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By R. G. Hudson, L. Yang

In electrochemical separation of metals, it is necessary to control the potential applied between the electrodes so that only the desired electrode reactions can occur. A knowledge of the minimum potential needed for a given electrode reaction to take place continuously is therefore pertinent to the success of the process. In molten chloride systems at high temperatures, activation polarization is believed to be small,1,2 so the minimum potential needed for the electrolytic decomposition of a molten metal chloride MC1n (n = valence of the metal ion) is therefore essentially the equilibrium electrode potential E of the metal-chlorine galvanic cell in the solution. If the decomposition products are pure M and chlorine at a pressure of p atm, E*Eo-rt/nf in [i] Since EO (the standard electrode potential of MCln) is a constant at a given temperature and R (the gas constant), and F (the Faraday's constant) are all constants, the variation of E with the electrolytic bath conditions is largely determined by the effect of the latter on the activity of the metal chloride amcln (standard state = pure MC1,). Measurement of E and study of how amCin varies with temperature and concentration, the nature of the solvent, and that of the coexisting solutes are therefore pertinent in the selection of optimum operating conditions for the electrochemical separation of metals. Because of its low melting point, high decomposition potentials of its components, and the low solubility of heavier metals in it, the LiC1-KC1 eutectic melt is a useful solvent and has been used in the electrodeposition of Mo,3Ce,4 and u5 metals. Senderoff and Brenner3 measured the potentials of Zn/Zn++, Fe/Fe++, Cu/Cu+, Mo/Mo+++, and Ag/Ag+ against an Ag/AgCl (pure) reference electrode at 600°C and a concentration of 4.1 mole pct of each chloride and came to the conclusion that complex ion formation occurred in some of the melts. Laitinen and LiUe gave an electromotive force series at 450°C for a number of {Metal/Metal ions (unit activity)) electrodes in LiC1-KC1 eutectic melt, the {pt/pt++ (unit activity)) electrode being chosen as the reference. Walker and Danly7 studied the ther-modynamic properties of NiC12 in LiC1-KC1 eutectic melt over a wide range of temperatures and concentrations by measuring the electrode potential between a nickel electrode and a chlorine electrode in the melt. Since potential measurements made by using the chlorine reference electrode are of more direct significance both in the study of electrochemical separation and in the evaluation of the thermodynamic properties of the melt, it is therefore decided to measure the electrode potentials of cells of the type {M/MCin (mole fraction = N) in LiC1-KC1 eutectic melt/Cl2 over a range of N values and temperature for a number of metal chlorides. The results should indicate the order by which the various metals plate out on the cathode and how this order is affected by temperature and the concentration of the metal chloride in the solu-

Jan 1, 1960

By D. D. Dunlop, J. R. Welker

The growing interest in the use of CO, in crude oil recovery increases the need for data on the effect of CO, on hydrocarbon physical properties. Data are presented on the solubility of CO, in various dead oils, the swelling changes in CO2-oil solutions and the effect of CO, on dead oil viscosity. This latter property shows the most pronounced effect, with viscosity reductions up to 98 per cent of the uncarbonated viscosities. An empirical method of estimating the viscosity of carbonated oils is presented. The apparatus and procedures used are described in sufficient detail to allow others to make similar studies. INTRODUCTION The effect of dissolved carbon dioxide on the swelling and viscosity reduction of specific hydrocarbon oils has been observed and recorded by a number of investigators.'- me object of this paper is to offer a means of predicting these effects for crude oils free from natural gas, using the dead state viscosity and gravity of the crude oils. The CO, solubility and swelling of numerous crude oils were determined in a visual cell at various pressure levels. The viscosity of the oils carbonated to various pressure levels was then determined by measuring the pressure drop across a capillary tube. From these data, the physical properties were correlated empirically. The resulting correlations allow the prediction of CO, solubility, swelling and viscosity reduction if the dead state gravity and viscosity of the oils are known. SOLUBILITY AND SWELLING MEASUREMENT EQUIPMENT AND PROCEDURE A high pressure visual cell was installed in a constant temperature cabinet. A test gauge was attached at the top of the cell for pressure measurement, and a line was run through the cabinet wall to a wet test meter which was used for volumetric measurement of the gas. The first step in making a test run was to put the oil in the cell up to a level about half to two-thirds of the total volume. This required about 50 to 65 ml of oil. carbon dioxide was then bubbled up through the oil for a time during which the pressure of CO2 in the cell was kept above 800 psia. Saturation of the oil with CO2 at this pressure and ambient temperature was confirmed by slowly bleeding CO2 through a valve to the atmosphere. If the oil was completely saturated with CO2, bubbles of gas would form in the oil at the first small decrease in pressure. If the oil was under-saturated, no bubbles formed until the pressure was decreased to the saturation pressure existing in the oil. If this saturation pressure was lower than that desired, more CO2 was bubbled through the oil until the desired level was reached. After saturation at ambient temperature was completed, the cabinet temperature was adjusted to the desired level and the cell was allowed to reach temperature equilibrium. After temperature equilibrium was reached, the pressure was again decreased slightly, and the oil again checked for full CO2 saturation at the cell pressure. The pressure now had changed because of the difference in solubility of the CO, in the oil at higher temperatures and the expansion of CO2 as the temperature increased. The outlet tube from the cell was then connected to the wet test meter and the CO2 was allowed to flow slowly out of the cell and through the wet test meter at ambient temperature and pressure. The water in the wet test meter had previously been saturated with CO2 at ambient temperature and pressure by allowing CO2 to flow continuously through it lor a period of several hours. The gas flow was stopped at several pressures during the run and the cell was allowed to come to equilibrium; this made possible the measurement of solubility and swelling data at the intermediate pressures. The volume of the oil in the cell was recorded at each of the equilibrium pressures in order to obtain swelling data. DATA AND RESULTS The solubility of CO2 in the oil was calculated by the relationship V — V, where R. = solubility of CO, in crude oil, cubic feet of CO, measured at 60F and 1.0 atm/ bbl of dead state oil at the temperature under which solubility was measured, V, = volume of gas released from the cell between the saturation pressure and zero pressure, corrected to 60F and 1.0 atm, cu ft, V, = volume of CO: contained in the gas space above the oil, corrected to 60F and 1.0 atm, cu ft, and V, = volume of the dead oil in the cell in bbl at the temperature of the run. The volumetric data of Sage and Lacey' were used to calculate V., from the volume of CO2 at high pressures. The swelling factor was calculated as where V, is the volume of the C0,-

By T. D. Yensen

I. INTRODUCTION IT is safe to say that of all the different materials that go to make up electrical machinery, iron is the most important. Upon its -magnetic and electrical quality depends not only the efficiency of the machine but, to a very large extent, the cost. Aside from the mechanical strength, there are three characteristics of iron that are of importance in this connection, viz., magnetic hysteresis, electrical resistance, and magnetic permeability. In the homopolar machine, where the magnetic flux is unidirectional, permeability is the only important factor, but in all other machines the flux is reversed in one or more parts and causes losses due to hysteresis and eddy currents. The eddy-current loss depends largely upon the electrical resistance of the iron; the higher the resistance the lower the loss, under otherwise identical conditions. These hysteresis and eddy-current losses cause heating of the machine, and as they depend upon the magnetic density in the iron, this density must be regulated so that the heating shall not be excessive. If the hysteresis and eddy-current Josses and the permeability of the magnetic circuit will permit an increase in the magnetic density, or, in other words, a decrease in the amount of iron, this in turn will mean a decrease in the amount of copper needed, with a consequent decrease in the copper loss. It is thus seen that; indirectly as well as directly, the above characteristics have an important bearing on both the efficiency and the cost of electrical machinery. In general, it may be said that iron for electrical machinery should have the following characteristics: (1) low hysteresis loss, (2) high electrical resistance, and (3) high permeability. These are the characteristics that investigators have been striving to attain since electrical machinery first came into use.

Jan 2, 1916

By Brian R. Castle, James J. Scott

INTRODUCTION Referring to a ground support system as a 'band-aid' borders on getting cute, but the application of cable slings in U.S. mining is somewhat analogous. Where problems in the roof or rib require additional support, the versatile cable sling is the answer in a variety of conditions. To fully understand how and why cable slings are used today we must briefly review their development history. Much of the thrust over the last five to seven years in ground support fixtures has been the development of hybrid systems. Taking the best of two or more existing roof bolt fixtures and marrying them into a new fixture which exhibits the good characteristics without the bad of the parent systems. Resin point anchored mechanical bolts, continuous threaded rebar bolts, and others have all be- come important fixtures in rock mass stabilization. HYBRID GROUND SUPPORT SYSTEM The cable sling system is also a hybrid, both in its parentage and in its ground support characteristics. See figure 1. Cable slings combine the techniques of cement. grouting high-strength cables, Friction Rock Stabilizers, and truss-like suspension into a versatile and high- strength ground support system. 1/2" high-strength cable is cement grouted in place in a manner similar to pre-

Jan 1, 1983

By RAY J. CORFIELD

IN a previous paper, "Electric Shovel Operation at Utah Copper Mine," which was read before the Western Division of the American Mining Congress, the problem of electrifying a fleet of steam shovels was described. This paper deals with the electrification of the haulage system which, when completed, will make the mining operation completely electric, with the exception of drilling operations which will continue to be performed by air. The general layout of the haulage system involves the use of heavy curves in addition to heavy grades of between 4 and 5 per cent. In a mining operation of this kind no trackage can be called permanent; this complicates the overhead construction somewhat and makes it necessary to design special forms of trolley construction, some of which will be described in detail below.

Jan 1, 1929

G. A. Burr, Parral, Chihuahua, Mexico (communication to the Secretaryt): I regret that Mr. Norris did not give more attention to the hoisting of water in inclined shafts or slopes: the only slope mentioned being Hickory Ridge Slope, No. 4, of the Union Coal Co. The surface arrangement, illustrated in Fig. 12 of his paper, if not unpractical, is at least unscientific and cumbersome. It is my opinion that the back- and sideguides shown in Fig. 12 are not only unnecessary where rails are used as a track, but are unsafe, excepting in the case of a very firm hanging-wall, or roof, and sides of vein-matter, having absolutely no tendency, either to settle from the back, or to squeeze from the sides, an effect which would inevitably force the guides out of alignment. The accompanying illustration, Fig. 1, shows what I consider a better method of hoisting water than that described by Mr. Norris. This method is based on the general practice in metalliferous mines of the West, where skips are used in slopes; and, while it is not original with me, I have frequently used it with very satisfactory results for dumping both ore and water.

Jan 1, 1904

By MARIUS R. CIMPBELL, Edward W. Parker

DESCRIPTION. ACCORDING to the estimates prepared by the U. S. Geological Survey, the area underlain by workable coal-beds in the United States is 496,776 sq. miles. Of this total area, 480 sq. miles contain the entire anthracite coal-fields of Pennsylvania. The bituminous coal-fields are estimated to be contained in areas aggregating 250,051 sq. miles. The grade of coal between bituminous and lignite, and which is designated by the Geological Survey as " sub-bituminous," is estimated to be contained within areas aggregating 97,636 sq. miles, while the areas containing lignite aggregate 148,609 sq. miles. The coal-fields are divided, for the sake of convenience in classification, into six main provinces, as follows: 1. The Eastern. Province, containing the anthracite coal-fields of Pennsylvania and the bituminous coal-fields of the Appalachian region-namely, those of western Pennsylvania, Ohio, Virginia, West Virginia, Kentucky, Tennessee, Georgia, Alabama, and small outlying areas in North Carolina. 2. The Interior .Province, containing the bituminous coal-producing regions of Michigan, Illinois, Indiana, western Kentucky, Iowa, Kansas, Missouri, Oklahoma, Arkansas, and Texas. 3. The Gulf Province, containing the lignite-areas of Alabama, Mississippi, Louisiana, Arkansas, and Texas. 4. The Northern or Great Plains Province, containing the lignite and sub-bituminous areas of North and South Dakota, eastern Montana, and northeastern Wyoming. 5. The Rocky Mountain Province, containing the bituminous and sub-bituminous areas of western Montana and western Wyoming, Colorado, Utah, and New Mexico. 6. The Pacific Coast Province, containing-the areas of Washington, Oregon, and California.

Apr 1, 1909

By I. C. Edwards, W. J. Dengler, D. F. Lillie

By 1959 the milling plant of Bicr oft Uranium Mines Ltd. had been in operation for two years. During this time many changes, both physical and chemical, had been made in an effort to improve plant efficiency. Investigational work had been facilitated greatly by the fact that the Bicroft mill consists to a large extent of two parallel circuits; however, the number of interrelated variables is great, and it is difficult to measure, let alone control, all of them simultaneously. The Bicroft mill staff feels that much progress has been made, but there is much yet to be done and many questions still to be answered. The Addendum outlines noteworthy developments to the fall of 1960. The property of Bicroft Uranium Mines is located in Cardiff Township in the Highlands of Haliburton County, southeastern Ontario, some 140 miles northeast of the city of Toronto and 70 miles due north of Lake Ontario. The ore-bearing dikes are classed as mafic. nonsegregated, syenite and granite pegmatite. Microline, microline perthite, quartz, sodic plagioclase, and pyroxene or biotite are the main constituents with uraninite, uranothorite, fluorite, titanite, cryolite, calcite, pyrite, pyrrhotite, and molybdenite as important accessories. The mill was designed for a nominal capacity of 1000 tpd with all sections except grinding, leaching, and clarification capable of 1500 tons. Feed was entered to one mill unit on Oct. 29, 1956, and to the second parallel line on November 13. The total feed rate was at 1000 tpd on November 15. The first precipitate was produced on November 12. By August 1958 the average entry had been increased to 1410 tpd without the installation of any additional major equipment. The overall recovery has been greater than 93.0 pct on several months, but a recovery of 92.5 pct appears to be most economical. Operating time for eight months in 1958 has been 97.1 pct although all grinding mills were relined during this period. A generalized flowsheet is shown in Fig. 1 and the plant layout in Fig. 2. The ore is crushed in three stages to -3/8-in. and then is wet ground in two stages to approximately 50 pct -200 mesh. The pulp is thickened to 68 pct solids and agitated by air for 33 hr at a pH of 1.9 as maintained by the addition of 93 pct sulfuric acid. Separation of the uranium-bearing pregnant liquor from the residue is accomplished by five-stage countercurrent decantation (CCD), following which the liquor is clarified for removal of fine slimes. The clarified liquor is treated in the ion exchange equipment in which both the upgrading of the solution and the removal of some impurities is accomplished. Addition of magnesia to the high-grade eluate from ion exchange precipitates the uranium as sodium-magnesium diuranate. After being filtered and dried this precipitate is packaged in drums for shipment. The residue from CCD and the barren solution from ion exchange are neutralized by the addition of lime and pumped to the tailings disposal area. CRUSHING All crushing is done on surface in a conventional three-stage unit consisting of a 36x48-in. Birdsboro Buchanan jaw crusher, a 4 1/4-ft standard Symons cone crusher, and a 4-ft Symons shorthead. Both the two primary and the two secondary screens are 4X 8-ft Symons rod decks. Moisture content of the feed ranges from 3 to 4 pct. In the initial installation the primary screens were equipped with 5/16-in. rods at 1 1/4-in. spacing and the secondaries with 5/16-in. rods at 1/2-in. spacing. With this arrangement the average crushing rate was better than 180 tph. To reduce the work required of the grinding circuit as tonnage was increased, several changes were made in the crushing circuit. By September 1957, both secondary screens had been reduced to 3/8-in. spacing, and rod size had been reduced to 3/16-in. to provide increased open area. Average throughput was reduced to 160 tph. Later, 50 pct of one primary screen was decreased to 1/2-in. opening to better balance the load between the two cone crushers. In May 1958,

Jan 1, 1961

By Eugene Guccione

Evidence that the United States is gradually converting to the metric system of measurement can be perceived today even by housewives in a supermarket. The question is no longer whether but when the country will have completed the conversion. To the extent that any bickering about metrication still exists, the debate now centers on such issues as finding agreement on details of implementation, and whether federal legislation should speed up the metric-conversion process or allow it to proceed along its present evolutionary and voluntary course. Apparently, the voluntary or "make-haste-slowly" approach is gaining widespread support. According to The Research Institute of America, Inc., if and when federal legislation is enacted it will likely include the following national ground rules: (1) A National Metric Conversion Board will develop and submit to the President and Congress a comprehensive plan to achieve a coordinated, minimum-cost changeover. (2) The change- over will be completed 8 to 10 years after the board's plan goes into effect, and by that time the US will be predominantly, though not exclusively, metric. (3) Costs will "lie where they fall"; subsidies, special tax concessions, and antitrust exemptions will not be authorized by the legislation. (4) The changeover will be voluntary because of the recognition that while some firms can "go metric" in a matter of weeks, others may require 15 years or more, and a few might never convert. (5) In determining whether or not to convert, on an individual company basis, adherence will be to the "rule of reason-that is, ". . . do not convert unless the engineering, economic, or other benefits outweigh any metric-related disadvantages. No one is talking about rip- ping up our railroad tracks or rewiring our homes just to conform to the practice of metric nations in Europe." (6) Government is to be part of the solution, not part of the problem; in effect, says The Research Institute of America, the leverage of federal procurement will not be exerted to force-feed the metric changeover but will be coordinated with the sector-by-sector conversion of the economy.*

Jan 12, 1975

By J. T., Norton

As cold working is an important feature in a great many of the fabricating processes now applied, this paper presents some ideas on the nature and results of the plastic deformation produced in this operation. The art of manufacturing metal for practical uses is very old and has undergone very great development. The science of metals has- also developed very rapidly recently and the various processes to which metals are submitted are much better understood now than they were even a short time ago. All the knowledge that can be obtained on this subject is useful because it promotes efficiency in converting metal into finished articles.

Jan 1, 1927

By J. Norman Bulkley

As electrical power is used to a greater extent on the Rand than in any other mining center, it is thought that a short description of the methods used and results obtained may be of interest. In comparing Rand practice with that on other fields, several general factors should be borne in mind: First, the mines are all working on large tonnages of low-grade ore (average $6.50). The annual crushing rate is about 27,000,000 tons. Second, the mines are all grouped under the financial and engineering control of mining houses, so that the results of a group, rather than an individual mine, are open for study, and practice follows more uniform lines. Third, coal of fair quality (about 12,000 B.t.u.) can be obtained for $2 to $3 per ton. Good supplies of condensing water are, however, scarce, and have to be carefully stored. Power Supply Power is supplied by the Victoria Falls & Transvaal Power Co., Ltd., and its subsidiary, the Rand "Mincs Power Supply Co. Both companies, which are practically one from an engineering point of view, operate the following stations, all fecding into the same system. Capacity Installed Turbo Capacity Installed Steam-Tur- Station Alternators bine Dliven Centrifugal Compressors Brakpan............... Two 12,500-kw. sets Two 3,000-kw. sets Simmer Pan............... Six 3,000-kw. sets Rosherville................ Two 11,000-kw. sets Six 3,500-kw. machines Five 9,600-kw. sets Three 7,000-kw. machines Verckniging ............. Two 9,600-kw. sets Two 12,000-kw. sets 162,200-kw. sets Total steam-tkbine capacity installed, 204,200 kw. There are also at the Robinson Central air station six motor-driven centrifugal compressors, each of 3,500 kw., equal to 22,000 cu. ft. per minute at 120 Ib. capacity at 3,000 r.p.m. Power is supplied from these stations as 50-cycle, three-phase current generally at 40,000 volts,

Jan 1, 1916

By John Freeman

THE tensile properties of steels at elevated temperatures have been studied by numerous investigators,1 primarily for the purpose of determining their suitability for structural uses. Tests with this objective have been confined largely to the temperature range of approximately 20° to 500° C., because of the rapidly decreasing tensile strength at the latter temperature. Tests have also been extended to higher temperatures for the purpose of determining the most suitable forging range. This temperature range is also of theoretical interest. The phenomenon of increased tensile strength and decreased ductility in the so-called "blue-heat" range, approximately 200° to 300° C., is well known. It was suggested to the Bureau early in 1926 that a study of the properties of rail steels in this temperature range might prove of interest in relation to the studies of transverse-fissure failures in rails. There were available from another investigation3 several new rails from several different heats made to approximately the same specification requirements, the complete manufacturing histories of which were known. It was decided to determine, at least in the preliminary series of tests, only the ultimate tensile strength, elongation and reduction of area, because of the difficulty, time and cost involved in determining the proportional limit and yield point at elevated temperatures.

Jan 1, 1930

By Gerald, Sherman

INCREASED production and con¬sumption of all metals, indicate the progress of industry toward that condition formerly thought to be normal. With no market limitations on silver and gold the two new precious-metal mines, the Silver Queen (now the Golden Queen), in southern California, and the Sunshine, at Kellogg in northern Idaho have made progress toward a high routine production. The Golden Queen 300-ton mill is finished and ready. The Sunshine mill has been enlarged and production is now at the rate of 500 tons per day of high-grade silver ore. The Hecla Mining Co. is developing the Polaris vein, which should be the extension of the Sunshine to the east. Some rich ore is reported. The developments of the' East African Gold Fields, Ltd., in the Lupa gold field of Tanganyika Territory, have made good progress, but operation in an isolated locality is not rapid and a large plant will be required. There have been no other discoveries reported that can be compared with the three mentioned, but production has increased, with greater capacity in dredging equipment and underground mines more adequately prepared for production.

Jan 1, 1936

Maryland was the third state to produce coal, and from the available information a small amount was mined each year after 1888, some of it being used locally but probably the larger portion being floated down the Potomac River. In 1798 some coal was used in the arms plant at Harper's Ferry, and while many of the records of this plant have disappeared, we know the tonnages delivered here from 1818 to 1837, the latter date being five years before the date usually given as the start of shipments. These data are shown in Table 54. In addition, some coal was used in an iron plant above Harper's Ferry, but the amount is not known. All of the coal to these plants came down the river, and for 1826-1830, both inclusive, some old canal records show coal passing through the canal at Great Falls, but practically all of the Cumberland coal used around Washington prior to 1842 was floated down the Potomac River during high water, and even at those times it was a precarious and dangerous business. After 1842, when the Baltimore & Ohio Railroad reached Cumberland, the records of shipments are unusually complete. The canal was completed to Cumberland in 1850, but its useful life terminated with the Civil War. The production records of this field are the most complete of any of the early coal mining states.

Jan 1, 1942

By AIME AIME

FOR the mineral industry, as for many others, the year 1944 brought to fruition the seeds planted in previous war years. Accomplishment in attaining ends in the production of minerals has given more time for the consideration of postwar problems, such as plans for resuming production for civilian uses and measures to prevent possible mass unemployment. The hectic atmosphere in production circles lessened during the latter half of 1943, conditions becoming static during 1944 as peak production rates were reached. Withdrawal of deferment of young men from the mining districts by Selective Service connotes that man power at the battlefronts became more important than the persistence of pressure for metal production. This is in contrast to the return of soldiers in 1943 to augment the labor ranks in the mining districts. The year ended in the midst of changing needs. Over-all metal production in the United States in 1944 will record a lessening, compared with the previous year owing to labor shortages which affected both development work and ore output.

Jan 1, 1945

By ALFRED D. FLINN

ENGINEERING COUNCIL has passed, not out, but upward! Therefore, its recent wake was conducted by itself as a joyful occasion somewhat in advance of its official demise. Council held its last meeting in Washington, Dec. 16, 1920. Business was transacted with dignified gravity in the forenoon. During the afternoon calls were made upon the chiefs of technical bureaus of the Government: the Chief of Engineers, U. S. Army; Chief of Yards and Docks of the Navy Department; Director of U. S. Reclamation Service; Director of U. S. Geological Survey; Director of Bureau of Mines. The Council pronounced them, each and all, able men and true. But what of the evening? Well, there was a dinner at the Washington Hotel. Twenty-six men gathered around a flower-strewn table-not a casket. As guests, there graced the festive board the hosts of the afternoon calls, and a number of members of the new American Engineering Council. The body about to be apotheosized-otherwise known as Engineering Council-was both jocular and reminiscent. Rewards were bestowed and appreciations expressed. To the man who had for three long years borne the burden of chairmanship and whose financial recklessness made possible the Washington office and the movement for a National Public Works Department, the following "note," duly engrossed and signed, was given, accompanied by "The Song of the Council Crew."

Jan 1, 1921

By Chester O. Ensign

Many publications to date have advocated under- seas mining operations, optimistically overlooking the paucity of information on mineral distribution and the ocean environments in which minerals occur. Such articles (smattered with opinion, as is this article) are herein tempered by my more conservative views on the economics of mining under the seas. For purposes of this paper, underseas mining refers only to the deeper surficial deposits of the continental shelf and the deep sea floor, i.e., the deposits of phosphorite and manganese nodules.

Jan 9, 1966

By Walter W. Bradley

AT ONE TIME OR ANOTHER and in greater or less amounts, gold has been mined in at least 40 of California's 58 counties. It may not be inappropriate, by way of introduction, to give a brief historical statement relative to her production of the yellow metal. The presence of gold in the gravels of San Gabriel, San Francisquito, and other streams near Los Angeles, was known and they were worked in a small way by the Indians, at least as early as. 1841' and possibly 1820. -On March 2, 1844, Don Manuel Castanares, deputy for California to the Congress of Mexico, reported' to his government that placers near Los Angeles had yielded up to December, 1.843, a total of 2000 oz. of gold dust, most of which had been sent (via Mexico) to tile United States Mint at Philadelphia.

Jan 1, 1932

By G. S. Jenkins

The statistics set forth by Professor Mitchell in a proceding paper very carefully brought out the points that indicate that a marked amount of consideration must be given to" the haulage problem to adapt it to local conditions as encountered. Professor Mitchell's paper showed a spread of from 10 tons per man to 50 tons per man on the production crews, which spread can be recognized as entirely too large when one considers that the product is being sold at a price within very close limits. While a portion of this spread may be explained by different methods in cost accounting as to what employees are applicable to the production crew, it cannot all be blamed on an accounting method. A good portion must be explained by the improper application of equipment to the needs incurred by the local conditions. It is in an endeavor to go into this phase that this paper is given. It will be necessary to qualify the points covered in order to keep the subject from becoming too wide in scope. Along this line, conditions will be only those involved in bituminous coal mine practices and only the haulage of coal that is loaded with mobile loading machines in seams 4 ft thick and better. Haulage Methods Employed The Consolidated Coal Co. (Illinois) has been operating on a modernized basis for about 20 yr. By modernized we mean the loading of coal with mobile loading equipment. In review of haulage methods, it must be remembered that the main line electric haulage locomotive has been in service for some 40 or jo years. To augment this main line haulage, the mule did a quite satisfactory job during hand-loading days, but was later replaced by the gathering locomotive, either battery or cable-reel operated. This type of haulage was the method in common use at the time the mechanical loading of coal became of major importance and the success or failure of loading machine installations may be largely accredited to haulage facilities in the early days; that is, in the period around 1930. The Consolidated Coal Co. had its struggle with this problem beginning in about 1927 or 1928. We were somewhat fortunate in that we were already using gathering locomotives powered by storage batteries at the time we introduced mechanical loading. This meant that we did not have to spend as much time training motormen and trip riders as many mines did that utilized only mules for their secondary haulage. This was all advantage, and our efforts could be focused on ways and means of providing adequate car service to the loading machine. Like most operations, we endeavored to gear the car service to the capacity of the machine, with a large crew endeavoring to load the maximum tonnage that the machine would handle. Toward that end our first move was to install switches

Jan 1, 1949

The world's largest steam-driven mine hoist, built by Nordberg Manufacturing Co. a half century ago, has become a major tourist attraction in Michigan's Upper Peninsula. The hoist, designed by company founder Bruno V. Nordberg, is located in the Quincy Mine Number Two, just north of Hancock. Nordberg began construction of the mammoth machine before World War I, but delayed completion until after the war. The hoist became operational in 1920 and continued running until the mine was shut down in 1931.

Jan 9, 1968