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The Mining Enforcement and Safety Administration has called attention to the increasing frequency of accidents occurring during mine maintenance and repair tasks in a recent publication. Data from the agency's Health and Safety Analysis Center have been compiled and presented in a report titled "Analysis of Injuries Associated with Maintenance and Repair in Metal and Nonmetal Mines,"* a booklet aimed at answering four questions: (1) Which pieces of operating equipment are most frequently involved in maintenance accidents; (2) Which maintenance functions are the most hazardous; (3) Which tools are most often associated with injuries; and (4) What is the comparative hazard of welding or flame cutting vs. mechanical or electrical maintenance functions.

Jan 3, 1978

By Emory Kemler

The problem of determining the most desirable operating conditions of an oil-well pumping unit or rig front, the selection of the proper material and size of sucker rods, and the design of a pumping unit require that sucker-rod loads be known with a reasonable degree of accuracy. The segregation of rig losses, the proper selection and operation of prime mover and reduction unit, and the analysis of the operation of subsurface equipment require a knowledge of polished-rod horsepower. The investigation of such problems as the instantaneous stresses set up in a pull-rod line or backside crank installation when the well is suddenly hooked on, a study of such problems as the effect of anchoring the tubing on rod load, tubing stresses and rod horsepower, and an analysis of the effect of subsurface equipment on rod loads make it necessary to have a dynamometer that is rugged, which can follow the sudden changes in load without any lag or damping effect, which will record the load in its true position with respect to polished-rod movement, and which will give a card large enough to allow the desired effects to be measured accurately. The inadequacy of the spring or fluid-pressure type of dynamometers has been covered in detail1. The data given show that dynamometers of the spring or fluid-pressure type exert a damping action on the peak loads and the inertia and friction of their load-indicating mechanism introduces a phase lag in recording the load. A dynamometer of that type will not give the load in the correct amount and will not record it in its true position with respect to stroke or time. New Type of Dynamometer Fig. 1 shows a magnetic strain-gage type of dynamometer, to be described in this paper. The strain gage A is used for measuring the load in the polished rod, a washer B and knife edge C take care of initial misalignment and reduce bending in the compression tube of the strain gage. The complete instrument can be transported in the carrying case E.

Jan 1, 1935

By Robert H. Holgers

Eveleth Taconite Co. was chartered on July 29, 1963, and is 85% owned by Ford Motor Co. and 15% by Oglebay Norton Co. The latter also serves as managing agent. The location of the company's facilities is depicted in Fig. 1. The Thunderbird mine is located midway between the cities of Eveleth and Virginia, Minn. (Fig. 2). The Fairlane plant and General Office are located approximately 10 miles south on the St. Louis River near the community of Forbes (Figs. 3 and 4). The crude ore and the finished pellets are transported by a common carrier railroad, the Duluth, Missabe & Iron Range Railway Co. The facilities are also serviced by the Duluth, Winnipeg & Pacific Railway Co. Pellets are hauled year around by the DM&IR to its docks 60 miles south in Duluth, Minn. Ford Motor Co. consumes its share of the high grade pellets at its Rouge plant in Dearborn, Mich., and Oglebay Norton Co. sells its share in the open market. HISTORY Following six months of preliminary engineering by the initial staff of Eveleth Taconite Co. and the Western Knapp Engineering Div. of Arthur G. McKee & Co., the project was approved by Eveleth's board of directors on Apr. 17, 1964. On May 1, 1964, contracts were awarded to McKee for the mine, coarse and fine crushing and concentrating facilities, and to Allis-Chalmer for the pelletizing facilities. The pre-production surface overburden stripping contract was awarded to Skubic Brothers Co., Virginia, Minn. Ground-breaking ceremonies were held at the Thunderbird mine on

Jan 1, 1969

By Harold R. Bradford

EXPANSION initiated during and after the war has placed industrial plants in new areas and increased reduction and manufacturing facilities in communities already established. With added expansion interest has grown in possible area contamination from waste products. Evolved flue waste contains many chemical contaminants that may or may not cause concern; however, atmospheric pollution has always been a problem to industrial communities. For some time effects attributed to small quantities of compounds of fluorine in various waste gases have been studied by industrial, medical, agricultural, and associated interests.1,2 Aside from an article by Churchill, Rowley, and Martin in 1948,3 little has been published on the subject of fluorine in coal except by foreign investigators.

Jan 1, 1957

By P. H. Royster

For a number of years the Bureau of Mines has been investigating certain problems relating to the blast furnace. In the course of these investigations it was desirable to measure, with the optical pyrometer, the temperatures occurring in the hearth of the furnace. Since no systematic measurements of these temperatures have been published a statement of the results may be of interest. The data given in this paper were obtained it thirty-two blast furnaces operated by seventeen companies; twenty of these furnaces were making iron, eight ferromanganese, and five spiegeleisen. The collection of this information was made possible by the cooperation of the American Manganese Co., Bethlehem Steel Corpn., Brier Hill Steel Co., Buffalo Union Furnace Co., Clinton Iron & Steel Co., Donner Steel Co., John B. Guernsey & Co., Jones & Laughlin Steel Co., E. E. Marshall, the McKinney Steel Co., National Tube Co., New Jersey Zinc Co., Republic Iron & Steel Co., Seaboard Steel & Manganese Corpn., Southeastern Iron Corpn., the Youngstown Sheet & Tube Co., and the Wharton Steel Co.

Jan 9, 1919

By H. G. Kok

The continuous increase in energy costs has made it necessary to consider a broader use of belt conveyors for the transportation of material from the mine pit to the processing plant. Hard rock has to be crushed before it can be moved by belt conveyors. Systems are in the planning stage for mining hard rock, such as copper and iron ore, by using high-capacity, mobile, or semi-portable crushers. The mobile crusher is located in the pit, and the crushed material is transported by energy-efficient, shiftable belt conveyors out of the pit.

Jan 1, 1983

By James F. Lewis

THE hematite iron ore mines east of the Hudson River are confined to a strip of country ten to fifteen miles wide, commencing on the south, near Fishkill, running northeast through Dutchess County, and striking the southeast corner of Columbia County, extending into Litchfield County, Conn., known there as the Salisbury mines, cropping out again at and near West Stockbridge, Lanesboro, and Cheshire, Mass., also in Bennington County, Vermont. The ores are found in beds or deposits and in veins, with a limestone ledge on one side and slate on the other, from six to thirty feet from the surface. Portions of it are quite solid, called rock ore, but

Jan 1, 1877

By Rudolf Bernhard

STATIC soil investigations with more or less heavy loads and extensive borings do not always have efficient results; also, they are very expensive. The new geophysical method of dynamic tests described herein is simple and cheap and avoids several disadvantages of the routine investigation, thus forming a useful supplement to the older methods and even at times replacing various static tests. The fundamental principle of dynamic soil tests consists in the appli-cation of artificial vibration. The technique employed is essentially geophysical in nature and in some respects is akin to seismic studies. Artificial vibration may be excited by centrifugal forces resulting from eccentrically supported rotating masses. The reactions of soil and structures caused by these vibrations may be measured. Their dynamic constants, such as amplitudes, phase speeds, damping, reflection, and interference effects, can be investigated. This geophysical method has been used for several years with increasing success. The results of these tests, summarized at the end of the paper, indicate that this method opens a new field for the practical engineer in investigating soils (capacity and formation), foundations, dams and structures, and especially buildings that must withstand earthquakes.

Jan 1, 1938

NEW MEMBERS The following list comprises the names of those persons who became members during. the period Mar. 10, 1919, to Apr. 10, 1919. AFFLECK, B. F., Pres., Universal Portland Cement Co., 210 So. La Salle St., Chicago, Ill. BENSUSAN, ARTHUR J., The Ouro Preto Gold Mines of Brazil, Ltd., Passagem de Marianna, Minas Geraes, Brazil, S. A. BIERBAUM, CHRISTOPHER H., Cons. Engr., & Vice-pres., Lumen Bearing Co., Buffalo, N. Y . DEWITT, OSCAR E., Geol., Vinegar Hill Zinc Co., 622 North Court St., Platteville, Wis. DOTY, L. C Mine Supt., Bullion Beck & Champion Co., Box C, Eureka, Utah. ESPIE, FRANK F Burma Mines, Ltd., Namtu, Upper Burma, Asia. FOZARD, J. L., Gen'l Supt., Beatson Mines, Kennecott Copper Corpn., Latouche, Alaska. GRANT, BENERE Supt., Bulluhacker Min. Co., Butte Mont. HARDEL, JEAN A., Engr., French Government, 21 Rue du Colonel Moll, Paris, France. JANSSEN, WALTER A., Operating Mgr., Canadian Steel Foundries.Ltd., 120 St. James St., Transportation Bldg., Montreal, Canada. KNOWLES, RALPH Roy, Supt., Radium Plant, The Minerals Recovery Co., 457 So. Elati St. Denver Colo.

Jan 5, 1919

By P. B. Bucky

THE purpose of this paper is to present a scientific method for deter-mining the proper span and shape of roof for safe and economical mining; at present, these two vital factors wherever pillars are left to support the roof are determined by local practice or general experience. To develop the method described here, experimental laboratory work was done. The arch adopted was a segment of a circle, a flat roof being considered an arch with an infinite radius. Hitherto, arches have been used underground without the background of stress analysis that generally precedes arch construction on the surface. In many cases results have not been as expected, because of the lack of knowledge of the factors affecting its strength and behavior. A theoretical and experimental study of arches should furnish informa-tion that will make it possible to design safe and economical surface structures as well as underground openings. For example, on the subject of mine drifts and tunnels, the present idea is that arching their backs increases their strength; this paper will indicate that this is not always true, and if it can be shown that under certain conditions arching becomes unnecessary an economic saving will result. In room-and-pillar work a question may arise as to whether arching the roof and gobbing the excavated material will result in timber saving, and a decrease in the dan¬gers from falls of roof. It is to be distinctly understood that each mine must be treated as an individual problem, and that answers to these ques-tions and many others can now be found after experimental laboratory data have been obtained.

Jan 1, 1934

By E. S. Burnett, R. V. Higgins, H. C. Miller

Information obtained from subsurface pressure and ,temperature measurements in oil wells now is recognized as invaluable to geologists, engineers, and operators of oil properties. Available only during the past few years, data resulting from subsurface-pressure surveys in oil wells already have found widespread application in the estimation of reserves and in the planning of comprehensive oil-field development programs. Subsurface pressure and temperature data, together with measurements of fluid volumes produced by individual wells and specific gravities of the fluids, also are included in the fundamental information essential in studying the movement of oil, gas and water through reservoir sands to wells. Heretofore, laboratory findings were relied upon almost entirely for information pertaining to the mechanics of flow of fluids through porous media, because there was no way to check laboratory results with actual performance in underground formations until subsurface pressure and temperature instruments were developed. Laboratory and field experiments now lend themselves to closer correlation—a fact that will accelerate the interpretation of many phenomena that occur when oil and gas flow through reservoir rocks, thousands of feet below the surface of the earth. This paper summarizes the results obtained thus far in a Bureau of Mines study of certain data pertaining to subsurface pressures and production of wells producing oil and gas (and water). For wells that have been studied, flowing naturally under volumetric or hydraulic control, a simple relation has been found between the mass rate of fluid (oil, gas and water) production and the corresponding drop in pressure in the reservoir sand. The equated relation embodies a productivity factor or "index" expressed in terms of mass rate of fluid production per pound drop in pressure through the sands. The equation as developed is an expression of the ability of a well to produce, which permits comparison on a uniform basis of the productivities of different wells. The study shows also that over the range of observed data a productivity factor

Jan 1, 1937

By J. David Lowell

For the first time in several years, Chile is again opening its doors to foreign investment. In its new investment code, the Chilean government has announced its willingness to become a partner in joint Chilean-foreign projects for a number of government-controlled porphyry copper deposits at the developed, semi-developed, or prospect stage; and, that it will allow privately owned deposits or deposits discovered by new exploration to be developed with up to 100% foreign ownership. Three deposits of particular interest are: El Abra, with at least 300 million mt of +100% Cu; Los Pelambres, with at least 428 million mt of 0.78% Cu and 0.03% Mo; and Andacollo, with 350 million mt of 0.70% Cu and 0.015% Mo. (El Abra is almost entirely government- controlled; but both Los Pelambres and Andacollo are mostly under private ownership.)

Jan 11, 1974

By Robert Roberts

(Butte Meeting, August, 1913.) IN order to obtain data on the thermal effect of the blast-furnace jacket and oil the water consumption in these jackets a series of tests were run on the 56 by 180 in. blast furnaces at the Great Falls Reduction Department of the Anaconda Copper Mining Co., at Great Falls, Mont. The arrangement of the jacket is shown in the transverse section of one of the furnaces (Fig. 1) on which the tests were made. The nose, spout, and breast jackets have independent water supplies and discharges. The end and side jackets are connected in pairs, as regards water supply, the feed water entering at the bottom of the lower jacket and overflowing into the bottom of the jacket immediately above it, and discharging into an independent overflow pipe for each pair of jackets. Tests were run on the main side and end jackets, the breast jacket, the spout, and the nose. Measurements were taken of the quantity of water discharged per minute and the rise in temperature of the water in its passage through the jacket. The product of these two results, expressed in the proper units, evidently gives the number of units of heat removed per minute by the water. Sufficient work was done on each type of jacket to determine its behavior under different conditions, and the results from each set of conditions were checked by repeating the work from three to six times.

Jan 7, 1913

By D. S. Sanders, E. W. Witcomb

FLOTATION tests, from which the flowsheet for the concentrator was determined, were made in a pilot mill at Chuquicamata and later comparative testing of full size flotation cells was done at the Andes Copper Mining Co. concentrator in Potrerillos. The principal sulphide copper mineral is chalcocite with varying amounts of covellite, enargite, and chalcopyrite. The oxidized portion is principally antlerite, a green basic copper sulphate. The gangue minerals include quartz, sericite, pyrite, feldspars and kaolin. Chuquicamata pit ores have proved to be hard grinding. The results of the flotation and metallurgical work prove that good extraction and concentrate grade can be obtained under a rather wide range of conditions. Metallurgy In general the metallurgy of the ore requires a fairly close control of the grind to the primary rougher flotation and of the regrind of the primary rougher concentrate before cleaning. Regrinding is necessary to reduce the insoluble content of the final concentrate since a large part of the middling combinations are between the copper and silica minerals. The alkalinity of the pulps can vary between wide limits and control of the percent solids gives the desired grind. Alkalinity Control Arroyo Salado water is supplied to the concentrator head tanks. It contains about 5000 ppm of salts but test work shows no deleterious effect. Actually this water permits a decrease of as much as 1 lb of lime per ton of ore as compared to San Pedro water, which is used for leaching oxide ore. About one quarter of the water flow through the concentrator will be new water from the reservoir. The remainder will be reclaimed from the thickeners. For primary grinding and rougher flotation, new and reclaimed water are combined in the head tanks. To avoid erratic results, only new water is used in the regrind system. Milk of lime is added to the rod mill feed chute to obtain the maximum benefit of mixing with the ore. This protects the equipment from corrosion due to entrained acids and soluble copper salts. Lime consumption is 3 to 5 lb per ton of ore. Grinding and Flotation The six bin gates over each belt feeder are opened in controlled combination and sequence to keep a live bed of ore in the bin to prevent arching and to obtain mixing. The milk of lime added ahead of the rod mill is regulated to suit rougher flotation requirements. The primary promoter reagent, Aerofloat 238, is added to the 10-mesh discharge of the rod mill as it is laundered to the ball mill scoop box. The classifier overflow is regulated to produce a grind of about 12 to 15 pct +65 mesh and 60 pct -200 mesh. A secondary promoter Z-4 (aml zanthate) and the pine oil frother are added in the overflow launder where a pH of 10 to 11 is maintained. Comparatively heavy beds of froth on the

Jan 1, 1952

By Nicholas M. Short

Many a geologist or driller has wished he could somehow climb into a borehole to see for himself what fractures looked like. Or why recovery was poor. Or how the bit was actually lost. Now it is possible to do the next best thing to climbing into the hole. TV cameras are being used for a close-up look at borehole conditions. Ever since television was invented, geologists and others interested in subsurface conditions have wanted a TV camera that could be used in the narrow confines of a borehole. But development of such a camera was slow, mainly because of the need for compact size. Not until the late 1950's did the technology of electronic miniaturization develop to a point where a camera satisfactory for the purpose could be put together.

Jan 1, 1963

By Thomas M. Barczak, Claude A. Goode

Principal criteria in the design and operation of longwall mining systems are examined. The decision to apply longwall mining is investigated from an economic viewpoint, and the impact of economics on system design are addressed. Geological considerations and requirements for effective long- wall mining are provided. Ground control factors determining panel design are outlined, as well as environmental considerations. Operational practices are discussed and alternatives recommended. The impact of face moves and the potential for mining wider webs are assessed. Constraints to production are identified and the potential for increasing production of longwall systems is established.

Jan 1, 1982

By Hsun Hu

The formation of annealing textures in high-purity silver, from the various rolling textures obtanled in the course of texture transition, was studied. It was found that from a brass-type rolling texture the recrystallization texture is mainly (120) [211] type, which is quite different from the recrystallization texture of brass. From a predominantly copper-type rolling texture, the reclystallization texture is mainly (100) [001]. The recrystallization texture of silver- varies also with the degree of purity. In each case, however, the reorientation can be expressed as [Ill] rotations of 30° to 40°, which is consistent with the oriented growth theory of the formation of annealing textures. ThE recrystallization textures of rolled silver were studied long ago by Glocker and co-workers (1924-27) and were reported to be (113) [iil] upon annealing at low temperatures.1 Since that time, no further study of the recrystallization textures of silver, particularly with the modern techniques of quantitative texture determinations, has been reported in the literature. In a previous study2y3 it was found that the rolling texture of high-purity silver (99.999 +pct pure) is changed gradually from the common silver- or brass-type to the copper-type by raising the temperature of rolling from 0" to 200°C. The formation of annealing textures from the various rolling textures in the same material is, therefore, of considerable interest. The present paper constitutes the results of such a study. MATERIAL AND METHOD Specimens were taken from the same strips of high-purity silver* that were used previously for

Jan 1, 1962

By T. R. A. Davey

A Survey of current and recent research and developmental work is supplemented by predictions for processes which should be developed over the remainder of this century.

Jan 1, 1970

By Howard W. Jacky

At Weed Heights, Nev., precipitation plays a major role in the plant operation. Almost two-thirds of the present copper production is leach-precipitation plant copper. The entire plant complex processes about 135,000 tons of low grade copper ore per week. Of this tonnage, 49,000 tons of about 0.78% sulfide ore are treated in the concentrator. This is handled in the conventional manner of crushing, grinding, and concentration of the copper sulfide by flotation.

Jan 6, 1967

By R. L. Perrine

This paper shows how stability theory can be used to optimize solvent recovery of oil. Application of the theory leads to definition of the limiting conditions required for stable displacement to occur. One of these conditions is that the size of a solvent "slug" must at least equal a prescribed minimum. The criteria to be satisfied are miscibil-ity and stability. Stability implies that no viscous fingering will occur and that mixing will be caused only by a dispersion process. Miscibility implies that complete recovery will be obtained from the swept regions. Thus, for any specified set of reservoir conditions, an optimum use of solvent is defined. INTRODUCTION The early outlook for solvent flooding as a means to increase oil recovery was very favorable. Some laboratory results indicated that a "slug" containing perhaps 2 to 3 per cent of a hydrocarbon pore volume could be successful. However, other data suggested as much as 30 per cent would be required. The difference is of considerable economic importance. A theoretical explanation for these divergent results has been advanced by the author.1,2 Stability theory defines conditions for two distinct flow regimes. In stable displacement, solvent and oil become mixed by a dispersion process, and the solvent requirement is small. On the other hand, unstable displacement can degenerate into viscous fingering. The practical result is a considerable increase in the extent of mixing and, thus, in the solvent required. The present paper shows how to use stability theory to optimize solvent recovery of oil. Oil is usually considered to be displaced by a small amount, or a slug, of solvent. Gas in turn follows solvent. Any fingering will permit contact of nearly solvent-free gas and oil, leading to immiscibility and reduced recovery. Thus, our optimum is defined by two restrictions — stable flow and miscibility. Although an immiscible solvent process could prove more profitable than any miscible process, such processes lie outside the selected definition of an optimum. The usefulness of computations based on the present work will depend on the validity of the general theory. Because the important idealizations required tend to minimize the predicted solvent requirement, the results should state correctly the limiting conditions required. Therefore, theoretical calculations should have practical value. This paper first reviews several principles that result from stability theory. The following section describes use of these ideas in relatively simple systems which symmetry makes appear one-dimensional. Of particular importance is the step-by-step design of 3 stable minimum-solvent slug. The use of stability theory in cases of multi-dimensional displacement is discussed and, finally, suggestions are given for simplified practical application of the theoretical results. PRINCIPLES OF STABILITY THEORY The use of perturbation methods to derive stability conditions has been shown by the author.l The discussion is presented in terms of the fractional concentration of solvent in the single hydrocarbon phase. Quite generally, any disturbance can be represented as a Fourier series, of which only the least stable term need be considered. Denoting this term at time t = 0 by cn,