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During the second quarter of 1983, the economic recovery showed further strength abetted by the performances of consumer spending, residential investment, and the slowing down of inventory reductions. Real gross national product (GNP) increased from the first to second quarter at an annual rate of 9.2 percent, compared with 2.6 percent from the fourth quarter of 1982 to the first quarter of 1983 and an overall 1.9- percent decrease in 1982. Total industrial production increased 1.8 percent in July, and productivity as measured by output per man-hour increased 1.3 percent between 1982 and the first quarter of 1983 (table 1). Especially noteworthy .was the performance of real consumer durable goods expenditures, which increased at an annual rate of 32.0 percent from the first to the second quarter (about half of the increase consisted of automobile sales) and real consumer spending, which increased between these periods at an annual rate of 9.7 percent. Residential investment increased at an annual rate of 76.1 percent between the first and the second quarters,1/ and private housing starts by about 38,000 units in both March and May.

Jan 1, 1983

By Joseph M. Kurtak

The Bureau of Mines (Bureau) and the U.S. Geological Survey (USGS) conducted a 4-year (1979-1982) mineral assessment study of the Chugach National Forest (CNF), Ak, as part of the Roadless Area Review and Evaluation (RARE II) Program. The USGS remapped the geology and distribution of mineral resources. The Bureau investigated mines, prospects, and mineral occurrences. This report describes the results of Bureau work in the central 790,880 acres of the Forest. Copper, with by-product zinc, silver, and gold, has been the major metal produced from the study area as well as from the entire Chugach National Forest. The majority of the copper deposits are concentrated within basaltic rocks on Knight Island but the major producers are hosted by sedimentary rocks on Latouche Island. Approximately 182.6 million lb of copper, 1.5 million oz of silver, and an unknown but substantial amount of gold were produced during a 30 year period. Currently no mines in the area are producing. Inferred, indicated and measured reserves having mineral development potential total 4.6 million tons, with weighted average grades of 1.6% copper, 0.30 oz silver/ton, and 0.04 oz gold/ton.

Jan 1, 2011

By R. S. Dean

This report, the second of a series of annual reports of the Metallurgical Division to be released in this form covers the fiscal year July 1, 1935, to June 30, 1936. The technological work of the division is performed by sections. Thus, an efficient organization is provided to prosecute the various problems under investigation, and a logical system is set up for presenting the material contained in this report.

Jan 1, 1937

By H. S. Caldwell

The objective of this investigation by the Bureau of Mines was to develop and test for laboratory use a retort embodying many features required for practical commercial-scale applications of vacuum distillation of metals. A gas-fired vacuum retort was developed comprising a hollow, cylindrical graphite liner encased in a thin shell of stainless steel. The liner prevents the shell from collapsing under vacuum and protects it from corrosion by metal vapors and the molten metal charge. The vacuum-tight shell protects the liner from oxidation and flame erosion. The retort was used to distill zinc from dross and die-casting scrap. More than 99 percent of the zinc was recovered as a condensate containing 99.8 to 99.9 percent zinc. (Atmospheric distillation recovers 95 to 98 percent at a purity of 99.5 percent zinc.) Distillation rates of 50 pounds of zinc per hour were attained at a temperature of 65° C. with pressures ranging between 50 and 100 microns. Distillation at this low temperature is not practicable at atmospheric pressure. Also, the retort is suitable for distilling other volatile metals such as cadmium and magnesium.

Jan 1, 1961

By Ellsworth R. Spencer

A lightweight fiberglass feed leg for hand-held pneumatic percussion rock drills has been fabricated and tested by the Bureau of Mines. Its lighter weight facilitates easier handling of the rock drill apparatus, thereby reducing the potential for back injury to the driller and in- creasing drilling productivity. Current hand-held feed leg drills of the same class are 50 pct heavier than the Bureau-devised feed leg drill, which is comprised of a reduced-noise drill and the fiberglass feed leg. In-mine tests of the fiberglass leg showed that its performance and cost are comparable to those of standard aluminum feed legs.

Jan 1, 1985

By Jean J. Tancous

Chromium recovery from wet-blue offal trimmings and shavings can be done with substantial chemical cost gains by incineration at 600° C for 5 hr. Pretreating the offal with 0.5 M Na2C03 and air-drying prior to incineration produce Cr04 .By simply incinerating the offal, without pretreatment, an ash containing water insoluble Cr203 was produced. The Cr203 in the ash was purified by leaching with water. Chromium and crude protein were efficiently extracted from offal using 5 pct Na103, 5 pct H2S04, and 3 pct NaCl at 40° C. This procedure was effective but expensive. Satisfactory leather as to odor, appearance and shrinkage temperature was made from chromium recovered from wet-blue offal by incineration and by extraction. Chromium conservation is possible by recycling chromium liquors and by precipitating chromium from spent tanning liquors prior to combining these liquors with other tannery wastes. Combining chromium liquors with other wastes introduces contaminants that make chromium recovery and reuse difficult. Leaching sludges with H2SO4 produced marginal chemical cost gains. Leather tanned with these solutions had satisfactory shrinkage temperature but the sludge odors and iron contamination were objectionable.

Jan 1, 1979

By B. J. Moore

This publication contains 14,242 analyses of gas samples from oil and gas wells and natural gas pipelines in 40 States and 24 foreign countries. These gas samples were collected in the period 1917-85 as part of the Bureau of Mines survey for helium occurrences. The gas analyses contained herein were made by several methods over the period covered. Analytical work on samples collected early in the period was done on the Orsat apparatus. The one-cut apparatus and four-cut fractional distillation equipment were added later. A mass spectrometer was acquired in 1949 and used for all gas analyses made after that time. From 1917 to 1978, helium analyses were made on special helium analytical equipment designed and built by the Bureau of Mines Helium Operations Laboratory. In 1978, this apparatus was replaced in the quantitative helium analysis work by a gas chromatograph.

Jan 1, 1987

By J. W. Watkins

This report describes in detail methods of making corrosion tests and chemical analyses that have been used extensively and satisfactorily in a study of plants in which various surface, waters and brines are conditioned and used for water flooding, brine disposal, and reservoir-pressure maintenance in Kansas, Oklahoma, and North Texas. The tests and analyses described were designed and adapted for use in the field in determining the relative corrosive and plugging tendencies of waters from various sources conditioned by different methods. Although the described methods were developed and used in testing oil-field waters in the Midcontinent oil-producing area of the United States, these same methods should be equally applicable to testing oil-field or highly mineralized waters throughout the world. Many of the methods used have been discussed by the writer (1)2/ previously, and some of them have been used for similar work in other laboratories. Early in the development of the practice of the subsurface injection of brines for disposal and increasing the recovery of oil, it became evident that different methods of chemical treatment and conditioning equipment would have to be devised to sustain desired injection rates into water-input wells. These changes became necessary because the highly mineralized waters produced with petroleum from deep formations became chemically unstable when pumped to the surface, owing to loss of dissolved gases as pressure and temperature dropped to atmospheric and to the contact with atmospheric oxygen at the surface.

Jan 1, 1954

By E. K. Stanek

This volume describes software developed for programmable calculators that is useful in the analysis and design of mine electrical power systems. The programs are equally useful for any industrial or commercial power system. All programs are written for both the HP-97 and the TI-59 programmable calculators. Listings of both versions of the twelve programs that were developed appear in the report. The programs that were developed can be broken into two groups. The first group encompasses design-oriented programs. The second group encompasses analysis programs. For each program the following items are provided: a description of the program's capabilities, the solution technique used, instructions on how to use the program, a worked out example with data and results and, finally, listings of the programs for the HP-97 and TI-59 programmable calculators. Typical problems that can be attacked with these programs include ground bed design, selection of contactor size, fuse size, relay settings, instantaneous overcurrent trip settings for trailing cables, allowable cyclic cable loading, short circuit analyses, prediction of transient voltages and others.

Jan 1, 1979

By Charles D. Litton

This U.S. Bureau of Mines report details the results of a series of large-scale experiments where small coal fires were used to ignite the conveyor belt at air velocities ranging from 0.76 to 6.1 m/s. In the tests, electrical strip heaters imbedded within a pile of coal were used to heat the coal to a point of flaming ignition. The flaming coal subsequently ignited the conveyor belt located approximately 5 to 10 cm above the coal pile. During the tests, temperature, CO, and smoke levels were continuously measured in order to determine both alarm time and level as the fire intensity progressed through the stages of smoldering coal, flaming coal, and flaming coal plus flaming belt. Analysis of the data leads to certain conditions of air velocity and sensor alarm levels that are required for early detection of conveyor belt entry fires. Two nomographs are presented, which define sensor alarm levels and sensor spacings as a function of belt entry cross-sectional area and belt entry air velocity.

Jan 1, 2010

By Donald I. Kurth

The Bureau of Mines conducted experimental work on comminuting coal. The size distributions of coarse fragments and fine particles were obtained under different modes of energy application--drop, impact crushing, wedge impact, compression, and shear tests. Four levels of energy application were used in the impact crushing and wedge impact tests. Airborne dust and respirable air-borne dust distributions were obtained for the impact crushing and wedge impact tests. Analyses of nonairborne dust and coarse fragment-fine particle distributions were carried out on impact, wedge, compression, and shear tests. The experimental size data on nonairborne dust were fitted to normal, log-normal, power law, Weibull, log-Weibull, and exponential distribution functions. Both the nonairborne dust and the coarse fragment-fine particle size distributions are best described by Weibull distributions. For the impact crushing tests, mean product size was found to be inversely related to specific crushing energy. The particle counts in a given size range of airborne and nonairborne dust were found to increase with increased input energy and specific crushing energy. However, in another sense the particle distributions were independent of energy level; that is, the percent-ages in a given size range were approximately constant regardless of energy level. Respirable airborne dust was related to respirable-size nonairborne dust by a power law.

Jan 1, 1975

By R. S. Dean

[Methods s of preparing the manganese metal that has been used in chemical and metallurgical investigations have passed through a cycle. Most of the investigations made before the turn of the century, used Moissen's pyrophoric manganese.3/ This material was made by electrolysis into a mercury cathode and distillation in vacuo. The material was essentially pure, and investigations in which it was employed (with proper precautions against oxidation) led to accurate results on tie intrinsic behavior of metallic manganese.]

Jan 1, 1941

By C. T. Baroch

This report summarizes cost data accumulated during 15 months of sustained operation of the Bureau of Mines Boulder City (Nev.) titanium plant, which had a capacity of about 1,350 pounds of titanium sponge per day. The plant was constructed during the 1952 fiscal year with funds supplied by the Ordnance Corps, Department of the Army. Its original purpose was to engage in process development work as a continuing phase of the Bureau of Mines policy to seek improvements in producing titanium metal. In early 1953 the Defense Materials Procurement Agency contracted with the Bureau of Mines for producing approximately one-half million pounds of usable ductile titanium sponge. Production began in May 1953, ended in September 1954, and yielded 492,503 pounds of acceptable metal. Operating costs covering this period of operation, with suggested depreciation and administrative costs, are given, as well as outlines of building and equipment capital costs. In addition, miscellaneous economic considerations are discussed, including labor and operating-time schedules.

Jan 1, 1956

By E. A. Pelczarski

Initially, the objective of this contract was to develop a PWSCSR that could meet proposed criteria (that were different from 30 CFR 11(Title 30 of the Code of Federal Regulation part II) and that would be less than twice the size and weight of a filter self rescuer. This objective was met. Consequently, the original contract was extended to develop a PWSCSR that would meet existing CFR-30 criteria within the same size and weight constraints. This resulted in the development of a PWSCSR (the SR-100) that received NIOSH/MSHA approval (TC-239). This report presents a historical discussion of the design and development of the SR-100 as developed by CSE Corporation under Bureau of Mines contract number H0368013. The technical parameters and the test results of NIOSH/MSHA 30 CFR 11 certification are also presented.

Jan 1, 1990

By Leo J. Neill, O&apos

Abrasives are essential to the manufacture of munitions - airplanes, gas, shells, tanks, and in fact every product that involves metal forming or finishing. An indication of the importance of abrasives in the national defense and aid-to-Britain programs is the close peace-time correlation between demand for abrasives and automobile production, which in recent years has consumed more than 35 percent of the total output of abrasives. Unprecedented demands on the abrasives industry are forecast by the rapid expansion in airplane output, tie increased mechanization of all armed forces, and the consequent speeding up not only of the factories where finished munitions are made but also of the steel mills and other factories were additional large quantities of abrasives are needed for snagging or rough-grinding semifinished products before they can be used by the fabricators. A recent survey by the artificial abrasives manufacturers indicates that they can readily increase their output 75 percent compared with the previous peak of 1937 without building new plants. By overhauling production schedules, their maximum production possible could be increased to 182 percent of the 1937 output, and the nature of the industry is such that plant capacity could be increased rapidly if need therefor should arise. No figures on the estimated requirements for abrasives in 1941 or 1942 have as yet been compiled, but the industry feels that it can meet demands as they develop.

Jan 1, 1941

By A. A. Berk

In the course of a study of the formation of external deposits on tubes in water-tube boilers it became desirable to determine the sulfur dioxide (SO2) and sulfur trioxide (SO3) in the Due gases. Determinations made by the A.S.M.E. method for SO2 and SO3 in gaseous products of combustion did not give accurate results. It was found that minute quantities of copper, present in the flue gases from the coal in use, caused oxidation of sulfite in the absorption bottle and that the carbon dioxide (CO2) in the flue gases caused high values for SO2. The A.S.M.E. test procedure was revised to prevent oxidation of sulfite in the absorption bottle and to allow for the effect of CO2; subsequent analyses of flue gases produced reliable results. The revised procedure is described.

Jan 1, 1950

By L. L. Oden

The Bureau of Mines has studied a number of processes to remove Cu from molten steel scrap with the objective of determining if any of the laboratory methods studied warranted in depth research investigations. Experimental approaches included oxidizing Cu from steel containing other metals that form stable mixed oxides with Cu (AI, Cr, Fe, Mn, Mo, and V), injecting the same metals as oxides to simplify the mechanism of complex oxide formation, partitioning Cu into alkali or alkaline earth silicate slags or oxide-moderated sulfides, and coremoving Cu and S by injecting active compounds of Ca and Mg. The most promising tests, producing nearly 0.3 pct Cu in the slag, used Ar injection of K20-moderated Na2S-FeS below the surface of molten steel containing about 0.6 pct Cu and protected by a CaO-SiOz slag; however, in depth research investigations currently are not felt to be warranted.

Jan 1, 1987

By Robert C. Dyni

This U.S. Bureau of Mines (USBM) report summarizes a field demonstration of pneumatic backfilling technologies conducted at the abandoned Hillside Coal and Iron Slope in Vandling, P A. Researchers demonstrated two pneumatic backfilling technologies recently developed under the USBM's Abandoned Mine Reclamation Research Program, the Pneumatic Pipefeeder and the High-Efficiency Ejector. Both systems had previously been evaluated at the USBM's subsidence abatement investigation laboratory near Fairchance, P A. The objective of the demonstration was to fill 100% of the abandoned tunnel with backfill stone to prevent further subsidence. The Pneumatic Pipefeeder was used for 21 days, at a rate of 63 to 124 t/ d (69 to 136 st/d), to fill 88% of the tunnel. The High-Efficiency Ejector was used for 2 days, at a rate of 125 to 132 t/d (138 to 146 st/d) to fill the remaining 12% of the tunnel. The backfill placed by both systems was tightly compacted. The major problem encountered was wear on the polyethylene pipeline from the abrasion of the high-velocity backfill. The use of heavier steel pipe minimized the problem. A cost analysis for the entire project is given.

Jan 1, 2010

By Robert H. Peters

How can employees be stopped from engaging in unsafe work practices? It is often easier to prevent employees from performing unsafe acts through manipulations of the work environment than through various training or motivational programs. Therefore, it is important that accident prevention programs seek to identify the reasons for the unsafe behavior and to redesign tasks and the work environment (e.g., tools, equipment, physical surroundings) in order to remove employees from sources of harm and to prevent situations from arising that would prompt them to perform unsafe acts. Unfortunately, in the mining industry the work environment is often innately hazardous, rapidly changing, and difficult to predict, making it very difficult, perhaps impossible, to fully protect the employee by environmental manipulations. Therefore, it is important that effective methods be identified for influencing mine employees to work safely. Various strategies have been used to convince employees to avoid unsafe acts and/or adopt self protective behaviors. The intent of this article is to provide guidance to mine operators concerning the use of four techniques for influencing mine employees to work safely: (1) employee surveys, (2) incentives, (3) fear communications, and (4) disciplinary actions.

By Irving Hartmann

Modern mechanized mining with high-speed machines, multiple-entry systems, multiple blasting, high-velocity air currents, and rapid haulage has brought many economic benefits and has on the whole enhanced safety in the coal-mining industry. It has, however, also introduced some added hazards, the control of which requires concerted effort and ingenuity. Mechanized mining has greatly increased the production and dissemination of fine coal seam or in mine entries. Use of high-speed machines has increased the probability of formation of incendive sparks, which are produced by frictional contact between moving metals and certain mineral substances in the coal seam or in the adjoining rock strata. In gassy seams rapid extraction of coal has increased the rate of gas evolution. These facts have made more urgent the need of preventing the ignition of coal dust and the development of widespread mine explosions. The ignition hazard can be controlled best by eliminating all potential igniting sources and by careful attention to ventilation designed to prevent accumulation of gas capable of triggering a coal-dust explosion. Frictional spark ignition by mining machines and suggested safeguards are discussed in a recent publication. Extensive research and long experience have shown conclusively that the propagation of coal-dust flames can be arrested and the development of widespread explosions prevented by properly applied, generalized rock dusting.

Jan 1, 1956