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By Philip B. Bucky

THE Mining Methods sessions, one of which was run jointly with the Industrial Minerals Division, were fortunate in having a number of exceptionally fine papers. At the Tuesday session R. P. Smith presented the results of six years' experience with prepaid medical care for the employees of the Hollinger mine. It was felt that this paper was a real contribution to the cross field of mining-medicine, and the presentation was exceptionally well done. Olof V. Lindqvist acquainted us with the consider- able progress made in blast-hole diamond drilling in recent times, especially in Canada. The opening of a mine is always a matter of considerable interest and the description of the procedure and problems encountered in opening the Mather mine of Cleveland Cliffs Iron was presented by L. C. Moore.

Jan 1, 1944

By Dan Chun

Abstract-To facilitate the efficient handling of large volumes of information generated by logging exploration drill cores, a computer data bank system (GEOBANK) has been developed to store and retrieve the normally difficult to handle geologic information as well as the physical testing data. The data bank systematized the logging of drill core by first developing a standard list of adjectives or descriptors (with the corresponding assigned numerical codes) for the various stratigraphic categories that are also assigned numerical codes. The system uses the "floating-slot" concept and handles the data bank with one single input form.

Jan 9, 1978

By Gerald Sherman

MINE fires are always dangerous and are frequently accompanied by loss of life during the period of confusion which is apt to follow their discovery. In metal mines, fires may result from the accidental ignition of some combustible material, or they may be of spontaneous origin resulting from the rapid decomposition of sulphide. They occur frequently enough to demonstrate the need of some special equipment and a general plan for controlling them, in addition to measures for their prevention. Nearly all the large copper mines have had fires, and the methods of fighting them have been well described in recent papers, notably-by C. L. Berrien,1 R.. E. Tally,2 and others in discussion. The Copper Queen mine has many shafts, which are connected by underground workings. The deeper parts are ventilated by fans, but in the shallower portions natural ventilation through numerous connecting raises or shafts is sufficient. There have been several fires in the past few years, of which all are extinguished but one, and that is under control. These notes cover particularly the preparations that are being made-to check a new fire, partially or temporarily, and to facilitate the escape of workmen in the interval before a definite plan of fighting it can be established. A fire may occur in a shaft or station, or in some working father away. In case of fire in an upcast shaft, the gas would escape to the surface and the immediate result would probably not be dangerous to workmen, as they could escape by other shafts. In a downcast shaft, however, the gas would be distributed very rapidly throughout a large portion of the mine, and men might easily be trapped and asphyxiated. A fire in mine workings, drift, raise, or stope, would be dangerous in a degree, but the draft there is likely to be less strong than in a shaft and probably a smaller area would be invaded by the fire gases.

Jan 1, 1918

By Robert H. Richards

DuRing the winter of 1868-9,I was called upon by Professor F. H. Storer, to put up the Bunsen filter pump in the chemical laboratory of the Masschusetts Institute of Technology. As the laboratory is on the lower floor, it was found necessary to use a great deal of cumbrous pipe and apparatus to get the necessary column. It was then suggested that if an instrun~ent could be devised which would make use of the hydrant pressure in the service-pipe, it would do away with the objectionable features of the Bunsen pump. After using the Bunsen pump for some years, the jet pump to be described in this paper was devised, and it has since been adopted by Prof, Wing in the quantitative laboratory of the school. I am much indebted to Prof. Wing for his aid in starting the manufacture in brass of these jet pumps, whieh are now to be had in Boston. The jet pump much resembles the Giffard injector in form. It, differs from it in the fact that water is the impelling fluid, and air the impelled, while with the injector steam is used to impel water. The principle of condensation of steam, which is availed of in the injector, is entirely wanting in the jet pomp. The jet pump consists in a water jet, w, (see figure), a constriction or waist, a, and a waste tube, o. The success of the jet pump depends on the follow ing conditions: 1. The relation between the sizes of sectional area of a and w. ' 2. The proximity of n and w. 3. The form and angle of the two hollow cones whose vertices make the constriction a. 4. The relative size of sectional area of w and o. 5. The zigzags, or an equivalent means of making foam. In the following discussion, let a, w, and o repre sent the diameters of these parts of the jet pump. A number of experiments were' .tried to ascertain

Jan 1, 1879

By D. E. Munson, H. J. Sutherland

Surface subsidence caused by underground mining is described through complementary influence functions. The complementary functions developed here differ from the simple functions previously used in that the surface displacement is the result of the combined contributions of the mined and unmined zones. This eliminates computational difficulties experienced with the simple functions in determining the deflections above the rib side and in the eventual application of influence functions to complex room-and-pillar configurations. Although the analysis framework presented is intended for predicting subsidence over complex mine configurations, use of the complementary functions is illustrated adequately by application to a longwall panel of the Old Ben No. 24 coal mine.

Jan 1, 1982

By Alex G. Sciulli

This paper discusses the primary computer programs used by the Mine Safety and Health Administration's Bruceton Safety Technology Center to evaluate coal refuse disposal plans. These programs are currently being used by private consultants, government, and the coal industry for today's coal refuse disposal problems. This paper outlines five programs, their special features, and their importance in the design and construction of coal refuse disposal facilities. The purpose of the paper is to present the general steps necessary in the computer-modeling of each program. The programs that are discussed include BISHOP, STABL, RWE, DAMS2, and HEC-2, which cover the subject areas of slope stability, hydrographs, flood routing, and water surface profiles.

Jan 1, 1983

By Joseph G. Wargo

A meteoric rise in selling price has revived gold exploration activity throughout the world. In the United States the effort is, in large measure, channeled toward discovery of disseminated gold deposits such as the Carlin-type, i.e., with size and grade characteristics similar to Newmont's Carlin mine in Nevada. The subtle surface indications characteristic of Carlin-type gold mineralization have been examined by a number of geologists, and the more obvious prospects have been tested by surface sampling and drilling. It is likely that most of these readily recognizable deposits have already been found and, as a consequence, prospectors are now entering a new, second stage of exploration for Carlin-type and related disseminated gold deposits.

Jan 9, 1979

By A. L. Field

This general subject has been so thoroughly discussed by Dr. Herty and his associates, especially with regard to the degree of oxidation of the metal at the time that the silicon pig or spiegel is added, that I am not going to spend much time on that today. I should like to propound a question, which is based on my own observations made some years ago while with a large alloy-steel company which had two open-hearth furnace plants. It is true that one of these plants was not engaged particularly in making alloy steels, but there were certain relations between slag and metal composition which appeared to me to be entirely different in the two plants. I have an explanation for it that is more or less incomplete, but possibly Dr. Herty or Mr. Reinartz or some of the others may be able to complete it. Suppose we take our three layers; the metal on the bottom, on top of that the slag, and on top of the slag, the gas. We cannot overlook the gaseous phase. Regardless of the effect of the iron oxide in the slag on the rate of carbon elimination—and that, of course, is rather important in alloy practice since it is not desirable to have the carbon dropping too rapidly at the time the deoxidizing is had in the furnace—it will probably be admitted that it depends on the iron oxide in the metal for a given carbon oxide. I have seen cases where with approximately identical metal and slag compositions one furnace would work twice as rapidly as another in removing carbon. Of course, there is some explanation of this in what others have already said, that the question of the exact lime and silica content of the slag determines the activity and viscosity of the slag; but I am convinced, without having reviewed the actual records since I was asked to make this talk, because they were not available at the time, that the slags in these two furnaces were not materially different. Putting it another way, one furnace would have

Jan 1, 1935

By A. L. Field

This general subject has been so thoroughly discussed by Dr. Herty and his associates, especially with regard to the degree of oxidation of the metal at the time that the silicon pig or spiegel is added, that I am not going to spend much time on that today. I should like to propound a question, which is based on my own observations made some years ago while with a large alloy-steel company which had two open-hearth furnace plants. It is true that one of these plants was not engaged particularly in making alloy steels, but there were certain relations between slag and metal composition which appeared to me to be entirely different in the two plants. I have an explanation for it that is more or less incomplete, but possibly Dr. Herty or Mr. Reinartz or some of the others may be able to complete it. Suppose we take our three layers; the metal on the bottom, on top of that the slag, and on top of the slag, the gas. We cannot overlook the gaseous phase. Regardless of the effect of the iron oxide in the slag on the rate of carbon elimination—and that, of course, is rather important in alloy practice since it is not desirable to have the carbon dropping too rapidly at the time the deoxidizing is had in the furnace—it will probably be admitted that it depends on the iron oxide in the metal for a given carbon oxide. I have seen cases where with approximately identical metal and slag compositions one furnace would work twice as rapidly as another in removing carbon. Of course, there is some explanation of this in what others have already said, that the question of the exact lime and silica content of the slag determines the activity and viscosity of the slag; but I am convinced, without having reviewed the actual records since I was asked to make this talk, because they were not available at the time, that the slags in these two furnaces were not materially different. Putting it another way, one furnace would have

Jan 1, 1935

By H. H. Lowry

Science attracts the attention and interest of an individual or an industry in general only in proportion to the apparent direct application to its immediate welfare or benefit. Engineering accomplishments, as aphlied science, therefore receive more recognition than the scientific discoveries on which they are based. Even self-evident truth needs endless repetition before recognition: engineering as applied science cannot advance beyond the science on which it is founded. Scientific research, and discovery, is sometimes forced by the limitations recognized by those active in its development for the use of society and industry and sometimes results from an apparently superficially illogical curiosity about natural phenomena. Research has received inadequate support except in industries born in the laboratory, the chemical and electrical industries, from which many lessons might well be drawn by their elder associates. The rapid growth of these industries has been largely due to close cooperation of scientists and engineers. Most rapid advance is made when the research worker and the engineer keep in close touch with each other's ideas and problems. Many of the developments of modern industry are based on discoveries buried for years in scientific journals because the "time was not ripe" at their discovery. The situation with regard to utilization of coal is quite the oppositre. The fundamental facts in regard to the scientific aspects of the problem of developing the energy from coal are scarcely known. The engineer, without much scientific cooperation, has accomplished much in increasing the number of kilowatt-hours per pound of coal from 0.31 in 1919 to 0.69 in 1934, in increasing the 1000 gross ton-miles of freight hauled from 12.2 to 16.4 per ton of coal in the same period, in fuel economy in production of coke, and in developing the production of motor fuel in Germany and England by hydrogenation of coal. This lack of scientific research on the utilization of our most important natural resource, coal, has been due undoubtedly in large part to the reluctance of investigators to study the interrelationships involved in the complicated processes in which coal is used. These complexities are made

Jan 1, 1936

By H. H. Lowry

Science attracts the attention and interest of an individual or an industry in general only in proportion to the apparent direct application to its immediate welfare or benefit. Engineering accomplishments, as aphlied science, therefore receive more recognition than the scientific discoveries on which they are based. Even self-evident truth needs endless repetition before recognition: engineering as applied science cannot advance beyond the science on which it is founded. Scientific research, and discovery, is sometimes forced by the limitations recognized by those active in its development for the use of society and industry and sometimes results from an apparently superficially illogical curiosity about natural phenomena. Research has received inadequate support except in industries born in the laboratory, the chemical and electrical industries, from which many lessons might well be drawn by their elder associates. The rapid growth of these industries has been largely due to close cooperation of scientists and engineers. Most rapid advance is made when the research worker and the engineer keep in close touch with each other's ideas and problems. Many of the developments of modern industry are based on discoveries buried for years in scientific journals because the "time was not ripe" at their discovery. The situation with regard to utilization of coal is quite the oppositre. The fundamental facts in regard to the scientific aspects of the problem of developing the energy from coal are scarcely known. The engineer, without much scientific cooperation, has accomplished much in increasing the number of kilowatt-hours per pound of coal from 0.31 in 1919 to 0.69 in 1934, in increasing the 1000 gross ton-miles of freight hauled from 12.2 to 16.4 per ton of coal in the same period, in fuel economy in production of coke, and in developing the production of motor fuel in Germany and England by hydrogenation of coal. This lack of scientific research on the utilization of our most important natural resource, coal, has been due undoubtedly in large part to the reluctance of investigators to study the interrelationships involved in the complicated processes in which coal is used. These complexities are made

Jan 1, 1936

By CHARLES M. SCHWAB

THE ENGINEERS have placed this great country of ours in a preeminent position with everything pertaining to manufacture, metallurgy, and the kindred arts. We are second to none in the world. We have a country which, another speaker has said, God has endowed with such riches in coal and natural resources as no other country in the world. But rich as these are, there is one thing greater; the sturdy character, energy, and integrity of its people, which will make these great resources an influence in the world's developments. Great as are these resources and the energy and integrity of our people, there is one problem of our .engineering, which I term human engineering, that is of far more importance than the creation of machines and methods, with which you have been so successful in the past. Of what value is the skillfully devised machinery, the complex process, unless manned and operated by people whose heart and soul are in sympathy with the work they are doing and who have before them the giving of a complete day's work for a day's pay?

Jan 1, 1920

By John H. Smith

Because of increased pressure from federal and state regulatory agencies, most acid flows will require some sort of treatment prior to being discharged to receiving streams. In many industries, the volumes of liquors are large and their acid content varied. Development of a waste treatment process minimizing equipment cost and utilizing land efficiently is mandatory. Methods of acid neutralization with lime have been known for years, however, the volume and characteristics of the resultant precipitated solids can create a disposal problem. Also, when standard lime treatment is used, the settling characteristic of the precipitated solids is normally slow. In some instances, the necessity of added dissolved solids removal, such as iron, needing aeration, add to the problem of concentrating neutralized solids.

Jan 12, 1972

Kaolin deposits in Georgia lie in a belt that stretches across the central part of the state from Alabama to South Carolina. In 1977 the state's kaolin production was an estimated 4.58 million tons (5.05 million st) or 77% of US production. While mining methods vary, stripping contractor W. F. (Billy) Jackson of Wrightsville, Ga., depends on a fleet of 18 twin-engine elevating scrapers to move the hulk of overburden and clay. Owner Billy Jackson explains that the soil in this part of the state is perfect for scraper operation; overburden ranges from Georgia red clay to a sandy gumbo material. Apart from some shale, very little rock is encountered, thus eliminating any blasting re¬quirement. Most of the material can be removed with cutting edge teeth or with drop center blades.

Jan 6, 1978

By H. G. Botset

A KNOWLEDGE of the water content of producing sands is becoming of increasing importance to the petroleum industry. It is now a generally accepted fact that practically all oil sands contain some free water. Recent experiments1 have shown that an appreciable fraction of the pore space of a sand may be filled with water while oil production from this sand is water-free. Crowther and Haines,2 in experiments on electro-endosmosis in soils, reported that there was no endosmotic flow of water when the moisture content of the soil was 14 per cent or less, indicating that the moisture content of the soil below 14 per cent was held by dif-ferent forces than the water content above this value. This result is confirmed qualitatively by Dunlap,1 who found that "as the volume of water in the voids exceeds approximately 15 per cent of the pore volume, the permeability of the core to kerosene is markedly reduced." The author3 has also found in other experiments that the gas flow through a water-saturated sand reaches essentially 100 per cent when the pores of the sand still contain from 10 to 15 per cent water. The velocities of the flowing fluid in the experiments cited were comparatively high, so that in practice one may expect, at lower fluid velocities, an even higher moisture content of the sands with water-free oil or gas production. Thus a knowledge of the water content of oil-field sands becomes of con-siderable importance in estimating petroleum and gas reserves, and effi-ciency of fluid recoveries from depleted reservoirs. Rapid and reasonably accurate methods of measuring the water content of sand cores have not been described so far in any literature that has come to our attention.4 The method described below is devel-oped from methods that have been used for some time to measure the water content of alcohols.5,6,7 It is an application of the fact that in the presence of certain organic liquids such as kerosene, carbon tetrachloride, xylol, etc., water and alcohol are only partly miscible. This relation-ship has been used for some time in the study of gasoline-alcohol mixtures where the presence of small quantities of water affect the solubility of

Jan 1, 1938

By Michael B. Kahle, Fred J. Scheaffer

Production scheduling, along with production planning, provides projections of future mining progress and time requirements for the development and extraction of a resource. These schedules and plans are used by management as a means of attaining the following objectives (1) maintaining or maximizing expected profit, (2) determining future investment in mining, (3) optimizing return on investment, (4) evaluating alternative Investments, and (5) conserving and developing owned resources. The first four goals are generally concerned with mining costs, both capital and operating requirements, and as such, play an important role in production planning. However, this chapter is concerned with the fifth management objective of resource development in order to conserve and perpetuate the corporate entity. The following discussion is based on the premise that detailed economic evaluations and market surveys have been performed and analyzed and that the results indi¬cate a viable project.

Jan 1, 1979

By Claude P. Heiner

W-hile the litle of this paper embraces the entire West Coast, the author, in the interest of simplification, has confined the discussion to California—particularly the central section. California's population has risen 45 pct since 1940. Its electric requirements have also increased, not only because of the growth in industry and population but also because of the widespread tendency of all types of electric consumers to use more electricity than ever before. The growth of California's electric utilities is shown by published data covering operations of three of its large systems and is given in Table 1. New Capacity Steam Driven In meeting these additional electric loads there has been a substantial increase in generation from fuel burning plants as shown by the published energy statistics given in Table 2. Increased Fuel Oil Consumption A study of construction plans of the three electric utility systems named in Table 2 clearly shows that expected new electric loads are to be met, to a large extent, by new steam generating capacity as shown by Table 3. D. D. Smalley, Vice President of the Pacific Gas and Electric Co., in an address before the Pacific Coast Electrical Association in June 1948, stated that California utilities plan to meet new electric loads through greater use of steal11 plank and that in 1951 approximately 45 pct of the area's electric production would be by steam as compared to 33.6 pct in 1946. He stated that if load growth develops as expected and if the year 1952 is dry, thereby requiring high load factor steam operation, the Pacific Gas and Electric Co. would need the equivalent of nearly 25 million barrels of fuel oil. Federal Power Commission reports show that the energy input to the Pacific Gas and Electric Co. system was approximately one billion kilowatt-hours greater in 1947 than in 1946. They also show that the steam plant operating capacity factor in 1946 was approximately 35 pct; in 1947 it, was 72 pct due, probably, to the extreme drought. able 3 shows that Pacific Gas and Electric Co. now has under construction 327,000 kw of hydro capacity which, by 1950, will bring its total hydro generating capacity to 1,313,899 kw. In addition to hydro capacity under construction that company also has 975,000 kw of steam generating capacity under construction, which by 1951 will bring its total steam capacity to 1,560,834 kw. If it is assumed that this total steam electric capacity is operated at a capacity factor of 45 pct, in 1951, over 6 billion kilowatt-hours would be generated. If the load growth on the Pacific Gas and Electric system continues at the current rate of approximately one billion kilowatt-hours per year and if it is assumed that 70 pct of this increase would be generated by steam (30 pct assumed to be generated by hydro facilities with average water conditions), the steam electric production in 1960 would amount to 12 billion kilowatt-hours, which would require fuel the equivalent of 24 million barrels of oil or 6 million tons of coal. Government Projects Inadequate Much has been written with respecl to the plans of the Department of Interior in regard to the installation of hydroelectric plants as a part of multipurpose dams relating to reclamation. flood control, and power generation. An examination of the effect of such plans on the power supply for central and northern California is of interest. The Depart,ment of Interior now has five 73,000 kw units at its Shasta hydro plant on the Sacramento River. It now appears that its three 25,000 kw unit Keswick hydro plant on the same river will be available during the winter of 1949 to 1950. Its estimates show that in a dry year there is sufficient water for operation of Shasta units at an average load factor of 36 pct and Keswick units at a load factor of 41 pct. It is also giving consideration to the development of the Pine Flat and Haas hydroelectric plants on Kings River for generating capacities of 45,000 kw each. The total installation of Government, units in Central Valley and Kings River in California is relat.ively small when compared with t.he

Jan 1, 1950

By A. L. Barnes

A number of reservoirs have been partially invaded by bottom water. Water flooding such reservoirs can be especially inefficient if the oil has a high viscosity because injected water will under-run the oil and emerge at producing wells without having displaced much oil. A possible means of improving water sweep efficiency would be to precede the water flood with a slug of water purposely thickened with a chemical additive. This possibility has been studied with a scaled laboratory flow model. The investigation was carried out on a model representing a 20-acre five-spot with one set of reservoir condition~. Displacements were performed with water, with viscous-water slugs of 10 and 25 per cent of the pore volume followed by water, and with all viscous water. Displacement tests were made at several rates of injection. For all cases, compared at the same producing water-oil ratio, an increase in rate resulted in an increase in volumetric sweep. The larger the quantity of viscous slug injected, the greater the crossflow of oil ahead of the displacing front and, thus, the lower the WOR during that period of a displacement. This investigation indicates that the injection of aqueous viscous slugs in this type of system would give some additional benefit over conventional flooding by (I) reducing the life of the flood, (2) reducing lifting costs and (3) increasing ultimate recovery. The benefits of a viscous-slug displacement would warrant its use if the viscous water could be created for a few cents per barrel. INTRODUCTION The most appropriate method for water flooding oil reservoirs which have been partially invaded by bottom water has been a problem of considerable interest. Such reservoirs, having good vertical permeability and unfavorable mobility ratios, are difficult to produce efficiently under normal waterflood procedures. Even though the injection wells have been plugged back above the oil-water contact and the water zone has been squeezed off, injection water will enter the formation and not only displace oil, but also much of it will displace the bottom water, thus creating a high producing water-oil ratio at the start of a flood (see Fig. 1). Since the rate of injection and the viscosity of the displacing fluid are the more easily controlled physical parameters of the reservoir, it is quite natural to study their effects on the volumetric sweep of the oil zone and on the producing water-oil ratio. Increasing the viscosity of the displacing fluid has two disadvantages—it reduces the maximum rate of injection into the reservoir, and it costs more than water. It was thought that the injection of a viscous-fluid slug, followed by water, would minimize these two disadvantages, increase the volumetric sweep of the oil zone and reduce the producing water-oil ratio. Water with an additive to increase viscosity would probably be the most effective. The primary purpose of this investigation was to determine the feasibility of injecting viscous-water slugs followed by water to improve or hasten oil recovery while reducing the producing water-oil ratios. The effect of injection rate upon recovery was also investigated. A laboratory model, scaled to a 20-acre five-spot prototype with one set of reservoir conditions, was constructed. Laboratory studies of displacements with (1) water, (2) viscous-water slugs of 10 and 25 per cent of the pore volume followed by water and (3) all viscous water were performed at several rates of injection. THEORY OF SAND MODEL SCALING There are two conventional means of determining scaling criteria. These are dimensional analysis and inspec-tional analysis. Determining scaling criteria by dimensional

By D. C. Seidel, E. F. Fitzhugh

The Colorado School of Mines Research Foundation has developed a hydrometallurgical process for recovering nickel from oxidized ores, including both the iron-rich laterites and magnesium-rich, soft silicates. Known as the HSO-HTCP (Hydrothermal Sulfidization Oxidation-High Temperature Cementation in Pulp) Process, the system consists of feed preparation, sulfidization, oxidation, precipitation (cementation), and calcination and melting. This paper deals primarily with the sulfidization and oxidation phases of the process. Nickel sulfide ores lend themselves readily to concentration before smelting or pressure leaching, but neither of the major oxidized ore types — the iron-rich laterites and magnesium-rich, soft silicates-has been directly concentrated. Upgrading of crude ore in current practice is limited to cobbing lumps of the harder, lower grade rock (protore) from the softer, enriched silicate ore, because only a small percentage of the nickel in these ores occurs in discrete, contrasting mineral particles. There is no apparent mineralogical contrast in the superficial, iron-rich lateritic ores and, in fact, there is no firm assurance that the nickel atoms are within the lattices of the limonite minerals, or else irregularly adsorbed on the limonite. Within underlying, "rotten rock" silicates, occasional veinlets of gamierite and related nickeliferous silicates are found.' The gamierite veinlets, however, are only incidental, and the majority of the nickel atoms occur as erratic replacements of magnesium atoms in the micaceous chlorites of the ore mass. Pyrometallurgical processes account for nearly all the nickel currently being recovered from oxidized ores. Plants in New Caledonia, Oregon, Japan, Brazil and Greece smelt the ores to make ferronickels or a sulfide matte,2 and the ammoniacal leaching3 at Nicaro, Cuba, is preceded by a reducing roasL4 The only fully hydrometallurgical installation has been the politically ill-fated Freeport Nickel Co. enterprise, and this process was limited to lateritic ores.5p6 A hydrometallurgical technique which might handle both laterite and the typically richer silicate ores has been an enticing goal. The technique described here was developed at the Colorado School of Mines Research Foundation, Inc. on behalf of the Republic Steel Corp. It uses sulfur, heat, air and metallic iron to recover nickel from these ores. Inasmuch as the ores are treated as aqueous slurries, the cost of drying a plant feed that normally carried 30% or more moisture is eliminated, and there are no dust problems. Patent applications have been filed by Republic Steel Corp. on the procedures used for getting the metal into solution and on the subsequent recovery without liquids-so l ids separation of the slurry. It is referred to as the HSO-HTCP Process (Hydrothermal Sulfidization Oxidation — High Temperature Cementation in Pulp). THE PROCESS FLOWSHEET The results of various experimental studies have been combined to form the continuous flowsheet illustrated in Fig. 1. This flowsheet serves as a general pattern showing the sequence of the operations which include: (1) feed preparation; (2) sulfidization; (3) oxidation; (4) precipitation (cementation); and (5) calcination and melting. This paper deals primarily with the sulfidization and oxidation phases of the process. Feed preparation: In general, the silicate ores can be considered as earthy rather than hard, and preparation might be carried out before the addition of water in a trommel, or with water in a scrubber or log washer. This breaks up the earthy particles, allowing the hard lumps to be separated by screening. The oversize material from most ores is relatively barren and may be discarded. If there is occasion to control the iron-magnesium ratio in the plant feed, laterite, which normally breaks up readily into fine sized particles, and silicates are mixed in suitable proportions. The fine product slurry from the initial steps is mixed with elemental sulfur and fed to a conventional ball mill, although the amount of actual grinding that takes place is relatively small. The object of milling is to complete the disintegration to natural particle size and to produce an intimate mixture of the ore and elemental sulfur. This pulp, which is almost entirely -200 mesh, has a pH of about 7.0 and normally can

Jan 1, 1969

By L. A. Wright, J. F. Emerson

The Pine Creek mine, owned by Union Carbide Nuclear Co., Div. of Union Carbide and Carbon Corp., is one of the world's largest producers of tungsten. The mine is located on the eastern slope of the Sierra Nevada Mountains, about 25 miles north- west of Bishop, Calif. Prior to 1948, production from the property came either from surface pits or from underground workings above A level haulage tunnel. The tunnel is at an elevation of 10,900 ft, which left 500 to 600 ft of vertical backs to the surface outcrops. Heavy production demands during World War II hastened the planning for long range development of orebodies below A level. A 7000-ft haulage tunnel, 1500 ft below A level, was started in 1943 and completed in early 1947. This haulage tunnel is at an elevation of 9400 ft and is known as Zero tunnel.

Apr 1, 1956