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By John C. Gagliardi, Walter K. Utt

The U.S. Bureau of Mines, in cooperation with Carter Mining Co., conducted vibration tests of four off-road vehicle seats. The purpose of the tests was to determine which seat provided the best vibration attenuation under laboratory conditions. Laboratory tests were constructed to simulate the mining vibration environment within the limitations of the test equipment. The acceleration test levels and corresponding response of the seats were low compared to IS0 2631's fatigue-decreased-proficiency time limits. Two of the seats employed mechanical suspensions and two seats employed air suspensions. The seats were tested using a 22,241-N (5,000-lbf) electrodynamic shaker. Mechanical suspension seats were tested with various preload-to-mass ratios (PMR's) and cushion densities. Air suspension seats were tested with various air pressure levels and seat cushion densities. Air suspension seats provided good vibration attenuation if pressurized greater than 552 kPa (80 psi). Mechanical suspension seats' attenuation performance decreased if the PMR exceeded 9.8. Seat cushions of lower density provided less vibration damping.

Jan 1, 1993

By Rudy J. Matetic

Over-exposure to noise remains a widespread and serious health hazard in the U.S. mining industries despite 25 years of regulation. Every day, 80% of the nation’s miners go to work in an environment where the time weighted average (TWA) noise level exceeds 85 dBA and more than 25% of the miners are exposed to a TWA noise level that exceeds 90 dBA, the permissible exposure limit (PEL). Additionally, MSHA coal noise sample data collected from 2000 to 2002 show that 65% of the equipment whose operators exceeded 100% noise dosage comprise only seven different types of machines; auger miners, bulldozers, continuous miners, front end loaders, roof bolters, shuttle cars (electric), and trucks. In addition, the MSHA data indicate that the roof bolter is third among all the equipment and second among equipment in underground coal whose operators exceed 100% dosage. A research program was implemented to: 1) determine, characterize and to measure sound power levels radiated by a roof bolting machine during differing drilling configurations (thrust, rotational speed, penetration rate, etc.) and utilizing differing types of drilling methods in high compressive strength rock media (>20,000 psi). The research approach characterized the sound power level results from laboratory testing and provided the mining industry with empirical data relative to utilizing differing noise control technologies (drilling configurations and types of drilling methods) in reducing sound power level emissions on a roof bolting machine; 2) distinguish and correlate the empirical data into one, statistically valid, equation, in which, provided the mining industry with a tool to predict overall sound power levels of a roof bolting machine given any type of drilling configuration and drilling method utilized in industry; 3) provided the mining industry with several approaches to predict or determine sound pressure levels in an underground coal mine utilizing laboratory test results from a roof bolting machine and 4) described a method for determining an operators’ noise dosage of a roof bolting machine utilizing predicted or determined sound pressure levels.

Jan 1, 2006

By R. V. Higgins

"INTRODUCTION When nations throughout the world are pitted against each other in a war in which petroleum plays a major role, scientist and engineers of the petroleum industry must give serious thought to ways and means for recover¬ing greater percentages of oil from natural reservoirs than in the past. Petroleum and its products are vital to highly mechanized modern warfare, and the victorious nations will be those whose armies, navies, and air forces are supplied with adequate fuel oil, gasoline, and lubricants until the war is won.Efficient recovery of oil from underground reservoirs depends on many interrelated techniques; evaluation of the producing performance of wells upon the basis of their productivity indexes is one such tool. Oil wells usually yield oil at a maximum rate when first ""brought in"". The rate of production begins to decline soon after the first oil is delivered to the tanks, and although part of the decline usually can be attributed to natural reduction of reservoir pressure as oil and as are withdrawn from the reservoir, a larger proportion frequently is caused by greater saturation of water and as in the producing formation about wells and clogging of the pores of the sands by silt, organic salt, and insoluble hydrocarbons. If the maximum quantity of oil is to be recovered from reservoir sands and rocks by wells, it is then imperative that the ability of wells to produce oil be watched closely and all adverse influences that affect the case with which oil can flow to wells be corrected if possible."

Sep 1, 1942

By M. F. Dunn

The objective of this work was to define jet fan performance in d variety of large cross-section underground mine applications and to develop guidelines for thin performance in open airways, dead headings, and multiple face areas. Measurements include common ventilation instruments, continuous recording remote electronic anemometers to measure air velocity, and sulfur hexaflouride tracer gas with chromatograph analysis to determine dilution rates and air recirculation. For open airways the following were determined: Large jet fans are leas efficient in smaller airways, but quite effective in larger open airways for achieving both uniformity end greater air entrainment, when inclined about 10° or elevated. For dead headings the following were determined: The jet fan must be placed against the rib of the heeding closest to the incoming airstream from the crosscut or recirculation will increase. The fan should be placed at the pillar corner to increase airflow. As the fan is moved closer inby, recirculation increases. Larger fans promote recirculation. Inclining fans about 12° improves airflow in large headings. For face areas the following were found: For panels having uncontrolled airflow, the fan should be placed in the incoming airflow, about one pillar inby, and directed diagonally across the faces. For panels having narrower rooms and controlled airflow, the fan should be placed alongside the panel side in the first room so as to direct or intersect the incoming airflow at the next entry or crosscut.

Jan 1, 1983

By Lowell Stroud

This report is the third in a series presenting equilibrium vapor-liquid data for helium-bearing natural gases. The first two reports contained phase data for the gases processed for helium at the Bureau of Mines Amarillo and Exell, Tex., helium plants. The present report offers similar information for a lower-helium-content (0.75 mole-percent) natural gas to be processed in the Department of the Interior's long-range helium-conservation program. A windowed-cell apparatus was used to obtain 218 samples of equilibrium vapor and liquid phases at 73 experimental conditions ranging in temperature from -100° F to -275° F and in pressure from 100 to 500 psi. From the phase data, the condensation characteristics, helium solubility, and equilibrium-vaporization-coefficient data for helium, nitrogen, and methane were evaluated. The effect of using a. preliminary hydrocarbon trap upon the subsequent vapor-liquid compositions is reported. A brief comment regarding the composition effect of passing the gas through a gasoline-removal unit is also included.

Jan 1, 1963

This chapter summarizes data on crude mineral production for the United States, its island possessions, and the Common- wealth of Puerto Rico. Included also are tables that show the principal mineral commodities exported from and imported into the United States and that compare world and U.S. mineral production. The detailed data from which these tables 'were derived are contained in the individual commodity chapters of volume I and in the State chapters of volume II of this edition of the Minerals Yearbook. Although crude mineral production may be measured at any of several stages of extraction and processing, the stage of measurement used in this chapter is what is normally termed "mine output." It usually refers to minerals or ores in the form in which they are first extracted from the ground, but customarily includes the production of auxiliary processing at or near the mines.

Jan 1, 1978

By I. Liebman

The Bureau of Mines conducted experiments on coal dust explosion suppression. The investigation took place on a beltway in the double-entry of the Bureau's Experimental Mine. Using conditions that simulate those in a working mine, the investigation showed that a coal dust explosion can be readily initiated in a conveyor belt entry. Also, the explosion can spread into adjacent entries through opened crosscuts (stopping destroyed by explosion) to propagate for long distances even though the adjacent entries are rock dusted in compliance with regulations. Passive water barriers (water-filled tubs) were found to be effective in suppressing explosions on a beltway; however, barrier efficiency was reduced by opened crosscuts. The study indicated that the beltway barrier should be the distributed type consisting of continuous rows of water-filled tubs covering long distances along the entry. A plan is outlined for the installation of a water barrier system in a working coal mine for the protection of a beltway.

Jan 1, 1981

By J. Kruttschnitt

This paper, describing the mining operations at Mount Isa Mines, is one of a series covering mining methods and costs being published by the United States Bureau of Mines. The Mount Isa property has been in operation since June 1931; during this period operations have changed from the production and treatment of carbonate ores to the mining, milling, and smelting of sulphide ores. This change involved revision of ore-extraction methods. Stoping methods have been designed to apply to parallel lodes ranging from 10 to over 100 feet in width and dipping at 50° to 60°. The hardness and strength of the ore and enclosing wall rocks, together with the strength and thickness of the country rock between lodes, have permitted the selection of a sublevel stoping method for mining the sulphide ores.

Jan 1, 1937

By Kenneth M. Maas

The Bureau of Mines inventoried all lands in Alaska to determine the availability of land for oil, gas, and coal leasing. Acreage for onshore oil, gas, and coal basins was digitized as was land ownership data. Regulatory policy concerning oil, gas, and coal leasing for various government agencies and private concerns was determined. Oil and gas basins underlie 79.4 million acres of Alaska's 378 million acre landbase. Federal agencies manage 44 million of these acres. The Bureau of Land Management is the lead agency for most oil and gas leasing on Federal lands. Lands have to be specifically opened for oil and gas leasing to be available. The state of Alaska manages 21.1 million acres underlain by these basins. More than 80 percent of this acreage is available for resource development. Native corporations manage the remaining 14.3 million acres of favorable oil and gas land. Coal basins underlie nearly 51 million acres of Alaska. Of this land, 26.4 million acres are under Federal jurisdiction. The state manages 17.3 million acres of land underlain by coal basins. Nearly 7.3 million acres of favorable coal lands are managed by Native corporations.

Jan 1, 1991

By Staff

"INTRODUCTION Sheet mica is one of the most important minerals in modern industry. It is used in many kinds of electrical devices, and up to the present time no satisfactory substitute for it has been developed. It is necessary for the successful operation of airplanes, ships, motor vehicles radios, and radar equipment. Early in World y r II, the Array and Navy, foreseeing the need for conserving the stock of sheet mica on hand and realizing that imports from India and Brazil were falling off, had strategic mica placed on the critical war-materials list.Examination and exploration by the Bureau of nines indicated that there probably are large undeveloped deposits of mica in Alabama, some of which are near the surface and others at greater depth. The quality of most of this mica is high.During World War I, Alabama mica producers added materially to domestic production, but after 1920 virtually all of the mines closed end miners scattered. During World War II, when imports from India, Madagascar,Brazil,,other foreign sources were reduced, sometime was required for Alabama to act into production. Operators began to produce small quantities in 1942.The Colonial Mica Corporation was created by the Government during 1942 to buy Mica for the Metals Reserve Company, end later Colonial was made sole buying accent for strategic mica. About this time the Bureau of Mines estab¬lished the graphite field laboratory at Ashland, Ala. Samples of mica wore submitted for examination, and advice was requested by property owners and mine operators. This continued during 1943, when as many as 400 visitors a month called at the Bureau's Ashland field laboratory."

Aug 1, 1946

Confidence in the strength of the U.S. economic recovery was considerably enhanced by third quarter 1983 profits, which showed a 12.8-percent increase over those in the second quarter (table I). Although the increases were not as great as between the first and second quarter of 1983, profits have grown each quarter since fourth quarter 1982. Both total profits and profits per unit of output increased, which the Bureau of Economic Analysis (BEA) attributes to decreases in labor and nonlabor costs (per unit of output), as well as to moderate price increases. [ ] A number of durable goods sectors, however, continue to show profit declines, especially electrical and non-electrical machinery. Profits in the primary metal industry are still negative, but the economic picture of this industry is improving. Between the second and third quarters of 1983, capacity utilization increased somewhat in primary metal manufacturing and stone and earth mineral mining but did not change at all in metal mining. Capacity utilization in metal materials increased from 47.4 percent in the fourth quarter of 1982 to 64.2 percent in the third quarter of 1983 (table 2).

Jan 1, 1983

By Russell E. Griffin

Dielectric constants and dissipation factors were measured by the Bureau of Mines for 13 simulated lunar rocks over the 20-to 100-megahertz frequency range by means of the susceptance-variation method. Measurements were made at room temperature and normal atmospheric pressure. Results are presented and some comparison is made with data reported by others. The rocks used include a broad range of physical characteristics and chemical compositions from the large areas of volcanism in Oregon and northern California, and two nonvolcanic types. These rocks make up a suite of rock standards used by a group of laboratories engaged in lunar research. The data presented will add to the basic scientific and engineering knowledge needed to utilize extra-terrestrial mineral resources for support of future space missions.

Jan 1, 1974

By M. I. Copeland

The investigation of the iron-gadolinium phase diagram is part of a project undertaken by the Bureau of Mines and sponsored by the Atomic Energy Commission to investigate rare-earth alloys. Data from the investigation of the iron-gadolinium phase diagram revealed a single eutectic system with very limited terminal solubility and three intermediate phases. The eutectic point occurs at about 85 percent gadolinium, and the eutectic isotherm, which occurs at 850° C., extends from the compound Fe2Gd to 99-plus percent gadolinium. Very little solubility of the solid phases in each other was observed. The three intermediate phases, FegGd, Fe3Gd, and FeaGd, melt incongruently at peritectic isotherms at 1,320°, 1,150°, and 1,080° C., respectively. The crystalline systems of the three phases were determined as follows: FegGd, hexagonal; Fe3Gd, hexagonal or rhombohedral; and FeaGd, face-centered cubic. No lowering or raising of the alpha-gamma iron transformation at 910° C., the gamma-delta iron transformation at 1,388° C., or the gadolinium transformation at 1,262° C. was observed. The principal methods used in determining the iron-gadolinium phase diagram were melting-point determinations, thermal analyses, metallographic examination, and X-ray diffraction analyses. Melting, heat treating, and thermal analyses were conducted in a vacuum or under a helium atmosphere because of the avidity with which oxygen combines with gadolinium at elevated temperatures. A few hardness values were determined, but they had no part in the derivation of the phase diagram. No other mechanical properties were determined.

Jan 1, 1962

By Edward L. Wilson

A general computer program is given for the linear elastic static analysis of complex structural systems. These elements have special advantages for the analysis of massive underground structures such as mine structures and above ground structures such as arch dams. New finite elements are developed which are useful in the analysis of two and three dimensional solids. Examples are given which illustrate the accuracy of the elements. A description on the use of the program and a FORTRAN IV listing are given in the Appendices.

Jan 1, 1971

The STATE MINERAL SUMMARIES publication provides estimated data and summaries of mineral activities at the State level for 1989. Most of the estimates are based on nine months data. These summaries have been prepared in cooperation with State geological surveys or related agencies. Individual State summaries are published separately as State Mineral Industry Surveys and copies can be obtained from the appropriate State Activities field office.

Jan 1, 1990

By Oliver Bowles

This paper is the third of a series of reports on asbestos prepared by the Bureau of Mines. The reports already issued contain general information, including descriptions of deposits throughout the world.3/ The present paper deals chiefly with milling and marketing. Many grades of asbestos are marketed, and an important phase of milling is the grading of fiber; these subjects therefore are related so intimately that contiguity in their treatment is fully justified. Although the Bureau of Mines is interested primarily in the mining and preparation of raw materials, the fabrication of asbestos products has attained such importance in the United States that brief reference to processes of manufacture is included. CLASSIFICATION OF FIBER Canadian asbestos fibers are divided into three main groups - crudes, mill fibers, and shorts. The term "crude" is applied to fiber of spinning grade measuring three eighths inch or longer, that is. hand-cobbed and not passed through a mill. Mill fibers are obtained by crushing and beating the fiber-bearing" rock, until the, asbestos is freed and, then removing the fiber from the rock by screening or air separation. Shorts are the lowest grades of mill products.

Jan 1, 1935

By Michael Rieber

In this study a generalized specification and costing model for high tonnage coal carrying conveyor belts of 3.5 to 100 miles is presented. These belt systems, in modular units or flights, of up to 9 miles in length can be considered in terms of gathering systems. The study format is sufficiently open to allow users to insert their own requirements and parameters. A specific case study is provided. Because conveyor belts are feasible almost anywhere, this study has not investigated any specific route or geographic location. Rather, it has concentrated on setting up an heuristic programming model for conveyor belt facility optimization and cost minimization. The analysis starts with the principle factors involved in the design of the system and their optimization for various cases. This is followed, in Section 5.4, with a factor by factor cost analysis based on industry data and the preceding optimization. The next step is the development of both facility and costing models suitable for computer analysis. Logic flow diagrams are presented at each major analytic step.

Jan 1, 1977

By R. D. Berkenkotter

Titanium and iron assays obtained from cores of three diamond-drill holes from the Cebolla Creek titaniferous iron deposit were evaluated by statistical techniques to obtain information concerning the mineral characteristics of the deposit and to make a preliminary determination of sampling requirements for the deposit. A range of sample volumes representing sizes from one-sixth NX core 2 feet in length through full NX core 10 feet in length were prepared by split-ting the NX core with a diamond saw and combining pulverized splits. Results indicate the existence of at least two statistical populations having different average grades of iron and titanium. Each has an assay frequency distribution that is not normal but is highly peaked (leptokurtic). Frequency distributions of assays from specific altered zones of the drill holes appear to be normally distributed. Increasing the cross-sectional area of the sample unit to change assay volume did not result in significant changes either in assay values or the resulting frequency distributions of assays. However, when assay volume is increased by increasing sample interval, the shape of the assay frequency distribution changes, and a normal distribution of assays is approached. Positive correlation exists between titanium and iron assays. The degree of correlation, although very significant, is too low to use for prediction purposes. Although the amount of data from three widely separated drill holes is not sufficient to establish an average grade for this large deposit, it indicates a range of expected assay values and provides some information for determining requirements of future sampling for evaluation purposes.

Jan 1, 1963

By W. J. Wenger

Colorado has been producing petroleum since 1863 but only recently has become a major oil State. The first well was drilled on Oil Creek near Florence, but out-put was relatively small until discovery and development of the Weber sandstone reservoir at Rangely. Oil was discovered in the Weber sandstone in 1933, and the reservoir was developed after 1940, bringing Colorado, in 1949, to 11th place among the 48 States as an oil producer. Colorado's output increased further because of the discovery and development of many fields in the Julesburg Basin since 1949 By 1954 Colorado was in ninth place and maintained that position through 1955.4/ Between 1946 and 1951, Colorado's oil production more than doubled, while the total United States production increased only 25 percent. It seems probable that production will continue to expand in Colorado for many years. This report presents analyses of 92 crude oils from 73 fields representing 90 percent of the production in 1955. Abridged analyses are listed for easy comparision, and complete analyses arc given in the appendix. Oil samples were collected for study from many different sources. Although many of the newer fields were not sampled, their oils probably are very similar to those from corresponding formations that were studied and tabulated.

Jan 1, 1957

This volume contains a series of papers describing research conducted by the Bureau of Mines to develop or improve equipment and systems that satisfy the communication requirements of miners doing work related to rail, belt-conveyor, trackless, and hoist haulage systems.

Jan 1, 1977