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By Frank H. Kneeland

Safety First is a popular motto—most mining companies have adopted it. It is probable, however, that in the majority of cases it is only a motto and gets no further than the office stationery or the bulletin board at the mine's entrance. In but few industries is there employed a greater diversity of machinery and mechanical devices than in coal mining. The list ranges all the tray from mechanical stokers to wood-working machinery and undercutters. Many of these devices, particularly those employed in wood working, are extremely dangerous. In 1913,23 per cent. of all fatalities occurring in coal mining in the U. S. were caused by machinery of some sort or other. Although the forms of accidents occurring with mining machinery are legion, they generally arise from one or more of five causes: (a) Falls from ladders, platforms, etc.; (b) coming in contact with moving machines or parts thereof; (c) electric shocks; (d) failure of some machine part; (e) mismanipulation of valves, levers, switches or other hand-operated controlling devices. The steps which may be taken to prevent accidents from the above causes are almost as numerous as the accidents themselves. There is, and can be, no panacea for all mishaps, nor for any one class of accidents. There is no mathematical or other formula that will bring immunity under any set of conditions. Common sense is the only guide. The remedy for the first-named class of accidents is simple and generally effective—namely, make the staging, ladder, platform, or other support, abundantly strong to carry any possible weight that it may be called upon to bear; provide ample railings on platforms or runways, and non-slipping feet on movable ladders. Coming in contact with moving machine parts is one of the greatest dangers met with in the operation and maintenance of mining machinery. Unfortunately, machine manufacturers have not as a class adopted the idea of thoroughly protecting and incasing the dangerous parts of their product. No one has, or should have, a better or more thorough knowledge of what the dangerous parts or elements of a machine may be than its builder. The desire to construct a piece of mechanism as cheaply as

Jan 1, 1915

By P. Somasundaran

Adsorption of a nonionic polyacrylamide (PAM), an anionic polyacrylamide with sulfonate functional groups (PAMS), and a cationic polyacrylamide with amine functional groups (PAMD), on hematite was investigated as a function of different solution conditions. Adsorption results indicate that the major mechanisms of adsorption of polyacrylamides on hematite is through hydrogen bonding, with electrostatic forces playing a secondary role. All the polymers exhibited irreversibility of adsorption upon dilution. Also, entropic effects were determined to be important in adsorption. Surface chemical properties of hematite and solution chemistry of the polyacrylamides are considered to explain the polymer adsorption behavior on hematite.

Jan 1, 1985

By John Blatchford, H. O. Hofman

The leading antimony mineral is stibnite. In smelting stibnite ore two processes are available, precipitation and roasting-reduction. The former is suited only for high-grade ores. As low-grade ores are more common than high-grade, roasting-reduction is of greater importance than precipitation. In the roasting process the aim may be to leave the oxidized antimony in the ore, or it may be to volatilize as much of the antimony as possible, collect the volatilized oxide as a rich intermediary product and smelt it for antimony, leaving the gangue poor enough to be considered a waste product. Whichever way the roast is conducted certain difficulties inherent in stibnite are encountered. These are: 1. The low melting point of stibnite which, according to Pélabon,' is 550°C., according to Wagemann2 540°C., and according to Borgstroma 546°C. 2. The ignition temperature: According to Friedrich,4 stibnite, if heated in air, begins to oxidize at 290°C. if the size of a grain is 0.1 mm. in diameter; at 343", if 0.1 to 0.2 mm.; and 430" if 0.2 mm. 3. The fusibility of a mixture of Sb2S33 and Sb203 which in the form of kermesite (Sb2S3)z.Sbz03 melts at 517°C.6 4. The volatility of Sb2Ss and SbzOs, for which no numerical data appear to exist, although practical experience has shown that they are volatile at low temperatures. As regards the oxidation of metallic antimony, we have the experimental evidence of C. F. Plattner6 that when fused and brought to a red heat, it burns with a bluish-white flame to Sb2Oa which passes off as a

Jan 1, 1916

By David B. Campbell

Production of both metallurgical and thermal coal represents a significant sector of the mining economy of British Columbia. The coal measures are located in the Rocky Mountains, and the majority of the coal is produced by open pit mining. The coal seams occur interbedded with siltstones, sandstones, mudstones, and shales. Consequently, large volumes of waste rock are generated in the course of open pit mining. The waste rock is consigned to waste rock piles that of necessity must be developed on moderate to steeply sloping terrain. Some of the waste dumps currently under development will ultimately contain in excess of 500 million cubic meters of material, and some of the proposed waste piles will attain heights in excess of 300 m. These waste piles must be developed in a manner that will assure their stability through all stages of development, as well as over the long term after mining operations have been completed. This paper describes methods of waste dump development, factors affecting stability, modes of potential failure, and a simple method for monitoring movements to provide a warning of pending unstable conditions.

Jan 1, 1985

By Cyril Stanley Smith

METALLURGISTS - or at least metals - have been of central importance in most of the inventions that have shaped the course of man's history. From the first Bronze Age tools to the iron armor of the Roman soldier, the cannon, cast type for printing, the steam engine, the electric motor and modern electronic devices, technological progress has revolved around some particular property or comb nation of properties selected from the metallurgist's repertory. The recent utilization of the energy of the atomic nucleus (currently for military purposes alone but with great constructive implications for the future) is no exception to this, although the use of uranium and plutonium in metallic form is of secondary importance, since the significant properties are those of the nucleus and not of the electrons responsible for metallic behavior. THE METALLURGIST AND ATOMIC ENERGY The metallurgist has a role of central importance to play in the future development of atomic energy. Not only must he make and shape the fissionable materials themselves, but he must also develop auxiliary materials to withstand the extreme conditions imposed on nuclear reactor components by the high heat-transfer rates needed for efficient utilization of the fuel and by the perplexing but interesting effects of radiation on the structure and properties of materials. It is doubtful if there is currently any other field potentially more rewarding to a young metallurgist. Quite apart from the all important but relatively short-range considerations of national security is the vision of the effect on civiliza-

Jan 1, 1953

By Raymond Mancha

WHEN calculating the pressure-volume characteristics of projected mine-ventilat-ing circuits by orthodox methods, certain basic assumptions are required in order to employ the various available empirical data. It is assumed, for example, that the mine air is an incompressible fluid subjected to isothermal flow, an assumption suffi-ciently accurate for practical purposes since pressure and temperature differentials are small throughout the average circuit. A more erroneous assumption, however, is that all air is accounted for as it travels throughout the mine. No attempt is usually made to evaluate stopping leakage as it occurs; instead, the air volume required at the last crosscuts is assumed to enter the mine, travel the vari-ous intake air courses intact, sweep the workings and travel out by the return air courses to the point or points of exit from the mine. Actually, there is a leakage of air from intake to return at every stopping, the quantity of this leakage depending upon the tightness of the stopping and the pres-sure difference across the stopping. Unfortunately, a lack of empirical data and knowledge of the condition of individ-ual stoppings makes an exact analysis of underground stopping leakage impossible. Generally, leakage is most severe through the old stoppings outbye the circuit. These are also subjected to higher pressure differ-ences than the newer inbye stoppings. Therefore the circuit air volume diminishes at a decreasing rate progressing from out-bye to inbye the circuit.

Jan 1, 1940

By E. E. Krist, W. H. Sweetser

Sampling of an orebody has a number of purposes. In the initial phase, it is necessary to define the limits of the orebody and mineral content to the extent that it can be stated whether it is, in fact, an economic orebody. Also, samples must be generated so that geological and metallurgical evaluations can be made. Finally, when sufficient information concerning the geology, mineralogy, and metallurgy are known, a mining method and plan can be developed and the metallurgical; plants constructed to process the ores as they become available. With today's large, complex open pit copper mines, single sampling methods would be inadequate. Diamond drilling, percussion drilling, underground shafts and drifts all play a part in the total orebody, definition. At Anamax Mining Company's Twin Buttes mine, sampling and orebody definition.wil1 eventually lead to the existence of three metallurgical processing plants and, perhaps, an underground mining operation. A 30 000 tons per day sulfide concentrator was placed in operation in September 1969 and a 10 000 tons per day oxide leaching plant was placed into service in May 1975. The aim of this presentation is to historically discuss the orebody sampling that has been done at Twin Buttes, briefly describe the orebody, and discuss the analytical methods currently used to assist the geologist, metallurgist and mine planner in their respective evaluations.

Jan 1, 1978

By John Cogan, P. M. Gomez

A typical problem in applied rock mechanics is an accurate prediction of support requirements for deep rock cuts. This paper presents experience with this problem as obtained from excavations for a powerhouse at the Pine Flat Dam near Fresno, California. The project, sponsored by the Kings River Conservation District is still under construction. Highly jointed and weathered rock was discovered during initial excavation. Wedge failures along clay filled joints and bedding planes presented potential support problems. Detailed mapping of joints and beds was undertaken to establish basic patterns of all rock discontinuities including mean orientations and an estimate of orientation variations. Rock bolting patterns were devised to meet these patterns as excavation proceeded. Shear friction angles across joints and beds were estimated from rock wedge fallouts. Friction angles as low as 27º were identified on highly weathered joints. Weathering strongly influenced stability conditions. Examples of bolting patterns to stabilize critical slopes are presented.

Jan 1, 1982

By A. J. Carlson, G. M. Marincel, M. L. Hovland, J. H. Healy

Research personnel of Erie Mining Co., a pioneer taconite mining firm on the Mesabi Range, have invented a new method to make an effective 325 mesh separation at high tonnage rates over stationary screens. The company regards this development as historically significant in that it represents the first successful method to commercially screen large tonnages of ore at fine sizes. Erie, which is now completing an expansion program at its plant site near Hoyt Lakes, Minn., has incorporated this screening method as part of that expansion. When completed, the concentration plant will produce 10.3 million tons of iron concentrate, all of which will have been efficiently screened at 325 mesh.

Jan 4, 1967

By G. H. Kennedy, H. E. Criner

CYCLONE thickeners are "hydraulic centrifuges" designed either to produce a maximum practical separation between the water and solids of a feed slurry or to classify the slurry solids according to particle settling rate. The possibilities of utilizing the thickener to "close" plant water circuits have been investigated. Since the thickener becomes an integral part of the plant water circuit when installed, the basic means by which the solids content of all circulating water systems must be controlled is reviewed. All coal not separated from the circulating water by means of dewatering screens or settling devices must be bled from the plant at the same rate as they are being fed or created by degradation. If this were not true, the circulated volume would finally be completely filled with solids. If the rate of bleed is low, the solids concentration in the bleed and circulating water generally will be high. To keep a reasonable circulating water concentration, large amounts of fresh water must be supplied and the bleed rate must be high. These conditions are usually undesirable because of the difficulty in securing fresh water, the loss of large quantities of coal, and the pollution of nearby streams. Thickeners are the primary stage in the separation of the water contained in the bleed from the coal. Since a thickener, when operating with reasonable efficiency, usually cannot be expected to deliver an underflow containing less than 50 pct water, secondary dewatering devices such as a slurry screen or vacuum filter must be used to separate additional water from the bleed. The surface area required by the filter or screen will be nearly proportional to the total water which must be handled, and therefore the thickener becomes necessary to hold down the original cost. The water separated from the coal is then returned to the plant circuit to maintain the water balance and thus becomes the source of fresh water. It is not necessary to return clear water to the plant to maintain control of the circulating water concentration. It is only necessary that the bleed dewatering devices remove coal in all sizes at a rate equal to that at which these sizes are entering the circulating water. However, practically speaking, in order to maintain low solids concentration, it is usually necessary that the thickener have good recovery characteristics on bituminous coals in those sizes down to 400-mesh. The thickener can remove the smaller sizes from the closed-circuit system at the "solids in" rate and prevent their "build up" in the circulating water as shown in Fig. 1. With the portion of the feed water going directly to the underflow, comes the very fine solids not concentrated by the cyclone. All the larger solids are removed from the feed and delivered in a concentrated condition at the underflow. To apply thickeners with some reasonable assurance that operating requirements will be met, it is necessary to know the rate at which solids of all sizes must be removed from the circulating water and to know the thickener characteristics. The required removal rate of fine solids not recovered by other dewatering devices may be estimated from the size distribution and tonnage of the plant feed with a reasonable allowance for degradation in the circulating water system. A more reliable estimate may be secured by sampling the plant bleed water during a constant load period.

Jan 1, 1952

By S. Suphi Yavasca, A. M. Gaudin

This paper is intended as a contribution to our knowledge of the mechanism of comminution and of the work of crushing. In a previous paper1 it was shown that with quartz comminution proceeds as follows: 1. The size distribution of broken fragments made by a single fracture is such that the new surface on each grade is the same. 2. Multiple fracturing results in a size distribution such that in the he sizes the surface per grade is the same in every grade; in coarse sizes the surface per grade decreases gradually with increasing size. In that paper it was mentioned that determinations on minerals other than quartz were in course of completion in order to establish the generality of these observations. In this paper, condensed data1 are presented for galena, pyrite and glass. Galena and pyrite are crystalline materials and glass is noncrystalline. Galena has excellent cubic cleavage. Pyrite, although cubical, does not have marked cleavage. Quartz, on which the original determinations were made, does not cleave and although crystalline (hexagonal) breaks conchoidally. Glass breaks much like quartz. It is apparent, therefore, that the minerals selected represent some range in character of the solid without covering all possible types. Glass Fifteen glass marbles were crushed individually in the pendulum crusher described in the preceding paper,' then subjected to careful screening for 30 min. Six sized fractions were selected and cleaned in a hot 0.12 N solution of hydrochloric acid, washed with distilled water and dried on a hot plate. This was followed by an examination with a binocular microscope, to remove foreign matters not eliminated in cleaning as well as to eliminate "compacts" of fine particles. These compacts are groups of he irag-ments that seem to be mechanically stuck together as a result of localized compacting during the comminution operation. The presence and the abundance of these compacts may be related to the amount and direction of the forces applied in different crushing devices. Since, properly, such compacts should be entirely eliminated in the sizing analyses, it is necessary to remove them to the last before making surface determinations on sized fractions. For example, with a — 28 + 35-mesh glass the surface areas of two samples, one cleaned with acid and under the binocular, the other only washed, were 102 and 172. cm' per gram, respectively. Examination of the samples under an Ultropak microscope showed that washing alone failed to remove the compacts and also that it fails to remove certain fine dusts attached to the particles. Cleaning with acid loosens the fine dusts and

Jan 1, 1947

By S. Suphi Yavasca, A. M. Gaudin

This paper is intended as a contribution to our knowledge of the mechanism of comminution and of the work of crushing. In a previous paper1 it was shown that with quartz comminution proceeds as follows: 1. The size distribution of broken fragments made by a single fracture is such that the new surface on each grade is the same. 2. Multiple fracturing results in a size distribution such that in the he sizes the surface per grade is the same in every grade; in coarse sizes the surface per grade decreases gradually with increasing size. In that paper it was mentioned that determinations on minerals other than quartz were in course of completion in order to establish the generality of these observations. In this paper, condensed data1 are presented for galena, pyrite and glass. Galena and pyrite are crystalline materials and glass is noncrystalline. Galena has excellent cubic cleavage. Pyrite, although cubical, does not have marked cleavage. Quartz, on which the original determinations were made, does not cleave and although crystalline (hexagonal) breaks conchoidally. Glass breaks much like quartz. It is apparent, therefore, that the minerals selected represent some range in character of the solid without covering all possible types. Glass Fifteen glass marbles were crushed individually in the pendulum crusher described in the preceding paper,' then subjected to careful screening for 30 min. Six sized fractions were selected and cleaned in a hot 0.12 N solution of hydrochloric acid, washed with distilled water and dried on a hot plate. This was followed by an examination with a binocular microscope, to remove foreign matters not eliminated in cleaning as well as to eliminate "compacts" of fine particles. These compacts are groups of he irag-ments that seem to be mechanically stuck together as a result of localized compacting during the comminution operation. The presence and the abundance of these compacts may be related to the amount and direction of the forces applied in different crushing devices. Since, properly, such compacts should be entirely eliminated in the sizing analyses, it is necessary to remove them to the last before making surface determinations on sized fractions. For example, with a — 28 + 35-mesh glass the surface areas of two samples, one cleaned with acid and under the binocular, the other only washed, were 102 and 172. cm' per gram, respectively. Examination of the samples under an Ultropak microscope showed that washing alone failed to remove the compacts and also that it fails to remove certain fine dusts attached to the particles. Cleaning with acid loosens the fine dusts and

Jan 1, 1947

By C. Dinis da Gama

In mining, all unit operations are closely interrelated, and the results of blasting are probably the key factor within that sequence. The drilling program prior to blasting is just as dependent upon the desired rock fragmentation as are the loading, hauling, and mechanical crushing operations which are economically and technically influenced by the results of blasting, namely, the size and scatter of the product. What is known today as optimum blasting is the process of designing a blast in order to obtain a certain degree of fragmentation so that overall mining costs are minimized. Applying this criterion often results in a different program than when an individual blasting pattern is chosen only on the basis of the lowest operational cost for that pattern, disregarding what comes before or after the blast. [Fig. 1] shows the characteristic variation of mining unit costs with the degree of fragmentation, or the maximum size of blocks obtained from blasting. From the figure, it can be seen that optimum breakage must correspond to the lowest total costs, but reducing drilling-blasting costs only does not achieve such an optimum solution. Methods of designing surface or underground blasting operations should comply with the optimization criterion, but this compliance is feasible only if a detailed mining system analysis is available. Therefore, predictions of costs of loading, transporting, and mechanical breakage of ore as a function of its size will define a narrow range of variation for drilling and blasting parameters in order to get the minimum total costs.

Jan 1, 1972

By K. N. Clark, N. B. Carter, C. G. Thomas, V 7. 0 / 300 dpi

A statistically designed, experimental study showed how gangue minerals, flux additions, fineness of grind, firing temperature, and time affect the properties of acid pellets made from a Western Australian hematite ore. Alumina has less effect than silica and lime, but interactions between the six variables occur, which influence abrasion index, reducibility, and cold compression strength. Finer grinding has little influence on reducibility but improves the other two properties. The major variable is firing temperature, which interacts with all other variables to affect pellet properties. Calculations based on the data show the implications for straight-grate pellet plants and optimum hood temperature ranges.

Jan 1, 1982

By E. W. Dewing

ROLIN1 in 1961 published a phase diagram for the CaF2-Na3AIF6 system in which substantial (-20 wt pct) solid solubility of CaF2 in Na3A1F6 at the eutectic temperature (945°C) was indicated. The evidence was that the halt in cooling curves associated with the eutectic was lowered progressively on the Na3AlF6 side. H olm2 has recently confirmed the experimental fact, but attributes it to evaporation losses shifting the composition into the ternary NaF-CaF2-Na3A1F6 system with a consequent lowering of the eutectic temperature

Jan 1, 1970

AMERICANIZE THE MINING INDUSTRY Americanization is the snaking of American citizens; men and women controlled by the ideals of American citizenship, which have been built up by this country's heritage and its unceasing struggle for freedom and democracy and opportunity. That means, first of all, a necessary understanding of what those ideals are and what they mean for the newly arrived foreigner. It means that every kind of anti-American propaganda must be stamped out; that racial prejudices and the misunder-standings which lead to unrest and disloyalty and make fruitful soil for anti-American propaganda must be overcome. The foreigner must understand. He must understand what we are trying to do here in America; he must understand something, at least, of the kind of government we have built up in our efforts to, accomplish our particular aims; he must understand how lie can fit into it all, not only to help America, but to help himself-to make it possible for hint to get from this country what he carne here seeking. First of all, he must learn the American language. He must be able to talk with his fellow Americans-those who were born here and those who have recently cone, like himself, but from a different land. The most dramatic, the most crucial demonstration of the urgency of the need of all this is given to us right now. At the time when it is most essential for this country to be solidly American, enemy propagandists are winning an occasional success here because they give their message to men and women and boys and girls who do not understand our language and consequently do not understand us. These foreigners, whom the enemy is trying to make disloyal, are really in our army, the big army that is fighting the war for America. Most of them are not among the soldiers who will fight on the battle front, but they are in the lines back of these soldiers. The worker in the shipyards and in the mines is just as important a soldier in this war as the man in the trenches. That has been said over and over, but it cannot be said too often. It is just as vital for that man in the mine to know why we are at war as it is for the soldier. His employer has just as great a responsibility to the country as has any general, and it is the same responsibility.

Jan 8, 1918

By R. W. Raymond

PROF. HENRY Louis, of Armstrong College, Newcastle-on-Tyne, England, a distinguished member of this Institute and other technical societies, has recently sent to the Institution of Mining Engineers, and to the Institution of Mining and Metallurgy, in Great Britain, a communication, the substance of which is as follows Prof. Louis calls attention to the absence of any recognized English term for the definite description of a frequent phenomenon-namely, the oblique position of an ore-body in the plane in which it. lies. In this connection, Prof. Louis says that in America the term " pitch " has been occasionally applied to this relation, and proposes that, in the literature of ore-deposits, it shall be hereafter restricted to this particular meaning, the angle of the pitch, like that of the dip, being always measured from the horizontal, and the dip being always taken at right angles to the strike, while the pitch is taken on the plane of the dip, in the direction of the strike. Thus, for example, in a vein or bed striking N-S., and dipping, say, 45° E., there might be an ore-body, the axis of which pitched northward, at an angle of 45° below the horizontal line, as measured on the plane of the inclosing vein or bed. If the term " pitch " had this universally recognized meaning, the situation could be simply and perfectly expressed by its use, in connection with the general data of strike and clip. As Prof. Louis says ?This suggestion has a certain practical value, and is not merely academic. Every mining engineer of practical experience in such types of ore-deposit will have met with cases, in which a vertical shaft has been sunk with the object of cutting the deposit, but has missed it, because the dip alone has been taken into account, while the pitch has been overlooked." He adds the acute observation that such an oversight is much likelier to occur with regard to a condition not definitely desig-

Mar 1, 1908

By E. J. Rapperport, J. P. Pemsler

Proton irradiation of high-purity distilled berylliuwz was utilized to introduce various hydrogen contents from 0.00075 to 0.075 at. pct (0.83 to 83 ppm) in a band 0.004 cm wide. After irradiation, the specimens were heat-treated to effect hydrogen agglomeration. Observations of agglomerates in all specimens of the lowest hydrogen content indicate a hydrogen solubility of less than 0.83 ppm in the temperature range 350" to 1050°C. Estimates of the inter diffusion coefficient in the hydrogen solid solution of beryllium were obtained from measurements of the dimensions of hydrogen-depleted zones survounding agglomerated bubbles. A value of (approximately) 3 xlo-' sq cm per sec is obtained for the diffusion coefficient at 850" to 900°C. PREVIOUS investigators found that We solubility of hydrogen in beryllium is very small. Gulbransen and Andrew' state that beryllium does not react with hydrogen at 23 mm Hg between 300" and 900°C. Cotter ill et a1.' report that as-machined beryllium has an adsorbed hydrogen layer of 0.007 cu cm per sq cm of surface. No additional hydrogen is picked up in hydrogen at 0.1 mm Hg and between 200" and 80O°C, or when hydrogen is bubbled through molten beryllium. Beryllium hydride has been reported to exist in an ether solution,394 but decomposes at about 200°C; there is no substantial evidence for the existence of the hydride in the solid phase.

Jan 1, 1964

Mellon Institute of Industrial Research, University of Pittsburgh, Pittsburgh, Pa. The Mellon Institute of Industrial Research has carried on for years research and investigations for all type and manner of indus¬try. One of the provisions of the foundation of the Institute is the

Jan 1, 1933

By Alex G. McKenna, Thomas M. Drown

The unsatisfactory character of most, if not all, of the processes for the direct determination of alumina in the presence of iron and phosphoric acid, and the sharpness with which both the iron and phosphoric acid can be determined, have led chemists to rely mainly

Jan 1, 1892