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By Barry W. Klein

The U.S. economy was considerably stronger in 1976 than in 1974 or 1975. Real gross national product (GNP) rose sharply in the first quarter of 1976 and then increased at a more moderate rate for the remainder of the year. The unemployment rate fell until June and then increased for moat of the remainder of the year, finishing at the same rate as it had started the year. The inflation rate continued to decline in 1976. Reasons for the relatively low rate (compared with those of 1974 and 1975) included small increases in food prices and only moderate increases in energy prices. Total U.S. output measured in terms of GNP increased 11.6% in 1976. Real GNP in 1972 constant dollars rose 6.2%. Inflation as measured by the implicit price deflator increased 5.1%. In real terms, gross private domestic investment for residential structures rose 22.7% in 1976 after declining 14.7%a in 1975; State and local Government expenditures increased 1.4% in 1976; and personal consumption expenditures for services rose 4.5%. The Federal Reserve Board (FRB) index of industrial production increased 10.2%.

Jan 1, 1978

By G. Richards Gwinn

"Mica" is a group name for a number of orthosilicates of aluminum with magnesium, ferrous iron, and the alkalies. They are characterized by their high reflection and a basal cleavage so well developed that they can be split into exceedingly thin laminae, which are more or less tough, elastic, and transparent, according to variety. Barium, manganese, lithium, chromium, titanium, boron, and ferric iron occur in same varieties. Eight distinct species of true mica, which appear in the following table, are recognized by mineralogists, but only the first five are of commercial importance. [Species General Formula Muscovite H2KA13 (SiO4)3 Phlogopite [H,K, (MgF)]) Mg3A1 (Si04)3 Biotite (H,K)2(Mg,Fe)2(Al)Fe)2 (S104)3 Lepidolite K,Li Al(OH,F)2 Al (5103)3 Ros coalite H8K(Mg,Fe) (A1,V)4 (S103)12 Paragonite H2NaAl3(S104)3 Zinnwaldite (K)Li)3 FeAl3 Si5016(OH,F)2 Lepidomelene HK2F3IIIFe6III A13 (S104)9]

Jan 1, 1951

By Neal M. Muir

The increasing demand for iron ores prompted the Bureau of Mines to investigate the sources of past production in Kentucky to determine whether reserves of usable ore still exist. Preliminary investigation showed that the holdings of the Rose Run Co. were the most promising, inasmuch as the deposit had not been exhausted by past mining and the property was near railroad facilities and but 80 miles from the blast furnaces at Ashland, Ky. The Bureau conducted a churn-drilling and sampling program to investigate the depth, thickness, and iron content of the ore beds so that they might be evaluated as a possible reserve of low-grade iron ores. The Rose Run area in Bath County, Ky., was explored by 74 churn-drill holes totaling 2,059.4 feet of drilling and 4 cuts and test pits. Fifty-seven drill holes and the four test pits penetrated the ore bed at an average depth of 22 feet. The bed had an average thickness of 2.54 feet. Analyses show that the calcium and magnesium carbonate content is more than sufficient to flux the silica and provides an excess that needs an admixture with other siliceous iron ores.

Jan 1, 1950

By Barry W. Klein

The performance of the U.S. economy in 1977 was similar to that in 1976 which, in turn, had been a considerable improvement over 1974-75. In 1977 real gross national product (GNP) showed a similar, but some-what slower, growth pattern compared with 1976. Real GNP increased sharply in the first quarter of the year followed by smaller increases for the remaining three quarters. With only two exceptions, the monthly unemployment rate declined or remained steady throughout 1977, falling to a low for the year in December. The inflation rate in 1977 was slightly higher than in 1976, but the rate still remained far below that of 1974-75. Total U.S. output as measured by GNP in current dollars rose 10.8% in 1977. Real GNP in constant 1972 dollars increased 4.9%, and inflation, as measured by the implicit price deflator, rose 5.6%. In real terms, gross private domestic investment for residential structures increased 19.3% in 1977, only slightly below the 22.9% rise in 1976; State and local government expenditures increased 1.1 % in 1977; and personal consumption expenditures for services rose 4.5%.

Jan 1, 1980

By A. J. Barry

[This is the third report related to fundamental retail roof-bolting research in underground mines (1, 2)3/ and describes an investigation of the torque-load relationship for 3/ -inch, expansion-type mine roof bolts. In a previous investigation the relationship between torque and bolt load was established for 1-inch slotted-type bolts (1). The two types of bolts differ in diameter and method of tightening and consequently may exhibit different torque-load behavior. The 1-inch bolt is tightened by turning the nut, the 3/4-inch bolt by rotating the beaded bolt itself. Experience indicates that roof bolts should be tightened to moors satisfactory anchorage sand to minimise nag of tie roof over the mine opening. The generally accepted means for determining the bolt load is to see a torque wrench to measure he torque applied in tightening the bolt and, from a predetermined relationship between torque and molt load, to, determine the corresponding bolt load. Because frictional effects may vary between one type of shell assembly or bolt and others, 7 types of expansion shell units and 3 types of 3/4-inch-diameter, mild steel bolts were tested.]

Jan 1, 1954

By D. H. Baker

This report, one of a series prepared by the Federal Bureau of Mines on the technology of titanium, describes the development of an electrorefining cell from which cathode deposits up to 30 inches long can be produced. Data show individual deposits to be homogeneous, comparable from top to bottom, and not varied in quantity or quality of metal over the entire length of the deposit. Investigations concerned with various diameter cathodes showed that cathode current efficiencies were materially reduced with cathodes less than 2 inches in diameter. Deposits produced on 1/2-inch-diameter cathodes showed cathode current efficiencies of 19 percent and on 1-inch cathodes, just over 22 percent, whereas deposits produced on 2- and 4-inch-diameter cathodes showed about 70-percent current efficiencies. A series of 20 deposits on 4-inch-diameter cathodes was produced under simulated production operation. The average current efficiency, based upon a divalent ion, was 72 percent with 11 1/2 pounds of metal produced per cycle of operation - 98.8 percent of which had a Brinell hardness number (B.h.n.) of 80 or less.

Jan 1, 1959

By H. D. Jacobs

A process for recovering both iron and manganese from four manganiferous ores of the Cuyuna Range was evaluated. It comprised: (1) Low-temperature gaseous reduction to convert nonmagnetic iron minerals to magnetite and manganic minerals to manganous oxide, (2) acid leaching to extract manganese, and (3) magnetic separation to reclaim iron from the leach residue. Iron recoveries from the magnetic products ranged from 70 percent to 90 percent; manganese recoveries from leach filtrates ranged from 75 percent to 95 percent. Two ores, from the Hillcrest and South Alstead properties, yielded magnetic products considered adequate for use as blast furnace feed. Although good yields of manganese were attained on all ores, appreciable iron accompanied the manganese into solution. Previous work, however, has shown that this iron can be precipitated almost quantitatively under autoclave oxygen pressure with very little loss of manganese.

Jan 1, 1970

By David A. Monaghan, Kenneth R. Maser, Adi R. Gurdar, D. Randolph Berry

7. Development of Acoustic Seal Checking System The acoustic approach was shown in Section 4 of this report to be the most promising concept for checking the seals. This section describes the development of this concept into a working hardware system to be used later in the field test program. This development effort included: (1) Theoretical analysis of the acoustic behavior in the mine using acoustic modeling- techniques. (2) Experimental determination of acoustic patterns in mine passages. (3) Refinement of the theoretical model. (4) Verification of final theoretical predictions in the quarter-scale laboratory model of a mine passage and seal. (5) Development of system specifications. (6) Development of the Acoustic Prototype Seal Checking System. 7. 1 Analysis of the Acoustic Seal Checker Concept The acoustic seal checker concept is based on a model which combines corridor acoustics and hole transmission theory. The idealized model for the mine sealing application is shown schematically in Figure 66. A high intensity acoustic- source is located in a corridor at a, position adjacent to the location to be sealed. The acoustic signal transmitted through the seal is monitored by a microphone pick-up placed on the opposite side.

Jan 1, 1973

By A. R. Taylor

Using solution calorimetry, the following heats of reaction were determined: (1) NaCN(c) + 1/Cu20(c) + 129H20(l) ? CuCN(c) + NaOH?128.5H2O ?H = -13.44±0.10 kcal/mole, (2) HCN(2) + NaOH?128.5H20 ? NaCN(c) + 129.5H20(l) ? = -2.52±0.02 kcal/mole. From these reactions, the heats of formation for CuCN(c) and HCN(2) were calculated to be 22.7±0.4 kcal/mole and 24.9±0.4 kcal/mole, respectively. Reaction 2 was made to check the consistency of literature values for heats of formation of HCN and NaCN. Adiabatic calorimetric measurements between 10° and 400° K showed the entropy and heat capacity of CuCN(c) to be 21.51±0.06 eu and 14.58±0.04 cal/mole deg, respectively, at 298° K. A broad anomaly in the heat capacity was found in the temperature range 285°-320° K. The heat of transition associated with this anomaly was less than 1 cal/mole, the sensitivity of the measurements.

Jan 1, 1971

By A. T. Coumbe

The first survey 3/ covering sales of liquefied petroleum gases was made in 1930 by the Bureau of Mines, which at the time was under the United States Department of Commerce. This original canvass covered national totals for 1922 through 1929, and most of the supply came from natural gasoline plants. The 1930 report showed approximate totals for butane and propane and for butane-propane mixtures and pentane grouped together. No attempt was made to breakdown the national sales by various uses until 1931, when the quantities for domestic or household consumption, gas manufacturing, and industrial requirements, including miscellaneous uses were indicated. As the market for these liquid petroleum gases expanded and as new uses came into importance, their respective quantities were shown separately in the annual survey. Sales for internal-combustion engine fuel and for raw material for chemical plants were first taken out of the industrial total in 1936. During World War II liquefied petroleum gases became important as feed stock diverted to synthetic rubber plants, and consequently the survey was broadened to cover this particular demand, beginning in 1944. Pentane was dropped from the survey after 1943, as, being liquid at atmospheric pressure, it is not considered as one of the liquefied petroleum gases and furthermore, the quantity reported made up less than 1 percent of the total sales. Thirteen producing companies reported to the Bureau in the first survey made in 1930, and in the 1952 canvass about 130 producers--petroleum refiners and natural gasoline companies--and about 1,300 dealers cooperated by filing schedules showing a breakdown of their sales. Their 1952 deliveries of approximately 4.5 billion gallons of liquefied petroleum gases were equivalent to about 3.4 billion gallons of gasoline or 3.1 billion gallons of distillate fuel oil.

Jan 1, 1954

By W. H. Eddy

The Bureau of Mines conducted laboratory batch-and small-scale continuous flotation processing tests on waste granite fines from Georgia, to determine the feasibility of recovering usable feldspar and quartz products by flotation. Two flotation methods were utilized for the removal of biotite and other iron-bearing minerals: One was in an acid-cationic circuit, and the other in an alkaline-anionic-cationic circuit. Feldspar was recovered using an acid-cationic method. To produce commercial-grade feldspar and quartz products it was necessary to employ either two sequential froth flotation circuits or one froth flotation circuit supplemented by wet-magnetic separation techniques to remove iron contaminants. Continuous flotation processing yielded a commercial-grade feldspar concentrate containing, in percent, 3.8 Na20, 5.4 K20, and 1.10 CaO, with recoveries of 77.8, 70.3, and 64.4, respectively. The feldspar tailing was high-quality glass sand containing 98.2 percent SiO2 and 0.024 percent Fe2O3. About 42 percent of the quartz was recovered at glass sand specifications. An effective separation of, potash feldspar from the bulk feldspar concentrate was achieved by batch flotation in a mineral separation cell.

Jan 1, 1974

By R. E. Peterson

The Bureau of Mines has undertaken beneficiation investigations on samples representing large tonnages of oxidized taconites in order to develop and evaluate applicable technologies for producing iron oxide concentrates from these materials. Information derived from the investigations can be used to expand the domestic iron raw-materials base and to establish the impact these taconite deposits may have on future national iron ore requirements. This report describes a process that includes reduction roasting, magnetic separation, and flotation, applied to a western Mesabi Range sample taken near Coleraine, Minn. The sample contained 36.8 pct iron and 46.0 pct silica, and represented 0.5 to 1 billion tons of crude material. An average of 962 lb/hr of oxidized taconite was roasted with 33 lb/hr of lignite in a 35-foot-long rotary kiln. Pulverized lignite and natural gas maintained the kiln operating temperature at 850° C. The roasted taconite was beneficiated by magnetic separation and cationic flotation in a 900-lb/hr pilot plant and yielded a product analyzing 68.1 pct iron and 4.6 pct silica, and containing 82.4 pct of the iron in the kiln feed.

Jan 1, 1981

By Charles E. Munroe

"It has been recently learned that certain foreign manufacturers are offering far importation into this country detonators at greatly reduced prices, some of these detonators being of such low grade (No.4), that their use would greatly increase the dangers in blasting.Detonators and electric detonators are used in initiating the explosion of the various high explosives that are now so extensively employed in a great variety of mining operations. Originally a large number of different grades (or ""strengths"") of detonators and electric detonators were marketed, the grade number indicating the weight of the charge of fulminating material contained in the copper case of the detonator. As late as 1914, a report of the Bureau of Mines (Bulletin 80, A primer an explosives for metal miners) shows that grades Nos. 3, 4, 5, 6, 7, and 8, containing from 0.54 to 2.00 grams each, were being offered for use. However, the writer bad observed as early as 1896, when the more insensitive types of explosives like nitro-substitution explosives began to be introduced for use in mining and other blasting operations, that use of a high-grade detonator was essential to insure certainty of discharge."

Mar 1, 1921

By Ludwig Schmidt

"IntroductionThe evaporation losses of gasoline in the refinery, can be reduced by proper methods of refinery construction and operation. When gasoline evaporates slowly, as when stored in tanks that are not vapor tight, the most volatile part evaporates first, so that the remaining liquid in not only less in volume, but is also lower in quality. In some,evaporation changes the characteristics of the product so much that it must be reblended to meet trade specifications.Refiners are, therefore, greatly interested in the various appliances and methods used to reduce these losses. In the past this interest has been directed largely to storage tanks, probably because evaporation from tanks is more readily observed than losses during other refinery operations. As tests by the Bureau of Mines on evaporation of gasoline from small storage tanks had indicated that the losses during the various stages of refining might be equal to or greater than those of standing storage, a survey was during the spring and early summer months of 1924 in a large number of refineries in the Mid-Continent field. In order to enable the refiner to select the results of those tests that conform most nearly to the conditions that he has to meet, tests were conducted at various stages of refining, as follows: (1) Randown tanks, (2) (agitators), (3) filling tank cars, (4) storage of refined products, and (3) miscellaneous handling. The results are presented in this paper."

Nov 1, 1925

By Mark Sheppard

[Considerable research work has been done on secondary crushing and coarse rued fine grinding, and the literature on the general subject of crushing contains many references to the work of investigators on the laws governing end the factors entering into the economical production of fine materials. However, little information on primary crushing in available. The literature deals mainly with problems and practices in ore dressing, end in this field the engineer or investigations is concerned largely with the production of fine material rind the unlocking of minerals in the ore. Under such conditions close control of screen sizes of primary-crusher products is a secondary consideration and has received very little attention. The growth and development of tae nonmetallic industries have drawn more attention to primary crushing. Many of these industries are interested is the production of a minimum amount of fines and a maximum amount of a coarse Product that meets certain definite size specifications, a condition entirely different from that in the field of ore dressing. Under such conditions tae proper type of primary-crushing equipment and a knowledge of the factors governing the operation of such equipment nest are essential to economical production of a satisfactory material.]

Jan 1, 1938

By A. G. Starliper

The report covers studies by the Bureau of Mines on the removal of metallic values in two waste products from the Longhorn tin smelter at Texas City, Tex. One product was a slag that contained tin, tungsten, iron, tantalum, and columbium. The other product was a spent acid solution that contained tin, tungsten, iron, lead, copper, zinc, and silver and that came from presmelting treatment of impure tin concentrates. Molten slag was treated with sulfur or sulfur compounds and with coke, calcium carbide, or gaseous reductants to form tin sulfide that volatilized from the charge and to reduce tungsten along with iron and silicon to form a carbon-bearing metallic layer. The metallic layer was treated by an oxidizing alkali roast and then was water-leached to extract the tungsten. The waste acid was used in other experiments to dissolve an iron-tin- tungsten alloy (hardhead) obtained by direct reduction of the slag. An insoluble fraction containing tungsten, silver, silicon, columbium, and tantalum was removed, and copper was cemented on metallic iron, Tin was recovered by cementation on zinc plates, and lead was precipitated by adding sulfate ion. Iron was precipitated by increasing the pH which left a solution containing principally zinc. Slabs of hardhead were electrolyzed in an electrolyte consisting of waste acid to plate out groups of metals at different pH?s. The time did not permit thorough exploration of this method of treatment.

Jan 1, 1962

By Andrew W. Berg

The Bureau of Mines Mineral Industry Location System (MILS) is part of the computerized Minerals Availability System (MAS), a comprehensive data base of known mineral deposits. MILS, the location subsystem of MAS, has become widely used by the minerals industry and organizations with land-use planning and land management responsibilities. Information on more than 135,000 mineral locations and processing plants in the United States is contained in the data base. This information includes the name, location, mineral commodity, type of operation, bibliography, and cross-references for each property or prospect. Computer-drawn map overlays at various scales showing clustered MILS locations and computer printouts keyed to those overlays are available for inspection and reproduction at the Bureau's Field Operations Centers at Juneau, Alaska, Denver, Colo., Pittsburgh, Pa., and Spokane, Wash.

Jan 1, 1979

By H. E. Sanford

"INTRODUCTION Of the occupations in and about coal mines, those of the haulage crews are among the most hazardous. Statistics indicate that the second largest number of fatalities about coal mines occurs during haulage operations and through the use or misuse of haulage equipment. Despite the fact that relatively few coal-mine employees are engaged continuously at haulage operations, approximately 20 percent of all coal-mine fatalities are attributable to haulage.Most of the hazards in haulage operations could be very greatly reduced if more serious consideration were given to the problems of the haulage crews and if sincere efforts were made to reduce the hazards. Underground haulage is similar in many respects to railroading; yet, railroading is now considered one of the safest of occupations a distinction that has been attained only by honest effort and whole-hearted cooperation on the part of all concerned. Underground haulage is also similar to street and highway operation and has in it some of the difficulties encountered in the reduction of traffic accidents the seriousness of which has not by any means been con¬trolled as yet, notwithstanding the fact that much effort has been expended through a multiplicity of laws, ordinance regulation, etc., as well as by thousands of enforcement agencies and officers.The men working on the locomotives are among the most important members of a coal-mine organization; without skilled haulage employees, the production of coal would be greatly retarded. Their jobs, particularly the job as brakeman, require physical endurance, agility, and mental and physical alertness; in thin coal beds, especially where the roof is not brushed and the coal is loaded into mine cars by hand, the need for these qualifications is greatly increased."

May 1, 1948

By Ronald D. Hill, Elmore C. Grim

The United States is richly endowed with mineral resources. However, mineral recovery by its very nature, involves a destructive process, Figures 1 and 2. In the past, mining practices were all too often conducted with the purpose of removing minerals by the simplest and cheapest method possible, without plans for the preservation of land, water, and air, and with too little consideration for the rights of others. A mining company is in business to make a profit, but every company, regardless of the nature of its business, has moral obligations to reduce its undesirable effects on the environment and to safeguard the rights of others. The problem of environmental degradation caused by surface mining is widespread and serious. Minerals in some form occur in each of the 50 States and several States are extensively mined. Data on the acreage disturbed in the United States, by commodity and State are presented in Table 1. Thirty-one States have laws regulating surface mining, (Table 2). Briefly reviewed in Appendix A-1 are the basic provisions of State laws governing surface mining. It can be seen that these laws vary considerably from State to State owing largely to the mining conditions within that State. Of the 24 coal-producing States, only three (Alaska, Arizona, and Utah) do not regulate strip mining. Even the states that are often cited as models of comprehensive regulations still have problems minimizing environmental damages. Uncontrolled surface mining presents a situation as critical to the well-being of the society as any it has ever faced. Many mining activities have imposed huge social costs on the public at large. These costs are long-range and are in the form of stream pollution, floods, landslides, loss of fish and wildlife habitats, unreclaimed land, erosion, and the impairment of natural beauty. In a 1965 Department of Interior study,(1)it was estimated that of the 25,000 miles (1+0,225 kilometers) of contour bench in Appalachia, approximately 1,700 miles (2735 kilometers) are affected by massive landslides. Additionally, 1+800 miles (7723 kilometers) of streams and 29,000 surface acres (11,716 hectares) of impoundments and reservoirs have been seriously affected by coal strip mining operations in the United States.

Jan 1, 1974

By Robert F. Randolph, Dana C. Reinke, Richard L. Unger

Purpose The NIOSH Hearing Loss Simulator is a software training and communication tool for promoting hearing loss prevention. It allows a user or trainer to demonstrate the effects of noise exposure on hearing without experiencing an actual noise-induced hearing loss. Estimates of the effects of different levels of noise exposure are based on the American National Standard Determination of Occupational Noise Exposure and Estimation of Noise-Induced Hearing Impairment, otherwise known as ANSI S3.44. This standard specifies the predicted hearing loss for noise-exposed populations of individuals based on risk factors that include gender, age, sound levels (in A-weighted decibels or dBA), and years of exposure. Algorithms specified in the standard were derived from empirical studies of populations that had no exposure to loud noise and other populations that had experienced various levels and durations of noise exposure. This manual explains the major objectives that can be addressed with the simulator and training scenarios that can be applied to real-life, real-worker scenarios. The majority of this guide explains the simulator's functions in detail. Simulator users are encouraged to read this manual while learning how to run the software. [ ] Training Objectives The main objective of the Hearing Loss Simulator is to increase motivation for taking effective hearing prevention action by demonstrating simulated noise-induced hearing losses. [The Simulator can also help teach the following facts about hearing loss. Hearing loss is affected by noise levels. Hearing loss worsens as the noise exposure duration increases. Hearing loss can become permanent. Hearing loss makes it harder to hear what others say. Most hearing loss is not caused by age. Speech is made up of both low and high pitch sounds. Hearing loss due to noise makes it harder to hear high pitch sounds. Hearing loss due to noise has less of an effect on hearing low pitch sounds.]

Jan 3, 2008