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By L. C. Morganroth

Magnesite both Massive and Crystalline MAGNESITES are. of two general classes-massive and crystalline. Massive magnesite occurs in serpentine, being formed by the breaking down or decay of serpentine-making minerals or rocks as olivine, etc. (All the magnesia contained by the olivine is not liberated, as a portion goes to make up the serpentine; the breaking up of this serpentine later forms more magnesite.) Serpentine in various stages of transformation is found in the vicinity of magnesite deposits. Massive magnesite is very widely distributed. It is found in Greece, . California, Africa, India, Australia, Mexico, South America, and deposits of varying sizes occur in several of the European countries. Those on the Island of Euboea, Greece, are probable the most important deposits of this character of magnesite. They have been worked for a number of years, the principal quarries or mines being 3 miles in the interior from the village of St. George. (St. George is on the west coast of the island, between the towns of Limni and Khalkis.) (Figs. 1 and 2). -The magnesite occurs in veins or lenses in serpentine. Some of these lenses are very large; one worked several years ago was approximately, 50 ft. in thickness, 75 to 100 ft. high and 300 ft. or more in length. The magnesite is pure white and makes a very prominent feature of the landscape. While massive magnesite is widely scattered over the world, many of the deposits are in veins too thin to work. The usual mode of occurrence is in the form of stock work, the deposits in Venezuela, Mexico, and many of those in California, being of this form. The veins vary in thickness from the thinness of paper up to several inches, running in all directions, occasionally leading to a mass or nucleus of some,size. The spaces between the veins are filled with a disintegrated serpentine in the form of sand. Several of the deposits in California would probably be workable, if they were more favorably situated with reference to transportation, but by far the majority of the deposits are too poor to work. At one deposit,

Jan 9, 1914

By E. P. Abrahamson II

The effect of transition element binary solid-solution additions upon the recrystallization temperature of vanadium has been investigated. Cr, Fe, Co, Ni, Mo, Ru, Rh, Os, and IY lower the recrystallization temperature, while Ti, Mn, Zr, Cb, Pd, Hf, Ta, W, Re, and Pt raise it. The majority of elements have their greatest effect in less than 0.15 at. pet. Both the rate of change of recrystallization temperature with atomic percent solute and the limit of initial linearity are found to Correlate with the free atom grozdnd state outer electron configuration of the sollte element. THE work of Abrahamson and Grant1 and Abraham-son and Blakeney2 has shown that the solute's elec- tron configuration appears to be a prime determinant of both brittle-to-ductile transition and recrystallization temperature in dilute binary alloys. It has also been shown by Abrahamson3 that the limit of linearity, i.e., the limit of initial linear change of recrystallization temperature with atomic percent solute, is also a function of the electron configuration of the solute in iron base alloys. Because of the systematic nature of the solute electron configuration correlation, it is to be expected that some systematic variation might be observed upon changing the solvent. Thus, this study of recrystallization in vanadium base alloys is the first of a series aimed at defining the role played by the electron configuration of solute in determining the recrystallization characteristics of dilute transitional alloys. PROCEDURE All alloys were made using 99.8 pct V containing 0.011 C, 0.024 N, 0.08 0, 0.006 H, 0.035 Ta, and

Jan 1, 1962

By G. V. Raymor, James T. Waber, I. Rex Harris

The lattice parameters of a series of fcc alloys of cerium and thorium were measured at 93 " and 298OK. Lattice parameters were also estimated for 171OK. Substantial deviations, y, from Vegard's law were observed. Although y was negative at the two higher temperatures, it was positive and large at the lowest temperature. A variety of models, which have been proposed in the past, were considered, and the calculated values of y were compared with the observed values. The best agreement was achieved with values computed with Friedel's equation. THE purpose of this investigation was to determine the effect of temperature on the lattice parameter and on deviations from Vegard's law of Ce-Th alloys. A large negative deviation from Vegard's law was first observed independently by Weiner, Freeth, and Raynor' and Van vucht2 in the room-temperature lattice parameters of Ce-Th alloys that form a continuous series of solid solutions. This observation was confirmed by Evans and Raynor. The allotropy of unalloyed cerium was reviewed recently by Gschneidner, Elliott, and McDonald. In two subsequent papers,5" these authors reported the influence of various alloying additions on the y= transformation, which occurs below room temperature. Although other rare earths tend to stabilize the double-hexagonal phase, thorium, plutonium, and scandium as solutes tend to stabilize the normal fcc phase. With addition of sufficient thorium as a solute, there is evidence that the formation of is suppressed and it becomes possible to pass continuously with decreasing temperature from the room-temperature phase to the fcc a phase. Thus there is a closed loop which is similar in many ways to the y loop well-known in ferrous alloys. A closed field also occurs in the pressure-temperature "equilibrium" diagram of unalloyed cerium. Because of interest in the effect of thorium additions and their influence on the a and phases, lattice-parameter measurements were made at low temperatures on the fcc phase for a series of alloys ranging from 10 to 90 at. pct Th. The results obtained at three temperatures are shown in Fig. 1. Evans and Raynors analyzed the deviations from Vegard's law in Ce-Th alloys in terms of changes in the occupancy of the 4f electron level in cerium,

Jan 1, 1964

Jan 1, 1969

For the seventh consecutive year, the value of nonfuel mineral raw ma¬terials produced in the US set a new record, reaching almost $20 billion-up 12.7% from the previous year, according to the US Bureau of Mines. The Bureau reported that this mineral production was the basis for about $200 billion worth of processed materials of mineral origin.

Jan 5, 1979

With one shaft almost completed and another shaft being sunk, the scope of the Saskatchewan potash area is beginning to come into focus. Some 18 companies have reportedly leased more than four million acres to explore potash possibilities. PCA, farthest along, is located about 15 miles southeast of Saskatoon, and IMC has its project underway near Esterhazy in the eastern edge of the province. U. S. Borax and Chemical Corp. is also reported exploring the area. The field lies in the middle Devonian geological formation which was probed by oil companies along the 200-mile area across the province. Extensive examination began after World War II and deep drilling was started a few years later.

Jan 5, 1958

• "This country eventually may have to rely on foreign sources for some metals, not because it does not have them here but because it may have difficulty getting the labor to mine them. Few people realize the extent to which the 'old timers' are still the backlog of the important districts." --Fred Searls, Jr. • A new filter has been developed by Arthur D. Little, Inc., for the ABC which will remove all dust from the air. Submicroscopic asbestos fibers are used as filter media and are claimed to stop all dust and pollen while passing suitable quantities of air. •Out in front public relationswise is the Peabody Coal Co. which has launched a 15-min television news program on WNBQ at 10:30 C.S.T., Tuesday and Thursday nights. Clifton Utley, news commentator, will tell how coal is mined today and indicate, with pictures, the improvement in efficiency and safety which has resulted from today's mechanized operations. •Two hundred coal mining companies are using roof bolts as a means of supporting about 14 million sq ft of roof surface, Edward Thomas of the Bureau of Mines reported. Various types of metal and wooden pins can be used. The method was first used by the St. Joseph Lead Co. over 20 years ago, but is now being studied and adopted widely in metal, nonmetallic, and coal mines. * The first ten technical graduates have reported at Hanford Works in the state of Washington, to begin the newly installed General Electric rotational training program, believed to be the first of its kind at any U.S. atomic energy plant. The program is to provide suitably trained personnel for the nation's atomic energy program. •The need for top-notch scientists and engineers to stimulate mining programs in British colonies is acute. About 60 American experts are being sought for the ECA sponsored program. Positions for mining engineers, geologists, assayers, topographers, and petrologists are open. •Production of primary aluminum for the first quarter of 1950 was 322,4250008 lb which is 6 1/2 million lb more than was produced in the first quarter of 1949. Shipments of aluminum sheet, plate, and strip amounted to 259.772,1571b for the first quarter. •Policy on manganese procurement for the stockpile is being studied by a House Armed Services Subcommittee with the possibility of lowering specifications. The U. S. Bureau of Mines is drafting a bill to encourage domestic production for stockpiling through producer subsidies. 'It will have to be cleared by the Bureau of the Budget and other agencies before going to Congress. •Oil men consider dry holes a necessary evil in their search for oil. Last year 34 out of every 100 wells drilled were dry holes. Yet Texas Technological College is attempting to drill a dry hole on its campus at Lubbock, taking every precaution to make sure it is a "duster" so its petroleum engineering students can play around with experiments without being bothered by any messy crude oil. --Natural Resources Notes. •A portable alertness indicator which signals lethargy in persons doing monotonous jobs has been developed for the Navy's Special Devices Center. A possible application to hoistmen is indicated but broaching the matter to them would be tricky.

Jan 6, 1950

By William P. Blake

The Rainbow Lode is situated at Walkerville, in the Summit Valley mining district, Silver Bow County, Montana Territory, about one mile from Butte City. It was so named ill 1876 by Mr. J. E. Clayton, in recognition of the broadly-sweeping curve of the outcrop across the rounded surface of the eastern slope of a granitic mountain, at an elevation of about 6000 feet above the sea-level. It is on the western side of the range which divides the waters of the Missouri from those of the Columbia. History.—The history of the district is an instructive one. The water-courses and flanks of the hills were worked for years for placer gold. Millions of dollars' worth of low-grade gold have been washed out of the surface gravels below the veins of the district. Missoula Gulch and Silver Bow creek, just below Butte, are noted for their rich placers, and they continue to yield largely, producing within narrow limits from $50,000 to $100,000 dollars' worth of golddust yearly. It is ragged vein-gold, and evidently is near its parent source. It is no doubt derived from the disintegration of the veins of the district, and this conclusion was soon forced upon the miners. The veins which were seen outcropping boldly upon the slopes above them were located, and prospecting commenced. These outcrops were found heavily stained and blackened with oxide of manganese, and were porous and honey-combed in places, showing that the quartz was formerly filled with pyritous ores, and that these ores had decomposed and dissolved away, leaving, however, portions of the precious metal behind, especially at and near the surface of the ground. Assays of the croppings gave variable and often contradictory results; but the fact. that these were the outcrops of lodes bearing gold and silver in depth was patent to any experienced observer of mineral veins. The lodes of the district were first brought prominently to notice by Mr. Clayton in 1876, and in October of that year the Alice mine, upon the central portion of the lode, was opened by Mr. Marcus Daly, now so well known as the superintendent of the Anaconda Copper mine, upon another extremely interesting lode, in the same region.

Jan 1, 1888

By G. F. Jenkins

ASBESTOS is a general term embracing the fibrous varieties of a number of minerals. Of these, the hydrous magnesium silicate, chrysotile (H4Mg3Si209), a variety of serpentine, is the most abundant and useful to industry. All other types of asbestos belong to the amphibole group of minerals and are classified as: crocidolite, NaFe(SiO3), FeSiO3; anthophyllite, (MgFe)SiO3; amosite, also a ferromagnesium silicate but with iron content higher than that of anthophyllite; tremolite, CaMg3(SiO3)4; and, actinolite, Ca (MgFe)3(SiO3)4. PROPERTIES The commercial value of asbestos depends largely on the physical property that permits it to be readily separated into fine filaments of high tensile strength and flexibility, which, coupled with the fact that it has the quality of incombustibility of a mineral-in distinction to vegetable and animal fibers-makes it of unique usefulness for many purposes. To some extent, the value depends upon the length of the fiber, although extreme length is neither necessary nor desirable for most purposes. Chrysotile occurs as cross-fiber veins, in which the asbestos fibers are approximately' at right angles to the vein walls, with vein width- or fiber length-seldom exceeding 2 or 3 in.; also as slip-fiber, in which the fibers 'lie in the same plane as the vein or on slippage planes. A cleanly broken vein of cross-fiber has a pearly luster and may range from a deep green or brown color to light shades of yellowish green or cream. When of good quality, the fiber filaments forming the vein may be easily drawn away from their neighbors and exhibit a fine silkiness and pure white color. They may be twisted into a thread and when flexed between thumb and fingers are found to be strong and pliable. Chrysotile withstands comparatively high temperatures without breaking down completely or fusing but begins to lose water of crystalliza-

Jan 1, 1949

By K. J. McGrew, J. W. Murphy

Introduction Maximization of profit consistent with environmental protection is the principal goal of new applications development for any conventional or in situ mining technique. Efficient evaluation of all the parameters that contribute to mining costs and production hinges on proper design and evaluation of testing programs and data. The program discussed uses several field and laboratory procedures to estimate ore deposit characteristics and optimize lixiviant compositions. Ore characteristics and lixiviant compositions are then used in a long path leaching test (stream tube test). Stream tube test data are analyzed by mathematical models with computer assistance to predict such wellfield rate parameters as target metal production, lixiviant consumption, and restoration. When these predicted rates are combined with market values for target metals, capital expenditures, prices of lixiviant chemicals, and other economic variables (labor costs, power rates, and licensing fees), an assessment of the relative feasibility of various proposed mining plans is possible. The flowsheet in Fig. 1 illustrates this process. [ ] Field and Laboratory Procedures In general terms, the procedures followed in the evaluation of an in situ leaching application aim at accomplishing: •rapid leaching and maximum recovery of the target metal in a marketable form, •low consumption of lixiviant chemicals, •unquestionably satisfactory restoration of the mined aquifer, and •minimization of capital and operating costs for the above through development of an optimum mine plan. Keeping these goals in mind, the following minimum test program is generally recommended. Geology •Estimate of ore reserves and their variability. •Average disequilibrium value for uranium deposits. •Ore thickness, depth to ore, water level, degree of confinement, and consolidation. •Characterization of quality and quantity of other ore deposit constituents (e.g. sulfide minerals, ion exchange parameters). Hydrology •Single well pump and injectivity test. •Downhole vertical permeability test to compare flow rates of barren and mineralized formations. •Groundwater quality as it may affect licensing, hydro metallurgy, and restoration. Hydrometallurgy • Flask or autoclave tests for optimization of lixiviant parameters and determination of specific reaction rate constants. • Flask or autoclave tests for assessing amenability of lixiviant solutions with ore, consumption of lixiviant, stability of metal in solution contacting ore, and environmentally important species mobilized. • A long-path leach test for modeling the behavior of the lixiviant solution flowing through a long mineralized streamline (stream tube testing). •Metal recovery tests from lixiviant solutions (ion exchange, electrowinning, etc.). •Lixiviant regeneration tests. •Environmental restoration tests.

Jan 1, 1985

By Frank Tolonen

IRON-ORE beneficiation is becoming of vital importance to the Lake Superior region, since only a few decades will be needed to exhaust the direct shipping ores even if generous allowances are made for discoveries of new orebodies. If the region is to continue as the chief source of ore to the steel industry of the United States, it must concentrate or otherwise beneficiate the enormous tonnages of available iron formations. A beginning along this line has already been made. About one-fifth of the total shipment, even now, is the product of some sort of concentrating process, while another fifth is improved in physical structure by crushing, screening, drying, sintering, or some other similar method. The amount of material amenable to these processes is limited, however; and, in order to be able to utilize the billions of tons of iron formations that cannot be so beneficiated, an intensive study of their nature and concentration possi-bilities is necessary. As long as high-grade ores are available in ample quantities, ore dressing is economically impossible, but as soon as the supply nears exhaustion it becomes necessary. At first the products of ore dressing must meet as nearly as possible the same specifications as the rich ores in order to be adapted to the reduction processes already established. The future requirements as to quality will depend on the one hand upon the ability of the ore dresser to eliminate undesired constituents and charac-teristics in the material, and on the other upon the adaptation of the reduction processes to the product that can be economically supplied. A better understanding of the blast furnace and other reduction reactions, and improvements in the preparation of raw materials, should enable the Michigan districts to continue to supply ore for a long time to come. The study and testing of the iron formations necessary to bring a utilization of the low-grade ores, though requiring time and effort on the part of all concerned, should not be postponed, especially since the economic situation forces the use of the highest grade ore in preference to the leaner material.

Jan 1, 1933

By W. H. Emmons

In 1922 Morey made a series of experiments in which he observed the cooling of a molten system containing H2O, 9.1 per cent; K2O, 17.3 per cent and SiO2, 73.6 per cent. This system was confined in a bomb; it was fluid at 500° C. and exerted no vapor pressure. In cooling to 420° C. a large part of it crystallized and at that temperature much of the water had separated from the crystals and remained as steam, which built up a pressure of 4998 lb. per sq. in., a force sufficient to lift nearly one mile of granite.' If granite, cooling at 600°, expels vapor in the process of crystallization it is reasonable to suppose that a considerably greater vapor pressure would result, and it is thought that the vapor expelled from crystallizing granitic batholiths probably has a pressure sufficient to lift two or three miles of granite. This vapor, collecting near the tops of cupolas of batholiths, is believed to exert sufficient pressure to fracture the hoods and roofs of batholiths above the cupolas. If that is true, one would expect to find that the fracture systems above cupolas are arranged in patterns that depend in part on the shapes of the cupolas. The mechanics of the situation seem to require that conical cupolas should have radial fracture patterns, that bluntly rounded cupolas should have fracture systems that are either irregular or rudely conjugated in plan, and that elongated stocks or cupolas should have fracture systems in which the fractu'res lie nearly parallel to the direction of the elongation of the cupolas. Study of essentially all the cupolas of the earth that have associated important vein-filled fractures shows that this is generally true. This

Jan 1, 1935

By W. H. Emmons

In 1922 Morey made a series of experiments in which he observed the cooling of a molten system containing H2O, 9.1 per cent; K2O, 17.3 per cent and SiO2, 73.6 per cent. This system was confined in a bomb; it was fluid at 500° C. and exerted no vapor pressure. In cooling to 420° C. a large part of it crystallized and at that temperature much of the water had separated from the crystals and remained as steam, which built up a pressure of 4998 lb. per sq. in., a force sufficient to lift nearly one mile of granite.' If granite, cooling at 600°, expels vapor in the process of crystallization it is reasonable to suppose that a considerably greater vapor pressure would result, and it is thought that the vapor expelled from crystallizing granitic batholiths probably has a pressure sufficient to lift two or three miles of granite. This vapor, collecting near the tops of cupolas of batholiths, is believed to exert sufficient pressure to fracture the hoods and roofs of batholiths above the cupolas. If that is true, one would expect to find that the fracture systems above cupolas are arranged in patterns that depend in part on the shapes of the cupolas. The mechanics of the situation seem to require that conical cupolas should have radial fracture patterns, that bluntly rounded cupolas should have fracture systems that are either irregular or rudely conjugated in plan, and that elongated stocks or cupolas should have fracture systems in which the fractu'res lie nearly parallel to the direction of the elongation of the cupolas. Study of essentially all the cupolas of the earth that have associated important vein-filled fractures shows that this is generally true. This

Jan 1, 1935

In 1922 Morey made a series of experiments in which he observed the cooling of a molten system containing H2O, 9.1 per cent; K2O, 17.3 per cent and SiO2, 73.6 per cent. This system was confined in a bomb; it was fluid at 500° C. and exerted no vapor pressure. In cooling to 420° C. a large part of it crystallized and at that temperature much of the water had separated from the crystals and remained as steam, which built up a pressure of 4998 lb. per sq. in., a force sufficient to lift nearly one mile of granite.' If granite, cooling at 600°, expels vapor in the process of crystallization it is reasonable to suppose that a considerably greater vapor pressure would result, and it is thought that the vapor expelled from crystallizing granitic batholiths probably has a pressure sufficient to lift two or three miles of granite. This vapor, collecting near the tops of cupolas of batholiths, is believed to exert sufficient pressure to fracture the hoods and roofs of batholiths above the cupolas. If that is true, one would expect to find that the fracture systems above cupolas are arranged in patterns that depend in part on the shapes of the cupolas. The mechanics of the situation seem to require that conical cupolas should have radial fracture patterns, that bluntly rounded cupolas should have fracture systems that are either irregular or rudely conjugated in plan, and that elongated stocks or cupolas should have fracture systems in which the fractu'res lie nearly parallel to the direction of the elongation of the cupolas. Study of essentially all the cupolas of the earth that have associated important vein-filled fractures shows that this is generally true. This

Jan 1, 1935

By W. H. Emmons

In 1922 Morey made a series of experiments in which he observed the cooling of a molten system containing H2O, 9.1 per cent; K2O, 17.3 per cent and SiO2, 73.6 per cent. This system was confined in a bomb; it was fluid at 500° C. and exerted no vapor pressure. In cooling to 420° C. a large part of it crystallized and at that temperature much of the water had separated from the crystals and remained as steam, which built up a pressure of 4998 lb. per sq. in., a force sufficient to lift nearly one mile of granite.' If granite, cooling at 600°, expels vapor in the process of crystallization it is reasonable to suppose that a considerably greater vapor pressure would result, and it is thought that the vapor expelled from crystallizing granitic batholiths probably has a pressure sufficient to lift two or three miles of granite. This vapor, collecting near the tops of cupolas of batholiths, is believed to exert sufficient pressure to fracture the hoods and roofs of batholiths above the cupolas. If that is true, one would expect to find that the fracture systems above cupolas are arranged in patterns that depend in part on the shapes of the cupolas. The mechanics of the situation seem to require that conical cupolas should have radial fracture patterns, that bluntly rounded cupolas should have fracture systems that are either irregular or rudely conjugated in plan, and that elongated stocks or cupolas should have fracture systems in which the fractu'res lie nearly parallel to the direction of the elongation of the cupolas. Study of essentially all the cupolas of the earth that have associated important vein-filled fractures shows that this is generally true. This

Jan 1, 1935

By L.W. Eastwood, Arthur E. Bousu, C. T. Eddy

The recrystallization and grain-growth phenomena of cold-worked metals have considerable industrial importance because of their role in the fabrication of metals. For this reason, and because of the general academic interest in the subject, these processes have received considerable attention since the time of J. E. Stead's paper1 on The Crystalline Structure of Iron and Steel. There are considerable differences of opinion regarding the theory of recrystallization and grain growth and also differences in the observation of the modus operandi of the processes themselves. The value of many of the existing quantitative data on grain growth is decreased by the failure to distinguish between the grain sizes just after complete recrystallization and those resulting from coalescence. For this reason also, the value of the diagrams of stable grain sizes, like those produced by Bass and Glocker2 and Czochralski3, is lessened in so far as an interpretation of the facts of recrystallization is concerned. It is hoped that the data presentcd in this paper will help to clarify and to simplify the facts relating to recrystallization, and at the same time will show that some of the present-day conceptions are untenable. A paper on the theory of recrystallization, with additional data, will be completed in the near future by the writers. Since the literature on the subject has been adequately and frequently reviewed, the only referenccs to it in this paper will be those necessary in the discussion of the data presented.

Jan 1, 1935

By John Chipman, Carl F. Floe

The system molten copper-oxygen-sulphur is of interest from both the practical and theoretical standpoints; practically, because oxygen and sulphur play an important role in the commercial production of copper, and theoretically because it offers a chance to study the reaction between an oxide gas, SO2, and a molten metal. Reactions of this type, such as that between CO or CO2 and molten iron, are important in many metallurgical operations. Again, the determination of any gas-metal equilibrium is of theoretical interest and value insofar as it contributes to the general development of the laws for solution of gases in metals. This problem is being given an increasing amount of attention in modern metallurgy. This paper is the first of a series and presents the results of a determination of the solubility of sulphur dioxide in molten copper at temperatures from 1100" to 1500ºC., and pressures from about 20 mm. of mercury to somewhat above atmospheric. Review of Previous Work The solubility of gases in most liquids has been found to obey Henry's law, which states that for a fixed temperature the amount of gas dissolved is directly proportional to the pressure. However this law does not hold for liquid metals. Instead, it appears that for many gases, particularly the simple diatomic ones such as O2, N2 and H2, the amount dissolved in liquid metals is directly proportional to the square root of the pressure. This is known as Sieverts' law. It may be recognized as a special case of Henry's law, which applies when the solute gas is dissociated into atoms or when it reacts with the solvent metal to form solute molecules containing single atoms of the gaseous elements, as, for example: 2M+G2=2MG K=(MG)2 /M2 X PG2 [I] which, if the solubility is not too high and the concentration of metal therefore nearly constant, can be simplified to: MG = K1 vPG2 [2 Following the same reasoning, it would be expected that the solubility of SO2 in copper would be proportional to the cube root of the pressure, the reaction being as follows: 6Cu + SO2 = Cu2S + 2Cu2O [3] K= Cu2S X (Cu2O)2 i - (Cu)6(Pso2) [4] or, neglecting the change in metal concentration and considering that the concentrations of sulphur and oxygen are both proportional to the volume V of gas absorbed: K1 =V3SO2 /Pso2 or

Jan 1, 1941

By John Chipman, Carl F. Floe

A year ago the authors published a paper on the solubility of sulphur dioxide in molten copper.l The data in that paper agreed closely with that obtained by previous investigators, which, however, did not agree with the theoretical predictions for solubility of triatomic gases of this type. It has generally been assumed that the reaction of solution is: 6Cu(l) + SO2(g) = Cu2S (in Cu) + 2 Cu2O (in Cu) [I] _ (CU2S)(CU2O)2 K = (Cu)6(Pso2) [2] Neglecting the slight change in copper concentration and considering that the concentrations of sulphur and oxygen are both proportional to the volume of gas absorbed, it follows that this volume should be proportional to the cube root of the pressure. It was found that a plot of the volume absorbed versus the cube root of the pressure gave a straight line, but that this line did not pass through the origin. Calculations of the equilibrium constant for the reaction showed that it was fairly constant for pressures above 100 mm. but that actually it approached zero at lower pressures. The conclusion was made therefore that the solubility as determined could not be expressed by Eq. I or by any other simple equation, particularly at low pressures. Other investigators have concluded that the solubility of sulphur dioxide in copper as well as in several copper alloys is more nearly proportional to the square root of the pressure.* Such a conclusion, however, does not satisfactorily account for the results, even when rather complicated mechanisms for the solution are assumed. The highly improbable speculations of Lepp2 and of Schneider and Esch3 based upon hypothetical dissociation pressures of Cu2O and CU2S dissolved in copper illustrate the type of reasoning that has been used to account for the discrepancy. In the discussion of the previous paper, the authors pointed out that the discrepancy might possibly be due to impurities in the copper, although the purest form available was used. Further consideration of the problem suggested that the impurities likely to have the greatest effect on the solubility of so2 in copper were oxygen, sulphur and carbon. Accordingly, further experiments have been made to show the effects of these elements. Experimental Methods The apparatus used for measuring solubility was essentially the same as that shown in the previous paper. However, since it was desired to make measurements at low pressures, a McLeod gauge was added and 6-mm. glass tubing was substituted for the capillary. This increased the "hot volume" considerably but was necessary in order to obtain good vacuums in a reasonable length of time. A mercury diffusion pump was also installed.

Jan 1, 1942

By Paul M. Tyler

Higher freight rates and better methods of beneficiation now may make it more economical to open inferior deposits closer to a glass factory than to work higher-grade deposits farther away. Nature of impurities and special treatments as well as common practice of sulphuric acid leaching are described. HISTORICAL concepts of the economics of the glass-sand industry are changing rapidly. The greatly expanded demand for glass containers combined with higher freight rates on raw materials and manufactured products have induced a migration of glass factories toward densely populated centers and the creation of new standards of place value for substandard sand deposits. This migration has been facilitated by the construction of pipelines to bring cheaper natural gas and liquid fuel to large cities and may be further speeded by the adoption of modern mineral dressing methods to permit economical utilization of local raw materials. Our national resources of naturally high-grade silica sand are abundant, but most of the best deposits are situated so far from large centers of population that it now costs $3.00 to $5.00 a ton to carry the sand from the mine to the optimum site for a factory making beverage bottles, scientific and electrical glassware, and miscellaneous blown and pressed ware for local markets. It follows that on the basis of freight savings alone it may be economical to use material from inferior deposits closer to the factory even though the f.O.b. cost of mining and treatment may be much higher than at a higher grade deposit farther away. Particle-size distribution is a feature of glass-sand specifications. As long as glassmakers insisted upon having their sand principally coarser than 100-mesh, any material was automatically excluded from consideration that could not be purified without fine grinding or other drastic treatment which greatly reduces the size of the quartz grains. However, re- cent large-scale tests in Norway' showed that finely-crushed quartz used in a soda-lime-silica glass batch caused it to melt and become refined appreciably faster than when ordinary coarse (Belgian) sand was employed. Dust losses were negligible. Since the pre-war cost of sand was only 3 pct of the manufacturing cost of the glass, it was deemed economical to pay twice as much for crushed quartz because of the saving in wear and tear on the furnace walls. In the author's unverified opinion, sand ranging in size between 150 and 400-mesh would probably be superior to that in the more usual range of 20 to 100-mesh. Former objections to fine sand (other than dust) were doubtless fostered by the natural concentration of impurities in the finer sizes. Ordinarily the most objectionable, as well as the commonest, impurity from the standpoint of the manufacturer of any but the cheaper qualities of colored glass is iron. No natural sands are really pure silica. Even water-clear quartz crystals are likely to contain impurities in the form of solid solution as well as inclusions which cannot be eliminated except by chemical treatment that will break down the silica lattice. Pure white pegmatite quartz will usually analyze 0.01 pct or more of iron oxide, and ordinary vein quartz and the quartz grains in most

Jan 1, 1951

By R. H. B. Jones

This paper reviews pertinent geology of the Biwabik iron formation, Mesabi Range, Minnesota. This iron formation is divisible into four members. Each member is distinctive and contains marker horizons, which are recog nizable throughout all phases of alteration from lean, fresh rock to high-grade iron ore. Some beds have a larger magnetite content than others. During the process of ore genesis, which is essentially an oxidation process, the magnetite content is lowered. Alteration from iron formation to ore includes both oxidation of iron minerals and silica removal by leaching and these distinct processes progress at variable rates for different locations and structures. Magnetic intensities, of each horizon of the iron formation are dependent chiefly upon its preoxidation magnetite content, upon the subsequent degree of oxidation, upon the character of the enclosing rocks, and on the extent of fracturing, folding, or faulting. The results of a number of magnetic surveys are described and are correlated with results of drill-hole and mine exploration and developmerit. The magnetic anomalies obtained are discussed in relation to phases of formation of ore within the iron formation. General Information One hundred years ago a party of surveyors, applying the principles of geophysical prospecting, discovered iron ore in the state of Michigan in the Lake Superior district. This event was officially reported as follows:' On Sept. 19 (1844) while running the east line of Town 47 North, Range 27 West, they observed by means of the solar compass remarkable variations in the direction of the needle, amounting to 87" from the normal. Ascribing this phenomenon to iron ore, they sought and found it in ledges or outcrops at several points. The solar compass referred to was invented by William A. Burt, deputy surveyor in charge of this party.2 It is used for determining the true meridian by an observation on the sun. Eight years later, on July 7, 1852, the first iron 're, consisting of 6 bbl. of Ore, was shipped from Marquette, Michigan. It was another 40 years before the first or> shipment left the Mesabi Range in Minnesota, in October 1892. It totaled 4245 tons. Fifty years later, 90 years after the original shipment, during 1942 the Lake Superior district shipped 93,495,392 gross tons of iron ore. Production came from Minnesota, Michigan, Wisconsin, and Ontario, Canada. Throughout the 90-Year period it was known that magnetic properties of most of the ore bodies, and of the iron formations in which they occur, affected the compass. This phenomenon, later to be made use of to outline areas of ground favorable for exploration, was at first a

Jan 1, 1949