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By T. Sterry Hunt

In my address on the " Geognostical Relations of the Metals," delivered before the Institute on the 20th of February last (Vol. I Transactions, p. 331), I spoke of the rocks in the vicinity of Thunder Bay, Lake Superior, where I indicated two series of uncrystalline rocks resting upon the Huronian schists, the lower one consisting of dark-colored argillites and sandstones overlaid, apparently in slight discordance, by nearly horizontal red and white sandstone and marls, which were compared with those of Sault Ste. Marie, and those of the Portage Lake district, on the south shore. These latter sandstones, according to Brooks and Pumpelly, overlie uncomformably the Keweenaw series of copper-bearing amygdaloids, sandstones, and conglomerates, and are in turn overlaid by the Trenton limestone. I then proposed to call this lower series of Thunder Bay, that is to say, the dark-colored argillites and sandstones which are traversed by the silver-bearing lodes of that region, the Animikie group. Shortly after the publication of that address I received an abstract of a paper on the geology of that region by Professor Robert Bell, read before the Montreal Natural History Society, February 24th. He there confirms the statement made in my address that the gold of Lake Shebandowan occurs in the Huronian, which is also seen to be cut by the silver-bearing lodes just mentioned. Professor Bell, in this paper, proposes to designate both what I have called the Animikie group, and the overlying red and white sandstones, by the name of the Nepigon group, for the reason that the upper series is best displayed about Lake Nepigon. This latter series is by Logan supposed to be overlaid by the copper-bearing amygdaloids with conglomerates and sandstones of the north shore (apparently identical with those of Keweenaw); and the whole together, inclnding the Animikie group, constitute his Upper Copper-bearing group. These copper-bearing strata are by him supposed to be overlaid by the red and white sandstones of St. Mary, which are apparently the same with those sandstones which, according to Brooks and Pumpelly, overlie unconformably the similar cupriferous rocks of Portage Lake, and are, in their turn, overlaid by the Trenton limestone. Thus the sandstones which at Thunder Cape overlie the Animikie group are by Logan placed in the midst of the Upper Copper-bear-

FREQUENTLY the careful engineer puts the word porphyry in quotation marks or precedes it with "so-called," when he writes of the Porphyry Copper mines. This is done by way of serving notice that he is aware that the term is not a precise one, though no one who is informed on the subject would in any event misinterpret it. The name originated from the fact that the rock containing the copper at Utah Copper, Morenci, Nevada Consolidated, and Braden-the first four to be developed-was in each instance known as porphyry. The term was convenient; and when Ray, Miami, and inspiration came along they fell into the Porphyry category even though the ore consisted essentially of a rock called schist instead of porphyry. The word is not inclusive enough; nor as a matter of fact is it sufficiently exclusive. Numerous copper deposits occur in porphyry rocks that are not Porphyry Coppers, paradoxical as it may seem. Desiring to be more accurate and at the same time to use a word that is in some degree descriptive, various engineers have adopted the expression "disseminated copper deposits." This alludes to the characteristic scattering of grains or specks of copper minerals more or less uniformly throughout the mass of the rock. Yet here again the implication is not entirely accurate, for the following reason: in some of the ores, the proportion of copper minerals "peppered" in the rock is small, compared with that which coats the walls of cracks and minute fissures; and that which is found as veinlets along planes of fracture. Many geologists have extended their interpretation of the term disseminated to include both types of mineral occurrence. One of the most striking features of the Porphyry ores is the intense shattering and fracturing that the rock underwent at some period or periods prior to the deposition of the copper

Jan 1, 1933

The stabilization of a gravel road with soil is a method of treatment developed in recent years by the United States Bureau of Public Roads for the purpose of binding the constituents together better, and maintaining a more durable surface. The process consists in adding to the gravel or crushed stone and sand, a soil mortar, so-called, of fine sand, silt and clay, mixed in the proper proportions. The coarse gravel and sand supply structural strength and hardness; the fine sand adds embedment support to the coarse sand; the silt acts as a filler to prevent the granular particles from rocking; while the clay serves not only as a binder but also provides pores minute enough to cause connecting moisture films which are supposed to have high cohesive properties'. It will be recognized that the clay is an important ingredient both when wet and dry, and should not show excessive expansion when wet, nor correspondingly high shrinkage in drying, as otherwise there is danger of unseating the nonplastie particles. Such a stabilized road, although an improvement on one with a floating surface, will in course of time be subject to wear, and become dusty when the clay dries out and breaks up. It has been found that if some salts are added to the road mixture they tend to maintain the soil moisture and prevent dustiness of the road or raveling of the road surface. In addition to this, it is claimed that these dissolved salts cause a thinning of the moisture films on the particles, thus permitting greater compaction of the road mixture, and thereby increasing its density. This fact can be proved by noting the increased compaction which a road mixture shows when certain salts are added to the soil water. Since certain chemical substances such as sodium chloride are electrolytes, the question arises whether they cannot have wine effect on the qualities of the clay in the soil mortar, and perhaps improve them. In view of the fact that certain salts seem to exert a favorable effeet on the road mixture it is desirable that they he held in the road soil as long a time as possible.

Jan 1, 1938

The stabilization of a gravel road with soil is a method of treatment developed in recent years by the United States Bureau of Public Roads for the purpose of binding the constituents together better, and maintaining a more durable surface. The process consists in adding to the gravel or crushed stone and sand, a soil mortar, so-called, of fine sand, silt and clay, mixed in the proper proportions. The coarse gravel and sand supply structural strength and hardness; the fine sand adds embedment support to the coarse sand; the silt acts as a filler to prevent the granular particles from rocking; while the clay serves not only as a binder but also provides pores minute enough to cause connecting moisture films which are supposed to have high cohesive properties'. It will be recognized that the clay is an important ingredient both when wet and dry, and should not show excessive expansion when wet, nor correspondingly high shrinkage in drying, as otherwise there is danger of unseating the nonplastie particles. Such a stabilized road, although an improvement on one with a floating surface, will in course of time be subject to wear, and become dusty when the clay dries out and breaks up. It has been found that if some salts are added to the road mixture they tend to maintain the soil moisture and prevent dustiness of the road or raveling of the road surface. In addition to this, it is claimed that these dissolved salts cause a thinning of the moisture films on the particles, thus permitting greater compaction of the road mixture, and thereby increasing its density. This fact can be proved by noting the increased compaction which a road mixture shows when certain salts are added to the soil water. Since certain chemical substances such as sodium chloride are electrolytes, the question arises whether they cannot have wine effect on the qualities of the clay in the soil mortar, and perhaps improve them. In view of the fact that certain salts seem to exert a favorable effeet on the road mixture it is desirable that they he held in the road soil as long a time as possible.

Jan 1, 1938

William B. Phillips, Birmingham, Ala.: The questions raised by Messrs. Wilkens and Nitze are in the highest degree interesting to owners of low-grade iron-ores, aizd no less so to blast-furnace managers. If it can be shown that ores heretofore considered worthless can be brought within the limit of economic use, many large and readily accessible deposits may come into market on the one hand, while on the other the possible increase in the output of the furnace per ton of ore used will prove of advantage to the iron-maker. It cannot, of course, be claimed that this process has been employed on a working-scale with respect to iron-ores, and in so far as concerns results on a large scale no one is any wiser than his fellow. Granting that the results obtained in an experimental way (and certainly the experiments were conducted with a great deal of care) can be attained in practice, we would still be facing the question, what it would cost to get them. In the absence of any specific data, we have to fall back on general principles, helped along, as far as possible, by indications afforded by the experiments. I must confess that as regards the Clinton ores, which I have studied to some extent, I am not sanguine of making a ton of 53 to 54 per cent. concentrates from less than 1.75 tons of 40 per cent. raw ore. It may be possible to get the iron in the heads to 56 to 57 per cent., but the lesser richness of the middlings will probably reduce this to 53 to 54 per cent. in the salable stuff. As the authors remark, it is not worth while to discuss the concentration of the better grades of " soft" Clinton ore; for the price at which they are now delivered at the furnaces, and the comparatively limited amount now remaining, render their concentration unadvisable. If it is to succeed in the Birmingham district, the process must be applied to the low-grade soft and hard ores now con-

Jan 1, 1897

By E. J. Longyear

The rapid development of the Mesabi range has been a matter of much wonder to those familiar with ore-deposits elsewhere, and much skepticism was shown when " millions of tons of ore on the Mesabi" was first reported. Now, however, with over 8,000,000 tons to its credit at the close of 1896, a prospect of 3,000,000 more this year, and more ore " in sight" than ever before, it is evident that the first claims for the range were not so greatly exaggerated as perhaps even those who made them thought they were at that time. An explanation of the ease with which these deposits have been explored is found in their mode of occurrence. Lying in flat beds and near the surface, and only exceptionally occurring under a taconite " capping," the prospector had only to sink a few vertical test-pits on a fortyacre tract down to the rock to be reasonably sure whether his property contained ore or not. If he found ore in one or more of these preliminary pits, he would then fill in with more pits until the ore-area was entirely outlined by test-pits from 200 to 400 feet apart. In the early days of the range the testing was almost entirely done by digging pits with pick and shovel. When water was encountered, work had to be stopped, unless a steam pumping-plant was put in, resulting in greatly-increased expenses. Latterly, drills have been used with great success in continuing the exploration after water has been struck in the pit, rendering further progress with pick and shovel impracticable. There are several kinds of drills in use. The diamond-drill is largely used, and possesses the advantage of being in readiness to drill rock if thought advisable, the taconite being very hard and almost impossible to drill except by the use of diamonds. Some form of churn-drill has been much used. This may be either a steam- or a horse-power-drill. The principle is the same in each, the cutting being done by percussion instead of by rotation, as in the case of the diamond-drill. A churning motion is given by passing a rope from the top of the

Jan 1, 1898

Jan 1, 1950

By C. E. Birchenall, R. H. Condit, M. J. Brabers

In the oxidation of pure iron above 700°C the overall rate is determined mainly by the rapid growth of wiistite, through which iron ions can diffuse rapidly.' Nickel added to the iron progressively decreases the stable range of composition of wustite.' When enough nickel is added to eliminate wiistite as a stable phase, the spinel is the fast growing phase. This investigation was undertaken to test the hypothesis that nickel substituting for iron in magnetite might decrease the rate of spinel growth by reducing the iron mobility. Nickel ferrite boules grown by the flame fusion process were purchased from the Linde Co. Chemical analysis gave an atomic ratio of iron to nickel of 2.88 and showed no other cations. They were cut into discs and ground to give flat, parallel faces. The experimental procedure employed was like that of Eisen and Birchenall in which the distribution of radioactivity diffused in from a vapor deposited surface layer was determined by counting the residual activity through a series of ground faces. The diffusivities were calculated in a manner consistent with the requirements discussed by Condit and BirchenallP The details will be given in connection with a more extensive spinel diffusion study now in progress. The results of the measurements are shown in the figure in comparison with earlier data on magnetite1 and zinc ferrite. The uncertainties arising from scatter in the activity vs distance relationship and uncertainties in the temperatures are shown by flags. Despite the scatter it is clear that substitution of a considerable part of the iron in magnetite by nickel, in this case about one third decreases the iron mobility substantially. sachs' determination of the distribution of iron and nickel in scales on iron-nickel alloys appears to show that nickel is less mobile than iron in the spinel layer. It is evident, therefore, that nickel plays several roles in reducing the oxidation rate of iron-nickel alloys. 1) It reduces progressively the stability range of wiistite. ' 2) It reduces progressively the stability range of the iron-nickel spinel phase in terms of the variation in cation to anion ratio.' 3) As shown in this investigation, it reduces the cation mobility in the spinel phase which is the faster growing phase in the absence of wiistite. The fe was obtained from the Oak Ridge National Laboratory. The research was supported by the Air Force Office of Scientific Research (ARDC) under contract number AF 18(600)-967.

Jan 1, 1961

By T. Koulomzine

The theory of the Askania mag-netometer, as well as a complete discussion of all factors influencing magnetometer readings, is very ably described by J. Wallace Joyce.1 We will assume that the reader is thoroughly familiar with this theory and we will use whenever possible the same notations for the physical values involved in the theory. On the other hand, we believe that the principal formulas of the magnetometer can be deduced much more easily by the use of differential calculus than by the methods employed by Joyce. Consequently, we are presenting herewith a resumé of the theory of the vertical magnetometer in order to determine the correct formula of the temperature coefficient which we propose to compensate. Short Theory of the Vertical Magnetometers We shall accept the following notations: m = total mass of the magnet system, in grams. g = acceleration of gravity, in dynes. a = projection on the axis of the magnet system of the distance between the axis of support and the center of gravity of the magnet system, in centimeters. h = projection on the perpendicular to the axis of the magnet system of the distance between the axis of support and the center of gravity of the magnet system, in centimeters. M = 2pL = M, magnetic moment of the magnet system. Z = vertical component of the earth's magnetic field. ? = deflection angle of the magnet system. = focal length of objective lens in the optical system S = scale reading. In a vertical magnetometer the axis of the magnet system is kept horizontal within 2". Therefore, referring to Fig 1, we see that the magnetic torque of the magnet system influenced by Z must be counterbalanced by the gravity torque. MZ cos ? = mga cos ? + mgh sin ? or dividing by cos ? MZ = mga + mgh tan ? If we now move to another magnetic station and the temperature conditions change, the values of all the variables will change also: M, a, and h under the influence of temperature. 2, both with time and space. ? and S, as a result of all the above changes. Taking increments in Eq 2 we obtain: (Mo + ?M)(Z + ?Z) = mgao + mg?a + mg(h + ?h) tan (? +??) but tan (? +??), because ? is small, can be replaced by tan ? + tan ??; in fact tan (?+ ??) = sin ?.cos ?? + cos ?.sin ??/ cos ?.cos ?? — sin ?sin ?? but sin ? sin ???0 tan (8 + ??) ? tan ? + tan ??. Fur-thermore, neglecting all terms of the equation containing two differentials becomes: or a differential and a tan ??, Eq 3

Jan 1, 1950

By W. H. Blauvelt

W. H. BLAUVELT, Syracuse, N. Y. (communication to the Secretary*).-I have read Mr. Howland's paper on Calculations with Reference to the Use of Carbon in Modern American Blast Furnaces with much interest, and believe that his method of analysis of the subject will be of material assistance in our study of the action of coke in the blast furnace. Mr. Howland quotes Professor Richards' statement that from the standpoint of the generation of the maximum quantity of heat in the furnace, Grüner was right in saying that all the carbon burned in the furnace should be first oxidized at the tuyères to CO and all reduction of oxides above the tuyères should be caused by CO, which thus becomes CO2. It is clear that the maximum quantity of heat is generated in the furnace when the greatest amount of carbon is burned to CO2 irrespective of whether it is burned at the tuyères or further up the furnace. So it would appear that Grüner's theory is sound regarding the maximum production of heat only because if all the carbon is burned to CO at the tuyères the reduction of the ores will have to be effected by the further oxidation to CO2. Whereas, if the reduction of the ores is effected in part by solid carbon, part of this carbon might be oxidized only to CO, resulting in a higher percentage of CO in the escaping gases than from Grüner's "ideal conditions.? But in studying the combustion of coke in the furnace, it is clear that the production of the maximum quantity of heat is not of the first importance in blast-furnace operation, or in the utilization of the fuel charged into the furnace. To my mind the production of a high thermal head at the tuyères is of the first importance, and the best coke is that which reaches the tuyères in proper condition to produce the highest temperature at the tuyères, and in just sufficient quantity to do the amount of work required there under the conditions produced by this maximum temperature. The combustion of a much larger amount of fuel at the tuyères, under conditions that will fall short of producing the highest possible temperature, cannot produce as good results, either in fuel economy or output. If this statement is correct, does it not correspond with Mr. Howland's statement that too much wind is inimical to low coke consumption? Nothing is more fatal to obtaining the highest temperatures than an excess of air for combustion. In the blast furnace an excess of air dilutes and cools the products of combus-

Jan 10, 1916

By Tormod Forland

FROM equilibrium measurements on the system NaF-Na 3A l Fo-A 1 2 O 3-Na CO 3-CO 2 with high contents of NaF, Forland, Storegraven, and Urnesl concluded that complexes are formed containing two oxygen, three aluminum, and a less defined number of fluorine per complex. The same number of oxygen atoms per complex was also found by cryoscopic measurements for mixtures high in NaALF 6. In a recent paper by Stokes: some other complex ions, Al2O2F42- and AlOF2-, have been suggested. Here an additional argument in favor of the complex ALO2F. suggested by Forland, Storegraven, and Urnes will be given. When fused Na3AlF6 containing some A12O3, is cooled slowly, the solid phase will consist of the two components as separate phases. The melting point and the heat of fusion of Al2O3 are so high that this component will form the stable solid phase even though in the liquid state the complex may have a high stability. If, however, the fused mixture is quenched, the decomposition of the oxygen-containing complex and the formation of solid Al2O3 does not proceed fast enough, and a solid solution of A12O3 in Na3AlF6 is obtained. Zintel and Morawietz3 obtained cryolite containing 10 pct AL2O3 in this way. The density and the lattice parameters of the A12O3 containing cryolite were also measured, and from this it was concluded that the Al2O3 enters the cryolite lattice as Al3AlO0 groups replacing Na3AlF6 groups. However, the experimental data could as well be explained by assuming that one Na+ ion and two of its neighboring F- ions are replaced by one Al3+ ion and two O2- ions. This may be pictured schematically as: F F F F F F F Al F Na F Al F ,-Na+ + Al8+ F Al 0 A1 0 A1 F F F F —2 F- + 2O2- F F F solid cryolite cryolite-alumina solid solution This means that the complex in the solid solution, derived from X-ray and density measurements, is the same as that which Forland, Storegraven, and Urnes derived from equilibrium measurements in the liquid state. References IT. Forland, H. Storegraven, and S. Urnes: Ztsch. fur anorgan-ische und allgemeine Chemie, 1955, vol. 279, p. 205. 2J. J. Stokes: AIME Trans. To be pubhshed. s E. Zintel and W. Morawietz: Ztsch. pubhshed.fur anorganische und allgemeine Chemie, 1939, vol. 240, p. 145.

Jan 1, 1958

By H. W. III Straley

SOME ten years ago the writer1 made a survey of college catalogues to determine what sort of training geologists were receiving in basic sciences. In the light of this compilation and subsequent experience, he made the statement at the 1939 meeting of the Institute that apparently only in schools offering a curriculum in geological engineering or in the geological option of mining engineering curricula could geologists hope to receive the training advocated by Hubbert.2 In the former study, schools of engineering were excluded because the preparation was known beforehand. The present study aims to consider engineering schools in an effort to determine not only what basic studies are required but what use is made of them in geological courses of the third and fourth years. The present study combined the method of consulting catalogues with a questionnaire. Letters were mailed to officials responsible for supervision of mineral industries curricula requesting information on: (I) the extent to which the engineering preparation of the first two years is actually used in the work of the last two; (2) the extent to which the engineering of the last two years is used in courses in geological engineering or geology; and (3) whether geologists or geological engineers teach descriptively or analytically. Both methods of securing information are open to criticism; the former on the basis of the incomplete information supplied by university catalogues concerning prerequisites and curricula and the latter on the ground that the questions may be phrased poorly or given insufficient consideration by replying officials. Fifty-six questionnaires were mailed and 39 (70 per cent) replies were received. Of the replies, 6 (11.3 per cent) were from colleges of liberal arts unconnected with engineering schools, 11 (20 per cent) were from schools having curricula in geological engineering and 22 (39 per cent) were from departments of mining engineering. The number of replies and their distribution were satisfactory in spite of the receipt of only six from liberal arts colleges. It should be understood that the universities of which the catalogues were examined were not necessarily the same in both compilations. No departments that are admittedly or known to be acting solely as service departments were recorded in the second study. Table I shows that all professional schools require mathematics through calculus, whereas only 7 per cent of the liberal arts curricula expect the same level of preparation; only 73 per cent require trigonometry and 40 per cent college algebra. The proportion of geological engineering curricula requiring differential equations is higher than mining. All of the engineering schools require general and analytical chemistry, whereas only 77 per cent of liberal arts curricula require general and 18 per cent analytical. Twenty-two per cent of the mining and 40 per cent of the geological engineering

Jan 1, 1941

By C. Wert, D. Keefer

The results of this study indicate that sudden increases in aging temperature lead to reversion phenmena in carbon in the a, iron system. These phenomena are thought to be associated with the dissolution of carbide precipitates. Reversion is studied with respect to three variables: 1) Specimen grain size, 2) the initial amount of carbon in solution, and 3) difference between initial and final aging temperature. It is found that of these variables the initial carbon concentration has the greatest effect on reversion. THE solid solution of carbon in n iron has been the subject of numerous investigations throughout the past few years. Despite the great amount of effort which has been put forth toward understanding this system, however, there persist a number of interesting aspects of the system which are open to further research' Studies Of the precipitate which forms as a result of aging a supersaturated solution of carbon in a, iron appear to be particularly interesting. The present work is an attempt to determine certain

Jan 1, 1960

By P. E. Price, N. J. Grant

DURING the course of creep studies in iron-chromium-nickel alloys, it became necessary to establish the limits of the two-phase ferrite-austenite field at 1300°C. The shape of this region, predicted from the iron-chromium and chromium-nickel binary

Jan 1, 1960

By J. H. Keeler

AN alloy of zirconium containing 18 atomic pct Cb was found to be body-centered-cubic and readily deformable at room temperature. The behavior of this alloy provided an opportunity to determine if

Jan 1, 1957

Jan 1, 1967

By F. J. Darnell

SINGLE crystals of a-titanium are difficult to obtain because of the phase transformation at 882 °C in which the structure changes from the high-temperature body-centered structure ß to the low-temperature hexagonal close-packed structure a. Preparation of single crystals of a-titanium has previously been accomplished by a strain-anneal method which takes several days and is not generally reproducible. Single crystals as large as 5 mm

Jan 1, 1959

By Harry Roe

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

Jan 1, 1937

By W. B. Triplett, H. I. Aaronson, G. M. Andes

THE morphology and mechanism of the proeutectoid a and the eutectoid reactions have been recently investigated in some detail in an iodide-base Ti—7.22 pct Cr alloy.' These studies have now been extended to an iodide-base Ti—10.8 pct Cr alloy in order to evaluate the effects of composition on the proeutectoid and eutectoid transformations in titanium-chromium alloys. The alloy used in this investigation had the following composition: 10.8 Cr, 0.0327 0, 0.011 N, 0.0063 H, and 0.011 pct C. Specimens of this alloy were heat treated in evacuated and internally get-tered Vycor capsules. The specimens were solu-

Jan 1, 1959