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By Ellis Clark

The greater portion of the brown ore in the vicinity of Easton, along the north slope of the Lehigh Mountain or Durham range of hills, is obtained from mines instead of from open cuts or quarries, as is the case in the ore-beds in the western part of Northampton County, in Lehigh County, and in Berks County. The reasons for this method of procedure are various, and the principal causes of the shaft and regular mine system of working being adopted instead of the open air cuts, are: First, the large amount of stripping that would be necessary, as the richer and more valuable portions of the ore do not appear to be found as near the surface as those in other portions of the Kittatinny valley; second, the occurrence of the ore in regular beds, interstratified with the clay, and, to a less extent, in pockets or erratic deposits, as is the case in the mines of Lehigh County; and third, on account of many of the mines being situated at the immediate base of the Lehigh Mountain, where the surface water would be in such large quantities as to be with difficulty handled, and where the subsequent caving in of the sides of the open cut would be almost certain to expose the gneiss rock, which is water-bearing, the large quantities of water coming from which would probably drown out the ore-bed. Shafts, and a regular system of gangways and mining are therefore required by the configuration of the surface, the depth of the deposits and their geological structure. The ordinary size of the shafts is about four feet square, but where an extensive plant of pumping machinery is required the size may be increased to eight feet by six, with two compartments for the hoisting and pump-shaft respectively. A man-way, consisting of ladders with rests at intervals of twenty or thirty feet, is comprised in the pump-shaft, the wire rope being used for purposes of ascent and descent only in exceptional cases, on account of accidents which

Jan 1, 1879

By R. Hogg

Sintering is a process in which the pore structure of an agglomerated powder is modified. For many applications, it is desirable to be able to control the pore structure in order to optimize such properties as mechanical strength and reactivity (availability and accessibility of solid surfaces to reactant gases, for example). In general, these properties will be determined by the total porosity and the pore size distribution of the agglomerate. In the work described in this paper, a physically realistic mathematical model for the sintering process has been developed. The model is based on the usual assumption that the pore system in an agglomerate can be treated as a network of interconnecting, cylindrical pores of continuously varying size. It is further assumed that the total pore length is conserved during the course of the sintering process. Using standard expressions for the rate of shrinkage of an individual pore, the model can be used to predict the changes in total porosity and pore size distribution as sintering proceeds. Experimental pore size distributions, obtained by mercury intrusion porosimetry, for the sintering of oxides appear to be in general agreement with the predictions of the model.

Jan 1, 1977

By S. C. Riemer, I. Iwasaki, J. N. Orlich

The effects of percent solids, mill loading, and grinding time on product size distribution and ball wear were studied in a laboratory ball mill for a taconite ore. Mild steel balls and HCLA steel balls were used to examine the role that ball hardness play in grinding. Net production of - 44-µm (- 325-mesh) material reached maximum at 70% solids, whereas the ball wear decreased as pulp density increased. HCLA steel balls ground the taconite ore finer than mild steel balls under otherwise identical conditions. Examination of ball surfaces with a scanning electron microscope suggested that corrosive wear was mini- mal under nitrogen flushing conditions, and that grinding with mild steel balls involved nipping rather than attrition, whereas grinding with harder HCLA balls involved both nipping and attrition. Pulp viscosity controlled the thickness of pulp layer on balls, thereby affecting grinding efficiency and ball wear.

Jan 1, 1986

QUICKSILVER is a body that consists of flowing and liquid materials, almost like water with a shining whiteness; it is composed by Nature of a viscous, subtle substance with an overflowing abundance of moistness and coldness together. This composition, in the opinion of the philosophic alchemists, is a thing that is very disposed to become metal-indeed they say that it is the original seed of all metals. When it lacks the warmness and dryness or the specific time that they require, it cannot congeal and so remains in the form that we see as an imperfect thing without becoming metal. These clever investigators have also called it mercury in consideration of its properties, perhaps because of its resemblance to the planet of him whose actions place him between gods and men, according to the poets in their stories. Thus these investigators think that this has a similar place among perfect metals, since it is the primary mineral matter. It might also be that they called it so because like the god Mercury it is winged and fugitive, and by virtue of its powerful subtlety penetrates all things and can issue forth from them at will. But let it be called by any name they wish-it does not matter to us. I, like them, shall sometimes call it mercury and sometimes [23 ] quicksilver as it has been named to me, and you will understand it as such. Now I shall leave aside the disputes on whether it is the primary matter of metals or not, since I have said enough concerning this question in the first chapter of the First Book. In order to approach what the philosophers say about it, I say that it may well be material about to be converted into metal, but since it is seen to be so ill-proportioned and so badly decocted, I cannot believe that it can be disposed to the generation of all kinds of metals. Indeed, if it is, I think that if its necessary processes had not been interrupted it would be more apt to generate lead, tin, iron, or even silver rather than copper or gold. And if we wish to consider it in relation to the natural complexions [of metals] or to the power of the, planets, I think that mercury is far distant from those of gold and from the power of the sun and of the moon. Therefore I say that if it is not what I have said, it is a thing that Nature has been pleased to make as it is. I am led to say this because all of it that I have seen has had the same

Jan 1, 1942

By J. C. Miller

In offshore oil drilling as it is done today, accidental blowouts cause considerable damage lo the environment. Public alarm over such accidents has already resulted in a number of legislative proposals which appear to favor the cessation of all drilling on the Federally owned continental shelf. Present concern for the environment and the increasing water depths associated with offshore drilling suggest the desirability of applying underground mining technology to offshore petroleum exploration. If offshore drilling were to proceed from underground accesses to the continental shelf, accidental damage to surface waters would be avoided, and so would the difficulties of exploring in deep or ice-filled waters. The specific approach proposed here is intended as a preliminary to offshore oil exploration in a known field or geologic structure. The end result of this method would be an on-shore vertical or inclined shaft terminating in an operating tunnel or haulageway as shown in the illustrations. From the haulageway, branching access tunnels would lead to drilling compartments. With this arrangement, it appears likely that one operating tunnel could serve all lessees ill a particular unit operation. Although an inclined shaft is not illustrated, this would probably be more practical than a vertical shaft owing to the length of the casings and the character of other equipment used in oil producing operations.

Jan 1, 1971

By Maurice Ewing, L. Don Leet

Assuming that wave velocities in seismic prospecting increase as a continuous linear function of the depth, the authors have derived formulas for computing, from two time-distance observations, the amount of velocity increase, depth of penetration and a graphical determination of the path of the vibrations, and have discussed the ground, reflected and refracted waves. The application of the formulas is illustrated numerically. Earlier Investigations Observations of the energy propagated from the center of an earthquake disturbance have been used to give information about the velocities and paths of elastic waves in the interior of the earth. One method of accomplishing this depends on the use of the times of transmission. Herglotz(7) § and Bateman(3) obtained a solution of the integral equation involved, which determines the velocity of propagation at any point as a function of the distance from the center of the earth, with no assumption as to the manner in which the velocity of the disturbance varies with depth below the earth's surface. The expressions on which the value of the time and the form of the ray of propagation depend contain an unintegrable definite integral, involving the velocity as an unknown function of the distance from the center of the earth. Wiechert and Zoppritz(15) obtained a manageable form for this function by assuming a law of variation which required a constant curvature form for the path within each of a succession of concentric spherical layers of the earth. C. G. Knott(9) worked out the problem for the first time by an absolutely rigorous method from the data of observation (Zoppritz-Turner tables), without making any assumptions as to the functional relationship connecting the speed of propagation and the distance from the earth's center. His method is a numerical solution of an integral equation, giving each velocity and the corresponding distance from the center of the earth in figures.

Jan 1, 1932

Assistant Professor of Mining Engineering.-Mining engineer to teach mine surveying, mine mapping, assaying, etc., but not metallurgy. Location, Ohio. Salary, $1800 per annum. No. 379. Metallurgist.-Experienced metallurgist capable of running 25-ton blast lead furnace. Man who knows the country and speaks Spanish desired. You may know that this state is in peaceful conditions and that even during the worst time of the revolution there were several mining concerns never idle. Besides, its resources are wonderful, and once a man gets started, he will find many possibilities. Notwithstanding that Sinaloa is a mining state, our smelter will be the only lead smelter on this coast. Location, Culiscan, Sin., Mexico. No. 381. Quarry Superintendent.-Engineer experienced in limestone quarry work for position as superintendent; must be capable of producing results; must increase output of quarries from 4 to 12 cars per day. Young man with abundant energy is desired. Permanent position, chance to grow up with the company. Location, New Jersey. Salary depends upon the man. No. 382.

Jan 4, 1919

By A. H. Jones

The Belmont mill at Tonopah, Nev., was designed and constructed by the Belmont staff. Ground was broken in August, 1911, and milling operation started July 25, 1912. The metallurgical flow sheet, and the machinery adapted 60 carrying out operations in accordance with this plan, were decided upon from experience gained in the treatment of Belmorlt mine ores at the old Belmont mill at Millers, Nev. The detail drawings were madc by the engineering staff of the Tonopah-Belmont Development Co., under the supervision of Otto Wartenweiler, who also had direct charge of the construction, consulting with the General Superintendent of the company, Frederick Bradshaw, and the writer.

Jan 1, 1916

By Keith T. Griffiths

INTRODUCTION The Empress Nickel Mine is situated forty-eight kilometres west of Kadoma in the Zhombe Communal Land of Zimbabwe. The mine came into operation in late 1968 based on a proved and probable ore reserve of twenty million tonnes. The initial production rate was 55 000 tonnes per month from underground. This was boosted to 85 000 tonnes per month in mid 1970 when the opencast operation came into production. The mining method at Empress is sub-level open stoping with main haulages mined at ninety metre intervals and sub-levels at eighteen metres. The extremely wide ore body of up to one hundred metres in width has necessitated leaving extremely large rib pillars and sill pillars in position to maintain mine stability and to act as regional support of the hanging wall. In early 1976 the opencast operation had reached its final economic depth and it was then necessary to increase underground production to 85 000 tonnes per month. Since a large portion of the ore reserve remained in both rib and sill pillars, it was necessary to embark on a positive pillar recovery programme. For this reason it was decided to introduce a sandfilling programme for the mined-out stopes and a modified system of sub-level open stoping with post filling of the lower stopes. ORE BODY GEOLOGY AND GEOMETRY The Empress orebody outcrop has a strike length of nine hundred and fifty metres on a north west - south east axis. It is a steeply dipping (65' - 75') tabular orebody of gabbroic rock which has been extensively altered. The north west - south east strike length of nine hundred and fifty metres on surface reduces to some two hundred

Jan 1, 1983

BROWN iron ore reserves of Franklin county are being proved economical by Heavy-Media separation at the Blackburn mine of the Shook & Fletcher Supply Co. about 120 miles north-west of Birmingham. The ore occurs under a cover of ferruginous chert and gravel and these materials are also disclosed as streaks in the ore body as it is mined. Previous methods of jigging and hand sorting the ore became too expensive because of rising wages but the use of Heavy-Media separation has proved economical and is making Franklin county the most promising source of additional reserves of brown ore.

Jan 12, 1950

By H. E. T. Haultain

The study of rock crushing or grinding in tube-mills is difficult on account of the large size of the units employed in the field and the large number of variables entering into the problem. Three or four years ago, in the laboratory of the Department of Mining Engineering of the University of Toronto, a serious effort was commenced to study the matter under laboratory conditions. Experiments were carried on in a cylindrical tube-mill 18 in. long and 12 in. in diameter, inside measurements,

Jan 1, 1923

By H. E. T. Haultain

The study of rock crushing or grinding in tube-mills is difficult on account of the large size of the units employed in the field and the large number of variables entering into the problem. Three or four years ago, in the laboratory of the Department of Mining Engineering of the University of Toronto, a serious effort was commenced to study the matter under laboratory conditions. Experiments were carried on in a cylindrical tube-mill 18 in. long and 12 in. in diameter, inside measurements,

Jan 1, 1923

By L. W. Pommier, L. R. Plitt, F. B. Brien

L. R. Plitt (Assistant Professor of Mining and Metallurgy, University of Alberta, Canada.) — It is indeed encouraging to see rheological studies being carried out in a mineral engineering school. The bulk of the work being done today in applied rheology seems to be concerned with the behavior of polymeric solutions and thus has limited application to the solid-liquid systems encountered in mineral beneficiation. The authors have approached the problem by carrying out a dimensional analysis which showed that for power law fluids the drag coefficient, Ds, must be some function of a generalized Reynolds number which has the form: If the power law adequately describes the behavior of a fluid, the dimensional analyses predicts that the Ds - RN function should hold for all values of n' or any other dependent variable. The experimental evi-

Jan 1, 1968

By Richard L. Coleman

Metallurgical testwork to develop a flowsheet is described, beginning with background information required right through to a final process flowsheet. Both laboratory and pilot plant testing are reviewed with emphasis on the former.

Jan 1, 1978

P. E. McKinney,* Washington, D. C.-Observation made after examination of a number of defective gun forgings, together with a history of their manufacture, has strongly suggested that so-called "flakes" and woody or fibrous fractures are not necessarily analogous and are often caused by entirely different conditions. While some flaked bars may show fibrous areas in the fracture, it does not necessarily follow that the conditions causing these areas are the same as cause the fibrous, or so-called laminated, structures so commonly met in gun forgings subject to transverse tensile test; the fibrous structure formed in some flaky bars are merely incidental to the conditions causing the flakes. It is believed that the so-called flakes, or bright silvery spots, are mainly due to inherent physical defects in the steel, which existed at the very origin of the steel, rather than metallographic defects caused by subsequent irregularities in mechanical or thermal treatment. While great care in forging and treatment may, in a measure, tend to overcome the evil effect of the defects, with many heats of ingots, no such precautionary measures are needed to produce perfect forgings- and with such heats of steel it would be impossible, no matter how carelessly handled, to produce intentionally a forging containing the defects commonly known as flakes. It has been found possible, on several occasions, to actually predict flaky forgings from an inspection f the ingot after it had solidified, and in such cases no amount of careful forging or heat treatment would prevent the occurrence of such defects in the forging. The inspection of the physical condition of the ingot, and especially the character of the shrinkage on. the top of the ingot, has been given too little thought and study in this connection.

Jan 5, 1919

By Shozo Saito, P. A. Beck

Mettrllographic and X-ray diffraction study of Cb-Co alloys in the Composition range of 7 to 33 nt. pct Cb, after annealing at 1175 °', showed that near 25 al. pct Cb on MgNi,-lype hexagonal Laves Phaseexists in a narrow composition range, and that an MgCl- type cubic Laves Phase occurs between approximately 27 and 32.6 ut. pd Cb. Lattice parameter and density measures indicated that, in both phases. the deviations from proper Loves sloichimetry result from the substitution of cobalt atoms for some 0f the columbium atoms. Tlle same phases occurant 1000'C, together with an additional phase of unknown structure, which appears between the hexagonal Laves phase and the cobalt-bose terminal solid solutions KOSTER and Schmid' identified a phase corresponding to the composition VCo,, and more recently the crystal structure of this phase has been determined.' In the Ta-Co system Korchynsky and Fountain recently found two intermediate phases at the composition Taco,, one of them metastable. In contrast to the V-Co and the Ta-Co systems, in the Cb-Co system no intermediate phase has been found4 at the composition CbCo,. The present investigation was undertaken in order to reexamine the question of the existence of such a phase. EXPERIMENTAL PROCEDURE Twelve alloys were prepared by arc-melting in a water-cooled copper crucible under helium atmosphere. Electrolytic cobalt and 99.9 pct pure colum-bium powder have been used as starting materials. It was found that melting losses can be reduced by compressing the colunlbium powder in the form of thin pellets before melting. For the alloys used the melting losses were not higher than 1 pct. The intended compositions of all alloys and the chemical analyses of three of them are given in Table I. Specimens from all alloys were annealed in evac- uated fused silica tubes at 1175°C for 3 days and quenched in cold water. A second set of specimens of most alloys was annealed at 1000°C for 7 days and then quenched in cold water. The annealed and quenched specimens were examined metallographically, using the following etchant: 60 pct glycerine +20 pct H,NO, + 10 pct HF + 10 pct water. Powder specimens for X-ray diffraction were prepared by crushing annealed solid specimens in a mortar. Alloys containing 27.3, 28, 29.7, and 32.6 at. pct Cb annealed at either 1175" or 1000°C were very brittle and it was found unnecessary to reanneal the powders. However, alloys containing 24.8 at. pct Cb, or less, especially those annealed at 1000°C, were much less brittle and re-annealing was required to remove the strains present in the crushed powders. In each case reannealing was done at the same temperature at which the corresponding solid specimens were annealed and it, too, was followed by quenching in cold water. In many instances X-ray diffraction patterns were also taken of the polished and etched solid specimens and compared with the corresponding X-ray diffraction patterns obtained with powders. The X-ray diffraction patterns were taken with an asymmetrical focusing camera, using CrK radiation. For precision lattice parameter measurements some X-ray diffraction patterns were taken with a symmetrical focusing camera, again using CrK radiation. EXPERIMENTAL RESULTS A microscopic examination of the alloys annealed at 1175°C revealed that the alloy containing 25.5 at. pct Cb was composed of a single phase, but that the 24.8 at. pct Cb alloy did contain a small amount of a second phase, identified by means of X-ray diffraction as having a fcc structure, undoubtedly the terminal solid solution based on cobalt. Apart from the few very weak lines corresponding to this minor phase, the X-ray diffraction patterns of these alloys could be well interpreted in terms of a MgNi,-type hexagonal Laves phase structure. The indexing of the X-ray diffraction pattern, Table 11, yas based on the lattice parameter values a, = 4.740A and c,

Jan 1, 1961

CHICAGO SECTION CHARLES H. MACDOWELL, Chairman, LUTHER V. RICE, Vice-chairman, HENRY W. NICHOLS, Secretary-Treasurer, Field Museum of Natural History, Chicago, Ill. ALEXANDER K. HAMILTON, G. P. HULST, HENRY P. HOWLAND, FREDERICK T. SNYDER. A meeting of the Chicago Section was held at the Chicago Engineers' Club on the evening of March 30, 1918, on the occasion of the visit of the President, Vice-president. and Secretary of the Institute. The meeting was called to order by Henry W. Nichols, Secretary of the Chicago Section. The first speaker of the evening was Mr. Allen, Deputy Fuel Administrator for the State: of Illinois, who spoke on the problems and difficulties encountered by the Fuel Administration during the past -winter, He paid high tribute to the spirit of cooperation shown by the

Jan 5, 1918

By Harry Roe

THE power drag scrapers and the slackline cableway excavator have been called "long-range excavators." Broadly, their field of usefulness is restricted to work in which their long range of action permits them to operate economically, and which other, possibly more conventional, excavating units cannot do. Both of these machines dig or lift material and transport it to a clumping point. They combine these two functions in a single machine, nearly always in a single straight-line motion. FIG. I.-SIMPLE FORM OF POWER DRAG SCRAPER. The purpose of this paper is to examine the important features that distinguish the machines in this group from each other, as well as from other groups.

Jan 1, 1937

Jan 1, 1909

By P. J. Ehret

By and large, I agree with many of the precepts discussed in the Saperstein paper. I believe there is much more that can be done on the local level to involve both government and planning in the mine permit review process. Admittedly, much can be done to improve discussion between the state regulatory authority, local authorities, and mine operators. However, I strongly disagree, as suggested in the paper's conclusion, that such a system, as outlined in Saperstein's paper, could result in a reduction of review time or a lowering in the cost of permitting. The implementation of such a system by its very nature would only add a new level of bureaucracy to an already cumbersome process. This system, in my opinion, would only add to the cost of permitting and the time necessary to obtain a permit. Admittedly, it would achieve the result of adding local influence into the permitting process, but at what off-setting cost? It has been my professional first-hand experience and observation in the permitting and lands unsuitable processes to note that under the present system, local governments that do feel they have a stake in local mines and actively advocate their position (not simply comment), have had significant input into the conduct of mining and reclamation plans in their areas. Mining companies that mine in these areas are aware of local interests and attitudes, and do consider them in their plans. Simply put, local governments that want to get involved and want to play significant roles can and do. Those that do not advocate a position or have no input to offer do not. Although the present system is not as direct in effect in regard to local control as Saperstein's, it does work. It does so without the red tape that would result from developing miniature regulatory authorities in every county in which mining occurs. Although local input is important, there are many more sections of the Surface Mining Control and Reclamation Act (SMCRA) than Sections 508(a)(8) and 522(a)(3)(A) that also are important. It appears Saperstein's paper may overindulge these sections. An additional specific comment is made in regard to the statement that while local areas benefit from mining (wages, salaries, and purchases), they also endure environmental deterioration caused by mining affects. It is believed that the whole purpose for which SMCRA and its resulting regulations were enacted and developed was so mining would not be permitted if significant environmental deterioration could occur. Therefore, it could be argued that this point under current law is moot.

Jan 1, 1985