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By Keith G. Wallace

Small scale open pit mining of the Lucky Mc property in the Gas Hills district of central Wyoming was started in the spring of 1954 and the first uranium ore went to Vitro's mill in Salt Lake City that July. Shortly after mining started it became apparent that accurate ore control for mining purposes would be an absolute requirement. A systematic drilling program was initiated in the spring of 1955, and has been continued up to the present time. Two main mining areas have been developed. Mine 1, at the site of the original ore discovery in the Gas Hills, covers a mineralized zone roughly 600 x 2800 ft. This orebody was outlined and developed by drill holes on 50-ft centers. Approximately 1300 holes were drilled in the area before preliminary mining plans were made and mineable reserves calculated. Reserve estimates were based almost entirely on chemical assays of drill hole samples.

Jan 10, 1958

By F. N. Rhines

STUDIES upon the sintering of metal powders, in the solid state, have led to the proposal that the surface energy of the powder particles provides the driving force that causes points of contact between pairs of particles to grow into broad welds which isolate the residual vacant space into pores that tend to spheroidize and gradually to diminish in total volume.' Investigators differ with regard to the mechanism of the movement of the metal, under the influence of surface energy, to accomplish these changes. One school asserts that there is a mass movement of the metal, referred to as a "viscous flow," while the other school prefers to view the movement as a self diffusion process, wherein individual atoms are, transferred without disturbance of the basic pattern of the crystal lattice. Extensive experimental studies upon the sintering of copper, conducted recently by A. J. Shaler,2 have been in- terpreted by their author as support for the viscous flow mechanism of transport, the theory of which was developed originally by J. Frenkel.3 Duplicating a portion of this work with minor changes, G. C. Kuczynski4 is led to the alternate view, namely, that the initial stages of sintering, at least, proceed as a self-diffusion process. Both of these investigations were designed to deal with an isolated unit of sintering, i.e., with the shrinkage of a single pore, or with the growth of a single point weld. It remains to ascertain the behavior of a typical metal powder compact composed of a large number of particles of varying size and sintering to a body with a multiplicity of pores. The observation of density changes alone during sintering is not sufficient in such a case; it is essential to know how the internal geometry of the compact changes. This has been the object of the present investigation, the results of which are used to support the self-diffusion mechanism of sintering. The present studies consist in the measurement of the number of pores as a function of size and time at temperature during the sintering of a copper compact made from a commercial copper powder lightly pressed and sintered in several different atmospheres. A brief survey was made also of the change in shape of the pores, under the influence of the same variables. All of this was done by direct observation with the microscope. Densities were measured on the same sample. It is found that, while the compact is exhibiting an overall shrink-

Jan 1, 1951

By S. Senderoff, D. E. Couch

A PROCESS for the electrolytic preparation of molybdenum from molten salts has been described previously. This previous work centered on electrowinning and electroplating characteristics of the process. In this paper the properties of the process as a refining medium are discussed. In producing metals from ores, it frequently has proven most economical to obtain a comparatively impure metal by smelting, and to purify the product by electro refining. Direct electrowinning from molten salts is rather difficult when a porous diaphragm is required in the process, as in the case of molybdenum, since satisfactory refractory materials for such a diaphragm in molten salts have not yet been developed. In electrorefining, however, a soluble anode is used. By suitable control of anode and cathode current densities, the lower-valent molybdenum compound used in the electrolyte is not oxidized, and a diaphragm is not needed, thus avoiding difficulties which are encountered with other electrowinning processes. Electrorefining may result from two different processes in the cell: Dissolution of the molybdenum and the less noble impurities with a separation of the more noble impurities as an anode sludge; the electrodeposition of molybdenum and the more noble metals at the cathode, leaving the less noble metals in the electrolyte. The amount of separation which occurs in each process is determined by the potential of the operating electrode and the relative concentration of the various species at (or in) that electrode. Since molybdenum has a comparatively noble position in the EMF series in molten alkali halides,2 most refining would be expected to occur at the cathode. In this work only the cathodic process was studied. The objective was to determine to what extent various metallic ions, if they dissolve from the anode or are otherwise introduced, were concentrated in the electrolyte. The necessary conditions for the separation of each and the limiting concentration which may be tolerated in the electrolyte for effective refining were studied. The deposits were chipped from the cathode and analyzed spectrochemically for metallic impurities. Besides determining the major contaminant, a general qualitative analysis was obtained to be sure that other metallic ions were kept at a very low level during each series of runs and to be sure that the baths were not being contaminated accidentally. Samples of the bath, for analysis, were taken at the temperature of operation so there was no chance of selective crystallization during cooling. In this way the ratio of molybdenum in the bath to the other metal could be determined readily. These data permitted a check on the anode efficiency and any volatilization that took place during the electrolysis. Experimental Apparatus—The apparatus as shown in Fig. 1 was used to determine the effect of the various foreign ions upon electrodeposited molybdenum. The entry chamber A allowed the cathodes to be removed without cooling the bath and without allowing oxygen or moisture to enter." The cathodes were made Prom 0.25-in. tungsten rods and were rotated during the electrolysis. The balloon in the lower arm B was inflated with helium after the cathode was drawn up into the upper section for removal. A new cathode was then placed into the entrance chamber A after which the chamber was flushed

Jan 1, 1959

By Christopher J. Bise

Introduction In August 1977, the federal Surface Mining Control and Reclamation Act was signed into law. It stated that: "The Congress finds and declares that because of the diversity in terrain . . . and other physical conditions in areas subject to mining operations, the primary governmental responsibility for developing. authorizing, issuing, and enforcing regulations for surface mining and reclamation operations subject to the Act should rest with the States." Section 516 of Title V (Control of the Environmental Impacts of Surface Coal Mining) of the Act deals with the surface effects of underground coal mining operations. "Each permit issued under any approved State or Federal program pursuant to this Act and relating to underground coal mining shall require the operator to adopt measures consistent with known technology in order to prevent subsidence. causing material damage, to the extent technologically and economically feasible, maximize mine stability, and maintain the value and reasonable foreseeable use of such surface lands, except in those instances where the mining technology used requires planned subsidence in a predictable and controlled manner: Provided, that nothing in this subsection shall be construed to prohibit the standard method of room and pillar mining." This section raises many questions. Precisely what is the "reasonably foreseeable" future as far as land use is concerned? And what is the "standard method of room and pillar mining"? The first part of the paragraph seems to rule out longwall mining, but isn't longwalling a "predictable" manner of "planned subsidence"? Does the Act take into account variations among mining methods in differing regions or coal seams? With these questions and the need to comply with the Act's provisions in mind, many states may turn to the Pennsylvania Bituminous Mine Subsidence Act of 1966- the only comprehensive subsidence act passed by any state-as a model for their own programs. Thus, it is very important to evaluate Pennsylvania's Act to see whether its basic assumptions can accommodate national application. This paper will note the Subsidence Act's provisions and guidelines, briefly analyze the current state-of-the-art in subsidence damage prevention and control, and list several recommendations for altering the Act's application guidelines for different mining areas.

Jan 1, 1982

By Henry Turner

THE following notes were taken on a trip through northern Korea in the fall of 1910. We started with about 19 Korean ponies, and as many Koreans, from Shin Anju, on the railway from Seoul to Antung. We passed through the ancient walled city of Anju, and thence up the valley of the Anju river. We then crossed over to the north into the Kalsan drainage, thence over another divide to the Chasung river, and finally reached the old Korean copper-smelting camp of Tong Jom-in all a distance by trail of about 200 miles. The return trip was made with ponies to Mampochin on the Yalu river, and thence down the river in a junk to Antung. The route of travel is shown on the sketch map, Fig. 1.

Jan 4, 1913

By Howard S. Strouth

Investors and mining companies in the U. S. have recently shown increased interest in the Union of South Africa. This has been sparked partially by the founding in the U. S. of a large investment trust which will hold substantial shares in many of the leading gold and uranium producers. The average U. S, mining man's judgment of the Union, however, may be somewhat clouded by recent headline news. We are inclined to take a strong dislike to the stern measures of the present Union government with regard to its native majority. Others possibly think of South Africa in krms of a British colony which, under pressure of rising African nationalism, must eventually be abandoned. These concepts frequently suffer for lack of precise information.

Jan 5, 1959

By C. B. Sawyer

ALTHOUGH the element beryllium was discovered as the oxide by L. N. Vauquelin in 1797, this metallic element was not produced until about 1828, and then only as an impure powder. Thereafter the greatest single contributor to our early knowledge of beryllium was Lebeau who, in about 1899, made pure beryllium crystals by electrolysis of the fluoride and then beryllium copper by the arc-furnace reduction of beryllium oxide with carbon and copper. About twenty-five years later, under the impetus of the work done by Siemens-Halske, beryllium commenced to make relatively rapid gains in industrial importance, principally when alloyed with copper. At the present half century mark, its use is firmly established in beryllium copper and in X-ray disks of pure beryllium. Its use as a moderator in nuclear processes in piles is engaging experimental attention and might become important. Other minor uses, but increasing in interest, are in nickel-base or iron-base alloys as a strengthening agent; as a protective agent against oxidation in aluminum and magnesium-base alloys; and as a ceramic in the form of the pure fused oxide. A false start was made in the wide use of beryllium oxide as a fired fluorescent powder known as beryllium-zinc silicate, a component of the inside coating of fluorescent lamps. This application, wherein general use by the public attained some importance, was abandoned a few years ago. This action was a consequence of the uneasiness which had been generated during the past decade by the sometimes fatal health hazard to the pulmonary tract now generally attributed to beryllium and some of its compounds. Numerous law-

Jan 1, 1953

By H. W. Smith

This paper presents a review of developments to date in computer control practice, based in large part on Canadian experience. The basic problem examined is that of stabilizing control; matters considered are control strategies, hardware and software aspects of system implementation, reliability, human factors, and economic results.

Jan 1, 1976

AMONG the fellow prospectors of Black Jack Newman, locator of the claims that became the Miami mine, were J. D. Coplen and Bud Woodson. Woodson was in the district when the Bloody Tanks Indian massacre occurred, near the present town of Miami. He was a prospector long before Jack Newman worked in a mine, and for years he had done assessment work on some of the claims that Coplen acquired for his Inspiration company. Woodson recalls that a Scotch geologist from Morenci once visited his claims; and that the geologist tried to get the Phelps Dodge company interested in the property, but without success. Coplen interested some people in Kansas City in his claims that lay west of Newman's. He induced them to organize the Inspiration Mining Co., and by 1908 this company controlled 23 claims, which had been prospected in desultory fashion by a series of adits. One of these, near the Keystone property, encountered some lean copper-bearing rock, but later development failed to disclose any substantial quantity of ore at this particular point. Coplen, as general manager, in September, 1908, was negotiating with several exploration companies which at the time were on the lookout for low-grade copper properties. As a matter of fact, when J. Parke Channing visited Globe, in December, 1906, F. C. Alsdorf showed him the Inspiration claims as well as Newman's. Channing evinced little interest in an option on Inspiration because he could get so much better terms from Newman. He decided to concentrate his work on the Newman claims, with the idea that if he were successful in developing ore, he could later get Inspiration on terms at least equally good. Subsequently, the United States Smelting & Refining Co., which has since added "Mining" to its corporate name, took an option on Inspiration.

Jan 1, 1933

By S. Stutz

Coal, like most other minerals, only exceptionally occurs in a sufficiently pare state to he directly available for general manufacturing purposes. And even where this is the case, the small coal or slack is usually more impure than the lump coal, as the slate, clay, etc., from the roof and bottom of the vein become mixed with it in the handling it undergoes. These impurities often exceed ten or more per cent. in addition to the impurities of the coal itself. The most common impurities of the coal are slate, or shale, clay, and sulphur. The latter occurs in different forms, but moat frequently as bisulphide of iron, or iron pyrites, and as sulphate of lime, or gypum. In both cases the impnrities add greatly to the amount of ash, and where they are present in considerable quantities the raw coal, and still more the coke made from it, is unfit for the manufacture of iron. Coke will coutain on an average at least fifty per cent. more ash and sulphur than the ram coal from which it is made. To the manufacturer of iron every additional per cent. of ash which his coal or coke contains is a source of additional expense, seemingly small, and yet very important in the aggregate. In the blast-furnace, for instance, the ash must be heated up to the melting-point, and, since it is composed largely of refractory substances, the consumption of carbon in melting it will be equal to at least one-half of its weight; that is, a certain part of tile coke is consumed for the melting and fluxing of the ash and is lost. Besides this, it is well enough known to the iron-master that coke containing lees ash makes the &lag or cinder more liquid and less incliner1 to stick to the walls of the furnace. Fuel containing much sulphur produces generally a white iron, poor in carbon, while from the same ore arrd flux, with a pure fuel, a good foundry iron might be obtained. The work of separating slate, sulphur, etd, from the coal has as yet only been successfully accomplished by the washing process. This process depends for its success on the differences in the specific

Jan 1, 1881

By Leon Borgman, Michael P. Lipkewich

Orebodies at or near the surface are generally amenable to open pit mining. The development of a mining program involves designing an ultimate pit and a production schedule. This pit maximizes total profit while the production schedule maximize6 the present value of the property. Optimum pit limits can be approximated by two-and three-dimensional numerical techniques. These techniques presuppose that the mineralized area has been sufficiently sampled to allow a reasonably accurate prediction of grade at any spatial location.

Jan 1, 1969

By J. E. Tiffany, S. S. Lubelsky

For blasting in coal mines the U. S. Bureau of Mines recommends that permissible explosives be used exclusively, that these shall be fired electrically, and that where feasible the working place shall be cut or sheared. These recommendations are made to promote safety and prevent mine explosions. Although permissible explosives are not flameless, their lower flame temperature and shorter duration of flanie make their use safer than that of nonpermissible explosives. Mixtures of air with both methane and bituminous coal dust, which are liable to occur in coal mines, may be ignited by coming in contact with any type of flame or spark of sufficient temperature and duration or by the firing of a blast. In a working place where a blast is to be fired, in addition to the use of permissible explosives, adequate ventilation for the dilution and removal of accumulations or outbursts of flammable gas should be provided. Bituminous coal mines should be rock-dusted as a means of rendering the coal dust harmless The efficient use of permissible explosives depends upon the proper preparation of the working place, standardized drilling, the strength characteristics of the explosive, and the use of a proper weight of charge. Experienced shotfirers should load, tamp and fire all holes. The major part of the information and data here presented is based on the results of efficiency tests made in large producing mines of Pennsylvania and Illinois. Bureau of Mines Report of Investigations, Serial No. 2697, describes how a standard method of blasting was worked out and put into operation in a mine in southern Illinois.' This paper contains a description of the methods worked out subsequently in another mine in that district. Descriptions of tests in two Pennsylvania mines are given in Bulletins 11 and 19 of the Carnegie Institute of Technology.2 These tests

Jan 1, 1928

By H. Reginald Hardy, Y. S. Kim

Recent studies of inelastic behavior and acoustic emission in geologic materials further validate the concept that such materials may be considered to consist of an elastic media containing an array of pores and cracks. In the present paper this concept is investigated further by experiments in which the mechanical behavior of a number of geologic materials were studied in detail at low stress levels using ultrasonic pulse methods. Experiments were carried out on cylindrical test specimens of Indiana Limestone, Tennessee Sand- stone and Barre Granite under relatively low confining pressures (0-5000 psi). Analysis of data from these experiments indicated that there existed a low-level critical stress at which there appeared to be a transition in the mechanical behavior of the material. Under triaxial stress, results indicated that the differential critical stress was relatively independent of confining pressure, i.e., the mechanism responsible for the transition in mechanical behavior was governed by a maximum shear stress criteria.

Jan 1, 1971

By William E. Milligan

SELENIUM and tellurium occupy adjacent positions in the odd division of group VI of the periodic table immediately below sulfur, with atomic numbers 34 and 52 and with atomic weights of 78.96 and 127.61 .† A recent investigation has indicated the figures in Table 1 as the order of natural abundance of their isotopes. [ ] Experimentally, as a result of bombardment, many additional isotopes have been produced and studied. They are characterized by a relative short half-life. The elements of group VI in the periodic table are of great in-

Jan 1, 1953

THE purpose of this chapter is to present a general outline of the basic open-hearth process for the benefit of students, practicing open-hearth operators, and metallurgists who wish to review the subject. The discussion is limited to a description of the sequence and purpose of the operations, illustrated by data and examples. Subsequent chapters deal with more detailed and fundamental studies of the subject. The function of the basic open-hearth furnace is to convert various types of ferrous material into finished steel of given composition and quality. In comparison with other steel-making methods, the basic open-hearth process is one of the most versatile, both from the stand- point of the raw materials that can be used and the types of steel that can be produced. The process can be considered as a sequence involving melting, refining, and deoxidation. In the case of some types of liquid-metal charges the melting stage is not present, but refining and deoxidation in varying degrees are fundamental features of the process. GENERAL DISCUSSION OF THE BASIC OPEN-HEARTH PROCESS The first consideration in open-hearth practice is the type of charge on which the operation is based. This consists of three components-fluxing, oxidizing, and metallic materials. Fluxes. In the basic process the fluxing material is primarily lime, added in the form of either limestone (CaC03) or burnt lime (CaO). This is supplemented by magnesia (MgO) and lime from the furnace bottom and banks. The function of these fluxes is to form a slag with the silica (SO2), manganese oxide (MnO), iron oxides (FeO and Fe203), and phosphorus oxide (P205) that are produced by the oxidation of varying amounts of the silicon, manganese, iron, and phosphorus in the charge during melting and refining. The slag, composed of the basic fluxes and the neutral and acid oxides, floats on top of the steel bath when the charge is melted. The composition of this slag depends on the amount of each slag-forming element present in the charge and on the extent of oxidation of these elements during the course of the

Jan 1, 1944

By William G. Pariseau, H. Douglas Dahl

Recent subsidence legislation indicates that mining engineers would be welt advised to be able to predict and control surface damage caused by mine subsidence. To date, such an ability is practically nonexistent. Model analysis is suggested as one of the alternative paths available which might yield fruitful results. Similitude requirements developed for a self-loaded body in static or quasi-static equilibrium indicate that complete similitude without centrifuging is an impracticability. However, a pilot experimental study which used a simplifying assumption to correctly model mine subsidence has produced results in qualitative agreement with field observations. The purpose of this paper is to present a discussion of the various approaches that can be taken in the study of mine subsidence phenomena. Particular attention is focused upon the rational selection and use of laboratory models. Broadly interpreted, mine subsidence is the deformation of the rock mass enclosing a mine. Depending upon a number of factors, the movement of the subsiding rock mass may disrupt gas and water lines or other buried utilities, damage surface structures such as buildings and bridges, dislocate streams, roads, and rail lines, aggravate acid mine drainage and fire problems, and generally mar the landscape. It is clearly a problem that no mine manager can safely ignore. It is also a problem that will grow with the general population increase. In the following discussion, a summary review of past and present approaches to subsidence studies is given. The possibilities of duplicating subsidence phenomena in laboratory models are examined, and an analysis of a particular type of model is presented. Some preliminary results obtained from a model of the particular type analyzed are then discussed. REVIEW OF PREVIOUS WORK Historically, subsidence investigations have been empirical studies in the field and laboratory or theoretical analyses of mathematically idealized media. Empirical and theoretical work in the United States has generally lagged behind investigations abroad. In the United States, field studies are mostly pre-World War 11. These are summarized in the Mining Engineer's Handbook. ' Field studies in Europe are more recent and more extensive. Those made in Great Britain are summarized in the Subsidence Engineers Handbook2 and represent observations made at 157 different collieries. Such studies by themselves are of limited usefulness as are all empirical studies. One can never be certain that conditions at one mine will be similar enough to those at another to warrant the drawing of like conclusions. European subsidence formulas rely heavily upon the "angle of draw" and "critical area" concepts. The angle of draw is defined as the angle between a vertical line through the face, and another line extending from the face to the surface at the point where movement is zero. The critical area is defined in relation to the least extraction necessary to produce maximum subsidence. Fig. 1 illustrates the angle of draw and critical area concepts. First and second "limits of influence" are also shown. The angle of draw and associated critical area concept are obviously not well defined, being dependent upon the accuracy of the surface survey. In Great Britain, the angle of draw has increased through the years from about 26 to 35°. In the United States, zero and negative angles of draw have been reported. In the authors' opinion, these purely geometrical concepts represent an oversimplification of subsidence phenomena and their use, in the United States at least, should be discouraged. Empirical observations of laboratory models containing layers of earth, sand, clay, and plaster were made by Fayol (cited by Peele) as early as 1885. An outgrowth of his work was the "dome theory," a verbal description of what is assumed to occur in subsiding rock masses. The dome theory has since fallen into disrepute. Theoretical analyses worthy of the name treat a subsiding rock mass as a deformable body. In these analyses, the actual rock mass is replaced by an idealized material that deforms according to a simple stress-strain relationship. The stress equations of equilibrium expressing the Newtonian laws of mechanical action and the geometry of strain furnish additional equations that must be satisfied. A loading criterion-generally understood, and in some cases stated explicitly-completes the theory.

Jan 1, 1969

By R. L. Frantz, R. W. Bouman

The authors investigated the comminution of quartz and limestone mixtures in a ball mill, showing that the distribution modulus of a comminuted material is the same whether it is ground separately or as part of a mixture. Analysis of the ground products indicates that quartz and limestone consume energy during ball milling in proportion to their mass fraction in the mixtures. Recently Schuhmann' made a significant contribution to comminution theory by proposing that complex comminution operations comprise the summation of many individual comminution events. By means of the single comminution event hypothesis, Schuhmann derived the Charles energy-size reduction relationship by considering that fragments of every particle crushed during a single impact have a size distribution characterized by the Schuhmann size distribution. In this paper, the size reduction of mixtures of solids in ball mills is analyzed by considering that size reduction occurs as many single comminution events. If a mixture of two materials is being ground in a ball mill, each successful impact of a ball with a particle of one material should yield an assembly of particles whose size distribution is characteristic of that material. Considering both materials to follow the Schuhmann size distribution equation, the size distribution of material 1 in the product is

Jan 1, 1962

[Furnaces (see also Blast jurnaces) :-(Continued.) McGill, Nev., LI, 765. roasting: XLIX, 184, 188. Anaconda, Mont., XXXVII, 462, XLIX, 676. concrete hearths for, XLVI, 419. Crouse, XLVI, 413. gas, XXXVIII, 163. Heberlein, XXXVII, 634.]

Jan 1, 1918

By C. E. Stafford

and tougher, and will carry double the tonnage of any of Dr. Dud ley's soft mils. C. E. Stafford, Steelton, Pa.: I must confess my high ap preciation of Dr. Dadlq's conscientious and painstaking work, and of his scientific methds in obtaining the data; but with his method of handling these results and with his conclusions drawn therefrom 1 canuot agree. The reasons for this difference of opinion I will endeavor to explain. It is apparent on inspecting his Plates 6 and 7 that the majority of the slower-wearing rails are from the north track, and generally have a longer time of service, a greater average tonnage per rail, and a smaller avernge tonnage per year per rail than the faster wearing, the majority of which are from the south track, and gener ally have a shorter time of service, a smaller average tonnage per rail, and a greater average tonnage per year per rail. Have these facts any significance Have these different of conditions to which they are subjected any baring on the relative wearing capacity of these rails I venture to say they have. I think, after a study of Table I (page 676), (an arrangement of linee 17 and 18 of Plate a), in connection with Plates 6 and 7, we will find that the slower wear of the 32 best rails is only partly due to qualities inherent in the rails themselves, but is principally due to external conditions favorable to slower wear. In regard to the north and south track, we know that over the rsoiith track come the loaded cam from the West, and that over the north track these cars return, most of them, empty. It is evident that this means for the north track a less average tonirage per rail per year; or, in other words, a lower wheel tonnage. When the load per wheel is less, the resistance and consequently the wear must, necessarily, be less, other things being equal. Time of service, alee, has an important bearing on the question in hand. It has been only within the last five or six years, as Dr. Dudley has pointed out, that the roadbed of the Pennsylvania Rail road has reached its present admirable condition. Before this time the njadbrd was more elastic, more yielding (and probably not uni tbrmly so) than at present. These circumstalices might cause a sofier rail to be more durable than a harder one, owing to the fact that it ulonId yield rnore or less to the bending force of the passing load and would thus get a bearing on each cross-tie. The harder rail, on the other hatid, being stiffer and more. unyielding, would not

Jan 1, 1881

By J. B. Stubbins, R. A. Blais

Extensive geological work was initiated — and continues — when operations of the Iron Ore Co. of Canada commenced in the Labrador-New Quebec area. Such geological operations include: mapping, test pitting, drilling, underground workings, volume factor and structure tests, and the calculation of ore grades and tonnages. Details of such work are given. Development is carried sufficiently ahead of mining to provide reliable tonnage and grade estimates and allow final mine planning. In order to make full use of geology in mining operations, the pit engineer combines the duties of geologist and mining engineer. The iron deposits of the Knob Lake range are located in the central part of the Labrador peninsula, a territory nearly twice the size of Texas, which is bounded by Hudson Bay on the west, Hudson Strait on the north, the Atlantic Ocean on the east and the Gulf of St. Lawrence on the south. The mining district proper is about 1000 miles northeast of Toronto. A 360-mile railroad links this mining area to the port of Sept-Iles on the Gulf of St. Lawrence. Schef-ferville, which is only a few miles from the open-pit mines, is the center of operations of the Iron Ore Co. of Canada. It has a population of nearly 5000. The nearest settlement is Labrador City, some 120 miles to the south, where this company is erecting a large plant for beneficiating its huge reserves of local low-grade iron ores. HISTORY The mineral possibilities of the area were recognized as early as the end of the last century, when A.P. LOW' of the Geological Survey of Canada made his famous trek across the Labrador Peninsula. After mapping several belts of iron formation, Lovr recommended that the area be thoroughly prospected for iron. In 1929, two well known Canadian geologists, J.E. Gill and U'.F. James, led a private expedition in central Labrador and discovered the first deposit of high-grade iron ore near what is now the Ruth Lake Mine. In 1936 the Labrador Mining and Exploration Co. was formed to 11ake over a prospecting concession of over 20,000 sq miles in central Labrador. An adjoining concession of 3900 sq miles in New Quebec was obtained in 1942 by Hollinger Consolidated Gold Mines, which had just Purchased the Labrador Co. The same year the M.A. Hanna Co. Purchased an interest in both exploration companies. From 1942 to 1950 extensive exploration was conducted by the Hollinger-Hanna technical staff to systematically appraise these vast concessions. More than 40 deposits of high grade ore were found and, by the end of 1950, the total ore reserves reached 418 million tons. In 1949 five American steel companies joined the Hollinger-Hanna interests and formed the Iron Ore Co. of Canada. Financing and full-scale construction were decided upon in 1950. This included the construction of a 360-mile railroad through very difficult terrain, the erection of two hydroelectric plants, the installation of terminal port facilities at Sept-IIes, the building of a modern town-site at Schefferville, the construction of crushing and screening plants, and the preparation of deposits for mining. Ore was first shipped in July 1954. Total open-pit mine production to date is 66 million long tons of direct-shipping ore. GEOLOGICAL ENGINEERING The above achievements would not have been possible without irtegrated teamwork of people of diverse skills and extensive use of geology. In their paper on the role of geologists in the development of this iron ore field, (Gustafson and Moss1 rightly emphasized the difficulties facing the early workers in the area. In an uninhabited land with no roads or railroads and no navigable rivers leading to the interior, everything had to be flown in. It was not until 1948 that aerial photographs and adequate base maps became available. In spite of these and other difficulties, an impressive amount of field work has been done since 1942. Nearly all this work has been directed by geological engineers and geologists. About 15,000 :sq miles have been geologically

Jan 1, 1962