Search Documents

By B. C. Peterson

Calumet Division, Calumet & Hecla, Inc., whose operations are in Houghton and Keweenaw Counties, Mich., is a highly integrated and complex organization. This division operates mines, a railroad, a concentrating mill, a reverberatory smelter, and the auxiliary generating plants and shops to service these operations. In addition, it operates a sands reclamation plant, leaching plants, a foundry, and a machine shop that serves varied industries with castings and parts for many applications. Calumet & Hecla, Inc. has produced over 60 percent of all the copper that has been produced in Michigan since discovery of the ore in 1864, and in 1959 the company ranked eight among the country's producers with a production of 17,407 tons. To keep abreast of modern accounting systems developed elsewhere in industry and to combat increasing costs due to higher labor and supply costs, as well as increased costs due to deeper mines and lower grade ore, the company has developed a modern machine cost accounting system. This not only provides the usual bookkeeping and cost accounting facilities but offers accurate cost data for engineering evaluation of the mining operation. This system is credited with being instrumental in permitting continued operation of these high-cost mines in a period of increasing costs with no corresponding increase in the price of metal.

Jan 1, 1962

By J. B. Gayle

The merits of the various methods for dry-quenching coke have been the subject of numerous publications and almost equally numerous controversies for the past 40 years.5/ Most investigators have concluded that dry quenching is advantageous. Some have based their arguments on the improved physical properties of the resultant cokes. Others have claimed little or no improvement and have based their arguments on the economies acquired from the recovery and utilization of sensible heat. The extent to which the method of quenching influences the properties of the resultant cokes is of importance in connection with the operation of both commercial and experimental ovens. On the other hand, the recovery and utilization of sensible heat are economic problems related solely to commercial oven operation and- depend on the method of dry quenching used and the demand for a low intensity energy source. The scope of the present Bureau of Mines investigation has been limited to a comparative study of the properties of wet- and dry-quenched cokes produced from six coals and blends carbonized at flue temperatures of 2, 000° and 2,400° F. in the Tuscaloosa oven.

Jan 1, 1959

The purpose of this report is to describe the work accomplished by Mine Safety Appliances Company under Contract No. H0110845. This contract required the design, installation and testing of a permissible mine surveillance and communication system for the USBM Bruceton experimental mine facility. While much of the design and operational detail of this system can be drawn from the instruction manuals delivered with the equipment, some of it will be repeated here in Volume I for the sake of clarity, but the principal objective will be to report on overall system and subsystem performance and to suggest design alternatives for future consideration. Details of the overall system design will be found in Volume II of this report.

Jan 1, 1973

By Frederick H. Raab

A power-line proximity-warning (PLPW) system must have a high probability of detection (alarm activation at a specific distance), low probability of false alarm, and minimal set-up and maintenance. Tests of electric-field sensors have not demonstrated a dependable alarm distance. Alternative sensing methods such as microwave radar, optical radar, and sonar can meet the requirements by direct measurement of the range from the boom to the power line. Suitable microwave techniques include RF pulse, chirp FM/CW, and baseband pulse. Baseband-pulse radar has adequate range capability and does not require expensive microwave components. The radar cross section of a power-transmission cable is adequate for its detection optical-radar systems based upon LEDs and photodiodes are inexpensive, but can achieve only marginal performance in this application because of their limited modulation bandwidth. Since laser diodes and cryogenically cooled photosensors must be used to achieve the desired range resolution, the cost of an optical-radar system is greater than that of a microwave radar system. Sonar systems are feasible, but are not as precise and cost at least as much as baseband-pulse-radar systems. The performance of both optical-radar and sonar systems is degraded by dirt, necessitating the inclusion of a "windshield wiper.' Baseband radar appears well suited to the PLPW application. The cost of a baseband-pulse radar PLPW system is expected to be comparable to that of an electric-field PLPW system. Development and testing of an experimental model are therefore recommended.

Jan 1, 1982

By Edmond Chin

The land mass of the Asia and Pacific region comprises 11 million square miles or about 15% of the total Earth's land area. The bulk of the region is contained on the Asian continental land mass. Australia, the world's largest island or the world's smallest continent, alone is almost as large as the continental United States. The islands of New Zealand, New Guinea, Borneo, Sumatra, and Honshu are among the largest in the world. Collectively, they constitute a land area of 1.1 million square miles or an area about one-fourth the size of the United States. The countries in the Asia and Pacific region represent some of the most vibrant economies in the world. Japan is undisputed as one of the world's leaders in manufacturing and commerce. Hong Kong and Singapore are significant both as entrepôt and banking centers. The economies of Australia, the Republic of Korea, and Taiwan compare favorably to the level of the industrialized countries in western Europe. Indonesia, Malaysia, the Philippines, and Thailand have maintained strong economic growth during the past two decades. All these countries in the Asia and Pacific region collectively constitute a significant bloc as to raw materials production and consumption, as to manufacturing, and as to world trade.

Jan 1, 1992

By R. C. Ellman

Since successful industrial lignite-burning equipment was developed in 1925, the commercial use of lignite as a fuel for power plants has increased. It has proved an entirely satisfactory fuel for generating power and can be burned efficiently by various methods.4/ Equipment to fire pulverized lignite was installed and used successfully at the Trinidad Station of the Texas Power & Light Co. as early as 1926. The lignite was predried in steam-heated grid driers before pulverizing.5/ This method of firing was used later in the Comal Station of the San Antonio Public Service Commission.6/ Both stations, however, have since been converted to use other fuels. Units for pulverizing and drying lignite are relatively new in the lignite-consuming region of North Dakota. The air which sweeps the pulverizer and transports the pulverized product to the burners is preheated to dry the lignite during pulverization. The first unit was installed in 1948 in one of the two boiler units of the Crookston Station, Otter Tail Power Co., Crookston, Minn.7/ In 1951 the 30,000-kw. W. J. Neal Station, Central Power Electric Cooperative, Inc., Voltaire, N. Oak., was designed and constructed for firing pulverized lignite exclusively. It is the largest lignite-fired, power-generating station in North Dakota. The 44,000-kw. Lewis and Clark Station of the Montana-Dakota Utilities Co., Sidney, Mont., is fired by a similar pulverizing system. Operation of this plant was begun in October 1958. At Fergus Falls, Minn., the 53,500-kw. Hoot Lake Station of the Otter Tail Power Co., also using a pulverized lignite-firing system, began operating in September 1959.

Jan 1, 1961

By Richard A. Allwes

This Bureau of Mines report presents a procedure for the design of an arch canopy for use in rehabilitating a high-roof-fall area. Only dy-namic line loading of an unbackfilled arch canopy at its crown is considered, and the procedure does not account for an asymmetrical loading condition. The evaluation of whether an arch canopy is suitable for a particular installation depends on many variables, including in-mine conditions and the engineering properties of the structure. However, a general evaluation can be based on a comparison of the arch's maximum crown deflection and a prescribed allowable crown deflection. The design procedure is based on the concept that when an arch canopy is sub-jected to impact loading at its crown and deflects from its unloaded state to maximum crown deflection, the structure absorbs strain energy, both elastic and plastic. As a result, this strain energy can be calculated from a static load-displacement diagram for the structure. The significance of this design procedure is that it gives mine personnel an analytical tool to select an arch canopy to meet the dimensional and functional requirements of a mine entry and a prescribed allowable crown deflection.

Jan 1, 1987

By K. P. V. Lei

The Bureau of Mines investigated molten-salt electrorefining as a practical method for reclaiming vanadium from vanadium scrap. An electrolytic process utilizing a KC1-LiC1-VC12 electrolyte at 615° C was developed for producing ductile vanadium with a purity over 99.9 percent. The recovery of the vanadium in the cell feed ranged from 88 to 93 percent with a current efficiency from 83 to 95 percent.

Jan 1, 1967

By J. J. Forbes

The activities of the Bureau of Mines include the development and testing of self-contained oxygen breathing apparatus and other devices for respiratory protection, the development and tasting of devices for detecting dangerous or noxious mine atmospheres, and the training of men in the mineral industries in the use and care of this equipment to enable them to render effective service in mine rescue and recovery operations following mine fires and explosions, or under other conditions where irrespirable gases may be found in mines or mining plants. The first use of self-contained oxygen breathing apparatus for com- bating mine fires and explosions in the United States dates back about 30 years. Previous to that time, exploration for any distance ahead of fresh air was virtually impossible without great risk to life; moreover, the men called upon to render service at mine disasters were not well-versed in the properties and physiological effects of gases likely to be encountered. It was also impossible to work ahead of fresh air to restore ventilation, and if many stoppings were blown out by an explosion, air had to be introduced into whole areas or sections at once without knowledge of the conditions ahead; moving an explosive mixture of methane and air over live fire had to

Jan 1, 1938

To provide a means for accurately and reliably warning of impending roof falls or rock bursts and for evaluating support systems. The Approach: Development of a device for measuring rockbolt loads which is not affected by harsh environments nor by eccentric loading conditions and is easily adapted to various size rock bolts. How It Works: The Rock-Bolt Tension Load Cell, developed by the Bureau's Spokane (Wash.) Mining Research Center, is installed on a bolt and sandwiched between a conventional doughnut washer bearing plate and a torqueing nut (Fig. 1). As the bolt takes load, the bearing plate transmits the load axially to the cell through a ball and socket arrangement, compensating for uneven bearing surfaces. The cell body strains in proportion to the applied load: the strain is sensed by welded strain gages as change in electrical resistance. The resistance change is read through a Wheatstone Bridge and, through calibration, the applied load is determined.

Jan 1, 1974

By Arno C. Fieldner

From July 1, 1949, to July 1, 1950, the Bureau of Mines conducted the research and technologic work on coal and coal products that is summarized in this report. The research, described in this fifteenth of a series of resumes, is presented in more detail in publications (see footnote references) that appeared during the fiscal year, though in some cases research data are given that have not been published elsewhere. Results of research in the experimental coal mine, on explosives, and on gas and dust explosions will be found in Bureau of Mines Report of Investigations 4228, Annual Report of Research and Technologic Work on Explosives, Explosions, and Flames, Fiscal Year 1950. An over-all view of our coal, oil, end natural-gas reserves was presented, and the future possibilities for the, production of synthetic liquid fuels from coal were delineated.3/

Jan 1, 1951

By Donald F. Reed

In the Coastal Plain sedimentaries of northeastern Mississippi, high-alumina clays and kaolins, which are bauxitized locally to varying degrees, are found in many places along the contact between the Midway (Paleocene) and the Wilcox (Eocene) series. The trace of the contact extends from Tippah County, on the Tennessee border, south to Winston County, thence southeast to Lauderdale County, and into Alabama. Its length within Mississippi, disregarding sinuosities, is 185 miles (fig. 1). Commercial production of bauxite from the region has amounted to about 400 tons, shipped from one outcrop in Komper County. In December 1941 and January 1942, the Bureau of Mines and the Federal Geological Survey made a reconnaissance survey of the contact zone and selected the most promising areas for further study. In 1942, four areas in Benton, Union, and Pontotoc Counties were investigated by auger and rotary core drilling, and in 194, core drilling was done on five areas in Kemper, Noxubee, and Winston Counties. The present report records the work done by the. Bureau of Mines and the factual data obtained from the investigations of the nine areas in the two projects.

Jan 1, 1952

By David E. Van Dillen

The computer program described in this user's guide provides for the static, three-dimensional, linear and nonlinear analysis of structural and geological systems by the finite element method. The guide describes the capabilities and general features of the program and shows how input is prepared. A number of recent advances in finite element theory and computer technology are incorporated in the program. Nonlinear material properties are provided for, including isotropic, anisotropic, and time-dependent material properties, gravity loading, simulation of a sequence of excavation or construction, and a slip or joint element. The finite elements include beam, rod, axisymmetric and plane quadrilateral, hexahedron, thick shell, axisymmetric and plane joint, and a three-dimensional joint. The program also has an automatic mesh generator to minimize user input preparation for continuum finite element meshes.

Jan 1, 1981

By Keith L. Harris

Recent data indicate a marginal decline in overall growth in world economic output from 3.1% in 1985 to 2.9% in 1986 (table 1),2, 3 Many nations experienced slower economic growth because of the huge trade imbalances existing between the United [ ] States and Japan and the Federal Republic of Germany, the U.S. budget deficit, and the growing Third World debt. Some developing nations, however, experienced booming growth. Declining prices for energy and nonenergy commodities and the fall of the dollar against the currencies of major industrial countries benefited several developing countries--energy importers and exporters of manufactured goods with currencies tied to the U.S. dollar, which were able to expand markets in the industrialized nations. The drop in commodity prices increased demand in industrial countries and depressed it in developing countries. Lower demand in the developing countries contributed to a decline in the real net exports from industrial countries. As a result, output growth in industrial countries declined from 3.0% in 1985 to 2.4% in 1986, despite growing internal demand, Average output growth of developing countries increased from 3.296 to 3.596 during the same period, however, primarily because of the low prices of their products and the strength of demand in industrial countries for those products. Developed country output growth was extremely uneven, however. For example, the economic output of nonfuel exporters grew 5.4% in 1986, while that of fuel exporters dropped 0.7%.

Jan 1, 1987

By Donald L. Siebert

This profile study of the commercial secondary aluminum industry examines not only the elements that form the industry but also the technological contributions of each toward industrial growth. Concise descriptions of processing methods trace aluminum scrap from generating sources to marketable industrial and consumer goods. Economic and marketing appraisals are used to illustrate the impact that recent technology has had upon the secondary aluminum industry. Price, supply, demand, competition, and substitutes are selected as components of an economic model of the secondary industry and are used to illustrate the aggregate effects of technological changes. The final section is a conceptual look at the future in which sensitive economic indicators (such as die casting in the automotive and appliance industries) are examined as well as the problems of conserving mineral resources by retrieving secondary aluminum from solid waste.

Jan 1, 1970

By E. L. Rawlins

Systematic leakage surveys of natural-gas transmission lines not only aid in the conservation of gas, but can be made to show direct financial returns of large magnitude. 1. Such surveys reveal the actual leakage from the lines, and indicate repairs to be made in order, to eliminate unnecessary waste. 2. Tests on lines, after repairs are made, show the actual saving that has been accomplished. 3. Tests on newly constructed lines reveal the presence of leakage that should be eliminated before the lines are put into service.

Jan 1, 1926

By Max J. Spendlove

The secondary copper industry is comprised of numerous enterprises which collectively employ many of the recovery and refining processes now used in primary plants as well as many other processes that are unique to the industry. Effective methods are used for identifying and segregating all types of scrap according to widely accepted standard classifications. Segregated scrap and waste materials usually require some preliminary processing to remove both valuable and deleterious associated constituents. Smelting, melting, alloying, and pyrorefining are common methods used for producing secondary metal, but operating techniques usually differ from primary metal operations because of the difference in physical and chemical properties of the respective raw materials. Some copper scrap is converted to copper chemicals rather than to refined metals or alloys. Recovery efficiencies of all processes are reasonably high, and the quality of products meets rigid specifications.

Jan 1, 1961

By Phillip R. Moyle

Several deposits in the Sheep Hole/Cadiz Wilderness Study Area (WSA) have small identified or potential for undiscovered gold and silver resources. One prospect area is a potential target for molybdenum. Most base and precious metals and one uranium deposit in the study area are of the fissure-filling, contact metamorphic type associated with late stage fluids of the Cretaceous Cadiz Valley batholith. Some evidence suggests limited Tertiary and Quaternary mineralization. Mineral deposits are controlled by faults, shear zones, and joints which strike northwest and dip northeast or southwest. Although undefined, calcium, sodium, lithium, and strontium brines are inferred within the study area. Some potential for oil and gas and geothermal resources is indicated by the interest private industry has shown in the eastern part of the study area. INTRODUCTION The U.S. Bureau of lines and U.S. Geological Survey conducted a mineral survey of the Sheep Hole/Cadiz Wilderness Study Area (p1. 1) which encompasses approximately 205,000 acres (83,000 ha) in south-central San Bernardino County, California. The U.S. Bureau of Mines studied the mineral resources of mines, prospects and mineralized areas; geological, geochemical, and geophysical investigations were conducted by the U.S. Geological Survey.

Jan 1, 1982

By Eleanor Abshire

[THE INCREASING use of hafnium as a vital component in atomic power reactors has brought this metal into recent prominence. A literature survey was made and this bibliography was compiled to provide research and production groups with a ready source of reference to this important metal anti its compounds. This service is rendered by the Zirconium Information Center, which is sponsored by the Department of the Navy, Bureau of Ships, and the F .S. Department of the Interior, Bureau of Mines, tit the Bureau's Northwest Electrodevelopment Experiment Station, Albany, Oreg. The following reference sources have been reviewed for this compilation : Chemical Abstracts; Industrial Arts Index; Crerar Metals Abstracts; Nuclear Sciences Abstracts; Bureau of Mine; Information Cicular 7771, Bibliography of Zirconium; anal Bureau of Mint' Information Circular 7830, Bibliography of Zirconium, suppllement to Information Circular 7771.]

Jan 1, 1960

By Irving Hartmann, F. P. Christofel, John Nagy, E. B. McGibbeny

"INTRODUCTION When permissible explosives are used in c procedure recommended by the Bureau of Mines 5/ they are relatively safe, and, no mine explosions are known to have resulted from this type of blasting. However, unsafe blasting practices - the use of nonpermissible explosives or the improper use of permissible explosives - have caused many serious disasters. In fact, such unsafe practices constitute the third most important cause (exceeded only by electricity and the use of open lights and smoking) of coal-mine explosions in the United States. During 1929-1947, inclusive, 81 explosions, resulting in 475 fatalities, were ascribed to unsafe blasting. 6/The hazards of black powder, dynamite, and other nonpermissible explosives in coal mines have been recognized for many years, and attention has been called to this in numerous Bureau of Mines publications. Not only can these explosives ignite flammable gas-air mixtures readily, but they can also ignite coal dust, as has been illustrated repeatedly in tests and at educational public demonstrations at Bruceton and elsewhere. 7/Research in the Experimental coal mine 8/ of the Bureau of Mines at Bruceton, Pa., and unfortunate experience in commercial mines have proved beyond doubt that improper use of explosives that have passed the official permissibility tests can cause as explosions. In limited tests with a fey American permissibles at Bruceton, and in more, extensive tests with permitted explosives at the Polish experiment station, 9/ explosive charges were fired from steel cannon and freely suspended in coal-dust clouds. In these experiments coal dust was ignited under some conditions. However, it has never been definitely established whether permissible explosives can initiate coal-dust explosions when fired in a coal seam. It is true that a few mine explosions were strongly suspected to have resulted from ignition of coal dust by misuse of permissibles, but in each case other complicating factors introduced some doubt in the minds of the investigators. Full knowledge of the problem is important, because coal dust is present in most blasting operations in coal."

Apr 1, 1952