerable extent on deep exploration and on the thorough examination of places in and adjoining existing districts where significant outcrops are lacking and only apparently insignificant geologic features offer encouraging clues—more so than on the discovery of entirely new districts. Even the possible discovery of new districts, which have escaped the intensive search by the nontechnical prospector, must be dependent on geologic information. There is therefore no need for argument as to the value of geology to the mining industry; and the need of continuing to advance the science. The U. S. Geological Survey&apos;s past contributions to mining geology, as expressed in its official reports and other publications, are recognized by Ransome in his historical review of mining geology in the Lindgren volume.&apos; These contributions have helped to form the basis of modern mining geology, which has grown rapidly in the last 25 years. This growth has witnessed the organization and maintenance of geologic staffs by mining companies in several districts, and their detailed work, together with the fact that nearly all of the larger mining districts have

Jan 1, 1935