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By L. BENEDICT

COMMENTING on the report of the latest Royal Commission for India, the September, 1926, issue of the National City Bank's monthly letter states, among other things, that "The decision of the Royal Commission is against the proposal for a gold coinage, but in favor of placing the silver coins and paper currency now redeemable in silver on a gold basis." Also, it quotes the following from the Royal Commission's report: The essence of the proposal * * * * * is that the ordinary medium of circulation in India should remain as at present the currency note and the silver rupee, and that the stability of the currency in terms of gold should be secured by making the currency directly convertible into gold for all purposes, but the gold should not circulate as money. It must not circulate at first, and it need not circulate ever. In this connection it may be stated that during the last one hundred and fifty years or so unsuccessful attempts have been made by the governments of different nations of the world to devise a plan or plans by which gold and silver could be used concurrently for money purposes and, particularly, as standard money; such, for example, as bimetallism, which, of course, is impracticable. But, since none of such plans has been adopted generally it is logical to conclude that their proponents did not shape them so as to conform to the basic principle of standard money, or else political issues were deemed to be dominant, or, perhaps, it was partly due to each.

Jan 1, 1926

By H. Demirel

This paper deals with concentration of hematitic-limonitic iron ores. The ore sample obtained from Karakuz (Turkey) contain:. about 40-46 I Fe. First, a low intensity magnetic separation process was employed to separate the strongly magnetic particles cf "-10+2 mm" and "-2+0.075 mm" size fractions and magnetic concentrates with 59.1 % Fe aid % 58.0 Fe were obtained respectively. The non-magnetics of both fractions were then fed to a nigh intensity permanent magnetic separator. The Fe contents of "-10+2 nun" and "2+0.075 mm" size fractions were increased from 28.2 to 51.13 and from 35.4 7. to 43.25 respectively after single pass. Easing on these results, it was concluded that the high intensity permanent magnetic separator could he used as a pre-concentrator f.7.1- hematitic-limonitic Karakuz iron ore.

Jan 1, 1991

By G. S. Scott

Safety problems in the mining and allied industries have led the Bureau of Mines to investigate over a period of years; the flammability (explosibility) of many types of combustible atmospheres principally at ordinary pressure; the results of these investigations have been made available as a bulletin. However, more recently, the demand for information on the flammability of gaseous mixtures at high and low pressures has increased greatly. In particular, the rapid development of high-altitude aviation has brought demands for information on the flammable (or explosive) characteristics of certain gases and liquids at low pressures. The present report gives the results of about 900 tests made to determine the flammability of the lighter paraffin hydrocarbons mixed with air and nitrogen at pressures of 400 200, 100 and 70 ram. Hg. The gases tested include natural gas, methane, ethane, propane normal butane and isobutane. The minimum pressures at which these gases are capable of propagating flame whorl individually mixed with air also were investigated.

Jan 1, 1952

By W. C. Holliman

Commercial production of synthetic rubber in the United States became a reality in 1931 when E. I. duPont de Nemours, Inc., announced the manufacture of Duprene, a synthetic rubber made by polymerizing r chloroprene. Duprene was later improved and reintroduced as neoprene. Since 1931 other synthetic rubbers and rubberlike materials have been announced and are now produced commercially or are in the pilot-plant stage in the United States. These include Thiokol, Buna S, Perbunan, Koroseal, Vistanex, Flamenol, Ameripol or Hycar, Chemigum, Butyl rubber, and Flexon. None of these is synthetic rubber in the strict chemical meaning of the word synthetic, as none is identical in chemical structure with natural rubber. However, all possess some of the physical properties of natural rubber, and in addition usually have some outstanding property not found in natural rubber that makes them superior for certain uses. Because of these superior qualitites, a considerable demand had arisen for synthetic rubbers before the present emer¬gency, although the price was several times that of natural rubber.

Jan 1, 1943

In 1970, the U. S. Bureau of Mines contracted with Theodore Barry and Associates, a management consulting firm, to perform a one-year industrial engineering study of working-face hazards in underground bituminous coal mines. The field data was accumulated from industrial engineering observations in fifty underground mines. Supporting data for the analysis was derived primarily from the Bureau's fatal accident reports for the years 1966 through 1970. This report, Industrial Engineering Study of Hazards Associated with Underground Coal Mine Production, consists of three main parts: 1) The Fatal Accident Reports Analysis, 2) The Industrial Engineering Analysis, and 3) Multiflow Process Charts and Standard Time Data. The Fatal Accident Reports Analysis (Volume I, Section II) is based upon individual USBM fatal accident reports for 1966-1970. These were read, coded and computerized in terms of 84 significant variables. Cross-tabulations of these variables have been used to identify major underground hazards and to quantify significant causal factors. A very strong relationship was found to exist between fatal accident occurrences and low task experience. This led to a recommendation for formalized training, certification and supervision programs for miners. Victim compliance with federal regulations, mine regulations and supervisor instructions was analyzed, indicating that supervisors provide the most crucial communication link to workers. Thus, every attempt should be made to ensure the competence of immediate supervisors in the industry. Analysis of roof fall variables revealed a fatal propensity on the part of the miners to work under unsupported roof or under support conditions that are marginal. The technical approach to the problem is to make it physically impossible for a miner to work under these conditions; the behavioral approach is to ensure adequate training and develop proper safety attitudes among the miners. The Fatal Accident Reports Analysis revealed a need for normalizing data to interpret the results more accurately.

Jan 1, 1971

By Mark Springett

The problems inherent in sampling low- grade deposits have long been recognized. As economic grades become lower with increasing metals prices and improvements in recovery technology then the previously difficult sampling problem has consequently become even more demanding. The breakdown of the sample process and error is illustrated by describing in the remainder of the paper some sampling practices that have been utilized on mining and exploration properties and by describing some problems that have been encountered, providing a series of cautionary tales to those involved in any aspect of mine or exploration sampling.

Jan 1, 1983

By V. F. Parry, John P. Goodman

"INTRODUCTION Review of Previous Work Many investigators and certain commercial interests have recognized that the briquetting process is a practical method to convert much of what is now considered undesirable fuel into a usable form of domestic fuel.The art of improving the form of solid fuels is ancient, as early records indicate that the Chinese employed crude hand briquetting of combustible materials long before coal was known in Europe and America.According to Franke, 4/ the earliest description of a briquetting proce¬dure employed in the Occident is contained in an English patent dated in 1773. Following this in rapid sequence, many methods and procedures wore developed in this country and in Europe. Stillman/ states that the first attempt to briquet coal in the United States was made by Loiseau 6/ at Fort Richmond Piers, Philadelphia, in 1872. The American briquetting processes outlined by Stillman comprise an imposing compilation of successes and partial and outright failures."

Jun 1, 1943

By Henry M. Howe

(Cleveland Meeting, October, 1912.) Manuscript received Aug. 20, 1912. PROFESSOR RUFF'S most illuminating paper' describing his extremely valuable investigation of the carbon-iron equilibrium diagram assigns definite temperatures to certain very important lines in the diagram, viz.: the eutectic temperature EB (Fig. 1) and the " near-eutectic " temperature E'B', but without indicating clearly enough the reasoning which warrants these assignments. These temperatures are of such primary importance that it is well to indicate the apparent gaps in the reasoning, in the hope that they may be filled in. In his diagram, Fig. 1, the point X and the lines B'D'HI represent the experimental results reached by Ruff and Goecke; 2 AB, AEB, and SE represent the liquidus, the solidus, and the solubility of the carbon in solid austenite in the absence of graphite according to Gutowsky,3 AB being also in accordance with Spiecker's data;4 ,S'E' the solubility of carbon in solid austenite in the presence of graphite according to Ruer and Iljin; 5 GS the line A3 after Goerens and Meyer;6 I and EBC the true eutectic line as inferred by Prof. Ruff from Gutowsky's data. B'D' is the carbon content found in cast-iron which had apparently saturated itself with carbon in the presence of the graphite of the enclosing graphite crucibles in which the determinations were made. From its straightness and its sharp inflection near 6.67 per cent. of carbon, the carbon content of * Professor of Metallurgy in Columbia University. 1 Metallurgie, vol. viii., pp. 456 to 464 and 497 to 508 (1911). 2 Idem, vol. viii., pp. 417 to 421 (1911). 3 Idem, vol. vi., pp. 731 to 743 (1909). 4 Idem, vol. vi., p. 524 (Wüst) (1909). 5 Idem, vol. viii., pp. 97 to 101 (1911). 6 Idem, vol. vii., pp. 307 to 312 (1910).

Nov 1, 1912

By Courtney A. Young

Cyanide is a fast-acting, highly toxic substance but, at the same time, is deemed essential for sustaining life as well 'as our standard of living. In this manuscript, the facts about cyanide are presented beginning with a brief history and definition and ending with a discussion on cyanide alternatives. Other topics include speciation, physical characteristics, toxicity, manufacturing, cyanogenics, cyanide cycle, separation, destruction, and markets including those outside the mining industry. Emphasis, of course, is placed on gold production by leaching and how it is influenced by ore type, mineral characteristics and economics as well as its advantages and disadvantages.

Jan 1, 1998

By Euclid P. Worden

INTRODUCTION Today, conventional raise boring is an accepted method of development in underground mines and on major construction projects. Over the years that this technique, and its associated machines and tools, have been under development, many articles have been written on the subject. To a great extent, these papers have reported operating results of one or more specific projects or have been generalized reviews of state-of-the-art machines and tools. This paper is intended as a review of the technique from an operational standpoint. Conventional raise boring, as opposed to the related variants box hole drilling and underground blast hole drilling, is a two step process consisting of the pilot hole drilling and reaming cycles. This author has covered the subject of pilot hole drilling in another article (1) . A good review of the current machines and equipment has been presented by Monroe (2) and an overall review of this entire technology was published by E&MJ (3) and Mining Journal, April, 1983 (4) . The subject of the reaming cycle is presented here together with some of the technical aspects of how the drilling tools are intended to be used. OPERATIONS Bit Change After the pilot bit has broken through at the end of the pilot hole cycle, a changeover takes place at both the machine and

Jan 1, 1985

Wildcat strikes in the Appalachian coal fields, primarily in West Virginia, have resulted in an estimated 4.5 million ton loss in coal production during July and through the first week in August. Since then, the strike intensified further, and on August 9, nearly all of West Virginia's 60,000 miners were off the job with another 10,000 miners on strike in eastern Kentucky. The Bureau of Mines estimates that West Virginia's coal output is currently (8/9) eight million tons below last year when the state produced 108 million tons. West Virginia, the Nation's second largest coal producer of coal behind Kentucky, has not failed to mine over 100 million tons a year since 1938. At the end of the second week in August, nearly all coal miners in West Virginia remained out. The strike is a protest against a cutback in union health and retirement benefits. An announcement June 23 about the United Mine Worker's health and retirement fund precipitated the strike, Fund directors said that because of inflation and production losses caused by earlier wildcat strikes and the severe winter, miners would have to pay the first $250 of hospital costs and 40 percent of doctor bills, up to $500 a year. Previously, the funds paid all hospital and doctor bills. According to the West Virginia Coal Association each day of the strike in West Virginia results in a loss of coal production of 500,000 tons, a loss of $3.8 million in miners wages and $1 million in contributions to the UMWA's health and retirement fund.

Jan 1, 1977

By Arthur Matzick

[1-1 1y IilJLJ,I~X" K pl.rw~~ts rt1s11l s I'I.IIIII 1.c1sc.n rcnlb cind d(~\,elopmrnt rnr- ried oitt by tllc* Illll.cv111 of .\li~~css (111 rlrc. ~ns-c-o~l~l)i~s~io~l oil-sllnlr rcdorting proc-rss. 15ffrc~t.s of t l\t. 1)roc.cBss ra~~irtl~lrs, resi~lts of ~ILS altrl stinle distribu- lion stutlic~s, lrsls 011 sl1nlr I)III-~ ic.lt* sixit. :rl~tl o1hi11- cl~*ti~ils of tks )erimrntnl pro- pSnrns arc* (lisc-~rss*tl. l-~trii)~~~ ~IIIS~~~ZII.~ ~II[O~IIIII(~III~ 111111 pr111) \ CI~S ~s~ocinted ill^ 11~r relurti~bg 1)1-o(.e1ss ,~lso 111.c. i~~c~l~~tl~.tl. "~'~I~III~I~I iolls of tl~r rrtorting test c1:itn I~II(~ elct~tilwl oil rc~~overv [I[I\v I~~~~~I-IIIIIS for tl~c* (i-, 25-, IIIIC~ 150-ton-per- clay rrtorts, tin1.1 tl~-n\vings reirlt illK 10 1.c1to~t i11g .rc.li~ip~llr.~~t nre given. ]

Jan 1, 1966

By Hugo Medina M.

Dado que la producción de carbón en el Perú es menor frente a la demanda de petróleo, es necesario plantear una planificación de su estudio y sus posibilidades de desarrollo minero. En este sentido, el presente texto revisa las áreas prospectivas de carbón, reservas y su potencial como mineral con la finalidad de incentivar la reconversión industrial y las inversiones del mineral. Asimismo, señala los factores que afectan el desarrollo minero como el potencial carbonífero no tangibilizado a reservas, superposición, acaparamiento, prioritización y áreas reducidas; asistencia tecnológica y técnica y financiamiento. Finalmente, entre las alternativas de solución está el plan exploratorio nacional, operación minera, apoyo técnico, política de precios, madera, costo del transporte, capacitación e investigación, centrales hidrometalúrgicos, plantas de lavado de carbón y una ley de promoción carbonífera.

Aug 26, 1988

By W. H. Oppelt

To provide a relatively structurally stable form of dried lump lignite, two North Dakota lignites from Mercer County were dried by the Fleissner process in an atmosphere of saturated steam at 200, 300, and 370 p.s.i.a. pressure, corresponding to steam temperatures of 382°, 417°, and 437° F., respectively. Two series of experiments were made at each test pressure with the individual lignites. In one series, the autoclave was preheated to the processing temperature before charging the lignite; in the other the lignite was charged into the autoclave at room temperature. In each case, heat losses were determined by blank tests of steam consumption over a similar operating cycle with the empty autoclave. The degree of moisture removal and net steam consumption were calculated from material balances. The amount of water removed as a liquid from the two North Dakota lignites during the heating and steaming periods was compared with results calculated from previously published data on drying Austrian lignite and Australian brown coal. These lignites, covering a wide geographical area, had original moisture contents ranging from 35 to 49 percent. The Austrian lignite and Australian brown coal are considered to be of Miocene Age, and the Dakota lignites belong to the Paleocene.

Jan 1, 1955

By Bo Forsman

METAFORA is a simulation model for determination and evaluation of strategies for operating loader/truck systems in mining. A specific version of METAFORA was used to evaluate the haulage system at Solider Mineral's Aitik mine in northern Sweden, one of the largest open pit mines in Europe with a production of about 11.5 Mtpy (about 34000 tpd) of copper are. A production level of 34065 tpd was estimated by simulation runs with METAFORA. Using METAFORA's dispatch rules (Fixed Dispatch, Maximize Trucks, and Maximize Loaders), the truck/shovel system in the Aitik mine was simulated for evaluating alternative dispatch control strategies. The Maximize Trucks rule gave about the same total production (ore + waste) as the Fixed Dispatch rule but a 9% higher ore production. The Maximize Loaders rule gave the lowest production. The marginal truck capacity decreases with increasing number of trucks serving the same loader due to increasing waiting times. In Aitik mine the low crusher capacity results in long dumping times. If the dumping time at the crusher could be halved, the ore production would increase by 14%. The paper indicates that the use of software like METAFORA can result in a substantial reduction of time, effort and cost in shovel/truck system design and evaluation.

Jan 1, 1992

By M. Ataee-pour, S. E. Jalali

So far, a large number of algorithms have been developed for the optimization of pit limits, most of which follow deterministic rules. In this paper, a new algorithm is introduced, which follows a probabilistic logic using the Markov chain process. The algorithm is implemented on a transition matrix that corresponds to the 2D conventional economic block model of the mining area. The probability of mining a block is proportional to the desirability it may provide. Applying this algorithm, the probability of mining each block is obtained, and finally, the optimum pit limits are defined as the pit, which provides the highest probability of mining. In order to validate the proposed model, a numerical example is given and the results of the algorithm are compared to those of a dynamic programming algorithm. A 2D analysis of the problem is discussed in this paper. Although dealing with 3D problems requires larger size matrices, the optimization method is the same and the algorithm does not need any smoothing.

Jan 1, 2006

The criterion for assessing the accuracy of coal reserve estimates proposed by Philip and Watson (1982) is criticized.Following Royle (1977), it is suggested that the global estimation variance found by geostatistical methods is more appropriate.This method is applied to coal data from the Bowen Basin. This shows that two factors (the inherent variability of the variable under study and the total number of drill holes) have more influence over the accuracy of the reserve estimate than the form of the drilling pattern. Comparisons between the relative errors for different sized regions demonstrate that the spacing between drill holes is of secondary importance. The dominant factor is the total number of holes.Comparisons between the relative errors show that some variables such as sulphur need a much denser sampling than the others to obtain the same level of precision.

Jan 1, 1983

By W. J. Kroll

This investigation was undertaken with the idea of studying a number of unconventional methods for making chromium to determine whether production cost could be lowered and to discuss some of the more recently described processes. These comprise carbon reduction of the oxide in vacuum, nitride dissociation, fusion electrolysis of the chloride, amalgam method, iodide dissociation, calcium reduction of the oxide, hydrogen reduction of the chloride, and reduction of this compound with zinc and with magnesium. Preference is given this latter method, which is shown in a flow sheet. Special attention is given purification of the chloride and separation of the vacuum at about 900° C. A reduction method for the elimination of traces of oxide contained in pure chromium by pure hydrogen obtained from the dissociation of zirconium hydride is described. The various methods are compared in a table in the appendix. Aluminothermic and silicothermic methods for the reduction of chromium oxide and the aqueous electrolysis have been disregarded in this investigation.

Jan 1, 1950

By K. E. Stanfield

This report presents the results of analytical studies made on two series of oil-shale samples from the Mahogany ledge of the Green River mine the character of the various grades of oil shale that are being mined and processed into shale oil and refined products at the Bureau of Mines Oil-Shale Demonstration Plant at Rifle, Colo. The analytical work was part of a synthetic liquid fuels program being conducted at the Petroleum and Oil-Shale Experiment Station, Laramie, Wyo. The 16 oil shales ranG6d in color from a gray brown ( or a sample that assayed 10.5 gallons of oil per ton to a very dark brown for a sample that assayed 75.0 gallons of oil per ton. In general, the samples were similar as to the types of organic and inorganic matter that they contained but varied widely in the amounts or these constituents. The principal constituents were calcite, dolomite, illite, and yellow organic material, while the minor constituents were quartz, feldspar and plagioclase feldspar, pyrite, marcasite, analcite, opal, black organic material, and small woody fragments. Some micro-fossils, spores and pollen grains were found also.

Jan 1, 1951

By William O. Vanderburg

[This circular is one of two papers on the tungsten industry in the United States end contains general information on the subject. The second paper which will be issued in the near future deals with the methods ailed costs of mining and milling tungsten ores. These two papers are abstracts from the general bulletin on tungsten which will be issued at some future time Modern civilization and progress depend largely on tools wherewith the forces of nature are brought under control and directed toward human comfort. These tools are made chiefly from metals derived from the earth's crust. During the present century powerful tools have been made available through the development of ferrous and. nonferrous alloys containing such elements as molybdenum, vanadium, titanium, tantalum, and tungsten, which were little used before 1900. One of the most important of these so-called rare elements is tungsten; its use ins alloys for high-speed cutting tool is partly responsible for the era of mass production. So widespread has the use of alloys become that the period may be termed an "Alloy Age".]

Jan 1, 1935