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SINCE I told you in the preceding chapter how the potter's art is followed in practice, now in this following one I wish to tell you how mortar* and bricks are made, and how and to what purpose they were discovered, although I know you will answer that you know it, inasmuch as it is an art known not only to skillful men but also to the unskilled ones by whom it is practiced, and that bricks and mortar were made and always will be made for the purpose of building. This I admit, but probably everyone does not know it as you do, and you perhaps, do not know its beginnings, although I remember having told you of them. Wishing to repeat it better now I shall begin with long ago, so that both you and I may be better satisfied. Therefore I tell you that you should know that all the arts that men practice in the world have been learned by them either through the process of reasoning from the principles of natural phenomena, from the actions of animals, by chance, or when forced either by some necessity or

Jan 1, 1942

By W. P. Blake

THIS furnace is designed especially for the oxidation of sulphur or arsenic in pyritic ores, but may be used for all oxidizing or desulphurizing operations, and for calcining, roasting and chloridizing ores, or for drying ores in large quantities preparatory to treatment by magnetic separators or otherwise. It is of the tabular, revolving type, with automatic feed and delivery, and is a modification of the Cornish calcining furnace, designed by Brunton, from which it differs, however, not only in construction, but in two or more radical features, for which novelty is claimed and patents have been applied for. The principal of these novelties are: 1. A series of concentric terraced floors, one above another. 2. The introduction of superheated air upon the charge without contact with the fuel. In the furnace which I have had in operation for more than a

Jan 1, 1893

By T. S. Hutchinson, C. E. Kemp

The bottom water drive analysis presented by Muskat has been extended to include fields with wider well spacings. Curves are presented from which volumetric sweepout, water-oil ratio, and rate relations may be calculated. The effects of non-unity ratios on sweepout eficiency and productivity decline have been studied by an approximate method. Also, the effect of gravity on volumetric sweepout has been approximated for a particurlar geometry. INTRODUCTION The purpose of this paper is to report work done in applying the analysis of bottom water drive reservoirs given by Muskat1 to a larger class of reservoirs, to extend this analysis to include the effects of gravity and non-unity mobility ratios in an approximate manner, and to investigate the rate of decline of productive capacity. The bottom water drive type reservoir is one where the oil is underlain by a water zone of sufficient thickness that water movement is essentially vertical. This system is defined in more detail in the appendix and a one well element is shown diagrammatically in Fig. 1. Muskat obtained solutions to the equations describing the volumetric displacement efficiency of idealized bottom water drive systems by assuming that gravity effects due to differences in density betwecn oil and water were negligible and that the mobilities of oil and water were the same. If either of these assumptions is not made, the complexity of the system makes an analytical solution well nigh impossible at the present stage of mathematical development. Coles and Stade' developed an approximation to consider these factors. The authors have refined approximations, starting with the same basic assumption, which should give a somewhat quantitative picture of bottom water drive performance when mobilities are not equal and the effects of gravity are not negligible. The results of these approximate calculations can then be used to obtain the decline in well productivity as the field is depleted.

Jan 1, 1957

By L. M. Kaas

Maintenance costs comprise a large portion of total operating cost, 30% to 60% of the operating cost dollar not being unusual. Thus even a relatively small percentage reduction in this cost would represent a sizable increase to mining profitability. Mine and mill maintenance management is a complex problem. An effective maintenance manager must study the experiences of the past and make decisions based on that experience. Data Processing equipment-more specifically, the computer-can be an effective and economical tool to simplify the job of maintenance record-keeping and to aid in the formulation of many accurate and timely management reports. These reports will enable improved control to be established over day-to-day practices; permit comparisons of unit and component performance; spotlight inefficient maintenance practices; and further, better, more efficient cost control. The net result can be increased profits through reduction of operating costs.

Jan 12, 1967

By R. E. Somers

THE Appalachian field is notable for four tests drilled in recent years to depths of over 7000 ft. and for one commercial gas well at 6822 ft. The latter is the Ligonier well and produces from the Oriskany FIG. I.-NATURAL GAS PRODUCTION OF PENNSYLVANIA AND WEST VIRGINIA. sandstone. Together with several other comparatively deep tests, these holes were drilled in search of natural gas, to make up for the decline in production of the field. The production curve of Pennsylvania FIG. 2.-EAST WEST SECTION OF APPALACHIAN FIELD. (AFTER ASHLEY AND ROBINSON, PENN. G. S.) and West Virginia from 1907-21 is given in Fig. 1 to illustrate the heavy decline from the peak of 1917. This diminishing supply has also been shown by Moyer,1 on the basis of decreasing rock pressures.

Jan 3, 1924

By H. Baldauf, H. Schubert

The structure of flotation reagents is important for their adsorption on mineral surfaces and thus for their flotation effectiveness. The influence of the structure of organic depressants on the flotation of fluorite and barite with anionic and cationic collectors was investigated using a modified Hallimond microflotation cell. In addition, adsorption, desorption, and electrokinetic results were employed to further elucidate the role and the correlation of the structural parameters for adsorption and the depressing effect. As hydrophilic reagents, different aliphatic and aromatic compounds capable of forming chelates with alkaline earth materials were used. For the depressing effect, the kind, number, and position of the polar groups in the molecule, as well as the structure of the reagent films play decisive roles.

Jan 1, 1980

By Rustum Roy, E. F. Osborn

THE investigation discussed in this paper concerns phase equilibria in the alumina-silica-water system. Studies in this system are part of a re¬search project sponsored by the Geophysics Branch of the Office of Naval Research2 directed toward increasing knowledge of the stability relations of metamorphic mineral assemblages. Inasmuch as metamorphic rocks consist largely of aluminosilicate struc¬tures, many of them hydrated, the system alumina-silica-water is a logical starting point for the systematic laboratory study of metamorphic mineral systems. Although logical, this is not, however, an easy approach to the problem because of the very great difficulty of obtaining transformations among structures in response to changes in temperature, pressure, and con¬centration. Commonly equilibrium among the phases in this system is exceed¬ingly difficult to attain. New laboratory techniques are required to produce certain structural rearrangements, such as inversion of diaspore to boehmite or the transformation of alumina-silica mixtures to andalusite or kyanite. Phase equilibrium data for the alumina-silica-water system are consequently only partly complete, and only a summary progress report is presented here. Crystalline phases in the alumina-silica-water system are numerous and many are common minerals. The oxide components exist as: quartz, tridymite, cristobalite, corundum, water, and ice. Binary compounds occurring naturally are: sillimanite, andalusite, kyanite, and mullite in the alumina-silica system and gibbsite, boehmite, and diaspore in the alumina-water system. The most abundant among the ternary compounds is the composition A12O3.2SiO2.¬2H2O, existing in the four structural modifications, kaolinite, nacrite, dickite, and halloysite. The hydrated form of halloysite, A12O3.2SiO2.4H2O, is here called endellite. Pyrophyllite, A12O3.4SiO2.H2O, is the third ternary compound of natural occurrence. In addition to these minerals, two other ternary crystalline phases have been encountered in this study. The first is a structure resembling montmorillonite and corresponding perhaps to the pure aluminian end member of the beidellite series. The other has a composition approximating A12O3.2SiO2.H2O but its composition and structure are still in doubt. LABORATORY PROCEDURE In these laboratory studies, a starting material such as an alumina-silica gel or one or more of the crystalline phases is wrapped in platinum foil,

Jan 1, 1952

By Edward C. J. Urban

ESSENTIAL requirements for ensuring safe working atmospheres in underground metal mines are planned systems of ventilation and provision for effective distribution of sufficient volumes of air by auxiliary equipment. Investigators1 in the past have suggested that quantities of air supply ranging from 300 to 800 cu. ft. of air per minute per man underground are necessary, to establish adequate general ventilation. These fundamentals are just as important as the use of water in dust suppression, control of blasting, the use of personal protective equipment, frequent inspection of working areas and education of employees in good dust-prevention practice. During the past two years the necessity for direct control of the underground working environment has become particularly urgent. The increase in production rate, with two-shift and three-shift operation replacing the single shift, has complicated the problem of dealing with excessive concentrations of blasting fumes and gases, carbon dioxide and monoxide, heat and oxygen deficiency. Although previous industrial hygiene programs had given consideration to these factors, they were generally regarded by mine operators as secondary to the control of dust hazards. Today, blasting smoke in a mining area means delayed production because the miner cannot return to his work place after a short interval. Smoke on the haulage level means a safety hazard and exposure of the underground employees to excessive concentrations of atmospheric contaminants. Exposure to the moderately excessive concentrations of carbon dioxide and monoxide found in metal mines has caused physiological disturbances and a decreased capacity for work; deficiency of oxygen, in some cases to as low as 3 per cent, has resulted in fatalities. During the past 10 years the Saranac Laboratory2 has been associated with the iron mines in the Upper Peninsula of Michigan and Wisconsin in developing and maintaining an industrial hygiene and silicosis-prevention program. At present, about 35 underground iron-ore mines are operated full time in this area. With two exceptions, all of them are ventilated by main fan installations installed either on surface or underground. ,The types of mining used in these mines may be classified either as sublevel cave, radial top slice or sublevel stope, and the procedures commonly employed in the ventilation of these three types are described in Figs. 1 and 2. A number of different methods of mine ventilation had been in use in this area when the study was started. Natural ventilation had proved unsatisfactory. The wide variation between low air volumes during the summer months and higher volumes during winter led to unpredictable conditions that were difficult to control. In the majority of the mines two separate shafts or openings to surface are utilized in

Jan 1, 1943

By Oscar Aguilar, Jin-ichi Nakamura, Kazuo Nakamura

Michiquillay deposit is porphyry copper type with over 500 million tons of 0.70% Cu ore. In order to reflect the true nature of the orebody as to shape and value distribution and to compensate for insufficient data in the outer perimeter and lower portion, "Triangular Interpolation Method" is used in the computation, wherein block grades are determined by "Plane Regression". The results thus obtained are compared with the data from additional investigation and are found to match well with each other. Aside of total Cu, assays of Fe, S, MoS2 and geological data such as alterations, rock types, faults, mineralogical compositions are also stored in the computer. By this system, their distribution and relation to alteration become clear and classification of ore into types affecting recovery become possible. The outputs of this system make clear the characteristics of the orebody and furnish valuable geological data on the orebody.

Jan 1, 1976

By A. V. Henry, W. Harry Vaughan

THE kaolins of the southeastern United States were known to civilization as early as the latter part of the eighteenth century-and yet the [ ] commercial history of Georgia kaolins may be said to begin in the year 1900. The U. S. Bureau of Mines reported for that year a production of 6885 tons of "miscellaneous" clays in Georgia. A comparison of these figures with those of 1934, when the production rose to 284,556 tons (65 per cent of the domestic production), indicates the growing economic and technologic importance of this raw material. Fig. 1 clearly shows that a part of the increase is due to a normal growth in the use of kaolinitic clays and a part is due to replacement of clays formerly imported. Occurrence Georgia kaolin occurs in an irregular belt extending diagonally across the middle of the state, a distance of approximately 225 miles. This belt

Jan 1, 1937

By Max Barber

PRESENT equipment and practices in open-pit mines of the Lake Superior iron ranges have been described recently in some detail by A. H. Hubbell.1 It is anticipated that any further improvements will be the result of gradual evolution of present methods and equipment, just as those now used have been gradually evolved from earlier methods. An exception to the process of gradual evolution during the last decade has been the adoption of electric power for operating shovels and trains in open-pit mines, but it is not expected that any such revolutionary changes will be made in the future. The use of Diesel, engine equipment will gain considerable headway, no doubt, and will find favor in certain lines of operation as improvements and adaptations are evolved to meet particular requirements. The question of installing belt conveyors for handling material from deep mines of restricted area, where haulage grades become a serious consideration, or even for transferring earth, rock, or ore material for distances of several miles, is now being studied and some very interesting data are being obtained.

Jan 1, 1932

By J. Donald Graham, John G. Kuhn

The goal of any development drilling program is the drilling of the exact number of holes necessary to adequately determine grade and dimensions of an ore body, no more and no less. Any technique which eliminates unnecessary drilling costs produces beneficial results, both to the company and to the person who can claim the savings. The method for controlling development drilling programs to be described was developed during the latter part of a major development drilling project at the Christmas mine of Inspiration Consolidated Copper Co. in Gila County, Arizona. It was used to test the need for drilling individual holes but could be expanded to control an entire project. Application of this method involves an evaluation of geological conditions present and a good bit of common sense. Projects involving large disseminated, rather homogeneous ore bodies of the porphyry-copper type would be the most likely candidates for application of the technique. Discontinuous ore bodies would not be amenable. The method is based on the measurement of the linear correlation between the spatial distribution of two sets

Jan 1, 1973

By L. C. Uren

THE resistance to flow of mixtures of gas and oil in passing up through the flow tubing of oil wells operated by gas-lift or by natural flow is a factor in oil-recovery technic that has received but little attention. Yet accurate design of a tubing installation for a particular set of conditions, where operation is by either of 'these methods, is impossible without quantitative data on the pressure loss suffered by the oil-gas mixture in its passage through the well tubing to the surface. Because of lack of such information, petroleum production technologists have been compelled to approach this problem by "cut-and-try" methods, which, doubtless in many cases, has resulted in the installation and use of tubing too large or too small for most efficient utilization of the expansive force of the gas used in lifting the oil. Impressed with the necessity for information of this character, the authors have conducted a series of tests with large-scale apparatus in the petroleum engineering laboratories of the University of California, designed to be productive of data that would afford a means of attacking the problem of flow-tubing design on a more scientific basis.

Jan 1, 1929

By Edward C. Morse

The metallurgical history of Republic has been completely reviewed in a paper presented at a previous meeting of the Spokane Local Section by Professor Thomson;' therefore, the present paper will be confined to matters directly pertaining to the San Poil mill: When I came to Republic last fall to look over the situation there was a plant in operation successfully treating the tailings from one of the earlier mills in the camp. I refer to the mill of the Rathfon Reduction Co. This mill was operating in accordance with modern cyaniding practice, and I was given to understand that the work was very satisfactory and profitable, else it would not have been continued as long as it was. At that time I obtained much metallurgical information of value from Harry W. Newton, Superintendent of the mill of the North Washington Power & Reduction Co. I took a number of samples from the San Poil mine, with the view of determining if Mr. Newton's experience with the ores from the other mines applied to the San Poil ores. I made a large number of tests under a variety of conditions, and found that it was possible to extract as high as 98 per cent, of the values from San Poil ore by the laboratory-tests when the ore was pulverized to 200-mesh and treated with a solution of a strength of 5 Ib. of KCN to the ton. A fairly strong solution was required because of the proportion of silver in the ore, which makes it, from a metallurgical point of view, practically

Jan 1, 1913

By Morgan Walker

ONE of the most serious problems in the produc- tion of natural gas is the removal of water from the wells. As a gas well approaches its period of exhaustion, the removal of water by properly de-signed devices becomes increasingly important. Sev-eral methods are used for dewatering gas wells. If the .gas velocity and pressure are high enough, the water in the well will be carried out by the gas on opening the well to atmospheric pressure and allowing the gas to flow unrestricted except for the resistance of the casing. This method of dewatering a gas well is detri-mental to the producing sand, and very wasteful if used frequently. When the well has declined in production a string of tubing is often run in the well, with a packer set at the top or bottom of the well. If the top of the tubing is opened to atmospheric pressure and the gas is allowed to flow unrestricted as in the above method, the water can be discharged at the top of the well, provided the velocity of the gas is high enough. However, if the water has accumulated in the well until the water pres-sure is equal to or greater than the gas pressure, the ,water cannot be brought to the surface. In dewatering :a gas well by this method the operator sometimes finds -that if the packer is set near the top of the well and -the casing is tight, the water can be blown out when .it is impossible to blow it out with the packer set at the top of the sand. This is largely due to some gas leaking into the tubing through the collars. This method of dewatering gas wells is also wasteful. Water can be pumped out of a gas well with virtually the same equipment, as used for pumping oil, but the method involves installing a separate pump for each well, and difficulties are encountered in attempting to pump water under high gas pressure.

Jan 3, 1927

By Arthur Taggart

IN 1900, Elmore found that if an acidulated pulp was stirred up with an oil which was relatively insoluble in and lighter than water, and the mixture was al-lowed to stratify, much of the sulfide would be found hanging to the lower surface of the floating body of oil and could be skimmed off or overflowed with it. The action of the flotation agent here is two-fold, first to select the sulfide from the gangue-what to-day is called collection-and second, to buoy the col-lected sulfide away from the gangue. The action in collecting is illustrated by Fig. 1, which contrasts the behavior of drops of oil brought, under water, to the surfaces of gangue and sulfide particles, respectively. The oil displaces water from the surface of the sulfide; the water displaces oil from the gangue surface. If, instead of considering the solid particles the fixed parts of the system of oil, water and solids, we consider the oil and water fixed and the solids pre-sented to the surface of contact, the condition will be as shown in Fig. 2 ; the sulfide tends to be drawn into the interface and the gangue to be excluded. The sul-fide particles are held in the oil-water surface by the tension of this surface. The buoyant effect is supplied by the oil droplets in bringing the sulfides to the water surface, but not in holding them there.

Jan 6, 1928

By W. F. Rochow, W. C. Burke

Numerous designs of linings and accessories, including dams, lifters, and heat exchangers, contribute greatly to kiln efficiencies. Greater conductivity is achieved with basic brick than with fireclay and high-alumina refractories, depending largely upon the use of steel plates in radial joints between adjacent brick to increase heat transfer through the lining. Refractory lifters expose all portions of the load to radiant or convective heat and raise some portions to higher temperatures by cascading the load down through the path of the hot gases. AMONG the many factors involved in rotary kiln efficiency, advantageous use of refractories is of major importance. So far as kiln lining alone is concerned durability is most significant, as shutdowns for repairs are costly in fuel consumption and production losses. Aside from selection of refractories best suited to the widely varying conditions under which rotary kilns are operated, lining design and accessory constructions within the kiln are highly important. The refractory most economical for any combination of operating conditions can be selected from a wide range of alumina-silica and basic refractories, including insulating, castable, and plastic fire bricks. In several cases silica brick can be used to advantage. Alumina contents of alumina-silica refractories range from 35 to 90 pct in increments of 5 to 10 pct. In general, bricks of relatively low alumina content are best for abrasion resistance, an important property for the brick used in chain sections of cement kilns or in feed end sections of limestone kilns. High-duty fireclay bricks of approximately 40 pct alumina and 55 pct silica are used to line the intermediate zones. Super-duty fireclay brick at slightly higher cost is warranted in operation of kilns with high intermediate zone temperatures and severe spalling conditions. Alumina-silica refractories with an alumina content of 50 pct and higher, termed high-alumina brick, are available in commercial classes of 50, 60, 70, 80, 85, and 90 pct alumina content. These refractories are generally used as high temperature zone linings or placed adjacent to the basic brick-lined sections when the treatment they are required to withstand is excessively severe. Use of basic refractories is confined mainly to zones of maximum temperature and most severe chemical action. Basic refractories ordinarily employed for high temperature zone linings of many rotary kilns comprise the classes shown in Table I. Each class is peculiarly well suited to various particular combinations of working conditions. The approximate chemical analyses of these classes also illustrate differences in compositions with respect to the major components.

Jan 1, 1956

By Edwin Higgins

INTRODUCTION IT is the purpose of this paper to set forth the relation and functions of the various organizations and institutions engaged in the promotion of safety iii the iron mines of the Lake Superior region; also to indicate the value of this work. Ten to 15 years ago there was practically no organized safety work; the accident rate was high, excessively so in some districts, and dangerous practices and conditions existed in many of the mines. During recent years, however, a gradual change for the better has been made. The chief causes of this change have been (a) public opinion, which has set the stamp of disapproval on the disregard for human life; (b) certain State laws which have made the operators responsible in dollars and cents for injuries to workmen; and (c) the humanitarian attitude of many of the operators, who have always decried the great loss of life in the mines. Today the Lake Superior region as a whole stands second to no other metal-mining district in the United States in its efforts to promote the welfare and safety of the miner. Dangerous practices in and about the mines are fast disappearing. The operators are ready and eager to adopt any expedient, rule, or device that holds forth a reasonable promise of reducing the hazards of the miner. Today the value of a mine captain or shift boss is reckoned, not alone on his ability to "get the ore," but also on his capacity for reducing accidents. While the progress made has been remarkable, there still remains much to be done, for the accident records of the Lake Superior iron mines, while lower than those of the chief metal-mining regions of the United States, still compare unfavorably with those of the metal mines of practically all foreign countries.

Jan 10, 1914

By C. K. McArthur

THE subject of classification is so broad that this discussion is confined to what the author believes is of prime importance in connection with proper grinding and classification. The years passed have witnessed many noteworthy changes in fine grinding and classification, which have been accompanied by a readjustment of ore-dressing flowsheets for the preparation of better ground and/or sized products at an expenditure of less power, steel and maintenance than formerly. Nowhere in the industry is more being done in the way of experimental work to lower costs than in grinding circuits, because, at best, grinding costs are high. Recent years have indicated that, on the average, finer grinding has a real application. Without careful preparation of the process feed, no operation can be highly efficient or successful. In an earlier paper, the findings of an extensive survey at representative concentrators were presented1. Also, in the year of 1935, a technical discussion was given by Dr. J. V. N. Dorr (Some Notes on Classification Trends in America) before the Chemical, Metallurgical and Mining Society of South Africa In both papers mentioned, much has been said regarding flowsheets, grinding and classification. The author is very familiar with these papers, having had considerable to do with the actual operation of the flowsheets, as well as large mills and classifiers in the work described. Some data from the second paper have been included in the following discussion. Circulating Load In this particular paper it seems advisable to deal with the classification phases of the work that to a major extent govern the success of any closed-circuit grinding unit. The question has often been asked in connection with a closed circuit: "What circulating-load ratio should be carried?" This is really an

Jan 1, 1937

By Morris M. Fine, Norwood B. Melcher

As a raw material, prereduced pellets can be considered symptomatic of the quiet revolution taking place in the quality and grade of blast furnace burdens for the past decade. In 1954, the average analysis of ores from U.S. ranges in the Great Lakes area was 50.86% Fe (natural), 10.22% SiO2, and 10.90% moisture; ten years later, the average was 56.67% Fe (natural), 8.13% SiO2, and 6.17% moisture. The advance in Canada was even more pronounced in a lesser number of years. In 1957 the average product of Canadian ore-producing areas was 51.62% Fe (natural), 8.59% Si02, and 8.02% moisture; in 1964, the average grade was 59.59% Fe (natural), 6.27% SiO2, and 3.94% moisture.2 These dramatic data are testimony to the giant strides made in iron ore improvement, and the next logical step is prereduction. Prereduction can well be considered as a beneficiation step in which oxygen is the gangue. Since the ultimate objective of milling and smelting is iron metal, non-metallic constitutents in general, whether oxygen or silica, are contaminants. The past and continuing attack aimed at lowering the silica content of concentrates is succeeding. One need only thumb through the Grade Name listings of the American Iron Ore AssociationVo note that virtually all commercial pellets contain less than 8% silica, many are lower than 6%, and a few below 45%. With natural technical evolution, it is expected "many" rather than "few" will ultimately be in the last category and further mechanical concentration will have reached the point of diminishing returns. At this level, oxygen would constitute the only major diluent worthy of attack.

Jan 7, 1966