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By Robert L. Grayson, Y. J. Wang, R. Mike Mishra

Prediction of ventilation needs in long range mining projections requires serious consideration when formulating those projections. Predicting the behavior of the ventilation system of an old, complex mine poses an especially provocative problem. Air-flow around and through mined-out areas via bleeder systems, leakage flows through stoppings or other air control devices, and the use of multiple fans all add to the basic complexity of a ventilation system and make predictions of ventilation changes very difficult. Fortunately, the task of making ventilation decisions can be greatly assisted by ventilation surveying and computer simulation. The Nemacolin Mine of Jones and Laughlin Steel Corporation, located in Southwestern Pennsylvania, is one such old mine which used the computerized approach successfully. A mine-wide pressure-quantity survey was used to obtain realistic values for airway resistance factors. These values, together with network topology, formed the basic input for computer simulation. Results from this simulation indicated that air quantities generated at critical airways by the model were generally within a couple of percent of those measured in the actual survey. It was then concluded that the model was acceptable for practical application, and it was used immediately for studying the effects on the ventilation system of changing the blade settings of fans. Additionally, the model was modified to incorporate projected mine development and used to predict future ventilation.

Jan 1, 1982

By Richard E. McElvain, I. Cave

The selection of centrifugal pumps for mill discharge duty should be based on the total circuit concept. The practice of operating the mill circuit based on limitation of the pump can result in losses in one day which would offset the pump cost. Operating data from 25 grinding circuits have been reviewed and comparative results on added mill capacity have established advantages far beyond the less significant maintenance costs with increased circulating load and better cyclone operation. Mill discharge pumps should be selected on the following basis: i) Best available design for wear performance ii) Size to provide best economic life iii) Liner material best suited to circuit conditions Pump efficiency is a secondary consideration because power consumed by pumps is small compared to mill power input. Energy dissipated in mill pumps is contributing to comminution of ore.

Jan 1, 1982

By Alfred H. Brooks

Less than a decade ago the consumption of coal in Alaska was practically limited to the salmon canneries and the few ode-mines and settlements along the Pacific coast of the The-itory. The sparse population of the interior depended on the forests, that of the shores of Bering sea and the Arctic ocean on driftwood for fuel. All this has changed. The thousands, who have sought and mined gold on the Seward peninsula since 1898, have much impoverished the long-accumulated supply of driftwood, and at the same time the constantly increas-ng demand for fuel, on the part of the placer-camps and steamers, has resulted in heavy inroads being made on the accessible timber of the Yukon and its tributaries. While, on the one hand, the immediately available store of wood has decreased, on the other, the consumption of fuel because of the rapid expansion of the mining and fishery industries, and the attendant growth of population has much in-creased. Alaska, therefore, offers a constantly growing market or coal and other fuels. As the local coal-production has been nsignificant, the demand has been met by importations from Washington, British Columbia, and even from Pennsylvania and Australia. Fuel- Consumption. Mr. D. H. Jarvis, Collector for Alaska, has kept systematic records of the trade of the Territory since 1903. The statis-ics of the coal-importations of the past two years are shown n Table I. If data were available for a longer period of years, he increase of coal-importations would be much more striking.

Jan 1, 1906

By Ralph Wilcox

THE diamond drilling of certain characters of unstable rock forma-tion, as, for example, the copper-bearing schists of the Miami district in Arizona, is rendered most difficult by what is known as " caving" of the sides of the drill holes. As this caving is very greatly increased by the action of flowing water, it occurred to me, after experiencing a great deal of difficulty with caving in diamond-drill holes which I was drilling for the Miami Copper Co., that if I could substitute air for water, much of the caving-with resultant difficulties, such as decreased speed of sinking and increased consumption. of diamonds-would be overcome. After some experimenting, I found that it was perfectly practicable to substitute air for the water; forcing the air down the hollow rotating rods in the same manner as is done with water, the air passing out around the bit, which is thus cooled, and ascending on the outside of the rods to the collar of the hole, carrying the borings in just as satisfactory a manner as had been done by the water, but without the accompanying destruction or caving of the sides of the drill holes such as had been so generally experienced with the water. When water was encountered in the drilling this water was forced up to the collar just as it would have been had water been used in the .drilling, but with the correspondingly decreased flow there was relatively less washing or caving of the sides of the drill holes. The only change necessary in the arrangement of the drill is that a cross instead of a tee is used at the collar of the hole. A tightly woven jute bag is attached to one arm of the cross, for collecting and filtering the sample; and when drilling in dry ground a jet of water is attached to the opposite arm of the cross, to collect the dust and wash down the sample into the bag. The rods rotate through a stuffing box attached to the upper opening of the cross. The distention of the jute bag by the issuing air indicates the operating conditions as sufficiently as did the flow of water when using water in the drill hole.

Jan 10, 1913

By F. W. Gordon

Since the waste gases of the blast-furnace came to be generally utilized in heating the blast and raising steam, the gradual improvement in the economy of fuel, mainly through the nse of higher temperature in the blast, has impoverished the gases. The increased output per unit of measurement of the furnace, and the increased height of the furnace, have markedly increased the resistance to the blast, thus enormously increasing the duty required from the gases. In other words, a gas reduced in heating power by a further dilution of CO, is required to raise the temperature of the blast to 1800' Fahr., where formerly 600' was a good temperature, and at the same time to raise steam enough to drive the air into the furnace at a pressure of from four to eight pounds in coke practice, and from eight to twelve pounds in anthracite practice, and also pump at least double the water formerly used at furnaces. Hence the necessity for the employment of the best scheme for thoroughly consuming these gases with the least dilution of air, and the use of the best device for absorbing the heat prodnced for the purposes above mentioned. In a former paper before this Society the writer called attention to such improvements as had been made by his firm, by which it was claimed 1400' Fahr. could be maintained in the blast by a less consumption of gas than was required to maintain 900' when using pipe-ovens; and it would not be too much to say that 1600' Fahr. might now be written in place of the 1-400. The object of this paper is to give the practice of our firm in the

Jan 1, 1884

J. S. UNGER,* Pittsburg, Pa, . (written discussion?).-The author of the paper has given an excellent description of the appliances used to cool parts of an open-hearth furnace, and some of the reasons why the refractories fail in service. Personally, I favor water-cooling, but to a limited degree. At one time I advocated more universal cooling than is now practised, but believe I must change my mind. Water-cooled, thin-lined blast furnaces have not proved as satisfactory as anticipated. While this may retard the building of many such furnaces, it will not prevent the use of regular tuyere- and bosh-cooling appliances. Water-cooling any furnace may be easily carried to the extreme. In an open-hearth furnace, excessive port or roof cooling, or cooling the working floors may preserve the lines of the furnace, lower the cost of refractories, acid to the comfort of the workmen, and necessitate fewer shutdowns for repairs, but it may not be good economy on account of the high first cost, the cost of cooling water, maintenance of cooling appliances, and the immediate reflection in a higher fuel cost. The question becomes a financial one, and is answered by using water-cooling devices up to the point at which they cease to show true economies. Open-hearth furnace bulkheads, roofs, and ports fail rapidly in about the order named. If they could be made to last indefinitely by water-cooling, the furnace would still have to be shut clown periodically for cleaning the slag pockets, regenerator chambers, and flues. Extra, or spare, pockets and regenerator chambers have been advocated to permit of continuous operation, but the space required, the cost of installation, and the fuel required to initially heat such cold chambers will largely prevent their adoption. Some particular fuels, as high-ash powdered coal, require frequent stoppages for cleaning, but for this particular fuel a special provision can' be made.

Jan 5, 1919

By F. G. Miller, J. M. Podgursky

Laboratory and pilot plant work on tabling of 14-mesh X 0 hydrocyclone under flow are summarized. Included are: operating principles of hydrocyclones and tables; performance of these two devices, separately as well as in combination; comparison of the combination hydrocyclone-table system with other fine-coal processing systems; and application of the hydrocyclone-table system in fine-coal circuits. The data show that the table actually compensates for the shortcomings of hydrocyclone and makes a combination table-hydrocyclone system attractive, particularly in those cases where fine pyrite is one of the major contaminants.

Jan 1, 1973

By Noel Stearn

WHEN the Age of Machinery was suddenly thrust upon civilization about the beginning of the nineteenth century, an unprecedented demand for mineral resources sprang up. This demand brought about the rapid development of the known ore deposits and the discovery of such other deposits as could be encountered by energetic and canny pros-pectors. Thus in the countries now reasonably ac-cessible nearly all orebodies have been located except those which are totally concealed even from the eyes and "senses" of experienced and expert prospectors. The high rate of exhaustion of known ore deposits and the necessity of looking farther and farther ahead for raw materials as a matter of insurance on the stu-pendous capital outlays involved in mining, develop-ment, and conversion operations, have resulted in excep-tional activity in three different fields of effort. The first is purely geographic. Prospectors are now pene-trating the few hitherto inaccessible regions in the hope of stumbling upon exposed ore deposits or locating visible indications of their presence. The second is chemical. Industrial chemists and metallurgists are seeking to facilitate the exploitation of lower grade ores to find methods of recovering valuable metals from common substances. In the third field of effort. lie the activities of the economic geologist and the mining engineer, who en-deavor to locate concealed ore deposits, which would remain hidden from the prospector, no matter. how expert or conscientious he might be. Obviously the task which such a man must face is both exacting and indefinite, and the tools which he has heretofore been permitted to bring to it are, for the most part, abstract-a knowledge of certain fundamental princi-ples and processes involved in the origin, occurrence, structure, and distribution of deposits. of natural re-sources and of the rocks which form the environments of those deposits, and a process-of reasoning by analogy supplemented by the .use of the diamond drill, or such artificial exposure as the test pit, trench, shaft or tunnel. His primary efforts are usually bent on acquiring a knowledge of the distribution of the rocks-as accurate -is possible-which is a natural prerequisite to any conclusion as to how they became so distributed. Over very extensive areas, however, he meets. the extreme difficulty of being unable to see the rocks, except at rare intervals, since .they have been concealed by an overburden of glacial material, of alluvium, of soil, or of other rocks.

Jan 9, 1928

By Theodore Nagel

Fuel-oil, natural gas and coke oven gas, producing the higher temperatures of open-hearth current practice, have been gradually displacing producer gas the lowest cost fuel for open hearth operations. The lower temperatures of combusts on products from producer gas is caused by nitrogen dilution. Practical Application of Combustion Thermochemistry One pound of carbon burned to CO produces 3,960 B.T.U. and one pound of carbon burned to C02 produces 14,140 B.T.U. The second unit of oxygen uniting with gasified carbon (CO) produces (14,140 - 3,960) 10,180 B.T.U. which is (10,180 - 3,960) 6,220 B.T.U. more heat than produced by the first unit of oxygen forming CO by uniting with solid carbon. A review of the relative combustion heating values of commercial gaseous fuels reveals CO requires a minimum of air for combustion and because of minimum nitrogen dilution and the high thermal release from CO higher temperature combustion products are produced from CO than from natural gas or from coke-oven gas under similar combustion conditions. Inert nitrogen diluent lowers the calorific value of fuel gas and its diluting effect is cumulative in lowering the temperature of the products of total combustion. It is not only logical but practical in partial combustion, converting bituminous coal to gas, to generate the gas with reduced nitrogen dilution.

Jan 1, 1936

By F. J. Haller

The need for permanent, fireproof support indicated structural steel sets. Experience over the past six years, involving more than five miles of permanent underground openings, has proved that steel is permanent, safer and, in the long run, cheaper than either treated or untreated wood supports. Excavation is reduced, as are installation, transportation, and handling costs. A number of hazards are reduced or eliminated by the use of steel.

Jan 4, 1950

By Daniel T. O’Brian

Exploration targets and results in the mining industry are commonly summarized in terms of tonnage and grade. Business appraisals require, as additional information, the expected profit or loss implied by the physical summary. The early incorporation of knowledge gained through financial analysis computations can provide a means for economically resolving many common exploration and development problems. Examples of such applications from the activities of exploration planning, reconnaissance, land acquisition and develoment planning follow. While prospecting for mineral deposits, geologists are frequently asked what they have found or hope to find. The response is usually descriptive, such as: "50 million tons of 1% copper," and the economic implications are deferred until a capital investment decision is required. At that time a financial analysis integrating the four analysis components-tonnage and average grade above cutoff grade, capital and operating costs, product value, appropriate profit or loss accounting-are completed.

Jan 10, 1969

By A. J. Fenn

Cananea is located at an elevation of 5,200 ft in the north-central part of the state of Sonora, Mexico, about 135 miles northeast of Hermosillo, the state capital, and about 30 miles south of the United States border. A graded road runs to Cananea from the border town of Naco, near Bisbee, and a branch road turns east to Cananea at Imuris, a town 36 miles south of the border on the Nogales-Hermosillo highway. Railway service is provided by a spur from the Nogales-Naco branch of the Ferrocarril del Pacífico Railroad. Fuel for the power plant, smelter, and town (population approximately 20,000) is natural gas, supplied through a pipeline from the United States. The Compa[n]ía Minera de Cananea generates electric power for its own installations and also supplies both electricity and water to the town. HISTORY The earliest record of mining in Cananea dates back to 1760, when Jesuit fathers worked the Cobre Grande mine for silver in spite of resistance from hostile Indians. About 1800, several mines were worked on a relatively large scale by the House of Guea of Chihuahua. From then until about 1890 when William C. Greene of Fairbanks, Ariz., acquired control of a large group of properties, mining continued in a rather sporadic manner. The mineralized district is approximately 6 miles wide and 15 miles long, and the orebodies are associated with breccia pipes and granitic intrusive rock. In the early days, many small mines operated within the area on high-grade orebodies. In 1899, Greene promoted the building of a mill and smelter and established the present company, The Cananea Consolidated Copper Co., S.A., now Cia. Minera de Cananea (S.A. de

Jan 1, 1969

By Terry G. Richard, Vernal H. Kenner, Sunder H. Advani

This paper presents and discusses the results of thirty-one fracture toughness tests on Pennsylvanian Age Clay Shale. Two different orientations for this anisotropic material were studied and two series of tests were conducted, namely, 1. a test series to determine the effect of moisture content on fracture toughness, and 2. a test series to study mixed mode fracture. Increased absorbed moisture is found to reduce fracture toughness. Several analyses of mixed mode failure are found to give varying non-conservative predictions of failure stress intensity level.

Jan 1, 1982

By Alex G. Sciulli

This paper discusses the primary computer programs used by the Mine Safety and Health Administration's Bruceton Safety Technology Center to evaluate coal refuse disposal plans. These programs are currently being used by private consultants, government, and the coal industry for today's coal refuse disposal problems. This paper outlines five programs, their special features, and their importance in the design and construction of coal refuse disposal facilities. The purpose of the paper is to present the general steps necessary in the computer-modeling of each program. The programs that are discussed include BISHOP, STABL, RWE, DAMS2, and HEC-2, which cover the subject areas of slope stability, hydrographs, flood routing, and water surface profiles.

Jan 1, 1983

IN order to make his work easier, every master of any art whatever keeps always to the road that he has learned or that his skill or good judgment has shown him to be the best. Although there are various methods used in making moulds for guns, depending on whether they are large or small, nevertheless almost the same road is traveled in all. You must first know that it is necessary to make a pattern of wood or clay exactly as the gun is to be, with those ornaments of cornices and rings that you wish to be in the bronze. Let us suppose that you wish this pattern to be of wood. You must try to have for this a piece of fir as long and thick as you wish, dry, solid, and well seasoned, with few or no knots if possible. This should be longer than the gun by the length of the head and foot rests where it is pivoted [83v] so that it can be turned as on a lathe. On the end where the mouth is to be it should project out enough so that you can attach a feeding head at the top of the casting. You can make or have this pattern made round, fluted, spiral, or half fluted, as you like best, making the measurements exactly correct with all care and attention. Then two bearing trestles must be fixed firmly in the ground, one at the head and one at the foot, as is usually done with roasting spits and as you see drawn here. This done, if it is fluted, put the cornice pieces at the place where you wish the mouth to be and at the foot where the fire is applied. These are

Jan 1, 1942

By J. F. Myers, F. M. Lewis

IN the mining and handling of sulphide ores, some degree of oxidation takes place on the sulphide surfaces, which are exposed to the atmosphere. It is, moreover, well known that the oxidation compounds formed are a factor when such ores are subsequently treated by flotation. Modern operating technique and reagents are capable of contending with this condition to a major degree, provided that the proportions of the reagents used are varied correctly. This is particularly true at the Tennessee Copper Co., where the ore treated contains pyrrhotite in addition to other sulphides. A number of soluble salts, some of which are unstable, can be formed during the oxidation of the sulphide ores. Those unstable salts, whose oxygen requirements are unsatisfied, are constantly changing to more stable forms because oxygen reacts with them during the crushing, grinding and other operations of ore preparation. We add no chemicals of any kind to the ore pulp in its preparation for flotation feed. Consequently the only compounds that are present in the flotation feed are those produced by the natural oxidation of the ore in the presence of air and water. The Tennessee Copper Co. ore is composed of from 60 to 70 per cent sulphides and from 40 to 30 per cent nonsulphide material. It is not the purpose of this paper to discuss the nature of these various oxygensulphur compounds nor their effect on flotation, but to describe a method for [ ] correcting the effect. Suffice it to say that we have found that the reducing sulphur and oxygen salts have a depressing action on our bulk flotation process.1 From long experience we find that the best means of correcting for this variation in our work is to increase or decrease the quantity of xanthate, the promoting agent, as the quantity of the reducing salts increases or decreases. It was, therefore, very desirable to provide the operators with some quick and

Jan 1, 1946

By H. H. Lowry

Science attracts the attention and interest of an individual or an industry in general only in proportion to the apparent direct application to its immediate welfare or benefit. Engineering accomplishments, as aphlied science, therefore receive more recognition than the scientific discoveries on which they are based. Even self-evident truth needs endless repetition before recognition: engineering as applied science cannot advance beyond the science on which it is founded. Scientific research, and discovery, is sometimes forced by the limitations recognized by those active in its development for the use of society and industry and sometimes results from an apparently superficially illogical curiosity about natural phenomena. Research has received inadequate support except in industries born in the laboratory, the chemical and electrical industries, from which many lessons might well be drawn by their elder associates. The rapid growth of these industries has been largely due to close cooperation of scientists and engineers. Most rapid advance is made when the research worker and the engineer keep in close touch with each other's ideas and problems. Many of the developments of modern industry are based on discoveries buried for years in scientific journals because the "time was not ripe" at their discovery. The situation with regard to utilization of coal is quite the oppositre. The fundamental facts in regard to the scientific aspects of the problem of developing the energy from coal are scarcely known. The engineer, without much scientific cooperation, has accomplished much in increasing the number of kilowatt-hours per pound of coal from 0.31 in 1919 to 0.69 in 1934, in increasing the 1000 gross ton-miles of freight hauled from 12.2 to 16.4 per ton of coal in the same period, in fuel economy in production of coke, and in developing the production of motor fuel in Germany and England by hydrogenation of coal. This lack of scientific research on the utilization of our most important natural resource, coal, has been due undoubtedly in large part to the reluctance of investigators to study the interrelationships involved in the complicated processes in which coal is used. These complexities are made

Jan 1, 1936

By H. H. Lowry

Science attracts the attention and interest of an individual or an industry in general only in proportion to the apparent direct application to its immediate welfare or benefit. Engineering accomplishments, as aphlied science, therefore receive more recognition than the scientific discoveries on which they are based. Even self-evident truth needs endless repetition before recognition: engineering as applied science cannot advance beyond the science on which it is founded. Scientific research, and discovery, is sometimes forced by the limitations recognized by those active in its development for the use of society and industry and sometimes results from an apparently superficially illogical curiosity about natural phenomena. Research has received inadequate support except in industries born in the laboratory, the chemical and electrical industries, from which many lessons might well be drawn by their elder associates. The rapid growth of these industries has been largely due to close cooperation of scientists and engineers. Most rapid advance is made when the research worker and the engineer keep in close touch with each other's ideas and problems. Many of the developments of modern industry are based on discoveries buried for years in scientific journals because the "time was not ripe" at their discovery. The situation with regard to utilization of coal is quite the oppositre. The fundamental facts in regard to the scientific aspects of the problem of developing the energy from coal are scarcely known. The engineer, without much scientific cooperation, has accomplished much in increasing the number of kilowatt-hours per pound of coal from 0.31 in 1919 to 0.69 in 1934, in increasing the 1000 gross ton-miles of freight hauled from 12.2 to 16.4 per ton of coal in the same period, in fuel economy in production of coke, and in developing the production of motor fuel in Germany and England by hydrogenation of coal. This lack of scientific research on the utilization of our most important natural resource, coal, has been due undoubtedly in large part to the reluctance of investigators to study the interrelationships involved in the complicated processes in which coal is used. These complexities are made

Jan 1, 1936

By R. A. Stauffer

THE chief ore of lithium is spodumene, a lithium-aluminum silicate containing up to 3 pct lithium. The preparation of lithium salts from spodumene is costly because of the low concentration of the metal and the difficulty of separating it from the other alkali metals present. Dr. Kroll's and Dr. Schlecten's recent paper' has reviewed various methods proposed for preparation of lithium. It will be seen from this paper that the methods proposed to date have required one or another of the lithium salts as a raw material. The high cost of these salts has been the chief item of expense in the lithium metal produced. This situation has made it interesting to investigate the possibility of producing the metal directly from spodumene. When spodumene is calcined at 1000°C in the presence of lime, lithium oxide is replaced in the ore as is evidenced by the fact that it may be leached from the reaction mixture with water.2 Free energy calculations suggested that lithium oxide might be reduced with aluminum or silicon and the lithium produced distilled from the reaction mixture by heating to about 1000°C in a vacuum. These facts taken together suggested that it might be possible to prepare lithium metal directly from spodumene by heating a mixture of the ore, lime, and a suitable reducing agent in vacuum and distilling off the lithium metal as formed. THE REPLACEMENT OF Li20 IN SPODUMENE A series of experiments were undertaken to determine the ratio of lime to spodumene necessary to free substantially all the lithium oxide present in the ore. The spodumene used in these experiments was supplied by Foote Mineral Co. in the form of powder of about 200 mesh. Analysis of the spodumene was as follows: [ ] Lime (cp -200 mesh) was added in various ratios to spodumene and thoroughly mixed in a ball mill. Two hundred gram samples of spodumene-lime mixtures were charged loosely in fireclay crucibles and held at 1000°C in a gas-fired furnace for 5 hrs. The product in each case was ground to pass 140 mesh and then placed in a thimble in a soxhlet extractor. Extraction with water was carried on for 6 hrs. After this period the extract was reduced in volume by evaporation in order to precipitate dissolved lime and was then filtered and titrated with 1/4 normal hydrochloric acid. After correcting for residual calcium oxide in solution, the alkali present was calculated as lithium oxide. The results of these experiments are shown in Table I and Fig I. At lime-spodumene ratios less than 1.5, the products were invariably fused. At the ratio of 1.5 and above, the product was loosely sintered with little evidence of fusion. When the ratio of lime to spodumene was three, replacement of alkali oxides in the

Jan 1, 1947

PRESIDENT OF THE COUNCIL. D. W. BRUNTON DENVER, COLO. (Term expires February, 1911.) VICE-PRESIDENTS OF THE COUNCIL. W. C. RALSTON SAN FRANCISCO, CAL. W. L. SAUNDERS NEW YORK, N. Y. H. V. WINCHELL ST. PAUL, MINN.¬ (Term expires February, 1911.) BENJAMIN B. LAWRENCE NEW YORK, N. Y. JOSEPH W. RICHARDS SOUTH BETHLEHEM, PA. ALBERT SAUVEUR CAMBRIDGE, MASS. (Term expires February, 1912.)

Jan 1, 1917