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H. N. EAVENSON, Gary, W. Va.-Judging from our own experience, the statement that only 40 per cent. of the accidents are caused by the human element is very low. We have adopted all the measures that Mr. Wilson recommended, such as systematic timbering, use of permissible expolsives and practically everything that anybody has suggested or can think of, and even after all that has been done, done for several years, and a systematic campaign maintained all the time to reduce accidents, we still

Jan 4, 1918

The Rio Tinto - Cerro Colorado operation was the first major cyanide plant built out of South Africa since the Carlin and Corte mills came on-stream in 1965 and 1969. Its flowsheet was presented in the original monograph, "Gold and Silver Cyanidation Plant Practice, " published in 1975, with a brief description of the plant but without the operating costs. The authors have recently received these data and it was believed worthwhile to present them in this volume along with the aforementioned flowsheet. The Cerro Colorado ore deposit is located at Minas de Rio Tinto in the province of Huelva, Spain, approximately 88 km (55 miles) north- west of Seville. The previously mined copper ore bodies lie on either side of the deposit which is mainly copper ore. The crest of the deposit is a capping of "gossan" containing hematite, limonite, gold, and silver. Separate facilities for primary crushing, concentration of copper ores and cyanidation of gold-silver ores are provided. Fine crushing is common to both ores. The run-of-mine open-pit ore is fed from a stockpile via a surge bin and apron feeder to a jaw crusher. After crushing to minus 150 mm (6 in. ), the ore is washed in a rotary scrubber to remove the clay material ahead of fine crushing. Minus 6 mm (1/4 in. ) screen undersize is pumped directly to the grinding circuit with the screen oversize being crushed to minus 19 mm (3/4 in. ) for feed to the primary ball mill; this is followed by two subsequent stages of ball mill grinding to 80% minus 43 microns (325 mesh). Grinding is with water only; no cyanide is used. After thickening, lime is added to the first two of seven Pachuca tanks for conditioning ahead of cyanide addition in each of the five remaining Pachuca tanks. This flowsheet indicates rapid cyanide consumption and the need to maintain a high strength cyanide solution for silver extraction. Agitation for dissolution of the gold and silver is followed by standard CCD practice employing four 67 m (220 ft) washing thickeners in series, with repulping between each thickener. A departure from American and Canadian practice is the use of Stellar filters developed in South Africa for pregnant solution clarification and recovery of zinc-gold-silver precipitates. The precipitate is treated with acid for zinc removal, the sludge filtered in presses, dried, calcined and smelted to produce dore bullion of 900 fineness containing 12% gold and 78% silver.

Jan 1, 1981

By W. B. Plank, A. C. Callen

WAR and normalcy do not walk hand in hand, whether it be in industry, the educational field, or in the daily lives of individuals. Schools and departments offering curricula in mineral engineering have been seriously disrupted, beginning with 1942 and reaching a low during 1944. Selective Service regulations and voluntary enlistments have effectually stopped the flow of college-trained men into the mineral industry, and the flow into the colleges is little more than a dribble. The year just closed has been a most serious one for our institutions. Until March many of our faculties had been kept reasonably intact because of the large training programs of the Army and Navy. Although the number of

Jan 1, 1945

A tentative plan for the Colorado Meeting has been formulated as follows: One day will be spent at Denver, one day at Colorado Springs, one day at Cripple Creek, a trip by automobile to the top of Pike's Peak, one day at Pueblo, one day at Leadville. All the principal mines and mills of the districts mentioned will be visited, including the gold mines in Cripple Creek, the lead, zinc, and steel works. of Pueblo, the production of ferro-molybdenum by electric furnace at Leadville, etc. Special arrangements are being made for the social entertainment of ladies at all points; one evening at Colorado Springs will be devoted to a reception and dance, and the usual dinner will he given on another evening. The following papers have already been accepted for the Colorado Meeting, and some have already been published: Fireproofing Mine Shafts by the Anaconda Copper Mining Co. By E. M. Norris. (March Bulletin.) Air Blasts in the Kolar Gold Field, India. By E. S. Moore. (March Bulletin.) The Use of Coal in Pulverized Form. By H. R. Collins. (April Bulletin.) Coal Mining in Washington. By F. A. Hill. (April Bulletin.) Carbocoal. By C. T. Malcolmson. (May Bulletin.) Gaging and Storage of Oil in the Mid-continent Field. By O. U. Bradley. (March Bulletin.) An Interpretation of the So-called Paraffin Dirt of the Gulf Coast Oil Fields. By A. D. Brokaw. (April Bulletin.) The Theory of Volcanic Origin of Salt Domes. By. E. DeGolyer. (May Bulletin.)

Jan 5, 1918

POSITIONS VACANT No. 228. Slate mining company desires men for the following positions: Superintendent to take full charge of underground work, quarrying and milling. Assistant or night superintendent. . Foreman for sinking a new shaft. No. 229. Chief engineer to take charge of drafting room, on furnaces and combustion apparatus. ENGINEERS AVAILABLE (Under this heading will be published notes sent to the Secretary of the Institute by members or other persons introduced by members.) Mining engineer and executive. Member. Columbia graduate. Age, 32. Married. 9 years' responsible work in mine examination and development. Experience in United States, Canada, Mexico and South America. Now superintendent large operating mine. Personal interview in New York. Available in August. No. 367.

Jan 8, 1917

By W. E. Brigham, P. W. Reed, J. N. Dew

By Basil B. Zavoico

The developments in the Russian oil industry during 1935 marked a very definite turning point from the time when the industry was being educated to the modern methods of oil-field finding and development, refining, transportation and marketing, to the time when the industry has thoroughly assimilated the modern technique and is now firmly standing on its own feet, as is shown by the remarkable qualitative, if not quantitative, progress in 1935. The oil industry promises that 1936 will be a record year in every respect with both quantity and quality approaching the desired high levels and standards. More particularly the Soviet Government is beginning to be successful in the development of new fields and such new production in geographically strategical points of the country will be in the coming years a factor of great importance in the industrial life of the country. The most notable achievements of the last year have been: the very successful development of the Ishimbaevo oil field in the Lower Oural-Permian Basin; the discovery and development of several promising oil fields in the Puta district of Azerbaijan, while large flush production of Baku area was extended 50 miles due southwest into the Saliani-Aliat district, where a 3000-bbl. well was completed early in 1936 at Pirsagat. Also, an apparently important discovery was made at Zikh, on the Apsheron Peninsula proper. These discoveries, as well as several important strikes in the deeper producing sands in the older fields of the Apsheron Peninsula, have greatly augmented the proven reserves of Russia and made them available either at the points where transportation facilities were already present or at points not too far distant from major industrial centers of the country. Of course, not all objectives were achieved during the past year, and several major difficulties remain to be solved in the coming years, the more important of which are: (1) supply of equipment and of parts; (2) the unavailability of competent technical men in sufficient numbers, which more particularly affects the distant fields; and (3) the problem of distribution of oil products throughout the country, especially the question of handling the needs of small consuming areas, which, while individually unimportant, in the aggregate require huge distribution.

Jan 1, 1936

By Basil B. Zavoico

The developments in the Russian oil industry during 1935 marked a very definite turning point from the time when the industry was being educated to the modern methods of oil-field finding and development, refining, transportation and marketing, to the time when the industry has thoroughly assimilated the modern technique and is now firmly standing on its own feet, as is shown by the remarkable qualitative, if not quantitative, progress in 1935. The oil industry promises that 1936 will be a record year in every respect with both quantity and quality approaching the desired high levels and standards. More particularly the Soviet Government is beginning to be successful in the development of new fields and such new production in geographically strategical points of the country will be in the coming years a factor of great importance in the industrial life of the country. The most notable achievements of the last year have been: the very successful development of the Ishimbaevo oil field in the Lower Oural-Permian Basin; the discovery and development of several promising oil fields in the Puta district of Azerbaijan, while large flush production of Baku area was extended 50 miles due southwest into the Saliani-Aliat district, where a 3000-bbl. well was completed early in 1936 at Pirsagat. Also, an apparently important discovery was made at Zikh, on the Apsheron Peninsula proper. These discoveries, as well as several important strikes in the deeper producing sands in the older fields of the Apsheron Peninsula, have greatly augmented the proven reserves of Russia and made them available either at the points where transportation facilities were already present or at points not too far distant from major industrial centers of the country. Of course, not all objectives were achieved during the past year, and several major difficulties remain to be solved in the coming years, the more important of which are: (1) supply of equipment and of parts; (2) the unavailability of competent technical men in sufficient numbers, which more particularly affects the distant fields; and (3) the problem of distribution of oil products throughout the country, especially the question of handling the needs of small consuming areas, which, while individually unimportant, in the aggregate require huge distribution.

Jan 1, 1936

By Gustaf Ising

For relative gravity measurements, the author in 1918 described an instrument1 of which the essential part consists of a highly astatized, standing pendulum turning about a horizontal elastic axis. This type of instrument has been used recently in practical field work, therefore a description of its principle and technical development is given herein. Part I, describing the principle, is a direct translation of the original Swedish paper.l Part II gives an account of the practical elaboration of the instrument, together with some description of measurements performed. I. Principle of Using Astatized Pendulums1 In order to reduce the trouble and waste of time attending the use of ordinary pendulums in measuring the force of gravity, various instruments of another type have been suggested for relative determinations, as a rule arranged in such a way that the attraction of the earth on a certain body or mass of fluid is balanced by elastic force from a spring or a shut-in mass of gas. A change in the force of gravity is then made manifest as a change in the position of equilibrium of the body, in that the deformation of the spring (or compression of the gas) is changed. With such instruments there are, however, great difficulties in keeping the elastic force constant or its variation known with sufficient exactitude, because of elastic after-working, influence of temperature, and so on. The author suggests for relative determinations of gravity another type of instrument, in which two directional forces (control coefficients) rather than two forces are compared with one another. By "directional force" or "control coefficient" is meant that quantity in a rotatable system that, multiplied by the angle of deflection, indicates the moment counteracting the deflection. In this way it will be possible greatly to reduce the influence of the elastic after-working, which in instruments with spring devices acts so disturbingly. The instrument is made with a rotatable system arranged in such a way that the total control coefficient acting upon it, is composed

Jan 1, 1940

By Gustaf Ising

For relative gravity measurements, the author in 1918 described an instrument1 of which the essential part consists of a highly astatized, standing pendulum turning about a horizontal elastic axis. This type of instrument has been used recently in practical field work, therefore a description of its principle and technical development is given herein. Part I, describing the principle, is a direct translation of the original Swedish paper.l Part II gives an account of the practical elaboration of the instrument, together with some description of measurements performed. I. Principle of Using Astatized Pendulums1 In order to reduce the trouble and waste of time attending the use of ordinary pendulums in measuring the force of gravity, various instruments of another type have been suggested for relative determinations, as a rule arranged in such a way that the attraction of the earth on a certain body or mass of fluid is balanced by elastic force from a spring or a shut-in mass of gas. A change in the force of gravity is then made manifest as a change in the position of equilibrium of the body, in that the deformation of the spring (or compression of the gas) is changed. With such instruments there are, however, great difficulties in keeping the elastic force constant or its variation known with sufficient exactitude, because of elastic after-working, influence of temperature, and so on. The author suggests for relative determinations of gravity another type of instrument, in which two directional forces (control coefficients) rather than two forces are compared with one another. By "directional force" or "control coefficient" is meant that quantity in a rotatable system that, multiplied by the angle of deflection, indicates the moment counteracting the deflection. In this way it will be possible greatly to reduce the influence of the elastic after-working, which in instruments with spring devices acts so disturbingly. The instrument is made with a rotatable system arranged in such a way that the total control coefficient acting upon it, is composed

Jan 1, 1940

HAVING previously shown you how ores are found and mined, and also how they are prepared and disposed for smelting, and then how the blast furnaces and other furnaces are made for purging their earthiness, all this would be as nothing if I did not proceed to show you the method of smelting them. Therefore, in the present chapter I wish to show you how you must proceed in this very important operation, telling you all I have seen and also how much work with this kind of blast furnace I have done or directed. For this reason I tell you first to take by weight or measure the quantity of ore that you wish to smelt and, particularly if it is a kind that contains silver, break it into small pieces about the size of [52v] beans. If the ore had previously needed evaporation by fire or cleaning by washing, you will have had this done well and have had it properly prepared by a master sorter or others. A layer of this is arranged on a bed of planks, bricks, or flat stones in front of the blast furnace and its companion is placed on top, then a quarter part of galena or a third if you can obtain it. Then an equal part of crushed iron slag or slag from the same or different ore is added. These materials are spread in layers one above the other. When the blast furnace has been constructed as taught above, correct in all its parts, and is full of well-kindled burning charcoal, then fill it up with charcoal and admit water to the bellows machine. When you see that it is well kindled again from this wind and that the flames begin to come out forcefully on top, work it down with a little rake and fill it up again. Then the pannier is filled with new charcoal, the blast furnace heaped full, and another basketful of the said composition of ore is also put on top. Proceed in this way, continually adding charcoal and ore as long as you have any, or as long as you wish to keep up the work, maintaining the blast furnace always full, or continuing in this way until the bottom of the blast furnace is filled with melted materials. Decide this by judgment, or by seeing through the mouth of the tuyère where the wind of the bellows enters that they are level with this. Then with an iron tool open the hole that was left as an outlet in front of the blast furnace and allow all the metal with its slag to run out. These two things, flowing through the chan-

Jan 1, 1942

By W. H. Furlonge

WHILE fulfilling professional engagements, my travels over this portion of the Transvaal have been quite extensive—always on horseback however, so that anything like a thorough investigation of the ground passed over has been necessarily impossible; still, the more minute examination of certain small areas, coupled with general observations, has enabled me to form some idea as to the prominent geological features of the country as a whole. Anything like a complete or comprehensive description is indeed out of the question, as there are no proper maps of the country and the facilities for observation are limited. A large plateau, called the "High Veldt," stretches from east to west across the Transvaal. It is generally level, or gently rolling, and has an average elevation of 6000 feet above the sea; it is destitute of timber, and in fact greatly resembles the western prairies of North America. Rock-outcrops are not common in it. It terminates very abruptly to the east and northeast, the descent of 2000 or 3000 feet into the mountainous country that occupies its borders being made in a

Jan 1, 1890

By D. E. Hawk, R. F. Burdyn, F. D. Patchen

Earlier work on a mud separator for barite recovery is extended to the design and construct ion of a rugged field unit. Problems associated with scale-up for field use include the me of dilution water and its effect on capacity, power requirements and pressures developed. Equations for these quantities are derived and applied in maximizing the beneficial effects of dilution and minimizing the power required. Tests on the full-size rotor show that its performance can be predicted by theory. The completed unit is compact and lighter than current decanting types. Its capacity is from 10 to 22 gal/min with corresponding barite recovery efficiencies of 92 to 86 per cent. INTRODUC'TION In an earlier publication a new type of centrifugal device was described for solid-liquid separations.l In that paper an operating equation was derived, and its validity demonstrated in laboratory scale experimentation. Some of the features apparent in this new device seem particularly well suited to the conservation of barite in field drilling-mud systems, hence the development was extended to the design and construction of a field unit. In the present paper the design problems associated with scale-up are considered. A full-scale, rugged self-contained field unit is described, and test results discussed which verify that the performance of the large field unit can be described by a simple operating equation. PRINCIPLE OF OPERATION OF SEPARATOR In principle, the new device is simply a perforated cylinder rotating within a body of fluid which is contained within a stationary case, as in Fig. 1. The frictional drag generated by the rotating cylinder causes part of the fluid to rotate. At the surface of the cylinder, assuming no slip occurs, the angular velocity of fluid and of the cylinder are identical. If there are suspended particles present of greater density than the fluid, the centrifugal force acting on these particles causes them to move radially away from the cylinder at some velocity vp . Where the Stokes settling equation holds, this velocity may be expressed as:2 d2 ?p rw2 If the case is provided with openings at both ends, a suspension can be pumped in at one end at a fixed rate. Part of the suspension can then be removed at a fixed rate at the other end of the case as underflow, and the remainder forced through the perforations and hollow shaft of the rotor to appear as effluent, also at a fixed rate. The radial component of the flow velocity of this stream as it reaches the rotor surface, is simply effluent flow rate divided by cylindrical surface area: Because up is a function of particle size, for some particular particle size, the velocities vp and v, will be equal in magnitude. This is defined as the critical particle size and represents the size above which all particles appear in the underflow and below which all particles appear in the effluent. For this equilibrium condition at the rotor surface, Eqs. 1 and 2 combined give

Jan 1, 1966

By F. M. Hamilton, H. F. Ameen

Results of a laboratory investigation of some sintering variables are presented. The effect on physical properties of mix component variation and rate of cooling of the sinter is illustrated by crush and tumbler test results and data of reducibility tests and microscopic examination of sinters are shown. The results of using solid additions in the mix to improve bed permeability are given. SOME of the variables encountered in the sintering of iron ores and their effect on sinter properties have been investigated at the Jones and Laughlin Ore Research Laboratory in Michigan. Ores requiring agglomeration before blast furnace utilization may be classed as coarse, intermediate or fine. Coarse iron ore is considered similar to a — 1/4-in. Mesabi wash ore containing some 95 pct of its particles between 94 in. and 100-mesh. Intermediate iron ore is considered similar to our New York State magnetic concentrates in which all the particles are — 20-mesh and about 60 pct are +100-mesh. Fine ores are considered as being at least 100 pct —100-mesh. This paper will deal only with the two coarser classifications. Most of the work has been done in a small experimental batch unit previously described in an AIME1 paper. Results being obtained form a basis for present and future trials in production sinter plants. It is expected that new production units that may be added in the future will benefit from laboratory studies. In general, the results reported here are obtained by laboratory study, but it is Experimental Sinter Machine: The laboratory sinter machine employed in the work consists of a chamber with 1 sq ft of grate area. It is mounted on

Jan 1, 1951

By H. F. Ameen, F. M. Hamilton

Results of a laboratory investigation of some sintering variables are presented. The effect on physical properties of mix component variation and rate of cooling of the sinter is illustrated by crush and tumbler test results and data of reducibility tests and microscopic examination of sinters are shown. The results of using solid additions in the mix to improve bed permeability are given. SOME of the variables encountered in the sintering of iron ores and their effect on sinter properties have been investigated at the Jones and Laughlin Ore Research Laboratory in Michigan. Ores requiring agglomeration before blast furnace utilization may be classed as coarse, intermediate or fine. Coarse iron ore is considered similar to a — 1/4-in. Mesabi wash ore containing some 95 pct of its particles between 94 in. and 100-mesh. Intermediate iron ore is considered similar to our New York State magnetic concentrates in which all the particles are — 20-mesh and about 60 pct are +100-mesh. Fine ores are considered as being at least 100 pct —100-mesh. This paper will deal only with the two coarser classifications. Most of the work has been done in a small experimental batch unit previously described in an AIME1 paper. Results being obtained form a basis for present and future trials in production sinter plants. It is expected that new production units that may be added in the future will benefit from laboratory studies. In general, the results reported here are obtained by laboratory study, but it is Experimental Sinter Machine: The laboratory sinter machine employed in the work consists of a chamber with 1 sq ft of grate area. It is mounted on

Jan 1, 1951

By Hiroshi Kato, Shin’ichi Nagashima, Hiroshi Takechi

The preferred orientations detleloped during cold rolling, annealing, and hot rolling of low-carbon steel sheets have been investigated by means of an inverse pole figure technique. And X-ray line profile meas-urerrlents were made for the study of the factor which causes the textural changes between cold-rolled and recrystallized sheets. From ND (sheet normal divection) and RD (rolling direction) inverse Pole figures tlze axis detisity change with increasing cold reduction was measured and the Preferred orientations were analyzed. These results can be explained by crystal rotation due to slip during rolling deformation. The ND axis density change during annealing of cold-rollitig sheets is contrary to the change observed in the case of rolling. It was found that the orientation dependency of stored strain energy resulting from cold rolling apparently corresponds to the textural changes during recrystallization. The texture in hot-rolled sheets was found to be influenced by finishing tenlperatltre. In a sheet kol-rolled below the Ar, temperature a significant differernce in texture between the surface and central layers was obtained, the former having {hkl}(111} and {110 )(uvw) orientations and the latter having {pqr}( 110) orientation. A large number of investigations1 6 have been made on the textures of iron and low-carbon steel sheets, and, since it was shown7 13 that preferred orientations are closely related to deep drawability of steel sheets, studies14" 7 on the influence of production processes upon textures have been made from the standpoint of industrial interest. Generally, the textures in low-carbon steel sheets have several components of preferred orientations, but the overlapping of poles makes it difficult to analyze texture quantitatively from pole figures. On the other hand, an inverse pole figure directly expresses quantitative values of components of preferred orientations as the density of a certain sample axis with respect to the crystallite coordinates. Such a texture representation is desirable for a study of deep drawability. The purpose of the present work is to use both inverse and conventional pole figures, with emphasis on the former, to clar~fy the textural changes ~n low-carbon steel sheets by the production processes of hot rolling, cold rolling, and annealing. And the factor causing the textural changes during annealing is studied using an X-ray diffraction line profile technique. EXPERIMENTAL PROCEDURE Sheet specimens for study of cold rolling and annealing textures were taken from a hot-rolled strip of rimmed steel 2.7 mm thick. The chemical composition is shown in Table I. Although the study of cold-rolling textures requires a suitable material with random orientation, it is difficult to produce a perfect random one. But the used specimens, obtained from the hot-rolled strip with a finishing temperature higher than Ar3, were nearly random, such as shown in Fig. 15. These were cold-rolled to various reductions by a 4-high rolling mill with 150-mm-diam work rolls and 300-mm-diam backup rolls. The influence of hot-rolling conditions such as finishing and coiling temperatures on textures of hot-rolled strips was studied. The chemical compositions of these hot coils are given in Table I1 and the hot-rolling conditions are given in Table 111. inverse Pole ~i~ure -~easurement. Two methods for determining inverse pole figures with high precision have been proposed. The first, by Jetter et a1.,18 consists of obtaining mean densities of divided regions in a unit stereographic triangle by solving simultaneous linear equations to approximate the integral relation between conventional and inverse pole figures. The second, proposed by ~oe'~-'~ and Bunge,22'23 consists of determining an expanded series of spherical surface harmonics which express axis densities from several sets of pole distribution data. Both methods require laborious numerical calculations which make them unsuitable for practical use. However, the axis densities of the locations corresponding to low Miller indices in a unit stereographic triangle can be obtained

Jan 1, 1969

An educated man is distinguished neither by his clothes nor by his knowledge; he is remarkable not for the things he says, but for the way he says them. You cannot even stand with him under an archway in the rain without finding him out. He may talk only of the weather. His words and his phrases alike my be simple. What distinguishes him is the arrangement of his words; however desultory his talk, it will be methodical; he has habituated himself to foreseeing the part to be played by each word he uses and the place to be taken by each sentence he utters. On the other hand, the uneducated man, though shrewd and well-informed, will relate facts and events as they recur to him, generally in disorder; in his effort to recollect and in his attempt to rectify forgetfulness he will pause irregularly, filling the intervals with meaningless phrases, such as "and then", "and so", or "said he to me", "said I to him"; and even the continuous parts of his story will be told confusedly-because he has not learned the proper use of words.* My own experience as an editor of technical manuscripts has taught me that the misuse of 'that' and 'which' is a fruitful cause of obscurity and confusion. The relative pronouns have distinct functions, and no writer can express himself clearly until he has learned to discriminate between these functions. For example : The engineers who refused to submit were discharged. The engineers, who refused to submit, were discharged. The engineers that refused to submit were discharged.

Jan 1, 1931

By Everett M. White

Numerous articles have been written in regard to the man who mines coal and he has been likened to brave men in all ages who have gone out to conquer some unknown hazard. Now, however, modern mining is no longer something to be avoided but is a vocation that anyone can well be proud of, with remuneration equal to or above that of almost any industry. A concerted effort is being made each day by both the operator of most mines as well as the state and Federal inspectors to see that coal mines are as safe or safer than any other industry. However, it is true that mine fires and explosions have occurred in the mining industry since its earliest inception. One of the earliest accurate references to such an occurrence is found in the transactions of the Royal Society of London. In the Colliery Managers' Handbook, 1898, Caleb Pamely writes of an explosion that occurred at Fatfield, England, which resulted in the death of 69 persons in August 1708. It is interesting to note that he states, "Three of them, viz, two men and a woman, were blown quite up from the bottom of the shaft, fifty-seven fathoms deep, into the air, to a considerable distance from the mouth of the pit." From this statement it is noted that women were employed as miners in England during that period. Numerous mine fires and explosions have occurred in mines in this and other countries. Several of them claimed more than 100 lives. Among the greatest losses was a mine explosion in West Virginia that claimed 361 and a mine fire in Illinois that claimed 259. Although no one would minimize the seriousness of a mine fire or an explosion, yet in too many cases they have been publicized out of proportion. This especially is so when compared with the accident rate of other industries or on our highways. It should be remembered that of these general classifications of hazards in mining, mine fires and explosions rank very low in the accident rate in any given year. In modern times the coal industry has completed two years or more, at various times, without a single major disaster. The

Jan 1, 1973

By Ravindra M. Nadkarni, Milton E. Wadsworth

The kinetics of cetnentation of copper with iron were observed to follow first-order kinetics and increase with speed of agitation to a limiting value. Maximum rates agree closely with theoretical values based upon a model of aqueous solution diffusion through a litniting boundary film. Back reaction kinetics are shown both theoretically and experimentally to be independent of ferrous iron concentration in solution. The inlportance of attnospheres of air, oxygen, nitrogen, and hydrogen was studied and the results have been correlated with several impovtant oxidation processes involving metallic iron and copper. The kinetics of the reaction of ferric ion with metallic iron were found to be slow in the absence of metallic copper and essentially proportional to the surface area of metallic copper present in the system. THE precipitation of copper on iron is classic as an example of a relatively ancient art applied successfully for centuries with little fundamental understanding of the important parameters involved. There is some indication that the process has been a commercial means to produce copper since the sixteenth century.' The amount of fundamental work on the cementation of copper with iron is not great. Wartman and Roberson2 carried out a series of detailed copper cementation experiments using natural and synthetic mine water. The following were presented as the three principal reactions: Reaction [I] is the desired cementation reaction and accordingly 0.88 lb of iron would produce 1 lb of copper. In actual practice iron consumption would more normally fall in the range of 1.5 to 2.5 lb per lb of copper. Wartman and Roberson attributed the excess consumption of iron to Reactions [2] and [3]. They found that Reactions [I] and [2] proceeded at approximately the same velocity while Reaction [3] was much slower and would be diminished by controlling the contact time. It was also pointed out that increased agitation is beneficial in removing hydrogen bubbles and barren layers of solution at the iron surface as well as removing contaminants resulting from the hydrolysis of iron. Episkoposyan3 and Episkoposyan and Kakovskii4 studied copper and silver cementation on rotating iron disks in chloride solutions. The kinetics based upon a diffusion model were first order and varied linearly with surface area and with angular velocity raised to the one-half power according to the Levich equation. The experimental activation energy for both copper and silver was approximately 3 kcal per per mole. Excess iron consumption was found to increase with temperature. The rate of cementation first increased with increasing acidity and then diminished at high acid concentrations. sutolov5 has presented an excellent review of the Leach-Precipitation-Flotation (LPF) process including a discussion of copper cementation from an electrochemical point of view although few experimental results were presented. From voltage considerations he predicted that cementation should not be influenced by the concentration of ferrous iron in solution. He considered several secondary reactions including Reactions [2] and [3] and pointed out the importance of oxidation of ferrous iron to ferric with oxygen. In addition it was suggested that Reaction [2] was enhanced by the dissolution of metallic copper by ferric iron which in turn consumed excess iron by the cementation reaction, Eq.[1]. Cementation of copper on metals other than iron has been studied by several investigators but, as in the case of iron, the amount of fundamental work is not extensive. Bashkova and kovalenko6 and Bashkova7 studied the cementation of copper on indium from copper and indium sulfate solutions. The rate was found to be first order and to increase with acidity. This was associated with a decrease in potential (EIn — ECu) and the simultaneous reduction of hydrogen ions at low pH. The rate of cementation also decreased with increasing indium concentrations which was postulated to be due to the decrease in the rate of diffusion of the ions in solution. Below 97°C the experimental activation energy was found to have the unusually low value of 2 kcal per mole and was attributed to diffusional control. Above 97°C the rate increased suddenly and was explained as a change in the rate-controlling step to a chemical reaction. In Part I of this study Nadkarni et a1 .1 have reported on preliminary results obtained in a laboratory study of the kinetics of the cementation process. The rate was found to be first order, proportional to the surface area of the iron, and to increase with speed of stirring until a maximum rate was observed. At low stirring speeds the deposit was spongy and adherent. At medium speeds the copper peeled off in bright strips and at high speeds finely divided copper was produced and continually removed from the surface. The amount of excess iron consumed increased with speed of stirring and with temperature. The average experimental activation energy combining results from several types of iron was 5.8 + 1.6 kcal per mole suggesting diffusional control through a limiting boundary film. Traditionally copper cementation has been carried out over the centuries in gravity-fed launders of various design containing scrap iron. More recently rotating drum precipitators and activated launders8'10 have been used. In the latter, copper-bearing solutions are

Jan 1, 1968

By H. G. Botset

ANY information that will increase the accuracy of our knowledge of the conditions prevailing in petroleum reservoirs should be of direct value in the determination of the proper operating technique as well as in the estimation of reserves and of ultimate production. The obvious method of obtaining this information is by studying a sample of the reservoir rock and its contents. In any such study, the problem of primary importance and maximum difficulty is that of getting the core to the surface in such a manner that its original fluid content is undis-turbed, which has so far proved to be an impossible task. Though it might be rash to say this will never be done, it is certainly safe to assume that a method for the recovery of a core at the surface in its undisturbed original state may not be developed in the immediate future, and certainly will not be forthcoming without a great deal of costly experimentation. Therefore any information that may be obtained that will help to correlate the state of a core (its fluid saturation) at the surface with its condition at the time it was drilled should be of value to the petroleum industry. The experiments described in this paper were undertaken with the purpose of determining, if possible, any relationship that might exist between the saturation of a core at the surface and its original fluid content. No consideration has been given to the question of contamina-tion by penetration of drilling water, since this problem has been exten-sively studied by other investigators. 1-3 Furthermore, it was regarded as being outside the scope of the present experiments, which were con-cerned only with the effect of pressure reduction upon the liquid content of cores. In an experimental study of this sort involving a large number of variables, accurate control of all factors is very important. The essen-tial and obvious procedure is to vary systematically one factor or condi-tion while keeping all the others constant, which necessarily involves a rather protracted and sometimes tedious experimental program.

Jan 1, 1939