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By W. R. Ingalls

I WAS led some time ago to draft a statement of economic principles immediately affecting our national welfare from the standpoint of the engineer. It was the intention to offer this to the American Engineering Council as a resolution to be adopted, or a declaration to be made, of course after suitable con-sideration and debate. The presentation has not been . formally made, but I have been asked to let it be made to the mining engineers through the medium of MINING AND METALLURGY, the American Institute of Mining and Metallurgical Engineers being a constituent part of the Federated American Engineering Societies. I shall welcome any expressions of opinion that this statement may inspire. The statement follows: The engineers of, the United States, functioning through the American Engineering Council of the, Federated American Engineering Societies, feel it their duty to advise the American people respecting the present state of economic affairs in the nation, just as an individual engineer would his client. The people of the United States constitute a great corpora-tion, whose business affairs are analogous to those of a commercial company -multiplied many times. The engineers feel constrained to offer their opinion owing to the responsibility to do things which rests upon them. Confronted by the steady impoverishment of natural resources and the operation of the economic law of diminishing returns it devolves upon management, functioning through the engineering profession aided by scientists, to make such improvements leading to increased production and such elimination of wastes as to offset the increasing adversities of nature merely to hold our own; and to do more than offset them in order to improve the scale of living of the people. The engineers accept this responsibility, but in so doing they demand attention to their advice respecting fundamental economic matters, lest they be unduly hampered in the performance of the professional duties, which they acknowledge. The American Engineering Council therefore declares the following as the advice of engineers to the American people:

Jan 8, 1923

AVERY great profit is derived from removing the gilding and retrieving gold, without destroying the works of silver or other metal. If this method did not exist, the greater part of the gold that is put on certain works would be lost. Even though you might think to scrape it off patiently with a sharp scraper, if it had been drawn with draw-plates, or if it were at the bottom of objects where the scraper could not enter easily, it would be utterly in vain. Therefore, I find that to do this it is necessary to use one of three methods. The first is when it is found on a thin object. Take a large crucible, fill it with mercury, and heat it on a little furnace. When you see that it begins to boil and simmer, put your work in it and stir it around, shaking and rubbing it well in this, and finally rub it with a scratching tool until you see that the mercury has drunk up and absorbed all the gold. Then, having done this, take the said mercury and pass it through an untanned leather purse, and in the bottom of this you will find all the gold like sand. Put this in the bottom of a crucible or in something else over a charcoal fire and evaporate it. If the objects are of a thicker form the gilding is removed from them in another way, by covering them with powdered sulphur and lighting a fire on them. When you see them burning well with the fire all around, beat them in a clean bowl of wood or something else and collect everything that separates with the sulphur from the work; this will be gold in the form of a leaf wherever it has been touched by the fire. The gold is then extracted from this burned sulphur by purifying it in a cupeling hearth with lead. The third method is to touch the gold that you wish to take off the works with an aqua fortis made from saltpeter, rock alum, vitriol, sal ammoniac, and some verdigris.* This acid dissolves and eats the gold by virtue of its corrosive power. Having thus touched the gold with this acid and having saturated the latter with a quantity of gold, put it in a cucurbit and evaporate it over a little furnace as is done with silver, collecting the acid and the spirits if you wish.

Jan 1, 1942

Jan 1, 1950

By B. K. Asdell

Crude kaolin exhibits a wide particle size range in which kaolinite is the predominant mineral. Bene-ficiation by wet processing produces high-brightness white pigments. The wet processing techniques peculiar to kaolin beneficiation are emphasized in this article in some detail. Included are discussions of long-distance pipeline transportation, centrifuga-tion, flotation, spray drying and shipment as 70% solids slurry. Georgia, a state seldom considered to be an important mineral producer, has one surprising feature — it is the nation's largest producer of kaolin. Kaolin is a highly important raw material in the paper, rubber, ceramic whiteware, paint and chemical industries. In 1965, more than 2.7 million tons of kaolin were produced in this state, a 150,000-ton increase over the preceding year, and production continues to climb. Strictly defined, the term "kaolin" applies to a group of hydrous aluminum silicates in which kaolinite is the predominant mineral. Kaolinite is inherently white, non-abrasive, chemically inert, and of a very fine particle size, ranging from sub-micron to 40-microns equivalent spherical diameter. An electron-micrograph of kaolinite is shown in Fig. 1. The particles finer than about 2 microns are thin, elongated plates, hexagonal in outline. The larger particles, coarser than 2 microns, are predominantly vermicular in outline with a foliated structure. Table I shows a typical chemical analysis of commercial, wet-processed kaolin compared to pure kaolinite. The sedimentary Cretaceous deposits of the Coastal Plain are the source of most of the kaolin produced in the Southeast. These deposits are of relatively high purity, and it is not uncommon to find the clays running greater than 90% kaolinite. Beneficiating plants using wet processing techniques are most numerous in an area within about 50 miles east of Macon, Ga., in a band approximately 15 miles wide. Kaolin may vary widely in quality from one deposit to another, or within the same deposit. The qualities critically examined are brightness index as measured by reflectance, viscosity of water suspensions, bleachability and particle size distribution. Crude kaolin always contains sand and mica in varying amounts, along with small amounts of many other minerals. These are classed collectively as "grit" because; they are generally coarser than 325

Jan 1, 1968

By R. L. Featherly, J. R. James

The replacement or reconditioning of oil storage tank bottoms due to external corrosion is an expensive maintenance item to the oil industry. Cathodic protection as a means of mitigating this problem has proved very successful in the past few years. One pipe-line company recently used magnesium anodes to cathodically protect two 55,000 bbl and two 20,000 bbl tanks. The tank bottoms were protected as individual units with considerable factual data being taken on one of the 20,000 bbl tanks. Twelve 60-lb anodes were installed about 2½ ft from the tank on approximately 17-½ft centers around the tank. Previous installations and tests have shown that sufficient protection is provided when the tank-to-soil potential using a copper-copper sulphate half-cell as a reference electrode is — 0.90 volts at the edge of tank. Potential measurements taken a few months after completing the installation indicated that the potentials were higher than were needed for protection. Resistors were then inserted in the individual anode circuits which increased the life of the anode installation and still provided adequate protection for the structure. All connecting pipe lines were then insulated from the tank. This limited the anode current strictly to the tank resulting in a greater degree of protection with a still longer anticipated anode installation life. The total installation cost for this tank was less than $300 which amounts to $20 per year The corrosion of metallic structures in contact with soil or water has been a very serious and costly problem for centuries. The annual loss to our nation's pipelines alone is estimated at $200,000,000. Mitigation of this problem by various methods has been carried on quite successfully for a number of years. An electrical method called cathodic protection has been used with considerable success to control corrosive influences on pipelines, tank bottoms, cable sheathing and other buried metal structures. Corrosion of oil storage tank bottoms has been a serious problem among the oil industries for years. In addition to damage costs and loss of oil, the replacement of one tank alone represents several thousand dollars. A reconditioning program at periodic intervals was instituted by several organizations and found to be a very expensive process. A few years ago two of the pipeline companies installed cathodic protection units at their tank farms.3'4 The average current required for protection of the tank bottoms varied from 0.7 to 1.0 milliampere per square foot. The results indicated that adequate protection was obtained at a cost of approximately 10 pct of the previous reconditioning program. The Republic Pipe Line Company experienced severe corrosion on their oil storage tanks. One of their 55,000-bbl tanks

Jan 1, 1948

By R. L. Featherly, J. R. James

The replacement or reconditioning of oil storage tank bottoms due to external corrosion is an expensive maintenance item to the oil industry. Cathodic protection as a means of mitigating this problem has proved very successful in the past few years. One pipe-line company recently used magnesium anodes to cathodically protect two 55,000 bbl and two 20,000 bbl tanks. The tank bottoms were protected as individual units with considerable factual data being taken on one of the 20,000 bbl tanks. Twelve 60-lb anodes were installed about 2½ ft from the tank on approximately 17-½ft centers around the tank. Previous installations and tests have shown that sufficient protection is provided when the tank-to-soil potential using a copper-copper sulphate half-cell as a reference electrode is — 0.90 volts at the edge of tank. Potential measurements taken a few months after completing the installation indicated that the potentials were higher than were needed for protection. Resistors were then inserted in the individual anode circuits which increased the life of the anode installation and still provided adequate protection for the structure. All connecting pipe lines were then insulated from the tank. This limited the anode current strictly to the tank resulting in a greater degree of protection with a still longer anticipated anode installation life. The total installation cost for this tank was less than $300 which amounts to $20 per year The corrosion of metallic structures in contact with soil or water has been a very serious and costly problem for centuries. The annual loss to our nation's pipelines alone is estimated at $200,000,000. Mitigation of this problem by various methods has been carried on quite successfully for a number of years. An electrical method called cathodic protection has been used with considerable success to control corrosive influences on pipelines, tank bottoms, cable sheathing and other buried metal structures. Corrosion of oil storage tank bottoms has been a serious problem among the oil industries for years. In addition to damage costs and loss of oil, the replacement of one tank alone represents several thousand dollars. A reconditioning program at periodic intervals was instituted by several organizations and found to be a very expensive process. A few years ago two of the pipeline companies installed cathodic protection units at their tank farms.3'4 The average current required for protection of the tank bottoms varied from 0.7 to 1.0 milliampere per square foot. The results indicated that adequate protection was obtained at a cost of approximately 10 pct of the previous reconditioning program. The Republic Pipe Line Company experienced severe corrosion on their oil storage tanks. One of their 55,000-bbl tanks

Jan 1, 1948

By J. C. Uy, A. A. Burr

A quantitative relationship between the allotropic phase boundaries of zirconium-base binary systenzs and the solute metallic valence is shown through an intermediate thermodynamic parameter. A simplified equation relating this parameter to the phase boundaries is briefly reviewed, and data from the literature are used to show the relationship of this parameter to the solute metallic valence. It has been reported that the solute metallic valence can be used as an index of phase stabilization in zirconium-base binary alloys.' It was shown that the algebraic sign of the slopes of the hcp/bcc phase boundaries of zirconium alloys correspond to the algebraic sign of the metallic valence of zirconium minus the metallic valence of the solute, or, in other words, a solute whose metallic valence is higher than that of the solvent tends to stabilize the high-temperature phase while one whose metallic valence is lower than that of the solvent tends to stabilize the low-temperature phase. Further analysis of the zirconium binary systems has revealed a quantitative relationship between the solute metallic valence and the relative slopes of the two-phase allotropic boundaries. This relationship involves a thermodynamic quantity whose significance can be seen in the following section. PHASE-STABILIZATION PARAMETER Let Qb be the difference between the partial molar heats of mixing of a given solute in the two allotropic phases of the solvent which are in equilibrium with each other at a given temperature, thus A relationship between this term Qb and allotropic phase boundaries has been employed by several au-thors'-= in the evaluation of phase diagrams, and can be briefly derived as follows. Referring to Fig. 1, consider the general case of two allotropic phases, each having a small mole fraction (Xa,Xb) of the solute, in equilibrium at temperature T and atmospheric pressure as represented by the reaction. solute in ß phase =solute in a phase If now a reaction occurs such that an infinitesimal amount of the solute is removed from the ß phase and added to the a phase, there would be a partial molar

Jan 1, 1967

By R. P. Aikman, F. G. Miller, J. M. Podgursky

In response to the growing demand for low-sulfur coking coal for iron-making, the coal industry is continually striving to perfect methods for cleaning coal to acceptable ash and sulfur levels while maintaining maximum product yield. By present standards the industry has adequate processes for cleaning coarse coal, (i.e., +28 mesh) at almost any desired specific gravity. However, in the case of fine coal (i.e., -28 mesh) neither of the two existing processes-froth flotation and hydrocycloning-in its present state of development yields products that are comparable in ash and/or sulfur content to products normally obtained from coarse coal processes. The work outlined in this article is part of a larger study directed toward maximum exploitation of froth flotation for fine coal processing. The concepts and data presented are now serving as a basis for designing fine-coal circuits in which improved efficiency is obtained by optimum use of froth flotation with other fine-coal processing methods.

Jan 7, 1967

By D. M. Davidson

The drill sampling and evaluation of the Piney River ilmenite property was carried out during the early part of 1944 by E. J. Longyear Co., using the company's standard core-drill outfits to complete 44 holes to an average depth of IIO ft., from which were collected 1100 samples. The Piney River ilmenite-apatite lode is 25 miles north of Lynchburg, in Nelson and Amherst Counties, Virginia (Fig. I). Its elevation is about 900 ft. above sea level and it lies in the old pre-Cambrian complex of crystalline rocks that make up the Piedmont physiographic province lying east of the Blue Ridge Mountains. The terrain is gently rolling and well watered and is drained by the Piney and Tye Rivers, which are tributary to the James. Geology The Piney River ore body comprises the upper, weathered part of a tabular basic rock, which occurs in a large area of granite-gneiss. The section containing profitable ore is about 3000 ft. long. It is separated naturally by thinning, into northeastern and southwestern segments with widths of 300 and 100 ft. respectively. The dip averages 4.5° southeast but steepens locally (Figs. 2 and 3). The unaltered rock is an even, granular mixture of feldspar, ilmenite, and apatite, to which Watson1 gave the name Nelson-ite. The decomposed ore body, which is now being exploited by open cut, is a yellowish clay material in which black ilmenite and glassy apatite are the only conspicuous minerals. An economically important structural feature of the deposit is a banding of minerals coinciding with the dip and strike of the dike. This is more pronounced in the footwall of the northeastern part of the intrusive, where there is also a higher than average concentration of ilmenite. According to Watson,' the TiO2 content of the Nelsonites of this region ranges from 10 to 42 per cent, while P205 varies from 4 to 15 per cent. It is inexpedient at present to disclose exact metal content of the Piney River ore body; suffice it to say that the average tenor lies well within the extremes noted by Watson. Sampling Methods and Procedure During a preliminary inspection of the ore body, Longyear engineers surmised that because of its soft, clayey character, drill sampling would yield little core, therefore they made all possible preparations to procure accurate samples of the drill cuttings, or sludge. The first requisite in obtaining representative drill cuttings is to secure their full recovery. Only under certain conditions, and by employing a most careful and rigid sampling technique, is this pos sible. There must be no loss of the water circulating in the hole, and the velocity

Jan 1, 1949

By W. C. Lacy

Urban development in semi-arid portions of the Southwest has upset a natural balance of geological conditions resulting in broad-scale and local subsidence or heaving ground conditions, Subsidence can be traced to two general causes: irrigation of reclaimed desert lands that have dry, low-density soils; and depression of the water table by ground water withdrawal. Accumulation of weathered volcanic tuff produces areas with swelling characteristics. Soil and subsidence studies made in the Tucson area in Arizona illustrate foundation problems typical of the Southwest that must be considered in the design of building codes. Anticipation of problems and the adoption of corrective measures in the design of engineering structures, establishment of pertinent building codes, and urban planning and zoning to obtain optimum land usage and conservation of natural resources demands a thorough understanding of geological conditions of a developing urban area. In the arid to semi-arid southwestern United States erosional and depositional processes result in special situations that require special precautions in building practices. A series of studies currently underway in the Tucson area, prompted by foundation failures and breaking of buried service lines, serves to illustrate some of these relationships between the geological environment and history and engineering problems. ENVIRONMENT The desert region of the Southwest is characterized by isolated mountain ranges rising abruptly from low valleys or plains — the ranges generally occupy less area than do the intervening valleys. In southern Arizona the valley floors step up from near sea level to 2000 ft or more in elevation, and the ranges may rise to over 7000 ft. Desert and steppe-type climates predominate — climate is controlled more by elevation than it is by latitude. Both climate types are characterized by a lack of precipitation, the former more so than the latter. Practically all the rain that falls in the region evaporates; runoff or recharge generally occurs only during the wettest period. Water table levels are generally being depressed. Vegetation is restricted and consists mainly of creosote bush, cacti and sage brush on the deserts, and mesquite, pinon juniper and various types of grass on the steppes. Precipitation varies from about 3 in. on the warm deserts to about 12 in. on the steppes. Most of this falls in the summer or winter, with only rare storms in other seasons. Summer thunderstorms, often accompanied by hail, bring cloudbursts which send torrents of water streaming down the mountains onto

Jan 1, 1964

By David White

While a country is small and its coal fields are not many, it may be possible to classify its coals on some basis that avoids both overlap and inconsistency, and that may be satisfactory to the particular country, such as geographic distribution or geologic age, or regional uses. In the adjoining country, however, the coals may differ more or less; broad areas may have escaped the erasure of transition zones by erosion, and the stages of alteration of the coals may lead to a classification different from and even incompatible with that of the other country. Such classifications, developed primarily along national lines, are essentially opportunistic. Further, many even of the "use" terms that have been in more common employment with a degree of international application have lost their significance and value, due to changes in industrial methods and urban life. When the number of coal fields is large and the classification is designed to cover the coals of many countries, the groups or divisions into which the coals are integrated are found to verge one into another; and, though the main divisions may be so naturally composed and oriented that they are relatively distinct and readily separated as entities or units when taken by themselves, the sequence, through classes, groups, and subdivisions, is so complete that we find transition zones through which boundaries must be arbitrarily drawn with minute technical definition. This situation, which is conspicuously illustrated in the United States, is due to the progressive evolution of all coals, irrespective of geologic age, from peats to successively higher ranks, which, if the progressive alteration goes far enough, ends with graphite. This evolution is now firmly established and its complete acceptance is but a matter of time. A classification of all coals in all coal fields can not escape this fact and must take into account all the stages in the transformation of the fuel from rank to rank through division to division, and through group to group. The plan here outlined aims at a natural classification of coals based on their evolution from peats to graphite. As in other classifications, the differentiation of the various groups and divisions takes account of changes resulting from the progressive losses of moisture and .of oxygen of constitution; the relative conservation of carbon; the progressive increase in fixed carbon (inverse to the loss of volatile matter) in

Jan 1, 1930

By D. M. Davidson

The drill sampling and evaluation of the Piney River ilmenite property was carried out during the early part of 1944 by E. J. Longyear Co., using the company's standard core-drill outfits to complete 44 holes to an average depth of IIO ft., from which were collected 1100 samples. The Piney River ilmenite-apatite lode is 25 miles north of Lynchburg, in Nelson and Amherst Counties, Virginia (Fig. I). Its elevation is about 900 ft. above sea level and it lies in the old pre-Cambrian complex of crystalline rocks that make up the Piedmont physiographic province lying east of the Blue Ridge Mountains. The terrain is gently rolling and well watered and is drained by the Piney and Tye Rivers, which are tributary to the James. Geology The Piney River ore body comprises the upper, weathered part of a tabular basic rock, which occurs in a large area of granite-gneiss. The section containing profitable ore is about 3000 ft. long. It is separated naturally by thinning, into northeastern and southwestern segments with widths of 300 and 100 ft. respectively. The dip averages 4.5° southeast but steepens locally (Figs. 2 and 3). The unaltered rock is an even, granular mixture of feldspar, ilmenite, and apatite, to which Watson1 gave the name Nelson-ite. The decomposed ore body, which is now being exploited by open cut, is a yellowish clay material in which black ilmenite and glassy apatite are the only conspicuous minerals. An economically important structural feature of the deposit is a banding of minerals coinciding with the dip and strike of the dike. This is more pronounced in the footwall of the northeastern part of the intrusive, where there is also a higher than average concentration of ilmenite. According to Watson,' the TiO2 content of the Nelsonites of this region ranges from 10 to 42 per cent, while P205 varies from 4 to 15 per cent. It is inexpedient at present to disclose exact metal content of the Piney River ore body; suffice it to say that the average tenor lies well within the extremes noted by Watson. Sampling Methods and Procedure During a preliminary inspection of the ore body, Longyear engineers surmised that because of its soft, clayey character, drill sampling would yield little core, therefore they made all possible preparations to procure accurate samples of the drill cuttings, or sludge. The first requisite in obtaining representative drill cuttings is to secure their full recovery. Only under certain conditions, and by employing a most careful and rigid sampling technique, is this pos sible. There must be no loss of the water circulating in the hole, and the velocity

Jan 1, 1949

Meeting of Oct. 23, 1914.-It was voted to take no action concerning the proposed amendments to Article VIII, Sections 2 and 3, but that they be sent to the membership, as provided by the Constitution, together with a statement of the arguments for and against the proposed changes. It was voted that the following proposed amendment, which had been unanimously approved at the annual meeting of the Institute on Feb. 18, 1914, be sent to the membership as provided by the Constitution, together with the approval of the Board of Directors of this change: Article III, Section 1, paragraph 3, sentences 2 and 3: substitute the following: "Any Member, Junior Member or Associate in arrears for two years shall be dropped from the rolls unless the time for payment is extended by the Directors. A Member so dropped may be reinstated by the Directors on paying the arrears of clues and other indebtedness with which he was charged on the books of the Institute it the time he was dropped. A Member or Associate thus reinstated shall receive the Transactions for the back year for which he pays." It was unanimously voted to extend the sincere thanks of the institute to Samuel A. Taylor, Chairman, and to each member of the several Committees of the Pittsburgh meeting, for the enjoyable and successful meeting which they brought about.

Jan 12, 1914

By A. W. Hesse

Ventilation of all types of coal mines is fundamentally the same, in that sufficient air must be provided to properly dilute and remove dangerous and obnoxious gases and leave the oxygen content of the air not under 1 9 per cent in all places where men and animals must work. Perhaps animals should not be mentioned, as the speed of mechanical loading leaves livestock behind and outmoded. Since this paper has to do with the influence of mechanical loading equipment on ventilation, the problems will be confined to the splits and the coal-producing places of the mine. The removal of coal dust from the air, or its rapid transmission to the return air courses; the possible increase in the liberation of gases by the multiplication of cuts in the coal made during one shift or multiple shifts; and the additional electrical equipment at the faces, are the factors that cause the added importance to good ventilation in the permissible equipment area of gassy bituminous coal mines. Ventilation tor Mechanical Loading in Gassy Mines In gassy mines, the air currents must be maintained across the faces in such a way as to prevent short cuts to the returns and leaving pockets in which accumulation of gas might occur. To do this, two or more doors are required on almost every entry containing a track to the face, so located that in no event will a trip of cars block open the doors and permit the air to bypass some place or places on the air-approach side. This method frequently requires the use of unusual lengths of duplex cables to reach the mechanical equipment at the faces, particularly where the distances between parallel working places are 100 ft., as at the Nemacolin mine. Fig. I shows a pillar section being worked with mechanical loaders. This layout requires carrying the air in on the right and releasing it on the left, because the track clearance is on the right side and the line brattice is built on this side from the last crosscut to the face. Thus, the air travels to the face with greater velocity and gives more assurance of sweeping out the gas that might be exuding from the crevices of the coal. All working places, in driving through solid coal, are thus treated alike. They are all potentially gassy and must be swept clear of whatever may contaminate the air. Once the air starts into the working section, it is not released until it does a good job. Of course the volume of air must be large enough not only to dilute the gases but to carry away explosive fumes and fine coal dust quickly. Mechanical loading entails cutting and drilling of the coal during the same working period as the loading when two-shift and three-shift operations are employed, and all three processes create finely pulverized coal, which in itself is hazardous if not controlled by some means. If the ventilation is inadequate and gas accumulates, and a spark from defective electrical

Jan 1, 1942

By C. P. Besse, G. W. Osborne

Drilling operations on the Gulf of Mexico continental shelf are following two general plans. The first plan placed all buildings. equipment, and materials on a large platform while the second copies Lake Maracaibo drilling methods by placing a minimum of equipment on the platform and using a floating drilling tender or drill barge anchored adjacent to the platform in an attempt to take maximum advantage of flotation in an effort to reduce costs. A complete power rig, mud pits, pipe racks, and small auxiliaries have been placed on the platform as shown in Figure 1, to assure proper handling of drilling operations under the most adverse weather. This has the economic advantages of eliminating the fabrication of a large structure, a material reduction of rigging up time on each structure. and elimination of delay time on equipment while quarters and equipment placed on the tender are being rigged up. These factors have certainly proved their economic value in drill barge operations in the Louisiana and Texas coastal area. Naturally the heart of such an operation is the anchorage. This anchorage, to permit taking advantage of maximum economies. must hold the ship in a relatively fixed position under the following weather conditions: (1) Winter northwesters (2) Southeasterly gales (3) Severe rain squalls In hurricane weather all operations must be suspended regardless of method of operation and the floating tender will, if possible, be moved to a protected location. However, in case of an emergency the floating tender should be prepared to swing with the wind and seas on a single anchor as there is considerable doubt that either ship or anchorage could withstand the severe strains imposed by fixed anchorage in hurricane weather. Northwesters are reported to have developed wind gust velocities as high as sixty miles per hour and steady winds of approximately forty-five miles per hour. Fortunately these winds do not travel a great distance over water before arriving at our location, and, while they can possibly develop seas approximately eight feet high, the waves are short, and if taken on the bow or stern of a ship 250 feet or more in length they should not present a difficult problem. On the other hand southeast gales having a long fetch and maximum steady wind velocities of approximately thirty miles per hour can possibly develop long swells approximately twelve feet in height. These should develop the most severe anchorage problem. To combat these waves any workable anchorage plan should permit maneuvering the ship in such a manner as to head the bow or the stern into the seas and still maintain contact with the structure. Rain squalls develop wind gust velocities as great as sixty miles per hour. However, they are local and the seas have not been a source of great trouble. To permit continuous operation the anchorage must be able to withstand these winds broadside to the ship as the wind direction often changes radically in a very sliort time. All of these weather conditions are dangerous to small craft, deck cargoes,

Jan 1, 1949

By R. A. Bell, R. Schultz, P. G. Hallof

The Ballyvergin area is located in County Clare on the southwest coast of Ireland. It is one of six areas in County Clare in which mining operations were carried out during the last century. The ores mined were high grade Cu-Pb-Ag deposits in the form of small fracture fillings and gash veins in the lower Carboniferous limestones. The zone of primary economic interest is situated on the north limb of a geosyncline which plunges moderately to the southwest. The zones of mineralization previously mined were associated with local structures and folds, and the initial geophysical investigations took the form of reconnaissance induced polarization measurements around, and between, the old mines. This work located an anomaly which, on drilling, resulted in a small extension of the Pb-Cu ore at the Ballyvergin mine. However, a potentially more important zone of mineralization resulted from the drilling of another IP anomaly near Ballyvergin. This wide anomaly was found to be a domal shaped deposit of disseminated chalcopyrite located at a depth of more than 100 ft. The deposit is controlled by local folding in the sediments and is of a type previously unknown in the area. More IP investigations are under way to locate other deposits of the same type. The Ballyvergin area is located in County Clare, about 35 miles northeast of Shannon Airport, near the Atlantic west coast of Southern Ireland (Fig. 1). Interest in the area stems from a number of occurrences of small, but high grade, Pb-Ag deposits. From the summer of 1960 to the spring of 1961, Irish Base Metals carried out a comprehensive exploration program on a 38-sq mile concession in east-central County Clare in an attempt to locate additional deposits of this type. Field operations consisted of geologic mapping, geochemical soil and stream sampling, geophysical surveying and diamond drilling. The geophysical program consisted primarily of detailed induced polarization (IP) surveys in the general vicinity of old mine workings, supplemented by electromagnetic and self-potential investigations. Subsequent diamond drilling of a well defined IP anomaly close to the old Ballyvergin mine disclosed a sizeable deposit of low grade disseminated copper, a type of deposit previously unknown in this area. REGIONAL GEOLOGY Topography: The topography is of the Karst type with low regional relief. The northern parts of the area are covered almost completely with glacial deposits including a large number of drumlins. Elsewhere the overburden is patchy and only moderately deep. A close network of roads makes every part of the area readily accessible, and rail and harbor facilities are available nearby — Fig. 2. Stratigraphy: The area was mapped on a reconnaissance basis by the Geological Survey of Ireland during the latter part of the 19th century at scales of 1 and 6 in. to the mile. Mapping is complicated in

Jan 1, 1962

By A. W. Hesse

Ventilation of all types of coal mines is fundamentally the same, in that sufficient air must be provided to properly dilute and remove dangerous and obnoxious gases and leave the oxygen content of the air not under 1 9 per cent in all places where men and animals must work. Perhaps animals should not be mentioned, as the speed of mechanical loading leaves livestock behind and outmoded. Since this paper has to do with the influence of mechanical loading equipment on ventilation, the problems will be confined to the splits and the coal-producing places of the mine. The removal of coal dust from the air, or its rapid transmission to the return air courses; the possible increase in the liberation of gases by the multiplication of cuts in the coal made during one shift or multiple shifts; and the additional electrical equipment at the faces, are the factors that cause the added importance to good ventilation in the permissible equipment area of gassy bituminous coal mines. Ventilation tor Mechanical Loading in Gassy Mines In gassy mines, the air currents must be maintained across the faces in such a way as to prevent short cuts to the returns and leaving pockets in which accumulation of gas might occur. To do this, two or more doors are required on almost every entry containing a track to the face, so located that in no event will a trip of cars block open the doors and permit the air to bypass some place or places on the air-approach side. This method frequently requires the use of unusual lengths of duplex cables to reach the mechanical equipment at the faces, particularly where the distances between parallel working places are 100 ft., as at the Nemacolin mine. Fig. I shows a pillar section being worked with mechanical loaders. This layout requires carrying the air in on the right and releasing it on the left, because the track clearance is on the right side and the line brattice is built on this side from the last crosscut to the face. Thus, the air travels to the face with greater velocity and gives more assurance of sweeping out the gas that might be exuding from the crevices of the coal. All working places, in driving through solid coal, are thus treated alike. They are all potentially gassy and must be swept clear of whatever may contaminate the air. Once the air starts into the working section, it is not released until it does a good job. Of course the volume of air must be large enough not only to dilute the gases but to carry away explosive fumes and fine coal dust quickly. Mechanical loading entails cutting and drilling of the coal during the same working period as the loading when two-shift and three-shift operations are employed, and all three processes create finely pulverized coal, which in itself is hazardous if not controlled by some means. If the ventilation is inadequate and gas accumulates, and a spark from defective electrical

Jan 1, 1942

By C. P. Besse, G. W. Osborne

Drilling operations on the Gulf of Mexico continental shelf are following two general plans. The first plan placed all buildings. equipment, and materials on a large platform while the second copies Lake Maracaibo drilling methods by placing a minimum of equipment on the platform and using a floating drilling tender or drill barge anchored adjacent to the platform in an attempt to take maximum advantage of flotation in an effort to reduce costs. A complete power rig, mud pits, pipe racks, and small auxiliaries have been placed on the platform as shown in Figure 1, to assure proper handling of drilling operations under the most adverse weather. This has the economic advantages of eliminating the fabrication of a large structure, a material reduction of rigging up time on each structure. and elimination of delay time on equipment while quarters and equipment placed on the tender are being rigged up. These factors have certainly proved their economic value in drill barge operations in the Louisiana and Texas coastal area. Naturally the heart of such an operation is the anchorage. This anchorage, to permit taking advantage of maximum economies. must hold the ship in a relatively fixed position under the following weather conditions: (1) Winter northwesters (2) Southeasterly gales (3) Severe rain squalls In hurricane weather all operations must be suspended regardless of method of operation and the floating tender will, if possible, be moved to a protected location. However, in case of an emergency the floating tender should be prepared to swing with the wind and seas on a single anchor as there is considerable doubt that either ship or anchorage could withstand the severe strains imposed by fixed anchorage in hurricane weather. Northwesters are reported to have developed wind gust velocities as high as sixty miles per hour and steady winds of approximately forty-five miles per hour. Fortunately these winds do not travel a great distance over water before arriving at our location, and, while they can possibly develop seas approximately eight feet high, the waves are short, and if taken on the bow or stern of a ship 250 feet or more in length they should not present a difficult problem. On the other hand southeast gales having a long fetch and maximum steady wind velocities of approximately thirty miles per hour can possibly develop long swells approximately twelve feet in height. These should develop the most severe anchorage problem. To combat these waves any workable anchorage plan should permit maneuvering the ship in such a manner as to head the bow or the stern into the seas and still maintain contact with the structure. Rain squalls develop wind gust velocities as great as sixty miles per hour. However, they are local and the seas have not been a source of great trouble. To permit continuous operation the anchorage must be able to withstand these winds broadside to the ship as the wind direction often changes radically in a very sliort time. All of these weather conditions are dangerous to small craft, deck cargoes,

Jan 1, 1949

By M. J. Hordon, M. A. Wright

ReCENT work has indicated that the substantial decrease in the rate of fatigue crack propagation for aluminum observed below a critical vacuum level can be attributed to the depletion of oxygen or water vapor from the vicinity of the fatigue crack opening.' At reduced gas pressures, generally below 10-2 Torr with fatigue strain amplitudes in the range *1 to 2 x 10-3 and cyclic loading rates of 25 to 50 cps, estimated rates of oxide or hydroxide monolayer adsorption on newly formed crack surfaces can fall behind the actual rate of crack extension. Changes in the critical pressure required for the transition in fatigue behavior with changes in temperature, strain amplitude, and cyclic frequency can be interpreted from variations in the adsorption and crack growth rates.'" Although the adsorption model generally appears to explain the enhanced fatigue resistance of reactive metals in vacuum, the specific adsorbing gas species and nature of the adsorption mechanism are uncertain. In addition to the direct dissociation and adsorption of O2 on the metal surfaces,3 the dissociation of H20 and subsequent adsorption of H ions have been advanced for aluminum alloys.4 The present note describes some measurements of the fatigue behavior of 1100 aluminum in reduced partial pressures of specific gases including O2, H2O, and H2 in order to provide additional experimental data. Cantilever-type specimens of 1100-H14 aluminum were fatigued in cyclic reverse bending at constant strain amplitude using a multispecimen vacuum apparatus and procedure described previously.' After initial vacuum evacuation to 1 x 10-7 Torr, the appropriate gas species was bled into the system through a calibrated leak valve. The input rate was adjusted to maintain the desired pressure level under continuous evacuation, thus minimizing possible changes in gas composition during testing. High-purity input gases including 99.9 pct O2, 99.999 pct H 2, and water vapor from triply distilled H 2 O were used to provide residual pressures. Trace amounts of contaminant species were limited by passing the Oz and H 2 input gases through liquid-nitrogen-cooled copper coils prior to entry to the test chamber. Care was taken to repeatedly flush the gas lines and valves before testing to minimize the effect of adsorbed contaminants. Residual gas pressures in the range 10-6 to 5 x x3 Torr were monitored by an NRC ionization gage corrected for each gas species. In the higher-pressure range, 5 x 1CT3 to 5 x 10' Torr, an NRC alphatron gage was used. In operation, eight simultaneous fatigue tests were conducted at a constant strain amplitude of *1.2 x 10 at cyclic bending rates of 25 and 50 cps to give an average fatigue life of 6.5x 105 cycles-to-fracture at standard atmosphere and 3.3 x 106 cycles in 1 x 10"7 Torr vacuum. Representative results for the effect of residual O2, H2O, and H2 contents on the fatigue life are shown in Fig. 1 for tests performed at 50 cps. It is apparent that the presence of either O2 or H2O gas in the system at partial pressures greater than 10"3 Torr was noticeably detrimental to the fatigue life. In contrast, the enhanced fatigue resistance typical of high-vacuum environments was retained with pure H 2 through the pressure range up to 1 Torr. For partial pressures of H2 gas above 1 Torr, the fracture life noticeably decreased. The critical Hz

Jan 1, 1969

Because common salt, sodium chloride, is necessary to all animal and much plant life, it is probably the most widely used of all mineral commodities, except for water. Nevertheless, of the total salt consumed, only 7% is used for food, including animal food. Two-thirds of the total is used as chemical raw material, principally for making such basic chemicals as chlorine, caustic soda, and soda ash. Other uses are for road thawing (16%) and water softening. Some 162.5 million tons of salt were used, worldwide, in 1972 (Table 15.4F.1). Production is from bedded salt deposits, salt domes, and evaporation of brines, including solar evaporation of seawater. Production is worldwide from at least 20 countries, of which the United States, China, USSR, the United Kingdom, and West Germany are the leaders. Consumption increases about 7 % annually. Reserves are plentiful: Other important sodium salts are soda ash (sodium carbonate) and salt cake (sodium sulfate). Soda ash comes mainly from the Solvay process (70% ) , which uses salt, limestone, and ammonia as raw materials. A large and growing portion of United States production is from mining large bedded deposits of trona, a natural hydrated sodium carbonate and bicarbonate found in Wyoming, and from brine evaporation in California. Soda ash is used for glassmaking, phenol, soap, detergents, and bleaches. Half of the United States salt cake used is a byproduct from rayon manufacturing. The other half comes from brines and playa lakes in California, Texas, and Wyoming. Salt cake is used mainly for papermaking. ACKNOWLEDGMENT Appreciation is expressed to William B. Dickson, president, Salt Institute. [ ]

Jan 1, 1976