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By Philip Henry

THERE is a difference of opinion among engineers on the subject of depreciation in general, and still more on its application to any given case. The committee which was appointed by the American Society of Civil Engineers to make a report on Valuation of Public Utilities, states "There is no subject connected with valuation about which there are more diverse views than those relating to depreciation;" and in the discussion which took place upon the presentation of the preliminary report of this committee in January, 1914, that part of the report dealing with depreciation called forth more discussion than any other. From this discussion it was evident that the word " depreciation" was not always used in the same sense, so it is quite important that some definition be adopted. As this paper relates to the proper method of treating depreciation by corporations or individuals operating oil properties, both of which must make a return of annual net income to the government in connection with the income tax, it will be in order to adopt the definition of the Internal Revenue Bureau. Under date of Mar. 29, 1910, the Commissioner of Internal Revenue of the Treasury Department stated "Deduction on account of depreciation of property must be based on lifetime of property, its cost, value and use." Again, on Form 1035, "Return of Annual Net Income" for miscellaneous corporations (Section 2, Act of Congress approved Oct. 3, 1913), a deduction from gross income is allowed for "Total amount of depreciation for the year." This item is defined more particularly as follows: "The amount claimed under Item No. 5 (b) for depreciation should be such an amount as measures the loss which the corporation actually sustains during the year in the value of buildings, machinery, and such other property as is subject to depreciation on account of wear and tear, exhaustion, or obsolescence. The amount taken credit for on this account in order to be allowable should be so entered on the books as to constitute a liability against the assets of the corporation. The amount claimed under this item should not cover losses in the value of stocks and bonds. Decrease in the book value of securities owned, so far as such decrease represents a decline in the actual value of such securities, should be deducted under item 5 (a) of the return.

Jan 1, 1915

Wartime geological studies by the U. S. Geological Survey and subsequent drilling carried on by the Bureau of Mines disclosed new ore in the Illinois-Wisconsin zinc field. As a result, several companies are carrying on drilling programs to locate and define new ore bodies. The Vinegar Hill company, which operates a custom mill to handle ores from various sources, now employs about fifty men in production at their Andrews mine. The ore is usually found in a 200-ft horizon below the surface. Water problems are not serious. Commercial-grade ore ranges up to 8 and 9 per-cent zinc and the cut off is approximately 41/2 percent.

Jan 1, 1948

By E. L. Bruce

GOLD occurs in many mineral deposits in the rocks of the Canadian Shield. It is present in the ores of many base metals and a considerable quantity is recovered as a by-product from the production of copper at Noranda, of nickel and copper at Sudbury and of copper and zinc at. Flinflon. But the greater part of the gold production of Canada is from deposits in which gold is the only metal of value. No gold is obtained from placer deposits within the borders of the Canadian Shield. A brief review of the geological relations of some of the gold deposits of the Canadian Shield will be presented in an attempt to explain certain associations. Only those which are being worked for their gold content will be considered and descriptions will be conned to representative types of deposits, chiefly those of major importance; a few others, differ-ing in certain features from those of the older and larger mines, will be included in order to illustrate the general conditions in which gold occurs in these ancient rocks. Brief summaries will be given of the geological relations of the Beattie and Siscoe mines of northern Quebec, of the mines of the Porcupine and Kirkland Lake areas of northeastern Ontario and of the Howey, Central Patricia and Little Long Lac mines of northwest-ern Ontario. Genetic relations to igneous rocks of granitic composition, outcropping in the vicinity, have been assumed for many of these deposits. Undoubt-edly the ore minerals have been derived from igneous sources and, for some occurrences, there is evidence suggestive of genetic relationship between the ore bodies and neighbouring intrusive rocks. During the past few years, however,, many investigators have expressed doubt of the genetic relationship of certain ore bodies to igneous masses near which they occur. As will be seen from references in the following descriptions the importance of the structural conditions in localizing deposition has been realized. This is pointed out for Canadian pre-Cambriang old deposits by E. T. Dougherty, who also refers to the

Jan 1, 1937

By A. F. Lucas

Belle Isle, located in the low sea marshes near Atchafalaya Bay, is the southeasternmost of the famous Five Salt Islands of Louisiana. Rising about 80 ft. (24 m.) above the level of the surrounding marsh and being some 800 acres (323 ha.) in extent, it constitutes a striking landmark on the low Gulf coast, and since the eighteenth century, when it played an important part in the operation of the buccaneers, it has been intermittently frequented by man. In 1897, the writer discovered the great mass of salt that underlies the island and shortly afterward published a brief account of the geology of Belle Isle and the neighboring salt islands.' In that paper he described principally the salt, but pointed out also the occurrence of petroleum and of sulphur in the strata above the salt. Since that time the island has been extensively explored by the drill, and the developments up to 1908 have been described by Veatch2 and Harris13 and Knapp.4 The writer's early conclusions as to the probable presence of sulphur in considerable quantity have been confirmed by the later drilling, some of the wells having found quantities of gas containing hydrogen sulphide and a number of sulphur-bearing strata as well. Under the stimulus of the present keen demand for sulphur for war purposes, a syndicate of New York capitalists was recently formed to explore the sulphur resources of the island in more detail. Under the writer's direction, six wells were drilled for this syndicate during the winter of 1916-17: The present paper presents briefly the results of this work and sums up the present knowledge of the geology of this highly interesting locality.

Jan 1, 1918

THE second part of the mould for making guns is the core. Without this the space could not be made where the powder is to be and through which the ball, impelled by the fire, can pass and take flight. To make this it is necessary to take two things into consideration, because they are very important. One is what you are to make it on so that it may be supported and kept true. The other is what composition of clay will stand up during casting and yet not be very difficult to extract from the body of the finished gun. For the first, it is found that only an iron spindle of a suitable thickness is able to support the weight of the clay without bending under the heat of the fire or wobbling as it is turned on its journals or when handled. This should be a braccio or more longer than the mould of the gun and worked exactly round, straight, and well tapered like a spindle; above all every one of its joints should be well secured and solid. At the upper end a per-orated heel should be made, and lower down, exactly at the point corresponding to the length of the mould, are one or two other holes through which the little crossbars can be passed that fasten the core to the outer mould and also serve for constructing the disc. Now this iron is to be arranged on two trestles, pivoted so that it may turn truly when rotated. In order that it may not run up and down, make a little iron fork which engages a notch made with a file at the foot, and another at the head. After this, you must prepare clay for the core which is well made and tenacious ,enough not to crack. Fint take care that there are no pebbles in it and that it is composed of a small amount of cloth clippings and much sifted horse dung and some washed and clean wash ashes so that it may be of a tender and crumbly consistency in order that it may later be more easily extracted from the space inside the gun. In the same way, in order that you may be able to take out the iron piece at the same time, first cover it with ashes, and then wrap it all over with a rope of ordinary thickness, leaving a dito of the iron uncovered in every palmo length. [86] Alternatively, you may cover it all very tightly with hemp tow in the same way after it has been covered with ashes. Or heat your iron considerably and then cover it all to the thickness of a good cord with wash ashes or powdered charcoal that has been made into a paste with a little

Jan 1, 1942

By O. Schaaber

THE existence of isothermal martensite without the presence of the athermal form thus far has been established only in a 6 pct Mn, 0.6 pct C steel' and a 23 pct Ni, 3.5 pct Mn-Fe alloy.' " Theoretical calculations, moreover, predict this phenomenon to be observable only within narrow composition limits.' In all other steels, it is generally considered that martensite inevitably forms upon cooling below the M, temperature. Even the possibility of isothermal martensite transformation has been questioned for the common steels, although Averbach and Cohen" showed that martensite formation does not stop when the cooling is arrested and that as much as 5 pct retained austenite may transform isothermally to martensite at room temperature. This note presents some observations made on a number of low alloy steels by dilatometric and inductive measurement of isothermal austenite transformation at various temperatures close to the Ms. In the dilatometer studies reported previously, austenitized specimens were immersed in a salt bath maintained at proper temperature and immediately inserted into the dilatometera8' already at thermal equilibrium with the bath. The dilation was read on a dial gage divided into 0.001 mm intervals. Induction measurements were made with a separate excitation source and a test coil, sealed together in a salt-tight case. The increase in the induced voltage caused by the transformation products was recorded at a paper speed of 4 mm per sec. The steels studied are listed in Table I. Specimens prepared from steels 1 and 2 were in the form of hollow cylinders 60 mm long, 10 mm ID, 14 to 16 mm OD, while specimens of steels 3 and 4 were in the form of notched-bar impact test specimens, DVM type. Specimens of steel 5 were in the form of strip, 7x0.3 mm. In the bainitic range, curves representing the amount of transformation vs log time have a single step appearance, as is shown by the curve of isothermal transformation at 320°C in Fig. 1.Y ransformation proceeds in accordance with the Austin-Rickett equationo P -----------= k t" 100-P where P is the percentage of transformed austenite, t is time, and k and n are constants. Near the M, temperature, however, complex curves having two steps are observed. As shown in a previous papera for steel 3 isothermally transformed at 245"C, such complex curves can be separated into two separate transformations or reactions each following the Austin-Rickett equation. The values of n in the equation for a number of such two-step transformations are listed in Table 11 for steel 1. At transformation temperatures of 250" and 235"C, evidence of a second transformation is very

Jan 1, 1956

By Tracy C. Jarrett

In 14-karat gold alloys, as in 10-karat gold alloys,3 the addition of such metals as zinc, nickel, copper and silver produces a wide range of physical and chemical properties such as color, hardness, corrosion resistance and melting points. These important factors made gold alloys desirable in the optical work and for jewelry. In 14-karat gold alloys, as well as in 10-karat or 12-karat, it is possible to have two golds of the same color, one of which will corrode more than the other, although it may be harder. Some of these alloys have been investigated by F. E. Carter,' E. M. Wise,= and L. Sterner Rainer.4 In this group of alloys the gold content of 58.3 per cent (14-karat) was held constant, while the copper varied from 36 to 24 per cent. The balance of the alloy consisted of one, two, or three of the metals silver, zinc, and nickel. All the alloys were melted in an induction furnace and cast into an ingot that measured 3 by 1/4 by 3/4 in. The method of determining the melting points, color determinations and acid test have been discussed in previous papers by the author.2, 3 It is necessary to use small test bars (Fig. I). The tensile bars were annealed at 1300oF. for 20 min. and then air-cooled. There being a very marked drop when the yield point was reached, "the drop of the beam" method was used in determining the yield point. Alloys Gold-copper.zilzc A~loys.—Gold-copper-zinc alloys melt, cast, and labricate easily. The low melting points, however, limit their use to some extent. The physical properties of these alloys are not entirely satisfactory. When the ultimate strength is satisfactory, the elongation and reduction of area are too low (Table I). Gold-copper-sinr-nickel A lloys.—In this group of alloys, in which zinc and nickel replace copper in approximately equal parts (Table I), the yield point, hardness, and ultimate strength increase with the increase of zinc and nickel content, while the reduction of area and elongation decrease. The physical properties are desirable, particularly of the white gold alloys. The alloys of this group are not difficult to cast and fabricate, and most of these colors could be used commercially. Gold-copper-nickel A lloys.—Gold-copper-nickel alloys are similar to the gold-copper-zinc and the gold-copper-zinc-nickel alloys. They do, however, possess high yield point, ultimate strength and hardness, somewhat higher than those of the other two groups mentioned (Table I). The difficulty with these alloys is that they fire-crack readily and heavy rolling is necessary between annealings. Being hard to fabricate, many

Jan 1, 1941

By George Packard

THE shaft of the Raven. mine, at Butte, Mont., is an incline 1,700 ft. in length and dipping at various angles. At the top the dip is 70° from the horizontal, but this is gradually flattened until at the 300-ft. level the inclination is only 47°. This angle continues to the 1,100-ft. level, below which it, curves with a 125-ft. radius to 78°. In addition to these variations in dip, the shaft does not lie in the same vertical plane, with the result that the hoisting rope not only rubs at intervals on both the hanging- and foot-walls, but presses strongly against the west, dividers near the collar, while 300 ft. below it runs close to the east end plates. The early operators used no idlers, and wall plates cut 6 in. deep y the rope resulted. Later operators first attempted to overcome the excessive friction, and the wear of rope and wall plates, by introducing solid cast-iron idlers, 3 in. in diameter. To allow for the travel of the rope from side to side some of these had to be 3 ft. long and were very heavy. Judging from the appearance of the old idlers of this type found at the mine, they often failed to turn in the bearings, which is not surprising when it is considered that they would have to make 1,000 rev.. a minute under ordinary hoisting conditions. The next rolls were made of wood, 6 in. in diameter, with an iron band about each end, and a pintle of 1-in. round steel driven in at the ends to serve as a shaft. These wore rapidly, and were soon replaced by rolls made from water pipe, 5 or 6 in. in diameter, cut to the desired length and fitted with a wooden cylinder into which the pintle was driven. Where the idlers were used on the hanging-wall of the shaft the original bearing was simply a piece of 2 by 1-1 in. strap iron, 10 in. long, turned up at the end in a circle of 18 in. in diameter to receive the shaft. A small hole served for oiling, and common black oil was generally used, although filtered oil from engine bearings and compressor bearings was also used. When the rolls were to be placed on the foot-wall the bearings were made from two pieces of 1 by 3 in. steel, 6 in. long. A half circle was cut on the flat side of each piece and the two half circles together formed a bearing. Oil holes were provided, and in some cases holes were bored through the two pieces so that they could be screwed or spiked to the wall plates.

Jan 8, 1914

By D. R. Walker, M. C. Shaw

The laws of Kick and Rittinger are explained as functions of particle size with metal cutting theory. Comminution is shown to be basically the same process as metal grinding. The machine shop type of grinding operation is used to study mineral crushing. Evidence indicates that plastic flow occurs in comminution. THE laws of comminution of Kick and Rittinger have been debated for many years. Certain data obtained from ball mill and drop tests are found to be in approximate agreement with Rittinger's law while other data would seem to support Kick's law. In all these tests the energy required to produce a wide variety of particle sizes has been studied. Surface area has also been measured with considerable difficulty, at first because it was thought that the energy associated with crushing was that required to create new surface, later because of precedent and because a more fundamental variable was unknown. Tests made with the machine shop type of grinding process show that normally brittle materials that are usually crushed can behave like the more ductile metals. Brittleness is then a relative prop- erty largely dependent on specimen size and stress state. The machine grinding operation offers a convenient means for studying the comminution of materials in which the important size variable retains its identity. The energy required to grind a certain volume of material is shown to be strongly dependent on size. Kick's law is found to hold very well for particles below 1 micron in size, while Rittinger's law holds approximately in the comminution of larger particles. While a physical origin of Kick's law is established in terms of the theoretical strength of materials having a perfect lattice structure, there is found to be no physical basis for Rittinger's law. Because of its industrial importance, comminution has commanded considerable technical attention and has been the subject of continuous study for nearly a century. A number of empirical rules have been proposed to make it possible for grinding energies to be predicted. Of these so-called laws of comminution those bearing the names of Kick and Rittinger have been most widely applied and debated.

Jan 1, 1955

By G. D. Delprat

The object of this paper is to describe an application of the crosscut system of mining, as carried on in the Cabezas del Pasto mine, one of the copper-mines in the sooth of Spain. The system is not new; but it is not very generally adopted. It offers, however, decided advantages over other systems more in use; especially where the ore is found in large masses or wide lodes, as it allows the extraction of all the ore without leaving any pillars or roofs. A somewhat detailed description of the various operations and costs of working may not only be interesting, but may possibly lead to a more general adoption of this method in cases where at present the pillar-andstall system is preferred. The principal features of the copper-lodes in the south of Spain and Portugal are the following: They are nearly all lenticular masses of great lateral dimensions and unascertained depth; their direction is approximately east-west, and their dip towards north. Some are contact-lodes, having slate on the hanging-wall and porphyry on the foot-wall; others are imbedded in porphyry, and others again are imbedded in clay-slate. The upper portion of these lodes consists of " gossan," a siliceous peroxide of iron, mixed with more or less clay. The depth to which the gossan goes down varies in different localities, from 40 feet to 120 feet, and more. Below the gossan is found the iron pyrites, with about 2 to 3 per cent of copper. The gossan is generally admitted to be the result of the decomposition of the pyrites, the copper rendered soluble, filtering into the underlying layers of undecomposed ore, and enriching the ore below the gossan above the general average. Very rich pockets and streaks of ore, containing sometimes 10 per cent of copper and more, are often found in the upper portions of the lodes. The copper contained in the ore is generally in the shape of gray and black sulphides and copper pyrites; rich pockets often show chalcopyrite and fahlerz. In nearly

Jan 1, 1893

By T. F. Bower, M. C. Flemings

The classical explanation for formation of the fine equiaxed "chill zone " in ingot solidification is that local supercooling near the chill wall causes copious nucleation in this region. This work indicates, however, that convection is an essential element in formation of the chill zone. In the absence of convection, no chill zone forms even though rate of. heat extraction is extremely vapid. Alloy studied was Al-l.5 pct Cu alloy solidified against a copper chill wall. When solidification was initiated at the chill wall in absence of. cor-vection, surface grain size was large (>I cm diam). When it was initiated in the presence of convection, it was fine (<0.05 cm diam). It is concluded that some form of "crystal multiplication" plays an important role in formation of the chill zone. INGOT macrostructures are generally classed as containing one or more of the three zones: "chill zone", "columnar zone", and central "equiaxed zone". These three zones are sketched in Fig. 1; their origin has been discussed in some detail.&apos;-&apos; The classical explanation for formation of the chill zone is that supercooling occurs in the region of liquid metal adjacent the mold wall, and copious nu-cleation then takes place in this region forming numerous small crystals. The columnar region then results by growth of favorably oriented grains (den-drites) which crowd out their less favorably oriented neighbors."5 The mechanism of the columnar-equiaxed transition has been the subject of considerable interest. The generally accepted mechanism, until recently, was that constitutional supercooling developed in front of the growing columnar grains with eventual nucleation of new, equiaxed, grains ahead of the growing solid front.&apos; Recently, it became evident this explanation was not completely satisfactory and it is now evident that "crystal multiplication" plays an important role. This crystal multiplication occurs by separation of dendrite arms from growing dendrites,8?"&apos; and has been shown to be strongly influenced by convection.6, 10-13 Reduced convection results, for a given alloy, in longer columnar zone, larger columnar grains, and larger equiaxed grains.7, 12

Jan 1, 1968

By I. Fatt

Networks of resistors are used as analog computers to obtain relative permeability and resistivity index curves for networks of tubes. These curves have all of the characteristics of those obtained on porous media and, therefore demonstrate the validity of the network of tubes model. INTRODUCTION In paper I&apos; of this series the network model was shown to give information on the structure of porous media that could not be obtained from the bundle of tubes model. The agreement between the capillary pressure characteristics of a network of tubes and those of typical porous media does not prove the validity of the network made. The bundle of tubes model, although it gives less information, also shows this agreement. In this paper the flow properties of a network of tubes are shown to be in agreement with flow properties of porous media. The flow properties of the bundle of tubes model are not in adequate agreement with those of porous media. The dynamic properties of porous media, such as fluid permeability and electrical conductivity, have been found experimentally to be more sensitive functions of structure and pore size distribution than are the static properties such as porosity and capillary pressure characteristics. The network model can, therefore, be best tested by comparing the dynamic properties of a network of tubes with the observed properties of porous media. All static and dynamic properties of a completely valid model must agree with the observed properties. The most commonly measured sensitive dynamic properties are the relative fluid permeability and the relative electrical resistivity. Experimental measurements of these dynamic properties on sandstone, sintered glass, sintered alumina, and soil are reported in the petroleum and soil science literature. These properties were chosen, therefore, for the test of the network model. In the network model, relative permeability is the permeability of the network when some of the tubes are not conducting fluid, relative to the permeability when all tubes are conducting fluid. Similarly, the relative resistivity is the electrical resistivity of the network of tubes when some of the tubes are filled with a nonconductor. relative to the resistivity when all tubes are filled with the electrical conducting fluid. Single Size Tube Network The simplest porous medium is one in which all pores are of the same size. Such media can be approached by packing beds or columns of uniform size particles of sand, glass, or metal. The model of such medium in this study is a network of single size tubes. The network form, the ß factor, is usually not known for real porous media. If the validity of the network model can be established, then the study of the flow properties

Jan 1, 1957

By R. H. Sweetser

There are probably as many variations of the method for blowing-in blast-furnaces as there are furnace superintendents. That some of these variations are poor practice is shown by the troublesome and sometimes disastrous experiences of many furnace-men, even within the last few years. It is the object of this paper to put on record a blowing-in practice that has gradually developed to the point where the results are sure, safe, and satisfactory; and also to bring into discussion several variations that are questionable. The blowing-in of a modern blast-furnace is one of the greatest of metallurgical operations. On its degree of success depends much of the future life of the lining and the subsequent behavior of the furnace; and it involves possibilities of danger to the men engaged in the work. The objects to be attained are the heating of the interior of the furnace to the high temperature necessary for smelting iron; the starting of the smelting process; and the gradual movement of the stock in its downward course. The most critical points are the placing of the kindling-wood, the " bringing down " of the gas, the closing of the iron-notch, and the first cast. The lighting of the first gas, the opening of the cinder-notch for the first flush, and the running of the first cast are anxious times for the superintendent and the furnace-men. Drying-Out the Furnace. As soon as a furnace-lining is completed it should be thoroughly dried out, whether it is to be blown-in soon or not; and the longer it is dried, the better for the furnace. At least two weeks is desirable; but good results can be had with 10 days of firing. The crudest and least desirable method of drying is to build a wood fire in the bottom of the furnace, throwing the wood in through a tuyere-arch, and using the iron-notch for

Jan 1, 1913

The Carol concentrator of the Iron Ore Company of Canada was completed in 1962 and through expansions .has become one of the largest iron ore beneficiation plants in the world with a new feed capacity of 147,000 It (149,350 mt) per day. The Carol ore contains specular hematite and magnetite having a bulk density of 166 lb/cu ft (2660 kg/m3) It is crushed to 7 in. (178 mm) for feeding to autogenous mills for subsequent concentration by Humphrey’s s spirals. Mine ore is loaded into 150 It (152 mt) trucks by 10 cu yd (7.65 m3) shovels and then, at a transfer station, is loaded into side-dump rail cars of 100 It (101.6 mt) capacity. Each train is composed of twenty cars and operates completely automatically as it hauls the ore to the primary crushing station, dumps its loads, and returns to the loading station, a 11.5 mile (18.5 km) round trip. The primary crushing station is composed of two 60 in. by 89 in. gyratories installed in 1962 and 1972. Neither crusher has a grizzly ahead of it. Rail cars are dumped into 300 It (305 mt) pockets which contain splitters for spider protection. What few oversize boulders which do not go through the crushers are drilled and blasted. Liners in the dump pocket and the crushed ore pokcet under the crusher are manganese steel. Both crushers are direct driven by 700 hp (5 15 kw) motors, and the hardness of the ore causes them to pull almost their full power. Crushed ore drops into a 160 It (163 mt) pocket equipped with radioactive level control units for low-intermediate, and high level indications. The low level unit stops and starts the apron feeder, the intermediate unit controls the feeder speed, and a high-level reading stops the car dumping. Apron feeders are 72 in. (1. 82 m) wide and are variable speed from 12 to 52 fpm (3. 7 to 15. 8 mpm). They discharge to 60 in. (1.52 m) wide takeaway belts. Crushing capacity, nominal and maximum for each crusher, is 4, 000 ltph (4. 064 mtph) and 4,600 ltph (4,674 mtph). The crusher eccentric is removed by a conventional cart which travels on removable rails. Mainshaft removal and maintenance is done by 65 and 75/10 ton cranes. Mainshaft replacement requires eight hours, a usual time, but concave replacement requires only sixteen hours, a result of a fine maintenance organization. Mantle relining is done at grade next to a repair track. Zinc is used for backing both mantles and concaves. Both the electrical rooms and the dust collectors are located below grade,

Jan 1, 1978

By Thomas F. Bates

ANALYSIS of the chemical and structural differences in minerals often results in a better understanding of the differences in the geological conditions under which they were formed. The minerals in the kaolinite group differ in the amount of interlayer water and in the nature and amount of ordered and/or random shifting of each 1:1 layer with respect to those above and below it. This paper is a progress report resulting from research on the morphology, structure, and origin of fine-grained minerals, supported by Contract N6onr26914 with the Geophysics Branch of the Office of Naval Research. The purpose of the paper is to present data obtained in the laboratories at The Pennsylvania State College and elsewhere, which reveal some of the details of structure of the minerals in the kaolinite group, and to suggest a number of interpretations that bear upon the conditions of origin of these minerals. Be¬cause most of the work in this investigation thus far has been concerned with the relationships of kaolinite, halloysite (4H2O; endellite), and halloysite (2H2O), must of the discussion deals with these members of the group. The first step in the analysis of the differences in two sets of geological conditions is an evaluation of the differences in the minerals that result. Thus the chemical differences between the montmorillonite and the kaolinite clays corroborate other evidence in support of the view that the montmorillonites are commonly formed when solutions are alkaline and leaching poor, while kaolinite usually is associated with acid solutions and good drainage condi¬tions. It is obvious that the greater the differences in the minerals, the more divergent may be the conditions that give rise to them and the more readily one condition can be distinguished from the other. In the kaolinite group, differences between individual members are small, therefore the differences in condition of origin are presumably subtle and difficult to define. At the same time, the very fact that the minerals differ only slightly makes them more sensitive indicators of the exact conditions under which they and the minerals associated with them were formed. Since clay minerals are being used more and more to evaluate the nature, value, and mode of formation of economic mineral deposits, an attempt to define these subtle differences would appear worth while. For purposes of the present discussion, the minerals nacrite, dickite, kaolinite, the so-called "fireclay mineral," halloysite (4H2O), halloysite

Jan 1, 1952

By John C. Smock

THE question of the proper valuation of mines of iron ore was suggested to me by the difficulties experienced in getting answers for the United States Census Office, while I was engaged in the work of collecting the statistics of mines in New Jersey and New York The answers to the questions relating to values of real estate of mine properties varied so greatly that it was necessary to revise them according to some general principles of valuation. Generally the returns of mine proprietors Seemed to be too low. There were, however, examples of what would be termed excessive valuation. The Subject appeared to be of practical importance, and led to the paper here presented. The following table of selected mine statistics is given, prefacing the discussion of the principles of valuation. It is in part made up of census returns and partly of data obtained directly from mine owners and managers. The mines which were Selected for the Several groups and mining districts include nearly all of those from Which the more full and carefully filled returns were received, and are also representative of their respective districts. Hence the averages obtained from them become good types of these groups or districts. The mines of New Jersey appear in Six groups, each containing from three to eleven mines, or, in all, thirty-four mines. The magnetic iron ores of New York are in four well-marked groups, and there are twenty-six mines in them. Then follow the red hematite mines of St. Lawrence and Jefferson counties; and, lastly, the brown hematite groups of Dutchess and Columbia counties, and those of the adjacent parts of Connecticut and Massachusetts. The whole number of mines represented by the table is eighty-eight, of which twenty-eight are hematite mines. The first column gives the value of the real estate; the second that of the plant; the third is the sum of these two, or the capital invested. Then follow the number of men employed, the amount of wages paid during the census year, and the value of materials used in mining and preparing the ores for market.* The seventh column gives the total expendi- * The value of materials is somewhat uncertain in many cases, as royalties are included under this head. Likewise, under wages, the cost of explosives and light is often included. Hence it is impossible to draw the line sharply between these items of expenditure.

Jan 1, 1882

By W. R. Hibbard

Pole figures, torque curves, and coercive force have been determined for the following rolled and annealed permanent magnet alloys: Cunife, Cunico, Silmanal, Vicalloy I, Vicalloy II, and Heusler&apos;s Alloy. IN the general category of precipitation-type permanent magnet alloys there is a group of ductile alloys, including Cunife, Cunico, Silmanal, Heusler&apos;s Alloy and Vicalloy, which can be extensively rolled and annealed to develop a preferred orientation in the crystals of the matrix material. The rolling and annealing textures of Cunifel and Vicalloy&apos; have been previously investigated qualitatively, but no pole figures are available in the literature. In addition, the role of precipitation in these permanent magnet alloys is still somewhat controversial. It

Jan 1, 1957

By T. A. Klinefelter, R. G. O’Meara, Glenn C. Truesdell, Richard W. Smith

THE investigation of domestic tales was undertaken by the Bureau of Mines, Department of the Interior, in cooperation with the University of Alabama, at the request of the U. S. Army, on Dec. I, 1941: "Considerable concern has been expressed by the Supply Arms and Service over maintaining continued availability of supplies of the necessary raw materials. These ceramic products are used by the Signal Corps in all army radio equipment, and to a greater degree in the new ultra-high-frequency equipment. The Air Corps has become a user of large amounts of radio-grade ceramics for aircraft spark-plug covers required for high-altitude operations. In addition, the use of this material is essential to the proper functioning of the radio air-navigation aids of the Civil Aeronautics Board." HISTORY The use of steatite and talc in ceramic bodies goes back a great many years. If pure, tales shrink little under heat-treatment and are very resistant to heat shock. The massive form, commonly called "steatite" by the trade, cuts and works easily, and this was naturally the first method used in obtaining articles of talc. When gas was in general use for illuminating purposes, a large business was carried on in the manufacture of tips for gas burners.1 With the development of uses for electricity, low-tension insulators were made in a similar manner; and, in fact, the forming of shapes from massive talc continues. However, as the business increased, cuttings and waste became more and more of a problem. In the twenties, one of the larger producing firms had a cooperative agreement with the Bureau of Mines at its Columbus station to work out a body using the finely powdered material. Somewhat earlier, manufacturers of spark plugs used the finely ground talc as part of the body and to some extent in wall-tile bodies. Somewhat later it came into use for kiln furniture and similar products and still more recently it has been used in some dinnerwares. With the development of the radio and the high-frequency fields generated, it was found that a dense steatite porcelain was far better than even high-tension electrical porcelain, which is a clay-flint-feldspathic type of body. Until the war increased the demand, the several pioneer steatite-porcelain manufacturers were able to furnish adequate supplies. When war began in Europe and Asia, three important foreign sources of raw material were cut off; i.e., the French, Italian, and Manchurian tales. Domestic producers of high-grade porcelain are few, and the trade

Jan 1, 1943

By O. U. Bradley

The utilization of casing-head gas in the manufacture of casing-head gasoline by both the absorption and the compression method is a most important factor in the conservation of our natural resources. Any industry connected with the oil business, in general, possesses particular attraction for a large number of people not conversant with its basic principles, for the reason that the large fortunes made in the production and utilization of petroleum and its products have been given undue prominence. The general impression of the public that enormous profits are to be realized in the casing-head gas industry with minimum expenditures of both capital and effort has, in a large measure, accounted for the phenomenal expansion of the industry in recent years and, likewise, has resulted in many mistakes and loss of investment funds. It is true that many installations have been very profitable, but such instances are always the result of careful planning, experienced judgment and conservative estimates. The inception and subsequent activity in the manufacture of casing-head gasoline, enabling the business to assume an important position in the petroleum industry, are of comparatively recent origin, as its greatest growth, particularly in Oklahoma, occurred during the years 1917 and 1918. Much information must yet be secured and systematized concerning the methods of manufacture of gasoline from high-yield casing-head gas, and a large field is still open for the application of accumulated experience and good engineering practice in devising better methods of extracting gasoline from casing-head gas of the poorer grades. The absorption process is coming into general use as a most efficient system of treating casing-head gas, and even so-called dry gas. In fact, there is a decided tendency toward the universal adoption of the absorption process as against compression methods. However, a general discussion of the relative merits of these two systems is not, within the scope of this article. A few of the facts that must be given &apos;consideration in arriving at a fair and impartial estimate of the actual investment value of the casing-head gas business are the quantity of gas available, the quality and

Jan 1, 1921

Discussion of the paper of E. G. Woodruff, presented at the Butte meeting, August, 1913, and printed in Bulletin No. 78, June, 1913, pp. 1001 to 1010. F. A. LINFORTH, Butte, Mont.:-I have not had an opportunity of reading this paper thoroughly, but I would like to call attention to the possible use of the contours on fault planes. It is obvious that if the contours of fault surfaces call be determined, we will be able to determine the axes of the hollows in the fault surface. It seems probable, and there are examples to point to the accuracy of, the assumption, that the axes of these hollows may be the direction of movements on the faults, and if that is true it will aid materially in locating faulted ore bodies or the shoots of ore on the opposite sides of faults. A few such contour maps of faults have been attempted on some of the faults of the Butte district, and those faults which are believed to have the nearly normal movement exhibit for the axes of these hollows a line nearly up and down in the plane of the fault, but in those cases where the throw is believed to bee nearly horizontal we find that the axes of the hollows are almost horizontal lines. In other words, the movements on faults, I believe, would be more nearly indicated by the larger grooves in the fault surfaces than by the small slickensides and minor hollows that are seen, so that contour maps might be valuable in geology in that way. C. W. GOODALE, Butte, Mont.:-I received a letter from Mr. Woodruff asking me to take part in the discussion of his paper, but I have not had time to give the paper any study. I can certainly add my opinion to that of all the engineers here that the topographic maps of the government are of great aid to the engineer. When I visit a new district, the first thing I do is to see if that district has been covered by the U. S. Geological Survey avid if topographic map has been issued. And I find that some of the younger engineers frequently come into my office to see if I have such maps. I know in some cases the reports made out by engineers contain copies of these topographic maps, or clippings from them. I am sure that. the topographic maps furnished by the government are of very great value to our engineers.

Jan 11, 1913