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By Phillip E. Butler

The Pennsylvania Dept. of Transportation is actively engaged in the utilization of coal mine refuse in the construction of highway embankments. Long-held objections for utilization are invalidated by research, laboratory data, and construction performance. Laboratory, engineering, construction, and environmental impact analyses are presented from the construction of the Cross Valley Expressway embankment at Forty Fort, Luzerne County, Pa. Comparisons of laboratory data and construction measurements are given. The refuse embankment is the first of its size in Pennsylvania, and possibly the U. S., covering 1.5 million cu yd.

Jan 1, 1977

By John Wulff, J. H. Hollomon

THE opinion has been widely held that the corrosion of alpha brass occurs by the selective solution of zinc. As late as 1939, Fink1 and Evans2 suggested that in the initial stage of the corrosion the selective solution of zinc produces copper-rich areas, which subsequently act as cathodes that facilitate the deposition of copper. Previously Abrams3 had shown that most of the copper found on corroded brass was redeposited and not residual, although he did not consider the nature of the initiation of the corrosion process. Enough data exist to indicate that any metal surface is sufliciently heterogeneous to provide the anodes and cathodes necessary for the initiation of corrosion .4,5 Thus, for alpha brass we need postulate not an initial selective solution of zinc, but only the existence of local differences in electrochemical potential. The heterogeneity responsible for potential differences may arise from oxide and other films as well as from alloy concentration gradients. Even though selective corrosion may be possible in some alloy systems, previous data on alpha brass as well as the experimental work reported in this paper do not require this supposition. Bengough and May,6 in a discussion of Abrams' paper, first suggested the addition of small amounts of arsenic (0.03 per cent) to alpha brass to prevent the redeposition of copper (dezincification). This suggestion was later substantiated by Nixon.7 In their studies of the inhibiting influence of arsenic, Evans and Fink were led to the selective-solution hypothesis in order to explain the initial corrosion of such alloys. "I hey believed that an arsenic film covered anode areas and prevented the formation of copper-rich spots capable of acting as cathodes for the deposition of copper. They (lid not consider, however, the mechanism by which the arsenical film was formed. Bengough and May,8 in another publication, suggested that the commonly found gray or black arsenical film may act to: (1) carry oxygen to the brass surface, (2) increase the discharge potential of copper on brass, (3) precipitate cuprous chloride from colloidal suspension in chloride solutions. Masing9 assumed that the film found upon arsenical brass was metallic arsenic. His measurements of hydrogen overvoltage of bulk arsenic led hint to believe that the inhibition of dezincification occurs because the overvoltage of a brass surface is lowered by the arsenic film. He reasoned that this film would permit the more rapid reduction of hydrogen at the cathode, which would prevent the redeposition of copper. In a recent paper,10 we have pointed out that the film formed (luring the corrosion of arsenical brass and copper in stagnant solutions is essentially arsenious oxide (AS208)

Jan 1, 1942

By E. Hoek

The stability of a rock structure depends primarily upon the extent to which fracture develops within the structure, The prediction of the extent of potential fracture, the first step in the study of fracture development, involves a knowledge of both the stress distribution in the structure and the criterion which governs rock fracture under various stress conditions. While a great deal of research effort has been devoted to the development of techniques for analyzing the stresses in mining and civil engineering structures1-3 and to the investigation of the fracture mechanism of rock 4-6 relatively little attention has been paid to the application of available knowledge to the solution of practical engineering problems. This paper describes a photoelastic technique for the determination of potential fracture zones in certain types of rock structures. A practical example, based upon a problem which might be encountered in designing the layout of deep-level mine excavations, is given as an illustration of the application of this technique. STRESS ANALYSIS AND ROCK FRACTURE In deciding upon the technique to be used for the solution of a problem involving the prediction of rock fracture it is necessary to consider: 1) What type of stress information is required to satisfy the fracture criterion for rock; anti 2) How this information can most conveniently be obtained. It has been established, both theoretically 4,7 and experimentally 5,6,8that the fracture of hard rock depends primarily upon the relationship between the algebraically greatest and the algebraically smallest of the

Jan 1, 1967

By Kenneth B. Ray, George R. Gardner

The application of wet cleaning processes for the beneficiation of bituminous coal has created in some localities a problem in the recovery and disposal of fine solids in the washery water. The maximum allowable concentration of these solids in the washery circuit that is consistent with satisfactory operation of the cleaning units remains a controversial point. It has, however, been generally recognized for a number of years that some degree of control should be exerted over the concentration of such material. Early methods of control involved intermittent or continuous discharge of a portion of the plant slurry into near-by streams or settling ponds, and this persisted even after the adoption of settling tanks or cones. The practice is not always economical, for two reasons: first, because of the waste of coal, and, second, because it is sometimes difficult and expensive to obtain an adequate supply of water. The latter condition often is aggravated by chemical treatment of the make-up water that is necessary to prevent excessive corrosion of plant equipment. The modern approach to this problem has been the adoption of continuous thickening devices. However, because such equipment occupies considerable plant space and is somewhat expensive to construct, the practice of loading these thickeners beyond their rated capacity is widespread, therefore often the performance of such units is not altogether satisfactory. In recent years, European washeries have increased the rate of settling of the fine coal from the slurry by the addition of specially prepared starch solutions. These reagents cause flocculation of the solid particles and thereby increase the rate of sedimentation. The first important work on the flocculation and clarification of coal slurry was done by Henry, who developed the Henry process and used it successfully in Belgian preparation plants. Soon after the initiation in Belgium, the process was introduced into England, where subsequent, investigation developed similar processes, which were successfully used in

Jan 1, 1939

By George R. Gardner, Kenneth B. Ray

The application of wet cleaning processes for the beneficiation of bituminous coal has created in some localities a problem in the recovery and disposal of fine solids in the washery water. The maximum allowable concentration of these solids in the washery circuit that is consistent with satisfactory operation of the cleaning units remains a controversial point. It has, however, been generally recognized for a number of years that some degree of control should be exerted over the concentration of such material. Early methods of control involved intermittent or continuous discharge of a portion of the plant slurry into near-by streams or settling ponds, and this persisted even after the adoption of settling tanks or cones. The practice is not always economical, for two reasons: first, because of the waste of coal, and, second, because it is sometimes difficult and expensive to obtain an adequate supply of water. The latter condition often is aggravated by chemical treatment of the make-up water that is necessary to prevent excessive corrosion of plant equipment. The modern approach to this problem has been the adoption of continuous thickening devices. However, because such equipment occupies considerable plant space and is somewhat expensive to construct, the practice of loading these thickeners beyond their rated capacity is widespread, therefore often the performance of such units is not altogether satisfactory. In recent years, European washeries have increased the rate of settling of the fine coal from the slurry by the addition of specially prepared starch solutions. These reagents cause flocculation of the solid particles and thereby increase the rate of sedimentation. The first important work on the flocculation and clarification of coal slurry was done by Henry, who developed the Henry process and used it successfully in Belgian preparation plants. Soon after the initiation in Belgium, the process was introduced into England, where subsequent, investigation developed similar processes, which were successfully used in

Jan 1, 1939

By R. M. Larsen

The Rocky Mountain region is defined with some variations for different purposes or by different organizations. For oil and gas development, Wyoming, Montana, Colorado, northwestern New Mexico, and Utah are included in the order of their apparent importance. Portions of adjoining states, such as North and South Dakota, Nebraska, Arizona, Nevada, and Idaho, arc attributary to this region, but have little or no oil or gas production. Nebraska and New Mexico are considered separately (see pp. 412 and 415), and most of the discussion in this report will be confined to Colorado, Montana, and Wyoming. Utah has produced about 200,000 bbl. of oil from the San Juan and Virgin fields, which are isolated and shut in at present. The Clay Basin field in northeastern Utah produces natural gas and distillate, and the Farnham field in central Utah produces carbon dioxide gas. Other Utah areas of some interest are listed in Table I. The Cedar Creek (Baker-Glendive) field in southeastern Montana extends into North Dakota, but is listed under Montana. The other states are in the main wildcat areas, and exploration in 1944 was at a minimum. However, geological and geophysical parties are reviewing them for further testing. Oil production in Colorado, Montana and Wyoming was 459,000 bbl. more than in 1943. Increases of 713,000 bbl. in Colarado and 731,000 bbl. in Montana offset a loss of 985,000 bbl. in Wyoming. This was the first decline in Wyoming since 1938. Field production figures and state totals are given in Table I. Total drilling activities in these three states and Utah increased from 687 wells making 1,442,511 ft. of hole in 1943 to 916 wells making 2,245,803 it. in 1944. Wildcat drilling increased from 163 wells making 331,193 ft. of hole in 1943 to 171 wells making 389,144 it. in 1944. These figures include all drilling wells making footage, not starts or completions, and represent an all-time high in drilling. The year 1944 witnessed the greatest concentration of seismograph activity that the region has had. The Rocky Mountain Oil Scouts Association reported that in 1943, the previous peak year, 91 crew months of work were performed; in 1944, the time was 254 crew months. About 67 per cent of the work was in Wyoming, 18 per cent in Montana, and 12 per cent in Colorado. Twenty-three blocks totaling 400,000 acres were reported assembled in Colorado, and 161 blocks totaling 4,000,000 acres in Wyoming. Information about other states was not given. Fourteen unit agreements were approved by the Department of the Interior, as compared with 13 in 1943. The 1944 agreements were all in Wyoming. In five of the unit areas, oil or gas discoveries were made, four were dry, and five were drilling Or pending' Oil companies find it advantageous to unitize blocks containing any proportion of public domain. Units for

Jan 1, 1945

NEW MEMBERS The following list comprises the names of those persons who became members during the period of July 10, 1917, to Aug. 10, 1917. ARNOT, STANLEY L., Engr., Plymouth Cons. Gold Mines; Ltd., Plymouth, Amador Co .2 Cal. BARRETT, LESLIE PARK, Asst. Geol.... Michigan Geological Survey, Lansing, Mich. BENNIE, JOHN WILLIS Gen'l. Mgr., Shannon Copper Co., Clifton, Ariz. BRINTON, OWEN FUGATE Mgr., Admiralty Zinc Co., Quapaw, Okla. BRODERMANN, JORGE, Civil Engr., Compania Minera San Francisco, Havana,Cuba. BROWN, RICHARD HENRY JR., Sales Engr., Ingersoll Rand Co., 300 N. Broadway, St. Louis, Mo. BROWN, STANLEY Chile Exploration Co., Chuquicamata, Chile. BUDDECKE, WILLIAM A Pres., Point Milling & Mfg., Co. Mineral Point, Mo. BURGESS, GEORGE K., Physicist and Chief, Division of Metallurgy, Bureau of Standards, Washington, D. C.

Jan 9, 1917

By Timothy Collins

There was once a speculative period of interest in small mining companies that is commonly referred to as "the uranium boom of the 50's." In the late 60's, there was a second mining stock boom: it centered around uranium and silver, when silver had reached a new high of $3.60. In the mid 1970Js, there may be a new boom in the making, and it appears that substantial public and institutional interest in mining equities will finally result in a viable long-term capital market rather than the boom-or-bust pattern of the 50's and 60's. The reason for Wall Street's renewed interest in mining is understandable: most mineral commodities have recently gone up in price. Domestically, these price increases have come in the wake of the inflationary spiral unleashed by years of unbridled government deficit spending and erratic fiscal and monetary policies. Internationally, of course, the biggest push for higher prices has come from third-world countries whose primary income derives from indigenous natural resources. Many of these countries-whose fiscal and monetary policies haven't been models of excellence either-have attempted to cope with the worldwide economic mess by forming cartels that could control the price of commodities. What's happened to petroleum is well-known; what's happened to copper, bauxite, phosphate, and uranium is part and parcel of the same syndrome.

Jan 9, 1975

By G. D. Van Ardsdale, A. W. Hudson

Heap leaching, as practiced at Rio Tinto, Spain, while one of the oldest, and probably one of the cheapest, methods of extracting copper from its ores, has not had, until recently, other than experimental application in this country. This has been due partly to a mistaken idea that the Rio Tinto ores possess some obscure and mysterious quality that renders them alone suitable to the process, partly to the fact that tests properly made meant the expenditure of large sums of money and several years time, and partly to the fact that favorable commercial and other conditions are not often found. This paper gives some views on the chemistry and mechanism of the method, an account of the preliminary experiments, and the final plans adopted for a large-scale installation of the method by the Phelps Dodge Corpn. for treating low-grade ore from Sacramento Hill, Bisbee. If results comparable with those obtained from the test heap are to be had from the large plant, this plant will operate on the lowest-grade sulfide ore now being treated commercially in the country. The method has several advantages: The installation cost is low. Interest charges must, of course, be made both on the cost of the ore delivered to the plant and for the plant itself, but as these are low, there is considerable advantage in the ability to regulate output by more or less complete shutdowns in accordance with market and other conditions. The amount of labor needed is small, and the cement copper produced may be considered nearer a finished product than the sulfide concentrates from a mill, and certainly means less installation cost per ton to put into final form by present methods. At Bisbee, conditions were favorable for a trial of the method for, in the preparation of the Sacramento Hill orebody for steam shoveling,' a large amount of material below concentrating grade had to be moved to

Jan 1, 1923

By A. W. Hudson, G. D. Van Ardsdale

Heap leaching, as practiced at Rio Tinto, Spain, while one of the oldest, and probably one of the cheapest, methods of extracting copper from its ores, has not had, until recently, other than experimental application in this country. This has been due partly to a mistaken idea that the Rio Tinto ores possess some obscure and mysterious quality that renders them alone suitable to the process, partly to the fact that tests properly made meant the expenditure of large sums of money and several years time, and partly to the fact that favorable commercial and other conditions are not often found. This paper gives some views on the chemistry and mechanism of the method, an account of the preliminary experiments, and the final plans adopted for a large-scale installation of the method by the Phelps Dodge Corpn. for treating low-grade ore from Sacramento Hill, Bisbee. If results comparable with those obtained from the test heap are to be had from the large plant, this plant will operate on the lowest-grade sulfide ore now being treated commercially in the country. The method has several advantages: The installation cost is low. Interest charges must, of course, be made both on the cost of the ore delivered to the plant and for the plant itself, but as these are low, there is considerable advantage in the ability to regulate output by more or less complete shutdowns in accordance with market and other conditions. The amount of labor needed is small, and the cement copper produced may be considered nearer a finished product than the sulfide concentrates from a mill, and certainly means less installation cost per ton to put into final form by present methods. At Bisbee, conditions were favorable for a trial of the method for, in the preparation of the Sacramento Hill orebody for steam shoveling,' a large amount of material below concentrating grade had to be moved to

Jan 1, 1923

By P. R. Swann, J. G. Parr

Quenched structures were studied in alloys containing up to 12.5 pct cobalt. The subsequent decomposition of a 10 pct cobalt retained-ß phase alloy was investigated using metallographic and X-ray diffraction methods. Hardness measurements also were made during the decomposition process. Precipitation of Ti2Co is by nucleation and growth; and an activation energy of 50,000 cal per mole was determined. The values of the coefficient ß suggest that the precipitate is pearlitic at temperatures between 450 and 475°C, and spheroidal between 500 and 525°C. THIS paper describes part of a series of invesligations into phase transformations in binary alloys of titanium with transition elements. The general approach is similar to that taken in work on titanium-iron and titanium-nickel alloys.' Previous investigators'' have established the titanium-rich end of the titanium-cobalt phase diagram, reproduced in Fig. 1. Orrell and Fontana' showed that alloys containing more than about 6 pct" cobalt quenched from the ß range, produced 100 pcl retained-p phase. The isothermal decomposition of alloys containing between 0.8 pct Co and 15.5 pct CO was investigated by the same workers in the temperature range 650 to 1000°C. They reported that these alloys transformed into a or Ti,Co depending on the cobalt content, but no quantitative data were given. In the work to be described a series of alloys containing 0.8 pct Co to 12.5 pct Co was examined in the quenched condition. The 10 pct Co alloy (the lowest cobalt content to retain 100 pct ß on quenching) was selected for further work on the tempering kinetics of the ß decomposition. Experimental Procedure Since our own melting equipment was not installed at the outset of this work, the Physical Metallurgy Division of the Department of Mines and Technical Surveys (Ottawa, Canada) prepared the alloys. These were made of Japanese sponge, (which when melted had a value of 103 DPH, using a 1-kg load), and electrolytically prepared cobalt. The al- loys, made up to contain 0.8, 1.6, 3.3, 5.8, 8.3, 10.0 and 12.5 pct Co, were homogenized by swaging into rods at 900°C. Filings were taken from the rods, and any iron chips from the file were separated magnetically. Size fractions of both plus and minus 200 mesh (about 75p) were shown by their constitution, after annealing just below the eutectoid temperature, to contain the same cobalt content. Consequently, it was permissible to use the —200-mesh fraction, knowing it to be representative of the rod composition. Quenching in argon was carried out in a newly designed furnace, whose features include (1) an Inconel furnace tube, (2) a positive pressure of argon maintained at all times in the furnace—even when a sample is removed or inserted. The furnace is shown in Fig. 2 and is described in the Appendix. The tempering processes were carried out on powder samples sealed in evacuated quartz capsules. Since the highest tempering temperature was 525OC, no protection against reaction with the quartz was necessary. (Tests were made on filings of iodide titanium and showed no hardness increase after equivalent heat-treatments.) A thermocouple was attached to the capsule, which was heated to the

Jan 1, 1959

By S. Chander

A review of the published literature on the mechanism of depression of sulfide minerals shows that a unified theory is not yet available. Various mechanisms that have been postulated include competition between depressants and collectors to adsorb at the surface sites, creation of thermodynamic conditions nonconducive for formation of a metal collector salt, or formation of a hydrophilic coating on the surface. The hydrophilic coating may or may not effect the adsorption of collectors. In another mechanism, the depressant may participate directly in oxidation/reduction reactions between collectors and sulfide minerals. Examples from the literature highlight oxidation/reduction effects in the depression of sulfide minerals.

Jan 1, 1986

By J. W. Rutter, K. T. Aust

Observations are presented of the formation of annealing twins during the growth of a recrystallized grain into a striated, melt-grown crystal of high-purity lead. The formation of an annealing twin resulted in replacement of the original migrating boundary by a large-angle grain boundary of the caincidence-site type or by a near-twin boundary. The results support the Fullman-Fisher theory of annealing twins and demonstrate the usefulness of the coincidence-site model. FULLMAN and Fisher1 have advanced the following theory to account for the formation of annealing twins during grain growth. Whenever a grain A grows into a matrix of grains S1 and S2, a twin A' of grain A may form, as shown in Fig. 1, if the following energetic condition is satisfied: where "E" and "a" refer to the specific interfacial free energy and the area, respectively, of the boundaries indicated by the subscripts. In effect, the twinned grain will persist when the energy of the boundary between the twin(A') and the matrix grain (S, or S,) is less than that of the boundary between the original growing grain (A) and the matrix grain by an amount which exceeds the energy of the coherent twin boundary between A and A'. Experimental observations on the changes in grain boundary free energy accompanying the formation of twins1 are in agreement with the theory outlined in Eq.[l]. Direct observations of the formation of annealing twins at moving grain corners1"3 and the depend-

Jan 1, 1961

By E. J. Schmitz

Coming from San Antonio, Texas, and following the Galveston, Harrisburg and San Antonio Railroad westwards, one enters soon the Cretaceous formation, which forms a belt of several hundred miles, extending westwards to the boundary of Arizona and across the Rio Grande into the State of Coahuila, Mexico. The members of this formation are very numerous and in petrographical character very diverse—from a whitish or bluish, slaty, impure limestone to a hard, beautiful blue-and-red striped, and a compact heavy-bedded,

Jan 1, 1885

By Frederick J. McGarry, Fred Moavenzadeh

An experimental investigation of the thermal and mechanical responses of rock materials to laser radiation is described. Specifically, the following three topics have been studied in detail: 1. Temperature measurements on thin discs subjected to laser radiation. 2. Strain measurements on thin discs subjected to laser radiation. 3. Observation and evaluation of cracking and spalling phenomena in constrained and unconstrained thin discs respectively, subjected to laser radiation. In conjunction with the experimental work done, use was made of a heat flow analysis and a stress analysis program developed for this purpose. It was possible to theoretically predict the thermal and mechanical responses of a rock specimen to laser radiation and then compare them with experimental observations. Good correlations were obtained.

Jan 1, 1971

Jan 1, 1928

By Michael P. Richardson

INTRODUCTION This paper is intended to be a summation of the state-of-the-art i n draw theory and draw- point spacing. Knowledge of this very important factor in the successful design and operation of a block caving mine is scarce and nonconclusive. It is hoped that the presentation of this paper will stimulate interest and discussion which will lead to a stronger understanding of these a1 1 important factors. Please note that block caving as used here- in refers to block, panel, and mass caving systems in general, not just to the specific system of block caving where discrete blocks of ore are prepared and caved as a unit. DRAW THEORY The knowledge of draw theory as related to the practice of block caving mines is, unfortunately, very limited. In recent years much work in draw theory has been done in respect to sublevel caving systems and an understanding of draw mechanics relating to sublevel caving seems to be emerging. This work is certainly helpful to those of us interested in block caving but the question of "what goes on up above" still hounds us since we are more interested in the region of draw which begins just above the area where sublevel caving interest ends. Herein is presented a brief summary of draw theory with an attempt to look at the factors which can help our understanding of the area of draw influence in block caving mines. Nature of Gravity Flow An understanding of the flow of granular material (rock, sand, grain, or prill as examples) is the first step toward understanding block caving draw. If we take a supported column of granular material and allow gravity flow through an aperture at the bottom of the column, an ellipsoidal shaped zone of disturbance of the in-place material will form and grow with extraction of material through the aperture. The volume of this zone of disturbance or loosening is about 15 times the volume of material extracted at any given time (Kvapil, 1980). Figure 1 shows the development over time of the zone of disturbance. The ellipsoid of disturbance represents a future ellipsoid of extraction which will equate to the volume of materia1 extracted by that future time. Extraction involves the movement of the particles located vertically over the drawhole directly downward while material outside this direct vertical volume moves radially inward and down toward the drawpoint as shown in Figure 2a. Figure 2b shows the result of this motion on originally horizontal strata within the ore column. Increased draw increases the eccentricity of the ellipsoidal volume or, in other words, the ratio of the height over the width of the disturbed area increases as ore is withdrawn from the column (Kvapil , 1980). This becomes important to block caving since eventually a vertical cylinder of draw will be approximated as this ratio increases without bounds. Figure 3 shows this result. The width of this draw cylinder is a critical dimension for the determination of draw point spacing in relationship to block caving mine design. McCormick (1968) for one, felt that within this cylinder of draw, mass flow would take place. This is the

Jan 1, 1981

By Robert L. Bates

On April 2 and 3, 1970, more than 100 geologists attended the Sixth Annual Forum on Geology of Industrial Minerals at Ann Arbor, Mich. After this brief appearance, the Forum apparently ceased to exist- but it didn't really, and another spring will see it again in action, in another corner of the country. The organization might be characterized as the country's largest permanent floating conference on the geology of industrial minerals. What is the Forum, where did it come from, and what is it up to? The idea originated in 1964 with a small group in the Department of Geology at Ohio State University, Columbus. This group felt that a forum was needed for the exchange of geologic information on industrial rocks and minerals. They envisioned an approach-which has subsequently been adhered to--that would be dominated neither by geological academics interested in theoretical problems nor by practical engineers concerned with processing large tonnages of rock. It was proposed to focus attention on the middle part of the spectrum, especially on practical problems of geological occurrence and how these problems affect extraction and use. In terms of the standard rock-products flow sheet, which starts with a truck unloading into the primary crusher beneath the words 'from quarry,' it was proposed to focus geological attention on what is beyond the primary crusher, out in the quarry.

Jan 1, 1970

By Franz R. Dykstra, R. F. Tatnall

A ferroalloy is defined as: "An alloy of iron with some element other than carbon used as a vehicle for introducing such an element into the manufacture of steel. The element may alloy with the steel by solution or, as the carbide, -neutralize the harmful impurities, by combining with them and separating from the steel as flux or slag before solidification."a The most commonly used ferroalloys are: ferromanganese, ferrochrome, ferrosilicon, ferrovanadium, ferromolybdenum, ferronickel, ferrotungsten, ferrocolumbium, and ferrophosphorus. Concern here is with the sources and markets of the major metallic alloying elements. The discussion is further restricted to those - ferroalloy ores, the principal use of which is in the production of steel. Phosphorus, silicon, and tungsten, for example, are ferroalloys of some economic significance, but other uses dwarf their alloying applications. Thus, this discussion will deal with the ores of managanese, chromium, nickel, molybdenum, vanadium, and columbium. As shown in Table 14.1B.1 ferroalloys serve to- facilitate processing and impart to the finished steel such characteristics as tensile strength, ductility, low-temperature impact, hardenability, high-temperature strength, corrosion resistance, toughness, and abrasion resistance. In the steel-making process, ferroalloys may be added in the charge, in the molten bath near the end of the finishing period, in the ladle, or in the molds. Timing of the addition depends on the effect of the addition on the temperature of the molten metal, the formation and elimination of reaction products, and the protection of subsequent additions from oxidation. MANGANESE General Approximately 95% of the manganese ore sold is consumed by the steel industry, either as ferromanganese or as manganese metal. Manganese is the universal alloy, without which good steel cannot be made. It serves as a scavenger, removing phosphorus, sulfur and, to a degree, oxygen from the melt. As an alloying material it makes steel hard, tough, and resistant to wear. Approximately 6 kg of manganese is required for every ton of common steel produced by United States steelmaking practice. The remaining 5 % of the manganese ore consumed consists of special or so-called "chemical" ores, including high-grade pyrolusite ores, electrochemically reactive "battery ores," and a number of special varieties, as well as those otherwise regarded as "metallurgical ores."

Jan 1, 1976

By Rizo-Pairón Alfonso, A. M. Gaudin

PREVIOUS studies of activation in flotation have directed attention to the action of the activator on the mineral to be floated rather than to the relationship of the activator to the collector The latter phase of the problem, however, seems to have definite scientific, if not also practical, interest In the investigation reported in this paper, experiments were carried out, largely with quartz as subject, barium as activator, and oleate as collector The results obtained indicate that a I I ratio of collector ion to activator ion gives optimum results, and that a 2 I ratio almost fails to achieve activation and flotation Yet, a 2 I ratio would have been expected on stoichiometric grounds, had the coating been a normal salt of the activator ion with the collector ion, since barium is a divalent cation and oleate a monovalent anion To interpret and rationalize the observations, considerations of the crystal chemistry of quartz are helpful The point of view to which these considerations lead may be of general applicability to systems involving suspensions of solids in liquids, they confirm that an adsorbed coating is inescapable APPARATUS AND SUPPLIES The experimental work consisted in barium-ion abstraction tests, hydrogen-ion and hydroxyl-ion abstraction tests, flotation tests, and determinations of the surface of the crushed quartz The flotation machine was built according to the design of D W McGlashan It consists of a drill press in which the bit has been replaced by a stainless-steel impellor surrounding a stainless-steel stator, as in the Fagergren laboratory machine The air intake is controlled by a valve, and the cell consists of a beaker The quartz was obtained from vein quartz stored in large chunks It was first crushed to 20 mesh, then sized on a 28-mesh screen The 20 to 28-mesh size alone was retained for use This size was freed of coarse iron by passage through a Ball-Norton magnetic separator, bleached with boiling hydrochloric acid to remove residual abraded iron, washed with distilled water until the washings were thoroughly free of ferrous, ferric, and excess hydrogen ion, and stored in covered Pyrex beakers under water until used The barium was used as barium chloride, Baker's analyzed C P The oleate was used as sodium oleate It was prepared from sodium hydroxide, Baker's analyzed C P , and oleic acid purified by R R de Arellano3 in the laboratories at the Massachusetts Institute of Technology The purification procedure was elaborated from the recent researches of Brown and Shinowara 2 It consisted in (I) saponification of olive oil with potassium

Jan 1, 1942