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By Robert W. Bruhn

An investigation was made of ground response to pillar retreat mining in a 1.7 meter thick seam at 108 meter depth at a site in northern West Virginia. This paper describes mining-related stress changes and movements at mine level, displacements within the overburden, ground surface subsidence and groundwater level variations. Subsidence approached 40 per cent of the mine height and continued more than a year after mining. Water levels declined in certain deep-lying strata.

Jan 1, 1984

By Virgil W. Carmichael

In the Fort Union formation of western North Dakota, eastern Montana and northeastern Wyoming there are immense tonnages of lignite and subbituminous coal that have not yet been evaluated in terms of present economic conditions. The general lack of detailed geologic and topographic maps of this region, coupled with a considerable interest in some of its deposits, has spurred the North American Coal Corp. to develop a rapid, economical method of producing its own maps on which to base a quantitative evaluation of the coal reserves involved. The techniques the company employs in this mapping and evaluation program are simple photogeologic and photogrammetric procedures that can also be applied to other exploration and mining work. The air photos, in addition to being used for photogeologic interpretation, have been successfully applied to locating drainage cuts, haul roads, and road metal deposits as well as for various property studies and general mine and reclamation planning. The present discussion will deal primarily with North American's photogeological reconnaissance method of mapping and evaluating relatively flat- lying to shallow-dipping coal beds with limited topographic control and a minimum of core drilling. The field tools employed under this method include aerial photographs and pocket stereoscopes, engineering levels, aneroid barometers, portable transceiver radios and core drills. Field information developed on the photos is transferred to maps for measurement of reserves and overburden. To date this method has been used to map and analyze nearly 6 billion tons of Fort Union lignite and subbituminous coal.

Jan 8, 1969

By Gene Long

10.4-1. Load Design and Construction. Surface mine haulage roads are used for transporting raw products to the mine site, preparation plant, or loading facilities, and to provide personnel and equipment an access to the pits and mine area. All of the aspects of highway engineering, including minimum slope inclines, properly banked curves, and adequate drainage, must be followed to facilitate construction of safe and efficient haulage roads for fast and economical transportation of the mined product to its destination. By maintaining good haulage roads, both truck and equipment maintenance will be kept to a minimum, resulting in reduced mining costs and subsequently higher profits. [ ] There are several basic considerations in haulage road planning. Most important, one must follow all safety procedures in both design and construction of the roadway. A maximum effort should be made to follow current mining plans when laying out and planning haulage roads (aerial photographs can be extremely useful in planning and routing of roadways). Grades, road widths, and curves must be maintained within limits of present and/or planned haulage equipment specifications, since all these factors can limit speed, and hence production (Table 10.4-1). Grades in most mining operations are adverse (against the loaded haul), which increases haul cost per mile. Operators must balance these increased

Jan 1, 1968

By Charles F. Herbert

In February of this year at the Washington, D.C., hearings of the Interior Department on the Alaska pipeline, the author was amazed to hear speaker after speaker oppose not only pipline construction but any development whatsoever in the State of Alaska. In one case, a man objected to development in Alaska because his neighbor in Maryland had cut down some shade trees. Another man recited at length from the poems of Robert W. Service. While it seemed inconceivable that such thoughtless opposition should have any effect, a check with the offices of some congressmen showed that mail was largely against any development of Alaska. In the barrage of words and redundant phrases directed against Alaska, it is difficult to find a thought worthy of study. Fortunately, there is a statutory guide towards resolution of the problem of development versus non- development. This law, the Environ- mental Protection Act of 1969, has indeed given much of industry the jitters; copper smelters see no way to comply with the new sulfur- emission standards, the Alaska Department of Highways estimates that the Act has nearly doubled the cost of planning and engineering for highway construction. In spite of these and many other troubles and costs, the Act provides a sound legal basis for defeating nihilistic emotions and, since Alaska is relatively undeveloped, adoption of environmental safeguards will be simpler than correcting longstanding abuses.

Jan 1, 1971

By John W. Cobb

The attempts of British investigators to arrive at definite knowledge concerning the nature of the nitrogenous constituents of coal have been mainly made through studies of the behavior of coal on carbonization and gasification. There have been carried out numerous determinitions of the distribution of nitrogen in the products of carbonization under laboratory and large-scale conditions; and by a careful consideration of the extent to which nitrogen is liberated, say as ammonia,. at different temperatures and under different conditions of operation as regards atmosphere, it has been possible to form some general notions as to the nature of the nitrogenous compounds present in the coal; and at the same time to arrive at clearer ideas as to what are the important operative factors in determining the ammonia yield under working conditions. This work has been spread over many years and is summarized below. The difficulties of connecting the results in such a way as to allow of the nitrogenous constituents of the coal being described in terms of specific organic structure are great. They arise, for example, in the carbonization process, because the phenomena of decomposition observed at any one temperature can only refer to compounds decomposing at that temperature, each of them with a previous history of chemical transformations occurring at lower temperatures. To put it in &other way, the compounds occurring in the coke at any stage are not in the least likely to be those present in the original coal. The same difficulty, in a milder form, occurs when the method of differential solution is attempted. There is always the preliminary question, almost impossible to answer, as to how far the separation by the use of the solvent has involved some form of decomposition of the original compounds. In the following summary, an attempt has been made to bring together results obtained by British workers.

Jan 1, 1925

By AIME AIME

THE career of Erie V. Daveler, reelected director of the Institute last February, illustrates, among other things, the value of technical schooling and experience as a mining engineer as preparation for executive and administrative work. For twenty years after graduating in the mining course at the University of California, in 1907, he was actively engaged in operating mines and mills in the West. After two years cyaniding silver ores at Tonopah, Nev., he joined the staff of the Utah Copper Co. at Bingham, his first assignment being research in ore dressing. Since that time he has been associated continuously with companies allied with Utah Copper, through D. C. tackling who dominated the affairs of the

Jan 1, 1937

By T. C. King

AT the new Graham-Central Mill of Eagle-Picher, near Galena, Ill., material is simultaneously dewatered and introduced into the ball-mill scoop boxes by the use of variable-speed, 24-in. spiral classifiers. This arrangement has proved satisfactory in that the moisture content of the wet feed is reduced, thus allowing maintenance of density within the mills, and a constant feed at any desired rate to the mills is provided. In this mill the primary feed is wet crushed to minus ½ in. and preconcentrated by jigs to produce a bulk lead-zinc-iron concentrate and a waste tailing. The jig concentrate is then dewatered by a conventional dewatering classifier and stored in, bins ahead of the ball mills. Even though this material is well dewatered, the discharge at the bin bottom is sloppy because of the gradual drainage of the water from the surface of the particles. Conventional belt feeders with vertical cutoff gates are unsatisfactory because of the flushing characteristic of the wet sand.

Jan 1, 1950

By George Riter

OUR mineral-land laws need revising so as to provide definite title at the outset to the mineral deposits within any definite piece of land. The laws as they now stand, especially those applicable to lodes, breed uncertainty as to rights of possession prior to patent; and to my mind this is the worst feature of all, worse even than the apex bugbear. It is now almost impossible for anybody to tell with certainty what mineral rights exist within any area that is not covered y patent, or whether any valid rights exist at all. Our system is unique in permitting individuals to appropriate and exploit mineral lands of the public domain without notice of any kind to the Federal government, and to relinquish them without any ceremony at all. The result is a clouded record that cannot be cleared' up until each claimant is put to some sort of final proof. In order to accomplish this, new Federal legislation will be required. The requirements for a mineral survey and the proceedings for patent have always been cumbersome and expensive; and perhaps out of regard for the poor claim owner, who can ill afford the outlay for that sort of thing, the law does not require him to go through it unless he chooses to do so. Consequently, every active mining district has become encumbered with tangled groups of doubtful or conflicting locations, whose rights and boundaries, when any valuable ore is found, must usually be determined by lawsuits that are as expensive and as distressing as the stakes are high. So deeply has litigation entered into our mining system that a claim whose rights have never been disputed would probably be set down offhand, y a miner of the old school, as of no value. Think of the litigation over rights of possession on the Comstock lode-12 leading companies involved in an aggregate of 245 suits within a period of less than eight years! Ambiguous local records; the chance of erroneously placed or obliterated monuments; doubt as to the sufficient performance of the statutory annual labor; uncertainty as to prior conflicting or overlapping locations; anxiety as to the changing attitude of the Department of the Interior and the Forest Service-such considerations as these make an unpatented mining claim an unclean thing in the eyes of possible investors. Is it any wonder that they keep themselves and their money at a safe distance,

Jan 7, 1914

By C. O. Babcock

In this Bureau of Mines report, the authors present the results of laboratory tests on the burst proneness of coal. Many researchers have studied the violent breaking of large coal masses in underground mines, called bursts, but the causes remain uncertain. They have often assigned to geology and gas pressure the causative roles. The objective of this work is to show that stress can produce bursts in many coals if constraint is necessary for pillar survival and is suddenly lost. We tested coal samples from 15 mines, in 11 coal seams, in six states in the laboratory, and 13 were made to burst. These bursts were produced in several ways, but segmented steel platens were used in the tests reported. Two parameters analogous to the momentum and kinetic energy were used to rank the burst proneness of the coals tested. Tangential strains over the lower surface of the model coal pillar were measured to reveal a periodic slipping prior to the burst. High-speed motion pictures (350 frames per second) reveal the burst behavior in slow motion. We propose a modified Mohr-Coulomb stress-failure criterion to describe the burst behavior. When the horizontal constraint is suddenly lost with little change in the vertical stress, the Mohr stress circle increases in size dynamically, exceeding the static failure condition. When the inertia of the coal mass is overcome, a burst occurs. We conclude that most coals can be made to burst and that such bursts can be expected in mining at increasing depths.

Jan 1, 1984

By E. D. Gardner

When the National Forests were created, all lands embraced in their boundaries were exempted from all forms of entry, except mineral claims. Later, by Act of June 11, 1906, and as amended by Act of Aug. 10, 1912, provision was made allowing homesteads on areas chiefly valuable for agriculture and not necessary for the public use. Patents to mining claims in the Forests are granted the same as on land not in the Forests, irrespective of timber or other values. It is the policy to encourage the highest use of the Forests. As a business proposition, it is a good policy to have mines developed in the Forests. Their development in remote or inaccessible regions causes the country to be opened up and, in addition to the local market which the mines create, means of transportation are afforded to outside markets. No examination of mining claims is made until patent has been applied for, unless they are actively interfering with the administration of the Forest. In this case, an examination is made, and if there is evidence that the claims are being held in good faith they are in no way interfered with. Timber is never sold from a mining claim except with the consent of the claimant, or unless it is clearly shown, after an examination, that the claim is abandoned. In the case of fire-killed timber, which rapidly deteriorates by standing, a contract bond arrangement can be made for the sale of the timber which protects the interests of both the mining claimant and the government. The promiscuous locating of mining claims has in the past caused considerable trouble. It has been, and still is, the custom in some parts of the West to locate a mining claim when the surface rights of any particular area are desired, irrespective of the mineral character of the ground. This has been done to hold power sites, town sites, summer residences, springs, etc. When the ground is desired for any of these purposes, what is known as a Special Use Permit will be issued at a nominal sum, to legalize the occupancy. In most instances, it is far cheaper to take out one of these permits than to do the annual assessment work on a mining claim, but, of course, patent to the ground cannot be obtained in this manner. If mineral were discovered on the land covered by a Special Use Permit, it would ordinarily be the policy to cancel the permit if it were clearly

Jan 1, 1915

By W. Julian Parton

Treatment of the breaker wash-water discharges to remove the suspended particles of finely divided material is usually most efficiently and economically accomplished in settling or thickening tanks. The purpose of these tanks is to separate the excess water from the solids by sedimentation whereby the solid particles suspended in the water are thickened by the force of gravity. The water overflowing these tanks is either reused for coal cleaning or discharged directly to the streams. The settled solids, which are in a relatively concentrated condition, forming a sludge or thick pulp, can be disposed of by pumping to a storage dam, by slushing into mine workings, by processing for recovery of coal, or filtering by vacuum or centrifugal means and discharging with the breaker refuse. The scope of this paper will be limited to the discussion of settling and thickening equipment, the factors that influence the settlement of solids, and a brief description of tests that can be made to determine the size of settling facilities required for any particular condition. The practical application of sedimentation to the treatment of coal falls into two groups, one of classification or hydro-separation, and the other of clarification and thickening. Classification may be employed to prepare a relatively low-grade fuel, which can be used as is or can be further processed separately. Clarification and thickening is employed where the primary objective is to recover a relatively dewatered solid and return a satisfactorily clear water to breaker or streams. Operation and Types oF Settling Equipment When a stream of water flows across a tank, the time required for a particle to travel from the feed inlet to the overflow must be a little greater than that required for the finest particles or flocs in the feed to settle out of the stream. Theoretically, the liquid in a settling tank should rise at a more or less constant rate throughout the area of the tank Under these conditions the rising velocity of the water must be less than the settling rate of the finest particles if clarification is to be obtained. When classification of particles is to be made in the tank, the overflow velocity must be greater than the settling velocity of the particles that are to be removed with the tank overflow. The performance of a settling tank, then, depends on the settling rate of the solids and the current velocities in the tank. The oldest types of sedimentation employ intermittent types of settling tanks of any convenient shape. Means are provided for filling the tank with pulp and allowing it to settle until quiet, for moving the clean liquor and for removing the thickened sludge. The operation is necessarily intermittent but a sufficient number of tanks is employed so that a continuous flow of clear water is maintained. Continuous methods for the sedimentation of slurries were developed in the metallurgical industry. Cones from which settled solids were discharged by gravity

Jan 1, 1947

By W. Julian Parton

Treatment of the breaker wash-water discharges to remove the suspended particles of finely divided material is usually most efficiently and economically accomplished in settling or thickening tanks. The purpose of these tanks is to separate the excess water from the solids by sedimentation whereby the solid particles suspended in the water are thickened by the force of gravity. The water overflowing these tanks is either reused for coal cleaning or discharged directly to the streams. The settled solids, which are in a relatively concentrated condition, forming a sludge or thick pulp, can be disposed of by pumping to a storage dam, by slushing into mine workings, by processing for recovery of coal, or filtering by vacuum or centrifugal means and discharging with the breaker refuse. The scope of this paper will be limited to the discussion of settling and thickening equipment, the factors that influence the settlement of solids, and a brief description of tests that can be made to determine the size of settling facilities required for any particular condition. The practical application of sedimentation to the treatment of coal falls into two groups, one of classification or hydro-separation, and the other of clarification and thickening. Classification may be employed to prepare a relatively low-grade fuel, which can be used as is or can be further processed separately. Clarification and thickening is employed where the primary objective is to recover a relatively dewatered solid and return a satisfactorily clear water to breaker or streams. Operation and Types oF Settling Equipment When a stream of water flows across a tank, the time required for a particle to travel from the feed inlet to the overflow must be a little greater than that required for the finest particles or flocs in the feed to settle out of the stream. Theoretically, the liquid in a settling tank should rise at a more or less constant rate throughout the area of the tank Under these conditions the rising velocity of the water must be less than the settling rate of the finest particles if clarification is to be obtained. When classification of particles is to be made in the tank, the overflow velocity must be greater than the settling velocity of the particles that are to be removed with the tank overflow. The performance of a settling tank, then, depends on the settling rate of the solids and the current velocities in the tank. The oldest types of sedimentation employ intermittent types of settling tanks of any convenient shape. Means are provided for filling the tank with pulp and allowing it to settle until quiet, for moving the clean liquor and for removing the thickened sludge. The operation is necessarily intermittent but a sufficient number of tanks is employed so that a continuous flow of clear water is maintained. Continuous methods for the sedimentation of slurries were developed in the metallurgical industry. Cones from which settled solids were discharged by gravity

Jan 1, 1947

By J. M. Oblak, R. F. Hehemann, R. H. Goodenow

STUDIES of surface relief and growth kinetics have lead to the concept that widmanstatten ferrite along with upper and lower bainite constitute a continuous series of decomposition products.1-4 Current models4 propose that these products form as plates with a coherent or semicoherent leading edge which propagates at a rate controlled by diffusion of carbon into the surrounding austenite. There are, however, important crystallographic and morphological differences between these products—particularly between upper and lower bainite. For example, upper bainite appears to exhibit a (11lIy orientation habit, whereas lower bainite develops with a more irrational habit near {2251y.5-7 Many of the morphological features of these decomposition products are not yet well-documented. Recent studiess have demonstrated that low-carbon martensites form as sheets of closely spaced needles on {lllly planes while higher-carbon martensites form as plates with {225}? or other orientation habits. The similarity in the crystallography of these two modifications of martensite with upper and lower bainite is striking. Therefore, a study of the morphology of bainite in a series of hypoeutec-toid alloy steels has been initiated to explore these relationships further. The question of immediate interest is whether upper and lower bainite form as plates or needles. A two-surface (approximately perpendicular) metallographic method was employed to study the morphology of bainite in a variety of low and medium alloy steels. Compositions of these steels have been reported elewhere. The behavior of 4340 and 4370 was typical and will be described here. Austenitizing treatments involved 20 min at 2350°F for 4340 and at 2000°F for 4370. Isothermal transformation was conducted in molten-salt baths. Upper bainite was produced at 925°F in the 4340 steel and lower bainite at 575°F in 4370 with transformation times adjusted to produce 10 to 15 pct of the decomposition product. Many of the morphological features of upper bainite have been catalogued in the recent literature.'' The two principal variants observed in the present investigation are illustrated in Fig. l(a). One form appears as long, thin plates or needles and the other as small, frequently irregularly shaped particles. Both variants may occur as isolated forms but more frequently appear in groups as demonstrated in Fig. l(a). Two-surface analysis reveals that these two variants constitute different sections through a single morphological form. To demonstrate this, a number of sections perpendicular to the plane of Fig. l(a) were prepared at various positions along the length of the elongated particles. A section taken at position 1 in Fig. l(a) is presented in Fig. l(b). Here, the dark line represents the edge of the sample and the left-hand portion of this photomicrograph is that from the surface perpendicular to the original plane of polish. Since it was necessary to repolish the original surface after each sectioning, the shape of the bainite particles on this surface, right hand side of Fig. l(b), changes with each sectioning. The disappearance of plate A, Fig. l(a), in Fig. l(b) emphasizes the small cross section of these structures. The group of particles in the lower left-hand

Jan 1, 1964

By C. Carlson, W. Muir

The oxygen demand of the complex lead-zinc-iron feed at the Cyprus Anvil concentrator was determined dependent on the cyanide ion concentration of the pulp. By redistribution of the cyanide added to the grinding circuit in direct proportion to the amount of surface area created, a more activated flotation feed is obtained. Monitoring the oxygen demand of the flotation feed and grinding mill discharges has proved useful in diagnosing metallurgical problems in day-to-day operation.

Jan 1, 1976

By W. B. Weeks, H. K. Shearer

The year 1937 brought to south Arkansas increased drilling activity and production. Oil production amounted to 12,159,440 bbl., an increase of 1,504,500 bbl., or 14.1 per cent over 1936. This was the largest production since 1931, and the first annual increase since 1925, when the deeper sands at Smackover were developed. There were 177 wells completed during the year, with 103 oil wells, 6 gas wells, and 68 dry holes, an increase of more than 100 per cent over 1936. Of the 56 wildcat wells drilled, 52 were dry and 4 produced oil. Two new fields, one important extension and three minor extensions were discovered. The trend toward deeper drilling is shown by the fact that 97 wells were more than 5000 ft. deep, including 80 over 6000 ft. and 13 over 7000 ft., although the depth record of 7973 ft., made in 1935, was not exceeded. Geological Section Deeper and more extensive drilling during the past few years, not only in south Arkansas but also in adjacent parts of north Louisiana and east Texas, has furnished much important geological information and has brought out some very unexpected facts in regard to structural and depositional conditions in the series of formations laid down in the interval between the end of the Pennsylvanian and early Cretaceous time. It is now evident that an important basin of salt deposition existed in the Arkansas-Louisiana-Texas area, but it is still an open question whether this salt basin was contemporaneous and continuous with the even larger Gulf Coast salt basin extending from Mississippi to Mexico. The accompanying columnar section (Fig. 1) shows the producing zones and names that have been applied to the several subsurface formations, most of which have no outcrop equivalents. This is for the convenience of readers unfamiliar with recent developments, but the correlations and nomenclature cannot yet be considered final. These formations will be discussed in more detail in various papers to be published in the near future.

Jan 1, 1938

The Committee on a Standard Gauge have been constantly engaged, since their appointment, in the duties assigned to them.§ They have corresponded with different persons interested in the manufacture and use of gauges in this country, and have received from several of them important information. They have also entered into correspondence with the governments of England, France, Gerniany, and Russia through their Consuls, ant1 with Austria directly. The Consuls of Germany and France

Jan 1, 1879

Jan 1, 1919

By Gifford Pinchot

The proposition that forest reserves are, from the mining point of view, not only desirable but necessary, is not one which would have received enthusiastic support in. the West a year ago. It is, nevertheless, easily susceptible of proof. A short and simple statement of the facts has seldom failed to carry conviction as to the wisdom of the forest-reservation policy. Hostility to mining interests was never contemplated by the men to whom the forest reserves are chiefly due, and it is most unfortunate that the opposite belief should have obtained wide

Jan 1, 1899

Jan 1, 1935

By A. S. Eve

IN the spring of 1930, the question was raised as to the possibility of estimating the depth to which the pyrrhotite-nickel deposit at the Falconbridge mine extended in the earth. This body is 7500 ft. long, it dips at 80° to the north, and it is fairly straight with slight sinuosities. Dr. F. W. Lee suggested that it might be possible to solve the problem by measuring the vertical magnetic intensity, with a good magnetometer, both near the surface of the earth and also at a level a 'few feet higher in the air. The writer regarded this suggestion with some scepticism, but it was decided to put the scheme to a prac¬ tical test. In July, 1930, Dr. Lee, Dr. Keys and I ' the writer, with Mr. Joyce and Mr. Belloc as assist¬ ants, made a firm, light wooden platform (Fig. 1) E measuring 4 by 4 ft. on the top, which was 10 ft. above ground. This platform could be moved easily a few yards by four men, and carried across I country in a wagon or by motor truck. Some iron nails were used in its construction, but we were not able to detect their influence on the - Askania magnetometer. Nevertheless, in future work, the use of iron should be completely avoided. Readings were taken along a traverse at right L angles to the orebody, at several stations, both on FIG. 1.-VERTICAL the ground and on the platform. The excess read- ASKANIA MAGNETOM¬ ETER ings, over the dike, as compared with those about 10 ETER ON A FT. HIGH. PLATFORM 800 ft. away, are shown in Table 1. The largest reading, 6.8, is open to suspicion and should be rejected. The depth of the top of the orebody is known by electrical survey, and by actual drilling, to be about 112 to 123 ft., and the covering is sandy glacial drift. Similar readings were taken over a long straight magnetic diabase dike. These also are shown in Table 1. The magnetic vertical intensity is consistently less at the higher level, which is l0 ft. above the lower level.

Jan 1, 1931