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By John. C. Reed

THIS paper presents briefly some of the principal results of 3 ½ months field work during the summer of 1938 in the Chichagof mining district, southeastern Alaska. The report is preliminary and presumably will be followed later by a more complete report to be published by the Geological Survey. The paper is concerned principally with the structural geology of a block of steeply dipping graywacke as revealed underground in the Hirst Chichagof and the Chichagoff mines, the two principal mines of the district. The two mines have produced about $16,000,000 worth of gold and silver. The attitude of the graywacke, which is locally cut by dikes and sills of aplite, is remarkably uniform and trends about N. 62° W. The average dip is about 67° SW. The graywacke is cut by large faults, the best known of which are the Hirst and the Chichagof, whose average trends are about N. 30° W. and average dips about 75° SW. The faults at some places split into the bedding of the graywacke and at others are deflected from their normal trends for considerable distances along the bedding. The relative movements along the faults was northwest and up at about 30° for the south-west or hanging-wall sides. The ore bodies are elongate quartz lenses in the faults. Most of the quartz is mineralized but locally large quartz masses are too low grade to be mined. The emplacement of the ore bodies appears to have been structurally controlled in large part by the intersections of the faults with the bedding surfaces. Places where the faults split or are deflected appear to have been particularly favorable places for ore deposition. There has been some post-quartz movements along the faults but it is thought that such movements have not been extensive enough to greatly modify the original positions and shapes of the ore bodies.

Jan 1, 1939

By G. E. Karantzavelos

Although jigging has been the subject of extensive studies, evaluation of the effect of various jigging factors on the efficiency of separation has been less comprehensive. The basic factors that affect jigging separation are reviewed, a mathematical model describing jigging kinetics is presented, and attention is focussed on the mechanisms of the stratification process. The parameters of the kinetic model (the Wei- bull distribution function) are redefined in a gravity concentration technological sense, and their values are estimated for a wide range of jigging conditions. Several mathematical relationships (regression models) are also formulated which express the dependence of total time required for the complete stratifaction of mineral particles on the operating jigging variables.

Jan 1, 1984

By H. M. Chance

In almost all coal-fields, the quantity of explosive gases given off by the coal increases as depth is attained, requiring correspondingly enlarged quantities of air to ventilate the workings properly, by diluting and carrying off the gas. Again, with increased depth there is a corresponding increased pressure caused by the weight of the overlying strata. Sandstone or slate, which would form a good roof for a coalbed at a depth of 300 or 400 feet, may be unable to sustain the pressure of 800 or 1000 feet of overlying rock. Hence, in nearly all deep mines, the miner will generally describe the roof as "bad," although the roof-rock may be a firm slate, forming an excellent roof for workings of moderate depth, but unable to stand the pressure resulting from the weight of a great thickness of overlying rock. With increased weight of rock-mass above comes also

Jan 1, 1901

By K. P. Wang, Virgil L. Barr

The U.S. Minerals Attaché Program, similar to the scientific and technical attache programs of other industrialized nations, is designed specifically to keep surveillance on significant worldwide developments in minerals, metals, and fuels. Knowledge of international minerals developments is essential for both domestic planning and conduct of foreign affairs. CONTROLLED BY DEPT. OF STATE Ten minerals specialists-eight minerals attaches and two petroleum attachés-man this far-flung, worldwide program for the U.S. Government as best they can. Minerals attach& also handle oil, in posts lacking petroleum attaché. The legislative authority for the Minerals Attaché Program is the Foreign Service Act of 1946 and succeeding amendments and Presidential Executive Orders. Therefore, this program is controlled by the Department of State. Interior (representing the Bureau of Mines) and State collaborate in policy formation and direction by means of a "memorandum of agreement" which covers establishment of posts, selection of officers, contents of reports, and supplemental training. State also has about half a dozen nonspecialist officers to complement the work of the minerals and petroleum attaché. It is not the intention here to evaluate the administrative arrangements of this program but rather to describe it and to provide examples of the important job it is doing.

Jan 11, 1965

By J. A. Fulton

GOLD was discovered in the Sierra Nevada by J. W. Marshall on Jan. 2, 1848. The town: of Grass Valley soon sprang up and contained several stores in 1849; but the population of the town has always reflected the fluctuations in quartz mining. Gold-bearing quartz was found on Gold Hill in September 1850, and in the next two years most of the quartz bearing veins in the vicinity were located. At first, the quartz was crushed in mortars with spring poles; the Huff Co. took out $20,000 in this manner during the winter and spring of 1851. The first mill was put up in January, 1851. In 1866, there .were in Grass Valley 248 stamps, crushing 71,420 tons of ore with an average yield of $30 to $35; in Nevada City, there were 142 stamps, crushing 14,200, tons, with an average value of $25. But in 1918, only two properties in. this region, the Empire and the North Star, were producing. Since then, there has. been a revival of mining in the district and the following properties are being opened up: The Golden Center, Grass Valley Gold. Mines CO , Idaho-Maryland Mines Co., while the Sultana is kept unwatered and work is going on in a half dozen small properties.

Jan 2, 1926

By T. Sterry Hunt

BUT little was known of the coals of Southeastern Ohio until the present survey of the State under Dr. Newberry began its work. The results of the geological investigations of Prof. E. B. Andrews in this region, and of the chemical investigations of Prof. T. G. Wormley, both of which appear in the reports of the survey for 1869 and 1874, and more recent special reports by the former, together with some data for which I am indebted to the kindness of Dr. Newberry, and my own limited observations, have served me for the preparation of the following notice of the coals lying on the western border of the great Appalachian coal-basin in the region drained by the Hocking River and its tributaries, and belonging to the Lower Coal-Measures. Some uncertainty exists as to the place in the succession of the lower coals to be assigned to the seams known and mined in the Hocking Valley. It is the opinion of Prof. Andrews that the inequalities of the original surface were such that we cannot identify in that region the lowest coals known in Northwestern Pennsylvania and the contiguous parts of Ohio, but that we must rather count from above downwards. These conclusions Dr. Newberry is not prepared to accept, and further researches will be necessary before certainty can be attained in this matter. Meanwhile it seems, from a study of its relations to the Pomeroy or Pittsburgh seam, that what is known as the great vein of the Hocking Valley, occupies the horizon of the Upper Freeport coal, E of the Pennsylvania survey, or No. 6 in Dr. Newberry's enumeration, counting from the base. This seam, in the region in question. assumes certain characteristics which, taken in connection with its geographical position, give it a great importance among the coals of the State. The area to be noticed includes the whole or parts of several townships in Perry, Hocking, Vinton, and Athens Counties, lying near the margin of the basin over which the vein in question assumes the character of a dry-burning or splint coal, and has a thickness varying from six to ten and even twelve feet. Its precise limit southward cannot at present be clearly defined, but it has been found as far south as the line of the Marietta and Cincinnati Railroad, with a thickness of six feet, and is mined at various points along the valley of the Hocking River, near Nelsonville, where it attains six or seven feet. To the northward, along the tributaries of this river, Sunday and Monday

Jan 1, 1874

The National Labor Board, on June 25, ended its activities preparatory to final, dissolution by the President. No new cases will be heard nor new applications received. Controversies, jointly submitted, that could not be concluded prior to June 30, were assigned to the joint chairmen or a section of the board for disposition. The conclusion of the board's activities marks the passing of. one of the governmental agencies created during the war to further production of war materials. The board was organized under a Presidential proclamation with former President Taft and Frank P. Walsh of Kansas City as joint Chairmen, and with five members representing labor, five employers' representatives, and two members acting for the public. Mr. Walsh resigned soon after the signing of the armistice and was succeeded by Basil M. Manly of Washington. During the year that ended May 31, the hoard received 1245 cases, made awards in 462 cases, dismissed 391 for various cases, referred 315 to specified agencies, and suspended one case. Fifty-three cases remained on the docket because the hoard could not agree, and 23 cases were pending.

Jan 8, 1919

By D. L. McElroy, J. L. Schroder

Although the earliest use of rubber-tired haulage was in Illinois in 1936, the first unit of this type of equipment used in West Virginia was shipped into the state in 1938. All units placed in West Virginia mines have been of the shuttle-car type. The Katherine Coal Mining Co., at Lumberport, W. Va., was the second company in the United States to install shuttle cars and the Gay Coal and Coke Co., at Mt. Gay, W. Va., was the first company in the country to install the thin-bed type of shuttle car. On Oct. 8, 1940, nine companies in the state were using 41 shuttle cars, of which 10 cars at three mines were of the thin-bed type. All shuttle cars of the low type were in the southern fields and all of the high type were in northern West Virginia. At that time several units were in the process of delivery. The data in this paper were collected in the field by Mr. Schroder in connection with graduate work on mechanical loading of coal in West Virginia by mobile loaders. In the course of his field work he visited five mines in the state that were using shuttle cars. All of these mines were in high-volatile coal beds of strong structure. The more pertinent data obtained at the mines visited are given in Table I. The maximum distance of shuttle-car haul is the distance between the transfer station and the farthermost place. Tonnage per loading unit per foot of bed thickness is to some degree a measure of relative efficiency, especially if the different operations are working the same bed or have somewhat similar conditions. The thin-bed operation is well up in the higher bracket of the afore-mentioned column, which is as

Jan 1, 1942

By J. L. Schroder, D. L. McElroy

Although the earliest use of rubber-tired haulage was in Illinois in 1936, the first unit of this type of equipment used in West Virginia was shipped into the state in 1938. All units placed in West Virginia mines have been of the shuttle-car type. The Katherine Coal Mining Co., at Lumberport, W. Va., was the second company in the United States to install shuttle cars and the Gay Coal and Coke Co., at Mt. Gay, W. Va., was the first company in the country to install the thin-bed type of shuttle car. On Oct. 8, 1940, nine companies in the state were using 41 shuttle cars, of which 10 cars at three mines were of the thin-bed type. All shuttle cars of the low type were in the southern fields and all of the high type were in northern West Virginia. At that time several units were in the process of delivery. The data in this paper were collected in the field by Mr. Schroder in connection with graduate work on mechanical loading of coal in West Virginia by mobile loaders. In the course of his field work he visited five mines in the state that were using shuttle cars. All of these mines were in high-volatile coal beds of strong structure. The more pertinent data obtained at the mines visited are given in Table I. The maximum distance of shuttle-car haul is the distance between the transfer station and the farthermost place. Tonnage per loading unit per foot of bed thickness is to some degree a measure of relative efficiency, especially if the different operations are working the same bed or have somewhat similar conditions. The thin-bed operation is well up in the higher bracket of the afore-mentioned column, which is as

Jan 1, 1942

By William G. Gates

INTRODUCTION The Heath Steele mine is located in the Bathurst-Newcastle area of northern New Brunswick. It is jointly owned by American Metal Climax, Inc. and the International Nickel Company of Canada who hold a 75% and 25% interest, respectively. The ore deposits of lead, zinc and copper sulphide occur in very fine grained pyrite and/or pyrrhotite masses. A consistent spatial relationship with a quartz feldspar porphyry is characteristic of these deposits and the many other similar sulphide deposits in the district. The two principal mineral assemblages of pyrite-sphalerite-galena, and pyrrhotite-chalcopyrite-pyrite, occupy characteristic positions relative to the enclosing rocks. This feature and the nature of the sulphide mineralization are described and the variations in metal content are noted .with special emphasis on the lead-zinc ore zones. The mine product ion rate is 3,000 tons per day of a mixed lead- zinc and copper ore which is extracted from the B-1 zone. The complex nature of the ores presents many metallurgical problems. Optimum metal recoveries are achieved when milll feed grades are relatively consistent and proportions of the contained metals are with in acceptable limits. Ore outlines and stoping blocks are delimited by close spaced diamond drilling. From this information it is possible to forecast the grade of any portion of a stoping block. Production from the various stopes may then be scheduled so as to achieve an acceptable mill feed grade.

Jan 1, 1970

By C. M. Weld

Attention has been turned recently to the exploration and development of certain large blanket-deposits of brown iron-ore in Cuba. The most conspicuous of these to-day, and the one upon which the most light has been shed, is the Mayari deposit, situated about 15 miles south of Nipe bag. Here the Spanish-Aniericau Co. has sole control over 18,500 acres of ore-bearing lands, reported by its engineers to contain 500,000,000 tons of ore. The necessary plant and equipment, with docks and railways, is now under construction for the early marketing of this ore. A similar deposit, and undoubtedly the next to be exploited, is the ore-field at Moa bay, where from 13,000 to 15,000 acres of ore-lands, immediately adjacent to the shores of an excellent harbor, have been generously covered by numerous mining-claims, practically all controlled by four large interests;. This deposit is now estimated to contain approximately 350,000,000 tons, on the basis of dried ore ready for shipment, a figure which may be increased when the western limits of the ore-deposit have been more accurately defined. Other deposits of the same type, but smaller and less accessible, are those at Cubitas, situated from 12 to 15 miles north of Camaguey city,

Jan 1, 1910

By Albert Hoskinson

PROGRESS on the earth depends to a large extent upon the rapid inter-change of ideas and commodities between the various nations of the world. The smooth flow of commerce, by which these ideas and com-modities move, is accelerated by accurate and complete maps of the various land and water areas of the earth, The production of accurate maps depends upon a complete knowledge of the figure and dimensions of the object to be charted, therefore a knowledge of the shape of the earth is a prime necessity for accurate charting purposes. Gravity observa-tions were first undertaken to aid in determining the shape of the earth so that the geodetic surveys of its land and water areas might be more accurately connected to form an undistorted map. A large part of the earth's surface is water and it is therefore necessary to get gravity values at sea as well as on land before a complete and accurate figure of the earth can be determined. Dr. F. A. Vening Meinesz, of Holland, was the first scientist to perfect a pendulum instrument that would accurately measure gravity at sea. He had previously developed a multiple pendulum apparatus for measur-ing gravity upon swampy and unstable land areas in Holland and it was therefore quite natural that he should adapt the instrument to give accurate results upon a still more unstable support, the surface of the sea. His instrument as perfected gives satisfactory results when mounted in gimbals on any vessel where the roll and pitch are not more than about 5° and where the vibrations from rotating machinery and wave action are not large enough to cause the pendulums to shift on the knife-edges. This degree of stability can be obtained on surface craft only in protected waters or on very calm days. Therefore, Dr. Meinesz mounted his instrument in a. submarine so that he could submerge below the disturbed surface waters and get the desired stability in nearly any kind of weather by simply diving to greater depths. Most of the gravity-at-sea work has been done with a Meinesz instrument and a very large number of the observations have been made by Dr. Meinesz himself. He has occupied nearly 1000 sea stations and probably has traveled as many miles by

Jan 1, 1938

By L. R. Blair

Many hydrated silicates have been synthesized and sold for commercial use. However, this paper discusses only hydrated calcium silicates and, to a lesser extent, hydrated magnesium silicates. Synthetic calcium silicates were first formed by man when he found that mixtures of silica or silicates and lime in water set up to form cements. The material which was responsible for the cementing properties was calcium silicate hydrate, although this fact was not recognized until early in this century. In the early 19001s, synthetic calcium silicates, reinforced with fibers and formed simply by reacting calcium hydroxide and silica in water with fiber at atmospheric or under low pressure autoclave conditions, found increased use in thermal insulations and in building products. These insulations were found to have a low thermal conductivity and would withstand temperatures up to 650°C. This, combined with their very low densities (from 8 to 50 Ib per cu ft) and fairly high strength, also made them suitable for use as building products. Following the disastrous Morro Castle fire of the 1930Js, calcium silicate board products were used as partitioning material in all shipboard construction in the U.S. As autoclaving techniques were improved and developed, it was: learned that under hydrothermal conditions new and useful calcium silicates which could be used under more extreme temperatures (up to 980' C) could be prepared. These had high surface areas and other unique properties which suited them for use as fillers, pesticide carriers, low temperature insulating materials, and adsorbents for the removal of fatty acids from various solutions. Hydrated magnesium silicates have not been studied as extensively as the calcium compounds. Their first important use was in the filtration of dry cleaning solutions for the removal of fatty acids. With the introduction of detergents, it was found that these products lost their advantage because of their high affinity for the detergent chemicals. However, in recent years these chemicals are finding increasing use as decolorizing agents for fats and anti-caking agents for resins. Some materials with very high surface are finding new use as adsorbents. CALCIUM SILICATE HYDRATE COMPOUNDS AND THElR CONDITIONS OF FORMATION Within the past ten years much has been done in the field of calcium silicate hydrate chemistry. As a result of this work it has been found that at least 25 different forms of calcium silicate hydrate can either be formed synthetically or found as naturally occurring materials. The stability and composition relationships among these 25 compounds present a very complicated picture, and many of these very closely resemble other forms and are difficult to dis-

Jan 1, 1962

By L. R. Plitt, M. K. Kim

The collecting properties of the fatty acid type collectors for barite were studied using zeta potential measurements, infrared spectroscopy, and Hallimond tube flotation tests. Based upon the experimental results, an adsorption model has been formulated which emphasizes the predominant role of the hydrocarbon chain in collector adsorption.

Jan 1, 1975

By R. Casting, J. Philibert, and C. Crussard

APPARATUS described in this paper uses the properties of X-radiation, emitted by substances under electron bombardment, as a means of rapid chemical point analysis. The method is based upon the principles of emission X-ray spectrography pioneered by Moseley in 1913. A very finely focused beam of electrons—the electron probe—is projected on the surface of a sample, which has a very large area compared with the beam diameter, at the point where it is desired to know the chemical composition. The minute volume of the sample which is thus irradiated emits a complex X-ray spectrum consisting principally of the characteristic radiations of the elements present in the volume. Measurement of the wavelength and intensity of each component of this spectrum thus affords a simple method of determining the chemical identity and concentration of these elements. The volume of sample which is analyzed at each position of the beam is limited by the diffusion of electrons in the sample. For an accelerating potential of the electron beam of about 30 kv, which is a convenient value for producing the characteristic radiation, this diffusion extends over a diameter of about 1 µ normal to the beam, and about 2 µ in the direction of the beam. Thus a beam of 1 µ in diameter leads to a volume of about 2 µ in diameter being irradiated. The limits of the analyzed region are thus considerably smaller than those obtained by using spark or arc emission spectrometry, which must extend to about 50 µ at right angles to the beam, and those obtained in X-ray fluorescence analysis, where the penetration of the specimen is considerably greater. The apparatus itself consists of three main parts: an electron optical system. an X-ray spectrograph and an optical microscope. The electron opticai system consists of a tungsten cathode emitting the electrow and a pair of magnetic lenses which focus the electron beam on the specimen to be analyzed. The specimen is prepared in the usual way, as in optical micrography. The X-radiation, emitted at the focal spot where the electrons strike the sample, is analyzed with a curved crystal, Geiger-Müller counter, vacuum spectrograph. The light microscope, designed to observe the surface of the sample in the region to be analyzed, is provided with a reflecting objective placed on the axis of the second magnetic lens. Its magnification is X450. The quantitative determination of an element A in the analyzed region is made by measuring the intensity I, of a strong characteristic line of the element, as emitted from the sample, and then the intensity I (A) of this same line as emitted from a

Jan 1, 1958

By R. H. Goodman, C. A. Brown

The development of improved new models of spiral concentrators is reviewed. The mechanics of separation of spiral concentrators are stated, including the effects of operating parameters. Some of the traditional areas of spiral application are described, together with examples of new applications such as treatment of fine alluvials and tailings, separation of liberated minerals at coarse sizes, and fine coal recovery.

Jan 1, 1986

By Robert E. Snow, Douglas J. Cosler

The application and development of computer models for simulation of transient ground water inflow to underground mines can assist in mine planning and operation as well as environmental impact assessment. Applications include planning for water handling, treatment, and disposal operations based on predicted mine inflow rates, determination of mining impacts on ground water movement and potentiometric surfaces in neighboring aquifers, evaluation of methods for minimizing ground water inflow, and determination of ground water inflow quality. The potential ground water inflow components to a mine consist of direct inflow from an adjacent aquifer and infiltration through intervening geologic formations. The rates of inflow are controlled by the geologic conditions, the potentiometric surface of the aquifer, and the hydrogeologic characteristics of the water-bearing and confining formations. The capabilities and potential use of a computer model for simulation of mine inflow are illustrated through an example problem.

Jan 1, 1983

By H. Carroll Weed

By caving a block into the workings of its open pit and using the block as an ore transfer, the lnspiration Consolidated Copper Co. has solved a transportation and sizing problem, making possible a great expansion of open-pit methods as applied to Inspiration ore-bodies. FROM 1915 to 1948 the entire production of Inspiration Consolidated Copper Co. was supplied from underground mining. The sole method used was block caving. Underground haulage and hoisting facilities were designed and geared to large-scale production. Beginning in 1948 open-pit mining was substituted for block caving in a portion of Inspiration's Live Oak orebody. The idea proved so attractive that before the Live Oak pit had come into production, another pit on the Colorado orebody (now the Thornton pit) had been laid out and stripping started. It should be noted that these orebodies were not new and the entire program was one of changed methods of mining. Since part of these orebodies had already been mined by block caving methods, it must be recognized that haulage levels had been established under the area or adjacent to it. The orebodies lay on the south side of Inspiration Ridge, while the shafts, crushers, and treatment plants are all on the north side of this ridge. The existing main crushing plant was designed to take a maximum of 12-in. material, and all ore was sized to this dimension by passing through grizzlies in the stopes. In the original planning for open-pit work much thought was given to the transfer of ore to existing underground levels for haulage and hoisting from the regular shafts. If this could be done the necessity of crossing the ridge could be eliminated. Final decision called for cutting a road through the ridge, installation of a primary crusher at an elevation of 3968 ft on the north side of the ridge, and railroad haulage with existing facilities to the main coarse crusher. This decision was brought about by the difficulties of properly sizing and transferring to underground haulage large tonnages of coarse breaking oxide which lay on the upper benches of the proposed pit. Trucking over the ridge on a 7 pct grade would give a cheaper and more flexible operation in handling this material. The benches in the pits are laid out at 50-ft inter-vals and designated according to elevation above sea level. The lowest bench in the original pit was laid out at 3500-ft elvation. All haulage roads are on a 7 pct grade and a vertical lift of 468 ft was considered about the maximum economically possible from a cost standpoint. After 2 years' operation the advantages of pit mining, both from the standpoint of costs and flexibility of operation, became more and more apparent. Studies were then started to develop the extension of open-pit mining to more of the ore reserve than had been planned originally. The idea of transfer raises was again explored. Obviously, as elevation of the pit was lowered, shorter transfer raises would be needed to reach the main haulage levels. Transportation from the lower elevations to the rim of the pit by belt conveyor or skip hoisting was also considered. However, it was recognized that sizing would be required both for conveying and regulation of feed size to the main crusher plant. This would necessitate a fixed or portable crusher located somewhere in the pit. It was known that the sulphide ore at the lower elevations was softer and easier to break than the overlying oxide of the upper benches. This sulphide ore is very suitable for grizzly sizing. Calculations indicated that for ore mined on 3650 elevation, costs for trucking to the primary crusher, crushing, and delivery by railroad to the coarse crusher would equal costs for dropping the same material to the 600 level, hauling underground, and hoisting directly to the coarse crusher bins, provided a suitable method of sizing and transferring could be developed. Above 3650 elevation costs would favor surface haulage; below they would favor underground haulage. The idea of caving an underground block from the 600 haulage level directly into the bottom of the pit

Jan 1, 1954

PRESIDENT E DEGOLYER, District 0 NEW YORK, N Y PAST PRESIDENTS J V. W. REYNDERS, District 0 NEW YORK, N Y SAMUEL A TAYLOR, District 3 PITTSBURGH, PA FIRST VICE-PRESIDENT GEORGE OTIS SMITH, District 4 WASHINGTON, D C TREASURER CHARLES F. RAND NEW YORK, N Y SECRETARY H. FOSTER BAIN NEW YORK, N Y

Jan 1, 1923

By C. H. Loux

This paper deals primarily with the advantages realized from the adoption of methods more suitable than those previously used. The improvements noted include: (1) modification of practice in shrinkage stoping, (2) use of sublevel caving over grizzlies, (3) improved haulage and loading, (4) use of contract wages wherever possible. The Washington mine is on Jonestown Hill, one mile south of Oxford, in northwestern New Jersey. It is producing 16,000 tons of concentrates a month, which are being shipped to the Alan Wood Steel Company's furnaces at Swedeland, Pennsylvania. History The first settlement in this region is reported to have been in 1735, and the magnetite ores were recognized immediately. The first furnace, built in 1741, began operation in 1743. During the Revolutionary War the output was chiefly used for making cannon balls, which, owing to the sympathies of the community, without doubt found their way into the hands of the British. This old furnace is still standing. Several important veins were soon developed, including the Martin, Strayley, McKinley, Adelaide, Welsh and Lanning. Mining was carried to a depth corresponding to the capacity of the pumps available. When these became inadequate, the workings were abandoned, and another vein was opened up. The Washington vein was probably discovered about 1850, and the first shaft started in 1854. In 1879, William H. Scranton made the first complete magnetic survey of the district and serious exploration of the deposit was begun. Rather indifferent success attended the earlier efforts of the many companies that attempted to mine and smelt the ore. In 1929 the property was leased by the Warren Foundry and Pipe Co. to the present operators, and the modification of practice then inaugurated is described in this paper. Geology These veins, like most eastern deposits of magnetite, are formed from, or are contemporaneous with, pegmatite intrusions into a gneissic country rock. The ore therefore follows the banded structure of the gneiss,

Jan 1, 1934