Search Documents

By E. K. C. Williams, Nathaniel Arbiter

INTRODUCTION The surface processes involved in preparing ores for flotation and for operations depending on their flocculation/dispersion characteristics * vary widely in agitation dependence. Most of the reagents used for these purposes are added to grinding circuits, pump sumps, launders, or directly to flotation cells with the turbulent flow conditions usually adequate both for mixing reagents and for surface reactions without special conditioners. However, some reagent systems do require specific control of agitation intensities and reaction times, the more important of these being the following: 1. Activation of ZnS with CuSO4. With the usual conditions pH about 10, with collector added with the CuSO4, Cu 2+ is almost completely precipitated as basic compounds and as collector salt. As a result the levels of reagent in solution are extremely low which probably accounts for the need for separate conditioning. The agitation intensities are at about the 0.01 HP/ton level.** 2. Flocculation with natural or synthetic polymers. In this case the agitation problem is two-fold; first, to insure adequate initial mixing of the viscous stock solution of the

Jan 1, 1980

By James A. Todd

Use of AN-FO in underground operations has greatly reduced the cost of primary explosives. AN-FO is also less sensitive than conventional dynamites, and when properly used, is safer. Maximum safety in the use of AN-FO, however, requires an understanding of potential hazards from toxic fumes as well as static electricity developed in pneumatic loading. Safe limits and guides have been established to permit most operations to pneumatically load holes that are bottom primed with electric blasting caps, but the toxic fume hazard is less widely understood. During 1959-1960 Du Pont cooperated with the U.S. Bureau of Mines to study the toxic fumes produced by prilled ammonium nitrate-NO. 2 fuel oil mixtures. The conclusions from this work were that oxygen balanced AN-FO, when thoroughly mixed, well primed and well confined in dry holes, produces no greater amounts of toxic fumes than conventional dynamites rated Class I by the Institute of Makers of Explosives. The study also showed, however, that any deviation from these guides tends to increase significantly the quantity of toxic fumes produced. This work was reported by the Bureau of International Symposium on Mining Research at Rolla, Mo., in February 1961.'

Jan 4, 1963

By James L. Sweeney

The Project Independence Evaluation System (PIES) is a complex evaluation, forecasting, and analysis system which represents the U.S. energy production, conversion, transportation and consumption activities. The system includes various models: An econometrically estimated energy demand model, used to evaluate the final demand functions for energy commodities ; A collection of supply models, used to evaluate the cost curves or supply curves for domestic crude oil, natural gas, coal ; An integrating model used to describe energy conversion and transportation activities and to calculate prices which equate energy supply and demand in each market. PIES has been used to generate conditional forecasts of the 1980, 1985, and 1990 states of the energy system--forecasts conditional upon the world oil prices, the energy policy environment, and other uncertainties. Scenarios have been structured to separately examine conservation initiatives, domestic energy supply enhancements, an extensive electrification strategy, and oil and natural gas well -head price regulation. This paper presents the basic model, discusses its use for examining policy options, and describes several forecast results. The paper draws heavily upon work completed for the 1976 National Energy Outlook, published by the Federal Energy Administration.

Jan 1, 1977

By F. P. Schwarz, A. J. Erickson, S. M. Weber

The Mount Hope stockwork molybdenum deposit, Eureka County, Nevada, occurs In a small igneous cauldron complex 32 to 38 mybp in age. The deposit is characterized by alteration zones and mineralized shells symmetrically distributed around multiple intrusive. For samples from the 25000 meters of 1981-82 drilling, an appraisal of error in in-house sample preparation and in commercial assaying has been made. After splitting, drill core is crushed and reduced in volume (8: 1 at 10-mesh, 8: 1 at 70-mesh, 6: 1 at 200-mesh) to supply 25 grams of 200-mesh pulp for replicate analyses. A 0.5 g portion of the pulp 1s used for dissolution and atomic absorption analyses. Factors which initially generated unacceptable data variances have been minimized by planning, repeat analyses, introduction of standards, and routine monitoring. Assuming that error between replicate assays defines a Gaussian distribution with its average ideally equal to zero, precision (from preparation including core splitting and analysis of 8400 pairs of molybdenum samples) is on the order of ± 25%. The error distribution is not based. Accuracy is approximately 4% lower than absolute as determined by replicate assays of commercially prepared samples.

Jan 1, 1984

By Robert A. Haney, Stephen J. Gigliotti, James L. Banfield

A series of investigations were made by the Mine Safety and Health Administration to evaluate the performance of various face ventilation systems as part of a program to reduce frictional ignitions of methane and to develop face ventilation systems that could be used with the line brattice more than 10 feet from the face. Tests were conducted in a full-scale laboratory model of a face area. Systems tested included unassisted blowing and exhaust line brattice, diffuser fan and spray fan systems. Systems were evaluated at air quantities ranging from 1.4 to 7.0 m3/s (3,000 to 15,000 cfm), and brattice-to-face distances from 1.5 to 9 meters (5 to 30 feet.). Tests were designed so that systems could be evaluated for the location of the high-point methane concentration in the face area, methane dilution capacity, and face ventilation index. The methane dilution capacity is the total amount of methane a system can dilute to 1.0 volume-percent. The face ventilation index is the efficiency at which the available face air volume is being used.

Jan 1, 1982

By Reynold Q. Shotts

Chemical methods, based on the relative rates of oxidation of fusain, bright coal, and dull coal by nitric acid, have been devised to determine these coal components.1-4 Results obtained by oxidation methods for fusain have been checked against results obtained from microscopic methods on duplicate samples of the same coals, but to the author's knowledge this has not been done for bright and dull coal components. For this reason it is not certain that the two methods of analysis identify essentially the same chemical or physical units. It would be highly desirable to see results of the application of both methods to duplicate samples, but in the absence of any such data the author has attacked the problem indirectly. From the U. S. Bureau of Mines samples were obtained of three Alabama coals which the USBM had analyzed optically and reported on over the past 30 years. These samples were subjected to analyses by oxidation rate methods. Results of this work, and comparisons with the USBM analyses, have been published. This was the first indirect approach to the problem. The present report attempts a second indirect approach by way of internal validation.

Jun 1, 1955

By John F. Elliott, Martin Weinstein

The solubility of hydrogen in liquid Pure iron and in a number of liquid binary iron alloys has been measured in a Sieverts'-type apparatus. Sieverts' law is obeyed in all alloys studied UP to 1 atm Pressure H2. The alloying elements, Al, B, C, Co, Cu, Ge, P, S, and Sn, decrease the solubility while Cb, Cr, Mn, and Ni increase it. ALTHOUGH the importance of hydrogen in steel-making has long been recognized, there has been, until recently, very little information in the literature on the effect of alloying elements on the solubility of hydrogen in iron. There is also disagreement on the solubility of the gas in liquid pure iron. Because of the earlier work in this laboratory,1,2 with the Sieverts method to determine the solubility of nitrogen in liquid iron alloys, it was decided to apply the equipment and procedure to hydrogen. The literature that is pertinent to this study (Ftefs. 1 through 15) will be discussed later when the results of this investigation are considered rather than at this point to avoid repetition. The reaction under study is:

Jan 1, 1963

Carlisle: Jim Knapp, has been the good friend of hundreds-maybe thousands-of mining men in these western states in the last 40 or 50 years. Jim is going to talk about many of the mining camps of Nevada, where he has done plenty in the mining field during the last 50 years. Jim, for a starter, how did you happen to go to Nevada? Knapp: In the summer of 1902, two years after the discovery at Tonopah, the professor of mining at Stanford sent out myself and another student by the name of Joe Miller to make a report on the camp. We left San Francisco at 8 p.m., got to Reno the next morning, then took the train to Sodaville, arriving about 4:30 in the afternoon. The first man I met when I arrived at the Tonopah station was Tasker Oddie, a gentleman who later became the Govenor of the State and then a United States Senator. Before we got away from the stage station I also met S. H. Brady, the first mining engineer to put out his shingle in Tonopah. He afterwards became general manager of the West End Mining Co.

Jan 3, 1965

By John F. Shaw

The Denver Mining Research Center headquartered at Denver, Colo., is typical of the new research units recently activated as a result of increased emphasis by the U. S. Bureau of Mines on research concerned with metal and nonmetal (except mineral fuels) ore extraction. The Denver Center, together with the recently established Minneapolis Research Center and the Offices of Mining Research at Reno and Spokane, and the older, well-known Applied Physics Research Laboratory at College Park, Md., share the responsibility for the comprehensive mining research program. The Denver Center specializes in two areas of research: (1) The development of engineering principles and mathematical techniques applicable to exploration, development and operational problems in mining, and (2) the study of rock mechanics as applied to ground control. The first area presently includes three categories: research on methods of ore sampling, mine-systems analysis, and applications of statistics to problems of mineral exploration. The second area emphasizes research in two main categories: laboratory investigations designed to develop a fuller understanding of how rock be- haves under the loads imposed by mining, and field investigations to evaluate stress-strength relation- ships in full-scale, operating mines.

Jan 3, 1962

The regular activities of the Institute are financed mainly by income derived from members' dues, from advertising in MINING AND METALLURGY, and from the sale of publications to the public. In addition, collateral activities and special projects are financed each year by means of income from endowed funds controlled and administered by the Institute. In the aggregate, the amount of these endowments totals more than $637,000. An active effort is being made to increase the endowment funds of the Institute through a standing committee, of which Henry Krumb is Chairman, and of which the other members are: George D. Barron, Cleveland E. Dodge, John V. N. Dorr, Howard N. Eavenson, D. C. tackling, Harvey S. Mudd, Wallace E. Pratt, Milnor Roberts, and Wilfred Sykes. This committee believes that there exists a tremendous opportunity for the Institute to be of evergrowing service to the public, to the mineral industries, and to the 'profession. It welcomes suggestions as to names of men of means who are vitally interested in the mineral industries, and to whom the opportunity to make a contribution or bequest might appeal favorably if presented in the proper light.

Jan 1, 1946

By J. E. Papin

Morenci ores contain as an average about 0.015 pct molybdenite, MoS2. Incidental to the concentrating operations applied for the recovery of copper minerals, approximately two-thirds of the molybdenite is floated and appears in the final copper concentrate. The economic importance of molybdenum and the success achieved in its recovery in milling operations elsewhere encouraged research directed toward its recovery in marketable form. Several procedures are utilized to effect separation of molybdenite from copper and iron sulphides, but only two have wide application. In the better known of these two methods the molybdenite in the copper concentrate is depressed in a flotation operation using soluble starch as the depressant. The tailing from this treatment thus becomes a low-grade molybdenite concentrate which after thickening, filtering, and low temperature roasting is repulped with water and subjected to additional flotation steps for recovery of the molybdenite. A thio-phosphate collecting agent is employed in flotation of the copper minerals. Presumably the stability and lasting effects of that collector type necessitated the practice of depressing molybdenite followed by subsequent roasting to insure elimination of copper and iron sulphides from final molybdenite concentrate.

Jan 2, 1955

By H. Reginald Hardy, Gary L. Mowrey

Field studies were conducted over a longwall coal mining operation to investigate the feasibility of using microseismic techniques to detect and to locate any areas of instability in the vicinity of the longwall. An array of geophones buried at depths of 3 to 8 m from surface were positioned approximately 130 m above the active area of the longwall panel. A mobile microseismic monitoring facility amplified, filtered, and recorded the microseismic activity sensed by the geophones. Microseismic events were detected at depths of at least 130 m and at horizontal distances in excess of 250 m from the source. Most events, which resembled decaying sinusoidal transients, had frequencies of 10 to 100 Hz, and particle velocities of 1 to 8 pm/s. Source locations for the 150 largest events were computed using a least-square travel-time-difference method. Both isotropic and unique wave propagation velocity models were considered when evaluating the source locations. Most of the events were computed to be within ± 30 m vertically of the coal seam and ± 15 m horizontally of the longwall face, when the unique velocity model was employed.

Jan 1, 1980

By Edward Sampson, Allan B. Griggs

SURVEYING of many holes drilled by the U. S. Bureau of Mines in the Metaline district has shown surprising deviations. The holes start in the Ledbetter slate (Ordovician) and pass into the underlying gently dipping Metaline limestone (Cambrian) at varying depths, locally in excess of 1000 ft. All holes start vertical, but one had deflected as much as 35° at a depth of only 300 ft. One hole was found to be deflected 70° at a depth of 1000 ft. These deviations were not indicated to the drillers by any action of the rods or machines. Analysis of the survey data in the light of the observed geology indicates that the holes deviate most in the Ledbetter slate and scarcely at all in the Metaline limestone. The upper part of the "limestone"' in most holes is a massive rock strongly altered by hydrothermal action and essentially homogeneous. The slate is only obscurely bedded but has a cleavage, varying from slight to strong, which is unrelated to bedding. Drill holes have deflected to become nearly perpendicular to the cleavage. Several plans and cross sections are submitted showing the behavior of various holes.

Jan 1, 1946

The objective of the mission was basically to study the utilization of engineers and engineering technicians and their interrelationship in the Soviet Union. Beginning with their graduation from the engineering institutes and technicums, we hoped to learn how the graduates started out in industry, what their training on the job was, what sort of work they did, and how they worked themselves up within their profession. However, it turned out that, as our host was the Ministry of Higher and Secondary Education, most of our visits were to educational establishments. Our itinerary covered Moscow, Leningrad, Kharkov, Rostov, Baku, and Tashkent, with a side trip to Samarkand. In all, we visited 13 technical institutes, three technicums, and five industrial plants or enterprises, as they are called there. Our trip was one of only four weeks. Our observations were limited by the few cities and enterprises we were permitted to visit. Nevertheless, we did come back with some definite impressions and conclusions which we feel should be of interest to engineers, educators, and those concerned with the relative economic and technical power of the USSR and the U.S.

Jan 9, 1960

By Eldon C. Pattee

Variations of a very reliable geochemical field test for beryllium developed by Patten and Ward, have been adapted by the U.S. Bureau of Mines to facilitate rapid testing of reconnaissance samples and to aid in rapid examination of known occurrences. Although several qualitative tests for detecting beryllium have been described in the literature,1,2,3, the Patten-Ward4 morin geochemical field method has the advantages of being rapid and being quantitative for minute amounts of beryllium. In addition to the morin field method, Patten, in cooperation with Griffitts, have developed a contact- print method for determining beryllium in hand specimens.5 The semiquantitative method can be used for rapid screening of samples in exploration or reconnaissance work. The use of beads for fusing samples provides a more rapid test, but gives less accurate results than the method developed by Patten and Ward. The semiquantitative method, however, requires less equipment and combines three stock solutions into one reagent for easy application. Estimates of samples in the range from 3 to 1000 ppm varied from about 0.25 to 5 times the actual beryllium content.

Jan 5, 1965

By John V. Beall

On weekends things get pretty interesting out our way because the fleet is usually in. Our No. 2 son is now based at New London, which Isn't far from here, and he brings his friends home. No. 1 son is a re- cent Navy veteran, and he lives at home. It is just as well that the Pentagon can't hear what is said. This is all aside from the point except that last Friday evening, Dave Meinhard, a redheaded nukie (nuclear sub crewman) from Indiana, commented on our late arrival home In obvious need of a pick-me-up. "Just like my dad; but he has it rougher than you. We live in La Porte, Ind., and every day he drives 35 minutes to work at Bridgeman, Mich., and loses an hour on the time zone. It's really exhausting. You should see him." We feel very sympathetic. He should receive extra pay. However, extra pay benefits are hard to come by although the reverse comes relatively easy. For example Grass Valley, Calif., was such a nice place to live 25 years ago that they compensated for it by making an appropriate deduction for the s

Jan 1, 1971

Discussion of the paper of Frederic P. Dewey, presented at the Cleveland Meeting, October, 1912, and printed in Bulletin -No. 70, October, 1912, pp. 1075 to 1101. EDWARD KELLER, Perth Amboy, N. J. (communication to the Secretary *) :-Mr. Dewey, in his paper, offers a liberal addition of new data to those already to be found in the technical literature on this subject. However, now as before, the work issuing from the U. S. mints and assay-offices conveys the impression that systematic sampling in those institutions is more or less a secondary consideration, the chief attention being given to the principle of producing approximately homogeneous bars; recourse being taken to remelting or refining the bullion. This practice has been definitely rejected in the realm of copper-bullion sampling, for the reason that in such operations there are always unaccounted losses. Does not the same objection hold true for gold-bullions; although, perhaps,in a lesser degree ? Differences of opinion would seem justified on the following statements made by Mr. Dewey: 1. "Only two classes of alloys can form homogeneous bars-those that are solid solutions, and the eutectics."

Jan 3, 1913

Edward S. Simpson, Perth, Western Australia (communication to the Secretary): In 1896 the East Coolgardie gold-field was divided into three fields, viz. : Area, square miles. Officia1 Centers. (1) East Coolgardie,. . 634 Kalgoorlie. (2) Broad Arrow,. , 588 Kurawa. (3) Northeast Coolgardie,. 22,960 Kanowna. The whole of the area embraced by the eastern gold-fields is covered with late Tertiary sands and gravel, with occasional beds of clay shales. These mostly overlay granite which occasionally shows through in small round hills. At Coolgardie, Kalgoorlie and other mining centers, belts of diorite, serpentine and highly metamorphosed sedimentary rocks appear on the surface. The rainfall at Kalgoorlie in 1897 was 4.75 inches. That the climate has not always been so arid is evidenced by the recent discovery at Coolgardie (only twenty-five miles away) in the late Tertiary formations of a thick bed of brown coal, containing numerous fossil fern-leaves. As assayer and mineralogist to the Government of Western Australia I have had occasion to examine a large amount of the Kalgoorlie ores, both in Perth and at the mines at Boulder itself. The only tellurides I have been able to determine are

Jan 1, 1899

By G. G. Reed

G.G. Reed, Jr. The authors are to be commended for finding a material for pellets binding that we were unable to uncover during the investigations that led to US Patent No. 3,748,116, "Method for producing metallic iron powder from iron ore concentrate," July 24, 1973, by G.G. Reed, Jr., J.M. Karpinski, and S.V. Fox. This patent concerns a method of processing "super"-concentrates prepared from magnetite or "blue dust" into molding-grade metallic iron powder for use as a bulk commodity, in contrast to current methods which produce small batches that are custom-blended with additives and/or alloys to customer specifications. The one thing we had not found at that time was an organic binder (mineral-matter-free) that would allow induration to produce hardened pellets that would survive SL/RN Direct Reduction. Peridur appears to provide this missing link needed for large scale (200 t/a, or 220,460 stpy) single line plant capacity consistent with a low market price to ensure greatly broadened use of metallic iron powder. I hope that industry will adopt this combination so that metallic iron powder usage can fulfill its potential. ?

Jan 1, 1986

By Arthur E. Granger

IN the early days of the science, and until the recent past, geologists worked as individuals or in small groups. Prior to 1930 perhaps the largest single group under one administrative head was the Geologic Branch (now Division) of the U. S. Geological Survey, which employed at that time (including temporary help) 100 to 150 geologists. Today that same unit employs some 1500. In industry some companies employ as many as 100 geologists in a single department. These numbers obviously pose a need for administration. The basic qualifications for good administration are the same for any group of human beings, but the administration of geologists presents some special problems. Choosing Administrative Personnel: There are two kinds of personnel needs: 1) technical, which requires professional geologists who have proved their capabilities in the field, and 2) clerical and fiscal, which provide the necessary supporting or housekeeping functions. This discussion will be concerned only with the first category, except to point out the need for competent and understanding help from clerical and fiscal people and close relationship between top administration, technical or professional personnel, and the clerical and fiscal groups.

Jan 7, 1957