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By Robert T. Oxnard

"EXECUTIVE SUMMARYThe history of Refractory Recycling indicates there was little recycling until the 1950s. Energy incentives were the primary reason for the beginnings of a recycling effort by the refractory brick manufacturers. Quality benefits quickly became evident and fewer rejects were the result. Today, economic factors including higher valued raw materials and increased competition are the driving forces of refractory recycling.There are some success stories in refractory recycling but we have a long way to go. Few incentives, quality concerns, relatively cheap energy, comparatively lax government regulations, inexpensive landfills and inexpensive substitutes make recycling a difficult choice for many companies. Marketing advantages such as ISO 14000, eliminating multiple audits and reduced liability exposure can tip the scales toward recycling viability. Increasingly, the ideological philosophy of a company, a desire to minimize environmental impact and develop favorable public and other interested party perceptions can drive recycling and waste minimization efforts.Recycled materials can be more trouble ""up front"" and harder to ""manage"" due to their suspect quality. However, due to their nearly inexhaustible supply and the fact that once developed, they constantly contribute to the bottom line, they are certain to be the materials of the future. Waste refractory materials will likely see the same bright future as the steel scrap yards and slag piles of yesterday. In hindsight, we will realize that now was the perfect time to prepare and plan for the bright future of refractory recycling."

Jan 1, 2000

By Deepak Malhotra

INTORDUCTION Mining operations are unique In that they handle large volumes of water (millions of gallons) daily. The water contains dissolved metals, processing chemicals, organics, and other contaminants, There are several sources of water contamination at mine sites: mines, mills, tailings ponds, and Industrial/utility complexes. Utility waste water generally represents a very small portion of the total process water utilized in a normal milling operation and hence will not be addressed in this paper. Mine drainage can represent a significant amount, thus having an Impact on the recovery of metals, especially In Industrial minerals operations, and may have to be treated separately. The National Pollutant Discharge Elimination System (NPDES) effluent limits are becoming more stringent, thereby requiring mining operations to treat process water prior to discharge to the environment. The general trend Is to move toward a closed-loop waste system and treat only that small fraction of process water which Is to be discharged to public lands. The following section discusses the reasons for waste water treatment and the existing and emerging technologies for meeting NPDES effluent limits. REASONS FOR WATER TREATMENT Due to the diverse nature of the mineral Industry, process/waste water contamination problems as well as processing flowsheets are site specific. However, certain generalizations can be made specific to processing of different minerals: • Acid mine drainage Is a problem at sulfide/coal mines. • Cyanide contamination of water Is a problem at gold processing plants. • Organics can be a problem at mines using flotation oils. • Tolling ponds are generally acidic at sites processing industrial minerals such as silica sand and feldspar. The cost for water treatment Is viewed as an added cost of production. Hence, large mines are moving toward dedicating personnel to management of water resources in order to minimize waste water for treatment. Very often, mines having closed-loop water systems will treat waste water for reasons other than meeting NPDES regulations. These Include situations where process requirements dictate use of high-quality water for separation of minerals, neutralization of acid mine drainage water, and portable water for the mill. WATER TREATMENT TECHNOLOGIES Water treatment process has to be cheap and simple because It has to process large volume, and It does not directly add to the bottom line, namely revenue. The water treatment process development has to be site specific because the contaminants In the water vary from site to site. and discharge limits for water vary from state to state. The current technologies for wastewater treatment have been divided Into the following three areas: • Removal of heavy metals • Cyanide destruction • Scale control A brief summary of the current technology In each area Is discussed below. Removal of Heavy Metals The physical and chemical processes for heavy metal removal are summarized in Table 1. The most common and cheapest approach has been the precipitation of hydroxides at high pH followed by sedimentation and thickening of solids. The remaining solids can be removed by filtration. The pH is adjusted back to neutral, and the water Is discharged. This process is most commonly used wastewater treatment technology in the mining industry. The basic processes can be modified by combining other operations in order to meet the objectives of the specific site as illustrated In the following examples: • AMAX's Mt. Emmons treatment facility uses Lectro Clear® process where the precipitated solids are removed by electroflotation. • AMAX's Climax Mine water treatment plant used Ion exchange columns to meet the discharge limits on molybdenum.

Jan 1, 1992

By E. S. Grumell

The correct sampling of coal and coke is becoming important to an ever increasing number of producers and consumers. This, therefore, may be an opportune moment to examine where we stand with regard to existing and proposed methods. In this paper an attempt will be made to review, as briefly as possible, some of the considerable amount of painstaking research which has been done in the last 10 years, and which has unquestionably led to a much better understanding of the subject. In so doing we shall try, on the one hand, to make clear where substantial progress has been made, and on the other hand, to draw attention to points that require further investigation. The paper is divided into sections in order to emphasize the major divisions of the subject; further, in order to retain this emphasis, detailed consideration of some of the points has been relegated to appendixes. No attempt has been made to give a complete survey of the literature, as this has already been done by L. A. Bushell.2 The following abbreviations will be used: A.E., average error; P.E., probable error; S.W.R., size-weight ratio; B.S.I., British Standards Institution. Section 1.—Cost It has often been stated that the cost of sampling should bear some relationship to the value of the product, and since coal is a relatively cheap raw material it would be a major error to specify, for ordinary commercial purposes, elaborate and costly methods of sampling which nobody would adopt. Specifications must be of such a nature that they will be used. We believe that one of the achievements of the last 10 years has been to reduce the cost of sampling. There is, however, another point to be considered; via., that the cost of sampling should bear some relationship to the value of the investigation. Correct sampling is a cog (possibly a small one) in the wheel

Jan 1, 1940

By E. S. Grumell

The correct sampling of coal and coke is becoming important to an ever increasing number of producers and consumers. This, therefore, may be an opportune moment to examine where we stand with regard to existing and proposed methods. In this paper an attempt will be made to review, as briefly as possible, some of the considerable amount of painstaking research which has been done in the last 10 years, and which has unquestionably led to a much better understanding of the subject. In so doing we shall try, on the one hand, to make clear where substantial progress has been made, and on the other hand, to draw attention to points that require further investigation. The paper is divided into sections in order to emphasize the major divisions of the subject; further, in order to retain this emphasis, detailed consideration of some of the points has been relegated to appendixes. No attempt has been made to give a complete survey of the literature, as this has already been done by L. A. Bushell.2 The following abbreviations will be used: A.E., average error; P.E., probable error; S.W.R., size-weight ratio; B.S.I., British Standards Institution. Section 1.—Cost It has often been stated that the cost of sampling should bear some relationship to the value of the product, and since coal is a relatively cheap raw material it would be a major error to specify, for ordinary commercial purposes, elaborate and costly methods of sampling which nobody would adopt. Specifications must be of such a nature that they will be used. We believe that one of the achievements of the last 10 years has been to reduce the cost of sampling. There is, however, another point to be considered; via., that the cost of sampling should bear some relationship to the value of the investigation. Correct sampling is a cog (possibly a small one) in the wheel

Jan 1, 1940

By J. H. Nead, J. W. Halley

The new low-alloy high-strength steels are obviously here to stay. With 75 per cent higher yield strength and 50 per cent higher tensile strength than plain carbon structural steel, they permit 20 to 40 per cent weight savings and 10 per cent or more increase in pay load in the construction of railroad cars, buses, trucks, and a great variety of material-handling equipment. Their cost is low enough so that the extra cost of the new lighter construction over that with carbon steel offers an attractive self-liquidating investment; in some instances new construction with these low-alloy steels may even be as cheap as with plain carbon steel. A considerable and rapidly growing demand for the low-alloy steels has already sprung up. The many steel compositions that have appeared on the market lately18, 27, 28, 29, 30 to meet this demand would seem to indicate that no single composition is uniquely fitted for the purpose. However, no doubt some compositions are more suitable than others. The purpose of this study was, therefore, to compare the effects of the various alloying elements that might be used in the low-alloy steels in order to choose the metallurgically most logical composition, paying due regard, of course, to the economic aspects involved. Properties Desired in Low-alloy Steel A distinction between the new low-alloy steels and the common alloy steels is that the latter are generally used in the heat-treated (that is, quenched and tempered) conditions, whereas the new low-alloy steels are not only not heat-treated but are not susceptible to heat-treatment in the ordinary sense of the term. In this lies one of their chief advantages. Their properties can be obtained in the as-rolled, air-cooled, or annealed condition, just as with mild plain carbon structural steel. There is no need for heat-treating. Such steels can be readily formed hot or cold, and their properties are not appreciably changed by hot

Jan 1, 1936

By J. H. Nead, J. W. Halley

The new low-alloy high-strength steels are obviously here to stay. With 75 per cent higher yield strength and 50 per cent higher tensile strength than plain carbon structural steel, they permit 20 to 40 per cent weight savings and 10 per cent or more increase in pay load in the construction of railroad cars, buses, trucks, and a great variety of material-handling equipment. Their cost is low enough so that the extra cost of the new lighter construction over that with carbon steel offers an attractive self-liquidating investment; in some instances new construction with these low-alloy steels may even be as cheap as with plain carbon steel. A considerable and rapidly growing demand for the low-alloy steels has already sprung up. The many steel compositions that have appeared on the market lately18, 27, 28, 29, 30 to meet this demand would seem to indicate that no single composition is uniquely fitted for the purpose. However, no doubt some compositions are more suitable than others. The purpose of this study was, therefore, to compare the effects of the various alloying elements that might be used in the low-alloy steels in order to choose the metallurgically most logical composition, paying due regard, of course, to the economic aspects involved. Properties Desired in Low-alloy Steel A distinction between the new low-alloy steels and the common alloy steels is that the latter are generally used in the heat-treated (that is, quenched and tempered) conditions, whereas the new low-alloy steels are not only not heat-treated but are not susceptible to heat-treatment in the ordinary sense of the term. In this lies one of their chief advantages. Their properties can be obtained in the as-rolled, air-cooled, or annealed condition, just as with mild plain carbon structural steel. There is no need for heat-treating. Such steels can be readily formed hot or cold, and their properties are not appreciably changed by hot

Jan 1, 1936

By T. B. Counselman

AfteR several years study, the Universal Atlas Cement Co. decided to rebuild its plant at Leeds, Alabama. The entire old plant, which was to operate during the new construction, was then to be scrapped with the exception of two kilns. The quarry was to be mechanized, new and larger kilns installed, with the most modern type of equipment all through the plant. Raw grinding operations at all of the Universal Atlas plants were dry. However, the dust hazard of this operation and the growing emphasis on occupational diseases made wet grinding attractive. Coal at Leeds is cheap, so that a slightly higher coal practice was unimportant. Power was cheap, so that waste-heat boilers were not desirable. Since new kilns were to be installed, these could be made long enough to make filters unnecessary. Wet raw grinding could be either the old practice of open-circuit compartment mills or closed-circuit grinding in accordance with metal-lurgical practice. The latter saved power and steel wear and saved initial investment. This had been demonstrated in cement plants. Also, the elimination of tramp oversize was a most important advantage. Ease of chemical control was another factor. Blending in the thickener, with elimination of slurry mixers had been found practicable. Therefore, if wet raw grinding were used at all, the advantages were clearly in favor of closed-circuit grinding. Detailed layouts of the most modern possible closed-circuit dry-grinding plant and of a closed-circuit wet-grinding plant were prepared, and careful estimates were made of initial investment and operating costs. Full consideration of all the factors involved resulted in a decision to install wet closed-circuit grinding. The capacity of the new kilns was established at 4000 bbl. per day. Two new kilns were installed, each with a capacity of 80 bbl. per hour. Since 625 lb. of raw material is required to make a barrel of finished cement, the capacity of the grinding plant for the new kilns had to average only 1250 tons per day. Sufficient additional grinding capacity had to be provided for the two remaining old kilns, or their possible replacement by a third new kiln. The grinding rate, therefore, was set at 90 tons per

Jan 1, 1939

By T. B. Counselman

AfteR several years study, the Universal Atlas Cement Co. decided to rebuild its plant at Leeds, Alabama. The entire old plant, which was to operate during the new construction, was then to be scrapped with the exception of two kilns. The quarry was to be mechanized, new and larger kilns installed, with the most modern type of equipment all through the plant. Raw grinding operations at all of the Universal Atlas plants were dry. However, the dust hazard of this operation and the growing emphasis on occupational diseases made wet grinding attractive. Coal at Leeds is cheap, so that a slightly higher coal practice was unimportant. Power was cheap, so that waste-heat boilers were not desirable. Since new kilns were to be installed, these could be made long enough to make filters unnecessary. Wet raw grinding could be either the old practice of open-circuit compartment mills or closed-circuit grinding in accordance with metal-lurgical practice. The latter saved power and steel wear and saved initial investment. This had been demonstrated in cement plants. Also, the elimination of tramp oversize was a most important advantage. Ease of chemical control was another factor. Blending in the thickener, with elimination of slurry mixers had been found practicable. Therefore, if wet raw grinding were used at all, the advantages were clearly in favor of closed-circuit grinding. Detailed layouts of the most modern possible closed-circuit dry-grinding plant and of a closed-circuit wet-grinding plant were prepared, and careful estimates were made of initial investment and operating costs. Full consideration of all the factors involved resulted in a decision to install wet closed-circuit grinding. The capacity of the new kilns was established at 4000 bbl. per day. Two new kilns were installed, each with a capacity of 80 bbl. per hour. Since 625 lb. of raw material is required to make a barrel of finished cement, the capacity of the grinding plant for the new kilns had to average only 1250 tons per day. Sufficient additional grinding capacity had to be provided for the two remaining old kilns, or their possible replacement by a third new kiln. The grinding rate, therefore, was set at 90 tons per

Jan 1, 1939

By H. A. Doerner, F. D. DeVaney, J.B. Clemmer

Production of magnesium metal in the United States during the past decade has increased from less than 600,000 lb. in 1928 to more than 4,800,000 lb. in 1938.1 The growing industry has stimulated interest in methods of production and in sources of raw material. All of the present domestic production is from brines. However, the availability of large tonnages of magnesite in the state of Washington, together with the possibility of cheap power, have created interest in the utilization of magnesite for the production of magnesium metal as well as for other purposes. Magnesite, the carbonate of magnesium (MgCO3), usually is associated with limestone (CaC03) and dolomite (MgCO3. CaC03). It occurs in crystalline and microcrystalline (sometimes termed amorphous) forms.2 The more common crystalline mineral is found in various shades of white, gray, yellow and brown, the colors being due to impurities, chiefly iron. Magnesite has a hardness of 3.5 to 4.5 and a specific gravity of 3.0 to 3.1. It forms rhombohedra1 crystals in the hexagonal system, having a vitreous, pearly luster. The quarries and mines of the Northwest Magnesite Co. near Chewelah, Wash., are large producers of magnesite for refractories. The deposits are extensive, some veins being hundreds of feet wide. The boundaries of the veins are indefinite, and the magnesite is interfingered with dolomite. Calcite, talc, serpentine, quartz and shale are disseminated through the deposits. The quality of the ore cannot be determined by appearance or by simple tests; chemical analysis is required. These features make it difficult to determine the boundaries or total quantity of workable ore.3 Only the higher-grade ores are mined, and a considerable proportion of the magnesite content is discarded by hand-sorting and log-washing methods. After calcining, the sorted product meets the specifications for usual refractory material, as it contains approximately 81 per cent MgO, 7 per cent SiO2, 6 per cent CaO and 6 per cent Fe203 + A1203. A sample of the reject material had the following analysis after calcining: 65.4 per cent MgO, 6.3 CaO, 21.1 SiO2 and 6.5 R2O3. The percentage reported as R2O3 includes compounds whose chlorides are acid-soluble but give precipitates in ammoniacal solution that are ignited and weighed. The more common constituents are Fe2O3, A1203 and TiO2. The sorted magnesite product is not the best grade. even for refractory purposes, and leaves much to be desired for a reduction process. The rejected material contains a large proportion of magnesite. It is apparent that an effective concentration method would yield a higher recovery and a better product. In general, the refractory grade is not suitably pure for other uses. Recent developments in the production of

Jan 1, 1943

By J. B. Clemmer, F. D. DeVaney, H. A. Doerner

Production of magnesium metal in the United States during the past decade has increased from less than 600,000 lb. in 1928 to more than 4,800,000 lb. in 1938.1 The growing industry has stimulated interest in methods of production and in sources of raw material. All of the present domestic production is from brines. However, the availability of large tonnages of magnesite in the state of Washington, together with the possibility of cheap power, have created interest in the utilization of magnesite for the production of magnesium metal as well as for other purposes. Magnesite, the carbonate of magnesium (MgCO3), usually is associated with limestone (CaC03) and dolomite (MgCO3. CaC03). It occurs in crystalline and microcrystalline (sometimes termed amorphous) forms.2 The more common crystalline mineral is found in various shades of white, gray, yellow and brown, the colors being due to impurities, chiefly iron. Magnesite has a hardness of 3.5 to 4.5 and a specific gravity of 3.0 to 3.1. It forms rhombohedra1 crystals in the hexagonal system, having a vitreous, pearly luster. The quarries and mines of the Northwest Magnesite Co. near Chewelah, Wash., are large producers of magnesite for refractories. The deposits are extensive, some veins being hundreds of feet wide. The boundaries of the veins are indefinite, and the magnesite is interfingered with dolomite. Calcite, talc, serpentine, quartz and shale are disseminated through the deposits. The quality of the ore cannot be determined by appearance or by simple tests; chemical analysis is required. These features make it difficult to determine the boundaries or total quantity of workable ore.3 Only the higher-grade ores are mined, and a considerable proportion of the magnesite content is discarded by hand-sorting and log-washing methods. After calcining, the sorted product meets the specifications for usual refractory material, as it contains approximately 81 per cent MgO, 7 per cent SiO2, 6 per cent CaO and 6 per cent Fe203 + A1203. A sample of the reject material had the following analysis after calcining: 65.4 per cent MgO, 6.3 CaO, 21.1 SiO2 and 6.5 R2O3. The percentage reported as R2O3 includes compounds whose chlorides are acid-soluble but give precipitates in ammoniacal solution that are ignited and weighed. The more common constituents are Fe2O3, A1203 and TiO2. The sorted magnesite product is not the best grade. even for refractory purposes, and leaves much to be desired for a reduction process. The rejected material contains a large proportion of magnesite. It is apparent that an effective concentration method would yield a higher recovery and a better product. In general, the refractory grade is not suitably pure for other uses. Recent developments in the production of

Jan 1, 1943

By Francis H. Crockard

During the past five years we have probably witnessed greater technological advances than in any similar period. Industry and science have steadily marched ahead. The makers of iron and steel products have watched with great interest the development of streamlined trains, faster and safer airplanes, the entirely new science of air-conditioning and the widespread use of stainless steels. Since 1930, we have witnessed the erection of the world's largest suspension bridge, the largest and fastest ocean liner and the spectacular Boulder Dam, while even greater things are planned in these particular fields. Other industries, too, have been moving ahead rapidly. This advance in a few years has been caused primarily by the fierce competition of the depression. Now, more than ever, is the emphasis placed upon quality and service. Makers of southern merchant pig iron have been no exception and have been confronted with increasingly strict chemical specifications and with much greater stress on physical characteristics than ever before. For example, sulfur in the iron must be held very low, competition demanding that it be in the 0.020's and low 0.030's; silicon content must be held within a very narrow range, and definite requirements of phosphorus and manganese are an essential part of the specifications. Physical characteristics are becoming of increasingly greater importance. The introduction of triple-skimmed, slow-cooled iron several years ago was the first step in this direction. Now there are a few customers who buy iron by chemical analysis and physical appearance, having found that the analysis alone is an insufficient guide to their requirements. In addition to questions of quality, the subject of cost has greatly altered the southern furnaceman's viewpoint on many things. Formerly we had low-grade but cheap raw materials, but recent developments, such as greatly increased labor rates, have raised the cost of the same

Jan 1, 1936

By Francis H. Crockard

During the past five years we have probably witnessed greater technological advances than in any similar period. Industry and science have steadily marched ahead. The makers of iron and steel products have watched with great interest the development of streamlined trains, faster and safer airplanes, the entirely new science of air-conditioning and the widespread use of stainless steels. Since 1930, we have witnessed the erection of the world's largest suspension bridge, the largest and fastest ocean liner and the spectacular Boulder Dam, while even greater things are planned in these particular fields. Other industries, too, have been moving ahead rapidly. This advance in a few years has been caused primarily by the fierce competition of the depression. Now, more than ever, is the emphasis placed upon quality and service. Makers of southern merchant pig iron have been no exception and have been confronted with increasingly strict chemical specifications and with much greater stress on physical characteristics than ever before. For example, sulfur in the iron must be held very low, competition demanding that it be in the 0.020's and low 0.030's; silicon content must be held within a very narrow range, and definite requirements of phosphorus and manganese are an essential part of the specifications. Physical characteristics are becoming of increasingly greater importance. The introduction of triple-skimmed, slow-cooled iron several years ago was the first step in this direction. Now there are a few customers who buy iron by chemical analysis and physical appearance, having found that the analysis alone is an insufficient guide to their requirements. In addition to questions of quality, the subject of cost has greatly altered the southern furnaceman's viewpoint on many things. Formerly we had low-grade but cheap raw materials, but recent developments, such as greatly increased labor rates, have raised the cost of the same

Jan 1, 1936

By J. Rogers. K. L. Sutherland, E. E. Wark, I. W. Wark

Soaps have hem used as collectors for many years, but only in the last eight years have other long-chain paraffin salts been used. It may be anticipated that these newer collectors will be used mainly with nonsulphide minerals, for which the xan-thates and similar compounds are of little value. On the other hand, the xanthates are both cheap and effective for sulphide ores and seem likely to retain their present cminence in this field. During 1938 and 1939 two of us (E. E. W. and I. W. W.) commenced a comprehensive investigation of the principles underlying the use of paraffin chain salts as flotation reagents. This research was sponsored jointly by the University of Melbourne and a group of Australian mining companies. † A broad, semiquantitative survey was then made of the field covered in the present paper. This was followed in 1940 by further work by one of us (K. L. S.). In 1941 the investigation was taken over by the Division of Industrial Chemistry of the Commonwealth Council for Scientific and Industrial Research, Australia. Discovery of some principles upon which are based the flotation of minerals by paraffin chain salts was followed by their application in the development of processes for the recovery of certain strategic minerals from their ores. Promising results in the flotation of cassiterite from various ores will be described in a subsequent paper. The Paraffin Chain Salts 'he basic requirements for a "collector " in flotation are that it should form a film over the surface of the mineral to be floated, and that this film should be orientated so that hydrocarbon (nonpolar) groups form the effective surface. When modified in this way, the mineral surface possesses some degree of air avidity. All investigators would agree with Taggart, Taylor and Ince23 that such a film can be produced only if the collector compound contains an active (polar) group to attract it to the mineral surface as well as the nonpolar group. One section of this large class of polar-nonpolar compounds is the paraffin chain salts: CH3(CH2)nX where .X signifies a polar group that ionizes in aqueous solution. Though the compound can ionize, it may be a weak or a strong electrolyte, and the hydrocarbon chain may be in the cation or the anion (Table I). Many compounds of similar constitution are available, but the usual polar groups are: -Co2Na, -So3Na, -So4Na, — PO4Na2, or an aminonitrogen group, the

Jan 1, 1947

By E. E. Wark, I. W. Wark, J. Rogers. K. L. Sutherland

Soaps have hem used as collectors for many years, but only in the last eight years have other long-chain paraffin salts been used. It may be anticipated that these newer collectors will be used mainly with nonsulphide minerals, for which the xan-thates and similar compounds are of little value. On the other hand, the xanthates are both cheap and effective for sulphide ores and seem likely to retain their present cminence in this field. During 1938 and 1939 two of us (E. E. W. and I. W. W.) commenced a comprehensive investigation of the principles underlying the use of paraffin chain salts as flotation reagents. This research was sponsored jointly by the University of Melbourne and a group of Australian mining companies. † A broad, semiquantitative survey was then made of the field covered in the present paper. This was followed in 1940 by further work by one of us (K. L. S.). In 1941 the investigation was taken over by the Division of Industrial Chemistry of the Commonwealth Council for Scientific and Industrial Research, Australia. Discovery of some principles upon which are based the flotation of minerals by paraffin chain salts was followed by their application in the development of processes for the recovery of certain strategic minerals from their ores. Promising results in the flotation of cassiterite from various ores will be described in a subsequent paper. The Paraffin Chain Salts 'he basic requirements for a "collector " in flotation are that it should form a film over the surface of the mineral to be floated, and that this film should be orientated so that hydrocarbon (nonpolar) groups form the effective surface. When modified in this way, the mineral surface possesses some degree of air avidity. All investigators would agree with Taggart, Taylor and Ince23 that such a film can be produced only if the collector compound contains an active (polar) group to attract it to the mineral surface as well as the nonpolar group. One section of this large class of polar-nonpolar compounds is the paraffin chain salts: CH3(CH2)nX where .X signifies a polar group that ionizes in aqueous solution. Though the compound can ionize, it may be a weak or a strong electrolyte, and the hydrocarbon chain may be in the cation or the anion (Table I). Many compounds of similar constitution are available, but the usual polar groups are: -Co2Na, -So3Na, -So4Na, — PO4Na2, or an aminonitrogen group, the

Jan 1, 1947

In our sessions devoted to geophysical prospecting, the greater part of the time heretofore has been given to the presentation of theoretical subjects or highly technical details by specialists directly engaged in the development and perfection of the various methods. This was necessarily so, for we wanted such information available for the benefit of other workers and for our members who were anxious to gain a reliable understanding of the principles involved, to enable them to form an opinion of the adaptability of this new technique to their special problems. The methods have now been actively applied by many reliable organizations for several years and in this period there has been opportunity for operating mining men, engineers and geologists to appraise them. We therefore felt that it would be desirable at this meeting to give some time to interchange of opinion concerning results from actual cases. Consequently, the Committee on Geophysical Methods of Pros pecting sent out letters of inquiry to numerous mining people, asking for frank statements of opinion based on results from geophysical surveys at their properties. We have received many replies, among which 30 or more are of specific interest. On the whole, the point of view is remarkably uniform. Except for one or two who were, perhaps, a bit irritated, the operating men who have replied consider the methods to be capable of yielding valuable information when suitable conditions exist. Their attitude is definitely one of tolerance and of confidence in the integrity and sincerity of the outstanding workers. There is, however, a very general feeling that the chances of attaining positive and trustworthy results are small unless the work is directed by, or at least carried on with the close cooperation of, a geologist or mining man who is thoroughly familiar with the local geologic and mineralogic conditions and with the relations of the orebodies to rocks and structure. From certain comments, I am inclined to think that some operators are not greatly impressed with the cheapness of the work. Probably they are not attaching much weight to cost per acre, but are thinking primarily of total cost in terms of significant results obtained. It is

Jan 1, 1932

By P. B. Bucky

In previous publications1 it was shown that a scalar model of any weighty structure, where the stresses produced are mainly due to gravitational forces, will behave similarly to its prototype if the model and prototype material are the same and the model is placed in a centrifugal field of force (substituted for the gravitational field) which has been increased in the same proportion as the linear model scale is decreased. This principle is now being applied to a study of the behavior of mine structures in an attempt to determine the laws that control them. The importance of using models as a means of solving mining problems has been discussed previously, yet it may be well to reiterate here that this method of research and type of solution have been productive of far-reaching results in other engineering fields, notably those of hydraulics and aerodynamics. Model research is a comparatively cheap and time-saving method of checking practical experience. Up to the present time the best guide to what will happen underground has been the judgment of the man who has observed most and been longest acquainted with the local conditions. His experimental work underground is limited by the elements of cost, time and danger, while failure is seldom permissible. In a model, as in a test tube, all elements that affect the solution of a problem are under definite control. Each element may be varied independently at hill and its effects noted. Experimental work on a small-scale model may therefore be performed at a comparatively small expenditure of time and money, instead of on a full scale in the mine, where the cost, time, and danger elements are necessarily great. The experiments described in this paper are to be considered as part of a progress report and a continuation of Technical Paper 425. One object of the research program is to make each experiment point the way for further research on that particular phase of the general problem. The results and conclusions presented here are therefore not to be considered as final, but arc to be interpreted as

Jan 1, 1934

By E. J. Duggan

It is a coincidence that the two plants in this country for treating copper ores by ammonia leaching came into existence at almost the same time, that of the Kennecott Copper Corporation at Kennecott, Alaska, in March, 1916, and that of the Calumet & Hecla Mining Co. in July of the same year. The success of both from their very beginning attests the merits of the process under widely different sets of conditions. As would be expected, in the time they have been operating these two pioneers in this field have greatly perfected their methods and improved their technic. The early difficulties inevitably encountered in undertakings of this nature have been largely surmounted and the process may now be considered to be well seasoned and matured. There have been no other commercial plants built in this country and but one elsewhere, the Bwana M'Kubwa in Northern Rhodesia, for the reason that this method of treatment may be employed on comparatively few ores. However, it has certain advantages, some of which are inherent to sand leaching processes generally and some to ammonia leaching in particular. Among these may be enumerated: (1) the avoidance of fine grinding; (2) the small amount of water required; (4) a high-grade product; (5) little likelihood of deleterious gangue constituents and fouling of solutions. It is true that great progress has been made in recent years in the flotation of the ores that come within the province of ammonia leaching. Nevertheless ammonia leaching has its possibilities and these may be overlooked in the present tendency toward the use of flotation for all ores. Probably the chief requisite to its further extension to suitable ores will be a cheap source of steam. Ammonia, the only reagent required, is unlimited in supply, readily transported and the price that is likely to obtain in the future should not make its cost at all onerous. Choice of Method for Kennecott Ores The Kennecott ores are typical limestone replacement deposits. The milling ores have a copper content of approximately 8 per cent in a limestone dolomite gangue. About half the copper occurs as sulfide, mostly chalcocite with some covellite, and the remainder in the form of the two carbonates, malachite and azurite. A comparatively coarse grind followed

Jan 1, 1934

By H. E. Nold

High-volatile coals are most desirable for kiln firing. Low-volatile and even anthracite coals can be used successfully. Most periodic kilns use coal and are hand fired. A few stoker installations have been economically successful. Continuous tunnel kilns reduce fuel consumption 40 to 55 per cent. They are rapidly replacing periodic kilns in the manufacture of the finer wares. They have found great favor in the refractory industry and are successfully used in firing almost all kinds of heavy clay products. Fuel oil has found rather wide application in the Southwest and West. Natural gas is a satisfactory fuel for kiln firing. It is the principal competitor of coal and has largely replaced it for firing the finer wares but cannot compete with it in firing heavy clay products except in regions where cheap gas is available. Figures are given showing the relative thermal efficiency of coal and natural gas as used for firing ceramic ware. The ceramic industry uses from 12,000,000 to 12,500,-000 tons of coal per normal year. The principal use of coal is in firing the heavy clay products. This potential market amounts to about 9,250,000 tons per year. Coal producers could increase sales by furnishing expert firing instruction.

Jan 1, 1934

By J. M. Hassler

Nowhere can there be found a more misleading statement than the old one that "Iron can be manufactured cheaper in the South." During the past decade ironmakers and users of iron have heard varied and sundry stories of the wonderful resources of the Birmingham district, including abundant ore and coal fields, cheap labor, a wonderful climate and similar industrial Utopian statements. Birmingham represents the major portion of the iron business in the South, and as Birmingham fares so goes the iron business of the South. The intent of this paper is to shed some light on the actual conditions surrounding ironmaking in the South, especially in the Birmingham, or North Alabama, district. By a presentation of facts it is desired to point out that the "cheap iron" of the industrial South is a thing of the past, primarily because of increased labor cost and because labor is radically different in performance to what it was years ago. Also, because most of the raw materials needed in ironmaking that would be classed better than inferior are gone. Important Factors The several important factors that have been responsible for this change are : 1. Shrinkage of the iron business in the South. 2. Increased labor cost. 3. The development of the South, with an industrial trend, without a substantial increase of its own iron-consuming market. 4. Increased freight rates, which has narrowed the market that might be reached from this district. 5. Depletion of the better grades of raw materials, both ore and coal. Shrinkage of Iron Business in South.—Table 1 was prepared in early 1936 and revised in 1937, of blast-furnace units in the North Alabama district, considering the year 1936 compared with a maximum number of furnace units of previous years, the peak point being very near the year

Jan 1, 1937

By Barnabas Bryan

In the year 1875, the Pennsylvania Supreme Court, acting on incorrect information concerning the production of oil and gas, established what has become the law of the land for the governing of oil production. While the decision was ideal for the refining monopoly which was completed in that year, there is no evidence that the court was in any way influenced by that refining monopoly. The evidence indicates that the court accepted the view of the royalty owner and independent oil producer. Throughout the life of the refining monopoly it accepted this law, which was so evidently to its advantage in securing cheap raw material. The same policy continued until the development of the exhaustion theory and the entry of the various units of the former monopoly into the production of crude oil. It is curious that no one doubted the new theory of shortage sufficiently to feel the need of changing the law. When the theory entered the economic field sufficiently to raise crude oil prices beyond justification it shortly disproved itself, but by this time the question of split ownership in producing fields made a change from legal error to justice too complicated to be undertaken by the large companies. Not even the ardent advocate of unit operation dared to carry the question to the United States Supreme Court, which has never been asked to pass on the complete question. The impossible position of the producing industry, hemmed in on one side by court law compelling wasteful production and on the other by the national law against cooperation, lasted until the demoralization of 1927 led to cooperation within a state and under state guidance. Since that time control of production has grown with the bringing in of each new field and at this time has the active support of the Department of the Interior in such ways as are definitely legal. As in 1875, the royalty owner and independent producer are opposing by all possible means the rational conduct of the business of producing crude oil. Fluctuation in Investments The investor in oil securities has not been as badly fooled as has the oil man himself. Fig. 1 is designed to show the composite regard of all

Jan 1, 1930