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By Jesse O. Betterton

Recently some experimental work was conducted by the author in connection with the direct leaching of certain zinc ores with sulfuric acid with the object of subsequently recovering the zinc by electrolysis. The ores contained relatively large quantities of soluble silica, making it necessary to evolve special methods for handling the silicate solutions resulting from a leach of the ore, and also for the final removal of the silica before electrolysis. The problem was complicated by the presence of vanadium in the ore, the commercial recovery of which was very desirable. This paper, however, deals only with the silica phase of the problem. The zinc in the ore occurs in the form of a silicate (hemimorphite) and, to a very small extent, as the phosphate (hopeite) and carbonate (calamine); the vanadium is found as descloizite and vanadinite but mainly as descloizite. The experimental work was done in a plant producing 50 lb. of zinc = daily, in which the complete cycle of operations, including the final electrodeposition of the zinc, was performed continuously for one year. Some of the conclusions given here are the result of the operations in -this plant; the others are from laboratory tests inaugurated both as a guide to the plant operations and, in certain cases especially, to determine the limits in question. The practice in the 50-lb. zinc plant was to direct leach the ore crushed to pass 40 mesh, with spent electrolyte from the cells containing approximately 3 per cent. zinc and 10 per cent. free acid. This resulted in an acid leach solution and an ore residue. The acid leach solution was ' subjected to a special treatment for subsequent removal of vanadium; then the silica and vanadium in solution were precipitated together and removed as a "silica residue" by pressing through an ordinary plate and frame press. The next step was to treat the filtrate from the silica residue with zinc dust as a final purification step before it went to

Jan 1, 1923

By Jesse O. Betterton

Recently some experimental work was conducted by the author in connection with the direct leaching of certain zinc ores with sulfuric acid with the object of subsequently recovering the zinc by electrolysis. The ores contained relatively large quantities of soluble silica, making it necessary to evolve special methods for handling the silicate solutions resulting from a leach of the ore, and also for the final removal of the silica before electrolysis. The problem was complicated by the presence of vanadium in the ore, the commercial recovery of which was very desirable. This paper, however, deals only with the silica phase of the problem. The zinc in the ore occurs in the form of a silicate (hemimorphite) and, to a very small extent, as the phosphate (hopeite) and carbonate (calamine); the vanadium is found as descloizite and vanadinite but mainly as descloizite. The experimental work was done in a plant producing 50 lb. of zinc = daily, in which the complete cycle of operations, including the final electrodeposition of the zinc, was performed continuously for one year. Some of the conclusions given here are the result of the operations in -this plant; the others are from laboratory tests inaugurated both as a guide to the plant operations and, in certain cases especially, to determine the limits in question. The practice in the 50-lb. zinc plant was to direct leach the ore crushed to pass 40 mesh, with spent electrolyte from the cells containing approximately 3 per cent. zinc and 10 per cent. free acid. This resulted in an acid leach solution and an ore residue. The acid leach solution was ' subjected to a special treatment for subsequent removal of vanadium; then the silica and vanadium in solution were precipitated together and removed as a "silica residue" by pressing through an ordinary plate and frame press. The next step was to treat the filtrate from the silica residue with zinc dust as a final purification step before it went to

Jan 1, 1923

By H. G. Doll

'This paper discusses a method and apparatus for determining the dip of formations traversed by a drill hole, by means of electrical measurements in the hole. The process consists in recording the Spontaneous Potentials present along three oriented generatrices in the hole. By comparison of the three curves thus obtained, after application of a correction factor to compensate for any deviations of the hole, the dip angle and the dip direction are determined. Excellent accuracy is obtained for dip angles over 10°. Because the method is simp1e and the apparatus rugged, the measurements are rapid and reliable; consequently, they can be made at all the levels that are of interest at any time after the well has been drilled. Mechanical cores are not needed to evaluate the dips. A convenient, time-saving procedure is to perform the dipmeter survey at the time the electrical log is taken, using for both operations the same cable and truck. Actual examples of results obtained in wells of the Gulf Coast area are given. Introduction The problem of determining the angle and direction of the dip of the strata traversed by a drill hole has practical interest, and sometimes vital importance, which need not be emphasized to the oil industry. The need for that type of information has existed ever since wells have been drilled. Certainly it has not subsided, in spite of the numerous inventions and improvements made in other fields of the art of drill-hole exploration. The few examples given in this paper are but illustrative of this fact. In the past, methods have been devised, and used, to solve this problem, but generally they have met with limited success, possibly because they failed more or less to answer the requirements of a modern age for fast yet accurate measurements. If accurate, the results were obtained at the cost of very tedious and lengthy operations. The new S. P.* dipmeter service offered to the oil industry is the result of exhaustive and in this particular field. In 1032 a dipmeter and electromagnetic teleclinom-eter service was made available. The apparatus employed then was of a rather delicate and costly construction, and the measurements had to be made with precautions sometimes difficult to secure on the rig. Although the information given by the electromagnetic dipmeter was limited to the direction of the dip, very interesting results were obtained in California, Trinidad, Venezuela, Rumania and, most notably, in the Netherlands East Indies.+ Apparatus The S. P. dipmeter surveys present none of the drawbacks mentioned above. The apparatus is rugged and free from constructional complications, therefore well adapted to field use. This, combined with the new, basically simple approach to the problem, explains the rapidity of execution of the measurements. The results are remarkably accurate and they are complete, giving the

Jan 1, 1946

By H. G. Doll

'This paper discusses a method and apparatus for determining the dip of formations traversed by a drill hole, by means of electrical measurements in the hole. The process consists in recording the Spontaneous Potentials present along three oriented generatrices in the hole. By comparison of the three curves thus obtained, after application of a correction factor to compensate for any deviations of the hole, the dip angle and the dip direction are determined. Excellent accuracy is obtained for dip angles over 10°. Because the method is simp1e and the apparatus rugged, the measurements are rapid and reliable; consequently, they can be made at all the levels that are of interest at any time after the well has been drilled. Mechanical cores are not needed to evaluate the dips. A convenient, time-saving procedure is to perform the dipmeter survey at the time the electrical log is taken, using for both operations the same cable and truck. Actual examples of results obtained in wells of the Gulf Coast area are given. Introduction The problem of determining the angle and direction of the dip of the strata traversed by a drill hole has practical interest, and sometimes vital importance, which need not be emphasized to the oil industry. The need for that type of information has existed ever since wells have been drilled. Certainly it has not subsided, in spite of the numerous inventions and improvements made in other fields of the art of drill-hole exploration. The few examples given in this paper are but illustrative of this fact. In the past, methods have been devised, and used, to solve this problem, but generally they have met with limited success, possibly because they failed more or less to answer the requirements of a modern age for fast yet accurate measurements. If accurate, the results were obtained at the cost of very tedious and lengthy operations. The new S. P.* dipmeter service offered to the oil industry is the result of exhaustive and in this particular field. In 1032 a dipmeter and electromagnetic teleclinom-eter service was made available. The apparatus employed then was of a rather delicate and costly construction, and the measurements had to be made with precautions sometimes difficult to secure on the rig. Although the information given by the electromagnetic dipmeter was limited to the direction of the dip, very interesting results were obtained in California, Trinidad, Venezuela, Rumania and, most notably, in the Netherlands East Indies.+ Apparatus The S. P. dipmeter surveys present none of the drawbacks mentioned above. The apparatus is rugged and free from constructional complications, therefore well adapted to field use. This, combined with the new, basically simple approach to the problem, explains the rapidity of execution of the measurements. The results are remarkably accurate and they are complete, giving the

Jan 1, 1946

By Ernest L. Ohle

The newly opened Hayden Creek lead mine represents a variation from the usual Southeast Missouri type. Galena mineralization occurs in sandy dolomite cementing a conglomerate of granite boulders and in cracks in the boulders. The conglomerate occurs at the base of the Bonneterre formation on the slopes of two buried pre-Cambrian knobs. IN 1943 diamond drilling from the surface in an area 2 miles southwest of Leadwood, Mo., discovered a lead deposit of a markedly different character from the usual southeast Missouri type. Subsequent drilling of about 500 holes indicated several million tons of ore, and in 1950 a 701-ft vertical shaft was sunk into the orebody. This paper describes the geology of this interesting occurrence insofar as it is known from the drilling and the small underground exposure at the bottom of the shaft. Geology The location of the Southeast Missouri Lead Belt and of the Hayden Creek property are shown in Fig. 1. As shown here, there are two separate producing areas, one from which the larger tonnage has come, located near Bonne Terre, Flat River, Desloge, and Leadwood, and the other to the south around Fred-ericktown and including famous old Mine LaMotte. The best published description of Lead Belt geology is by Tarr.* In pre-Cambrian time in this area, an assemblage of granites and rhyolitic flow rocks was eroded to a mature topography. Sedimentation, beginning in the Upper Cambrian, filled in the valleys and gradually covered even the highest hills. The first formation deposited was the La-motte sandstone; it is successively overlain by the Bonneterre dolomite, the principal lead-prodbcing formation, then the Davis shale. the Derby-Doerun limestone, and a succession of Cambro-Ordovician cherty dolomites. Several of these formations may be found in direct contact with the pre-Cambrian as their deposition progressively overlapped the older rocks on the flanks of the igneous knobs and ridges. Immediately overlying the pre-Cambrian there is, not uncommonly, a thin basal conglomerate of granite or porphyry boulders, which is incorporated into the overlying sediments. Deposition of the lower part of the rock section was fairly continuous, and the Lamotte sometimes grades almost imperceptibly into the lower sandy Bonneterre. Since the sediments were deposited on an uneven floor, they tend to reflect the irregularities in that floor. Most of the steep dips found in the district, that is, dips in excess of 10°, are original dips and not caused by deformation. Such domelike structures in the sedimentary rocks around the igneous knobs have localized a considerable number of the orebodies in the district and particularly those in the Frederick-town area. Many of the larger orebodies, however, have no close relation to the pre-Cambrian topography. Most of the lead production has come from the lower 150 ft of the Bonneterre formation, where disseminated ore spreads laterally parallel to the bedding for great distances. Average stoping height is about 20 ft, but in a few places there are stopes over 175 ft high.

Jan 1, 1953

By Ernest L. Ohle

The newly opened Hayden Creek lead mine represents a variation from the usual Southeast Missouri type. Galena mineralization occurs in sandy dolomite cementing a conglomerate of granite boulders and in cracks in the boulders. The conglomerate occurs at the base of the Bonneterre formation on the slopes of two buried pre-Cambrian knobs. IN 1943 diamond drilling from the surface in an area 2 miles southwest of Leadwood, Mo., discovered a lead deposit of a markedly different character from the usual southeast Missouri type. Subsequent drilling of about 500 holes indicated several million tons of ore, and in 1950 a 701-ft vertical shaft was sunk into the orebody. This paper describes the geology of this interesting occurrence insofar as it is known from the drilling and the small underground exposure at the bottom of the shaft. Geology The location of the Southeast Missouri Lead Belt and of the Hayden Creek property are shown in Fig. 1. As shown here, there are two separate producing areas, one from which the larger tonnage has come, located near Bonne Terre, Flat River, Desloge, and Leadwood, and the other to the south around Fred-ericktown and including famous old Mine LaMotte. The best published description of Lead Belt geology is by Tarr.* In pre-Cambrian time in this area, an assemblage of granites and rhyolitic flow rocks was eroded to a mature topography. Sedimentation, beginning in the Upper Cambrian, filled in the valleys and gradually covered even the highest hills. The first formation deposited was the La-motte sandstone; it is successively overlain by the Bonneterre dolomite, the principal lead-prodbcing formation, then the Davis shale. the Derby-Doerun limestone, and a succession of Cambro-Ordovician cherty dolomites. Several of these formations may be found in direct contact with the pre-Cambrian as their deposition progressively overlapped the older rocks on the flanks of the igneous knobs and ridges. Immediately overlying the pre-Cambrian there is, not uncommonly, a thin basal conglomerate of granite or porphyry boulders, which is incorporated into the overlying sediments. Deposition of the lower part of the rock section was fairly continuous, and the Lamotte sometimes grades almost imperceptibly into the lower sandy Bonneterre. Since the sediments were deposited on an uneven floor, they tend to reflect the irregularities in that floor. Most of the steep dips found in the district, that is, dips in excess of 10°, are original dips and not caused by deformation. Such domelike structures in the sedimentary rocks around the igneous knobs have localized a considerable number of the orebodies in the district and particularly those in the Frederick-town area. Many of the larger orebodies, however, have no close relation to the pre-Cambrian topography. Most of the lead production has come from the lower 150 ft of the Bonneterre formation, where disseminated ore spreads laterally parallel to the bedding for great distances. Average stoping height is about 20 ft, but in a few places there are stopes over 175 ft high.

Jan 1, 1953

By Charles W. Wright

At most mines where large tonnages are handled, "bulldozing" or secondary blasting is an important and costly operation. To reduce the large blocks from primary blasting operations or stoping so that they will be small enough to pass through the chutes into the cars at the haulage level, and not too large for the crushing plant, requires blasting. Often this is done by placing a few sticks of dynamite on top of a block with or without a capping of mud, but to consume less dynamite and to promote safety, most secondary blasting is now done by blockholing, or the drilling of holes 6 to 12 in. long in the blocks, using only a part of a stick of dynamite per hole. Regardless of the method of blasting, however, the term "bulldozing chamber" is applied to the room where this work is done. Bulldozing chambers permit secondary blasting at all times in a safe place without disturbance to the other mining operations. The chambers are usually high above the haulage level and well below the stope level or open-pit floor. In most instances the material is passed through a grizzly in the bulldozing chamber, but sometimes no grizzlies are used. One to four raises extend from the chamber to the stope floor and one or two from the haulage level to the chamber floor. Occasionally large slabs of ore or rock choke the raises above the bulldozing chamber, and these have to be blasted by attaching a bundle of dynamite sticks on the end of a long pole and placing them up in the raise between the pieces causing the choke. This is called "chute-blasting." To give a picture of the progressive developments in the use of the bulldozing chamber, a few typical mines that show the application of this method to both metal and limestone mines have been selected for description here. Limestone mines have been included because many metal miners do not realize to what extent the nonmetallic, or rock, miners' are now applying metal-mining methods successfully in their operations. The bulldozing chamber is the "neck of the bottle" for some mines.

Jan 1, 1937

By Joseph D. McClung, L. G. Austin

INTRODUCTION Run-of-mine (ROM) coal generally falls into two major groups, that from underground mining (continuous mining machines) and that from strip mining. Continuous miners produce a finer product and strip mining a coarser product that is crushed to produce the desired size. Further size reduction depends on the proposed use or uses for the coal. For example, for pulverized coal power plants as a rough general rule, the coal is ground or pulverized to 80% less than 200 mesh (0.075 mrn) before it is blown into the boiler furnace as a coal-air suspension. For solvent-refined coal processes, the desired size is about <30 mesh ( <0.60 mm) ; in fluidized bed uses, the coal is typically < in. ( < 1.6 mm); for Lurgi pressure gasifiers, the desired size is 1-2 1/2 in. (25-63 mm). Coal preparation plants typically work with a coarse size fraction of 6x1 1/4 in. (15Ox32mm). It seems probable that the next decades will see much wider application of coal cleaning before use and that the stages of crushing and pulverization from ROM coal to end use will be integrated with coal cleaning processes. Since different cleaning processes work better with different ranges of coal size and the degree of cleaning possible is inti-

Jan 1, 1979

By Arthur Phillips

DURING the past few years considerable interest has been shown in the study of fiber, and its effect, in wrought metals. Fiber has recently been defined as a "condition of parallelism of important lines or details in the structure. "1 Briefly stated, two distinct types of fiber are commonly encountered. One results from the alignment in the direction of working of constituents, more or less segregated, such as slag, oxides, carbides and dendritic formations. The second, and least understood, type is produced by working the metal below the recrystallization temperature in such a way as to develop a parallelism of the grains. This condition is readily recognized by the pronounced elongation of the grains in the direction of working. Under certain deformational treatments the grain fragments produced by cold working tend to orient in certain definite directions with respect to the axis of extension. Furthermore, even in metals that have been annealed after cold working preferred orientations may be present. It is perhaps logical to assume that such marked parallelism of structural elements would be manifested by directional properties in the metal. As a matter of fact, tests on many kinds of materials have shown differences in varying degrees. In recognition of this condition, propel design, for many purposes, places the fiber axis in such a way as to present the direction of maximum strength to the greatest applied stress.

Jan 1, 1931

By Marcel Daly

THE writer has devoted a number of years to practical operations and to the study of geology in the oil fields. In consequence, he has been brought to investigate the theories advanced to account for the accumulation of oil and gas in commercial deposits. It is the result of these investigations and his personal conclusions that he wishes to sum up in this paper. The writer is an advocate of the organic origin of petroleum found in pools. He has been led to believe that the present theories of oil and gas accumulations are incomplete and, in certain respects, incorrect, although they may embody certain elements of truth; that the forces that are called upon to explain the movement are only secondary forces in the process, and insufficient, by themselves, to cause this movement; and that the phenomenon of accumulation is of much larger order than heretofore admitted and bears an intimate relation with the general as well as with the local deformations of the crust and is a direct consequence and a mechanical effect of these deformations to which the term "diastrophic" has been applied. As a complement to this theory, the writer offers a new interpretation of the "rock pressure" and of the mechanism of the "sealing up" of this pressure in oil and gas pools.

Jan 7, 1916

By D. J. Brown

Froth flotation is now used to recover millions of tons of fine coal,(-1/2 mm), every year. For example, in Great Britain, 4-million tons of flotation concentrate was produced in 1960, about 3% of the mechanically cleaned out- put and 2% of the total salable output. Coal flotation is not so widely practiced in the U. S. as it is in Europe since much American coal occurs in thick seams of high grade and does not require cleaning. However, in the U. S., as elsewhere, the increasing mechanization of coal mining machinery has lead to a lowering in size and grade of product from the mine and to an increasing need for cleaning of coal to improve the grade before sale. With an increasing proportion of fines in the product, froth flotation has assumed a greater importance as a cleaning process for coal. In the last three years, over 40 flotation plants have been put into operation in the Appalachian area of the U. S.80 Fine coal recovered by means of froth flotation may be used as a powdered fuel alone or mixed with coarser grades. The removal of this fine coal from washery water makes possible the recirculation and re-use of the water and also leads to improved and more consistent operation of jigs and other separating machines which function less effectively when there is a build-up of fine solids in the washery water. Finally, froth flotation is of assistance in the production of a clarified effluent which may be discharged from the washery without polluting local rivers, streams, or wells. The 1961 cost of installing a new coal flotation plant in Great Britain would be about $19,000 per ton of dry solids input per hour, including the cost of new buildings and coal and shale filtration and water clarification equipment. The figure for the gravity concentration of the large coal, the main plant, would be about $4,800 per tph. The operating cost for the new coal flotation plant would be about $1.10 per ton. Even at this level of cost the cleaning operation is economic in Great Britain for coking coals. In the U. S., a froth flotation cost of 14$per ton of cleanfilter cake was quoted early in 1958 for one operation,l though admittedly this was a special case. Assuming a cake moisture con- tent of 30%, it is estimated that this cost is equivalent to a figure of 256 per ton of dry solids input, for the incorporation of coal flotation in an existing washery. A cost oh 416 per ton of concentrate was quoted76 in a recent analysis of flotation economics, this cost being brought up to $1.11 per ton after payment of royalty, welfare and association dues and taxes. Capital cost was $120,000 for a plant producing 133 tpd of concentrate. Before considering the treatment of coal by flotation it is appropriate to survey some of the properties of coal which are of importance in the process.

Jan 1, 1962

By K. T. Aust

The relative interfacial energies of symmetrical tilt boundaries in silver of greater than 99.999 pct purity were measured as a function of orientation difference 0 between 9° and 36° about <001>. The results are in good agreement with the dislocation model of the grain boundary. The energy vs H curve may be represented by the Shockley and Read equation in the form Eoe (0.55—In 8). READ&apos; has indicated that an ideal experimental method of testing the predictions of the dislocation theory of the grain boundary would be to measure the interfacial energies of symmetrical tilt boundaries between face-centered-cubic grains that have a common <001> axis, as a function of orientation difference 0. The misfit H should be defined by a rotation of each grain through an angle of H/2 away from the boundary. Such boundaries might be expected, from geometrical considerations, to be made up of a series of edge dislocations, at least for small values of 0. Energy vs H relationships for tin&apos; and lead:&apos; were previously obtained for an asymmetrical tilt boundary separating two grains in which generally only one grain was rotated about a <001> specimen axis through an angle of H away from the boundary, the other grain remaining fixed. It is possible, however, that the boundary atoms in tin and lead may have attained a symmetrical position, in relation to the orientations of the grains on either side of the boundary, during equilibrium annealing. The two sets of measurements on silicon ferrite&apos; were somewhat better suited for comparison with theory, since the boundaries were symmetrical tilt boundaries in which the axis of relative rotation was <110> in the first series and <l00> in the second; but this alloy has a body-centered-cubic structure. Although the grain boundaries in silver" were symmetrically tilted, the axis of relative rotation was not a simple crystallographic direction, and it varied from boundary to boundary. Although the above measurements were in good agreement with the Shockley and Read equation,"&apos;: it appeared desirable to carry out experiments under the ideal conditions specified by Read.&apos; Consequently, the relative energies of symmetrical tilt boundaries in silver between grains that have a common <001> axis were measured. The technique of equilibrating grain boundaries in oriented tricrystals was used rather than the less satisfactory thermal groove method previously employed for silver bicrystals." Experimental Details and Observations The solidification and seeding techniques, described previouslyh for growing tricrystals of controlled orientations, were used to prepare tricrystal specimens from silver of greater than 99.999 pct purity. The silver was obtained from American Platinum Works, Newark, N. J., in the form of poly crystalline rods 10 cm long and 7 mm in diam. These rods were then cold worked by rolling or drawing them into suitably shaped blanks. Single crystal seeds and tricrystals were grown in a high purity graphite boat by means of a movable furnace with globar heating elements. The graphite boat was enclosed in a Vycor tube, which was first evacuated to about l00/u Hg and then filled with a static argon atmosphere. The maximum temperature outside the Vycor tube was 1250°C. A typical tricrystal specimen of silver is shown in Fig. 1. Grains B and C were grown from seed crystals with a <001> specimen axis or longitudinal direction parallel to the direction of growth and with another <001> direction perpendicular to the surface. Each of the two seed crystals was rotated 18" about the <001> specimen axis but in opposite directions away from the boundary. A symmetrical tilt boundary, therefore, separated grains B and C with an orientation difference 8 of 36" about <001>. Grain A in Fig. 1 was grown from the middle seed with a <110> direction parallel to the specimen axis and with a <001> direction inclined at 45&apos; to the surface of the specimen. The interfaces sepa-

Jan 1, 1957

By Reuben B. Ellestad, Fremont F. Clarke

Lithium chemical plant extraction methods are discussed with reference to 1) base exchange with alkali sulphates; 2) processing based on roasting with lime; 3) miscellaneous methods; and 4) application of the Lithium Corp. process to extraction of lithium from run-of-mine, low grade spodumene ore, or concentrates. IN the early days of the lithium industry most of the production was from lepidolite, zinnwaldite, and amblygonite. Nearly all the early extraction processes described in the literature involve heating the finely ground mineral with sulphuric or hydrochloric acid. On subsequent water leaching most of the bases present in the mineral (especially aluminum) are dissolved as sulphates. As a result, the leach solution required extensive chemical purification before the lithium could be precipitated as carbonate. Following the remarkable growth of the lithium industry to its present size, zinnwaldite and amblygonite ores must be considered of minor importance only. Attention is now focused on spodumene, abundant enough in North America to be a major source of supply, and there are important supplies of lepidolite and petalite in Africa. The extraction processes described below all apply to spodumene, although several will also operate on other lithium minerals, such as petalite. Base Exchange with Alkali Sulphates: A distinct advance was made with the disclosures of Wadman and von Girsewalt. In these methods the finely ground silicate ore (spodumene or lepidolite) is intimately mixed with an excess of alkali sulphate (usually K2SO4) in at least a 1 to 1 proportion, and the mixture was heated to a relatively high temperature. Base exchange results, with the formation of lithium sulphate. A water leach dissolves the lithium sulphate, together with the excess potassium sulphate. Successful operation of this type of process requires very thorough grinding and mixing, as well as careful temperature control. The use of K2SO4 is objectionable from cost considerations since purification of lithium carbonate requires the use of potassium carbonate, if the K2SO4 is to be recovered and recycled. The lower solubility of K2SO4 as compared with Na2S04 is also objectionable, since it limits the concentration of the Li2SO4 solution to be precipitated by K2SO4. Early laboratory-scale investigation of this process by Lithium Corp. was not encouraging. Other related base exchange processes are those of Lindblad, Wallden, and Sivander3 and Sivander, Gard, Villestad, and Wallen4. The former covers the reaction of lithium silicate minerals with a sodium sulphate solution, at 100" to 300°C (under pressure), while the latter involves the extraction of silicate minerals with molten sodium sulphate. Both these processes would seem to be difficult and expensive to operate.

Jan 1, 1956

By C. F. Willis

Many of the failures in vocational education are due to the fact that the educational methods were not designed to the capabilities, habits, and environments of those to be trained; rather they were based on the policy that education is education and lessons are lessons, whether for youngsters of fifteen or for men of forty. Vocational education among miners involves, first, a study of the men themselves, their habits, and the use of their leisure time; second, a study of the differences between the methods of teaching required for men and for children. Certain fundamental requirements of training methods for miners are reasonably universal and may be applied with success to any ordinary mining community. The rate of labor turnover is another consideration; it would be useless to design a four-year course for men who remain in one place only a few months. Length of Course The first consideration should be the length of the course. Few mining communities have a sufficiently stable population to make it possible successfully to carry on a course for over a year. While some men might complete a four-year course, the number is comparatively small compared with the number to whom a shorter course would be of service, and it is better to raise the standards of education even a little for a large number than to raise them to a high level for a few. It is perfectly possible to attain both objectives by arranging the courses in small units; all the units, when grouped together, should comprise a fairly complete course, yet any one unit should be complete in itself and of benefit to the workman. It should not take many of these units to make a miner or a timberman out of a mucker; but to do this the course should be short, because muckers seldom stay in one place long. By grouping a number of these units together it Would be possible for a miner to become a shift boss or a shift boss a foreman, and so on. As far as possible the units of the course should not be dependent on those preceding or following. The workman understands the completed job but he is not accustomed to carrying on several jobs at the same time and

Jan 1, 1920

By Franklin Moeller

THE application of electric power for driving, mine hoists handling heavy loads at high speeds has recently been extended by the installation of what is probably the largest electrically driven hoist in this country at the Granite Mountain shaft of the North Butte Mining Co., Butte, Mont. While the weight of rock which is hoisted by this machine is not the largest now being handled by electric mine hoists, the speed of hoisting is so, and the combination of the high speed with the heavy load has resulted in a machine of considerable interest to all those actively engaged in mining. Aside from mere consideration of size, this installation deserves attention because of the careful attention given, not only to the question of economy of operation, but to the details of construction and installation of the entire equipment. The conditions to be met in this installation were as follows: Weight of rock to be raised per trip, 7 gross tons 15,680 1b. Weight of skip 8,0001b. Weight of cage 1,8001b. Maximum depth of hoisting 4,000 ft. Diameter of rope 153 in. Total weight suspended on one rope from drum 42,000 1b. Normal hoisting speed 2,700 ft. per minute. Maximum hoisting speed : 3,000 ft. per minute. Desired capacity-200 tons per hour from 4,000 ft: depth. The ore is mined in several levels and hoisting is carried on from the 800-ft. level down to the 2,700-ft., which is at present the maximum depth from which the ore is raised regularly. Development is proceeding and a depth of 2,900 ft. has already been reached. The rock is handled underground in cars holding ¾ ton, and about 10 cars are the usual load for a skip. All of the ore is clumped into underground bins, which are of different capacities varying up to 250 tons. From the bins the ore is fed into the skips without passing into measuring pockets. At the surface the

Jan 2, 1916

By Robert F. Winkle

A detailed breakdown of mining costs, available to management on monthly and year-to-date bases, is mandatory for a controlled and efficient mining operation. A simple lump sum reporting of costs may indicate a profit or loss differential, but it does not allow an effective search for areas of possible cost reduction. Moreover, functional reporting is necessary on a timely basis so as to note trends of increasing costs In specific areas, which in turn allow possible preventive action by management. Definitive cost information helps to eliminate the tendency to overlook areas where cost Improvements can be made. A good cost control system points out salient operational weaknesses by: ( 1 ) allowing comparison of functional costs with similar costs of other mines and (2) pinpointing sudden increases over unit empirical costs within the organization. In general, the cost accounting structure is relatively uniform within large open pit mines, but surprisingly some systems will overlook the need for detailed breakout in comparatively high cost areas. In some other systems, unrelated costs will be lumped together, preventing careful analysis of cost accrual.

Jan 1, 1979

By J. Ellzey Hayden, Lucien Eaton

The Cliffs Shaft mine of the Cleveland Cliffs Iron Co., located in the city of Ishpeming, Mich., is the largest producer of hard hematite ore on the Marquette iron range. The two shafts, A and B, lying 820 ft. (250 m.) apart on the east-west trend of the ore formation, were sunk in the early eighties, and, except for four years, have been steady producers of iron ore. Their location, on a hill overlooking the general offices of the company on the one side and the city of Ishpeming on the other, has made the shaft houses landmarks. In the spring of 1919, as the old wooden shaft houses had become shaky and out of line, and would soon be unsafe, it was necessary to replace them with the least possible delay. Three plans of construction were, therefore, considered: To replace the old shaft houses by somewhat similar structures made of wood; to use steel and radically change the design; or to build reinforced-conerete shaft houses outside of the wooden structures, completely enclosing them. The first plan was disapproved, because it is anticipated that the mine will have a long life and the proximity of other buildings makes the danger from fire rather great. Delay in receiving material, and the necessity for closing the shafts during erection, were other factors in the situation. The second plan was disapproved on account of the high cost of steel, slow delivery, and interference with hoisting during the period of erection. The presence near one of the shafts of a large bed of hard gravel suitable for concrete made the cost of the third plan considerably less than the second, and little, if any, delay in hoisting was expected. Our expectations in this regard were fully realized. Furthermore, the work could be done by unskilled labor, which was plentiful, and the erection could be quickly started. When the proposition was submitted to W. G. Mather, president of the company, he recommended that, on account of the prominence of the buildings due to their location, an effort should be made to combine in the design as far as practicable something of architectural beauty. Following his recommendation, the original plans were submitted to the

Jan 1, 1922

THE record of the development of physical metallurgy since the founding of this Institute embraces by far the greater part of physical metallurgy as this subject is recognized today. Yet it is not to be supposed that the metallurgist interested in the properties and behavior of solid metals at the beginning of this period was without important and even fundamental information. He had an empirical knowledge of the behavior of solid metals which extended backward into prehistoric times and he had the early beginnings of many of the chapters in the science of metals. Industry was burgeoning in many directions, for methods had been developed, especially in the manufacture of steel that provided materials in extremely large tonnages, permitting applications of metallic materials on a very widespread scale. These multitudinous new uses of metals created an increased interest in the behavior of metals, and provided the basis for the rapid development of a science of metals. Indeed, the development of science generally that accompanied the industrial revolution reached a flood tide toward the end of the century, furnishing the metallurgist basic principles in chemistry, physics, mechanics, and crystallography that would shortly be extensively applied to metallic behavior. In this account, the early developments in the wide metallurgical field will be traced, in order that the status of physical metallurgy in 1871, when this Institute was founded, may be clearly seen. The subject of metallurgy in antiquity has been written upon frequently and at length. We shall here no more than indicate the main features that we need to define the position in 1871 and to provide a proper background for discussing subsequent developments. The writings of Pliny,1 23-79 A.D., to which Robex-ts-Austen3 fre-

Jan 1, 1948

By K. A. Natarajan, I. Iwasaki

The effect of poisoning on the behavior of platinum electrodes in redox potential measurements in metallurgical systems was studied in the presence of such inorganic surfactants as cyanide and sulfide and such organic surfactants as dodecylammonium acetate, trimethyldodecylammonium chloride, potassium ethyl xanthate, and potassium diethyl dithiophosphate (Aerofloat®). These chemical species represent, more or less, typical constituents encountered in leaching, flotation, and sewage treatment systems. Triangular wave voltammetry was used as the experimental technique to study the nature of poisoned surfaces. Among the species studied hydrogen sulfide and dodecylamine were found to form a resistant surface film affecting charge transfer. Platinum electrodes appeared to have a weaker tendency to adsorb sulfide species in alkaline pH ranges, while cyanide, xanthate, and dithiophosphate affected the normal electrode behavior differently. Possible methods of reactivation of a poisoned electrode by mechanical cleaning are suggested.

Jan 1, 1974

By Fred C. Bond, Jen-Tung Wang

Comminution energy is principally energy of deformation before break-age, which appears as heat. An empirical equation is presented which covers the entire comminution range. The new strain-energy theory considers comminution from the known principles of mechanics and the reduction ratio. Energy requirements according to the different theories are compared.

Jan 8, 1950