Search Documents

By David L. Bickel

The following instructions and descriptions are presented in two parts to assist an individual to make the borehole deformation gage transducer, and to assemble and test the three-component borehole deformation gage. This Bureau 8 of Mines three-component borehole deformation gage (4, 8, 11)2 fits in a 1-1/2-in-diameter borehole that is drilled in rock and then overcored to determine rock stress.

Jan 1, 1978

By Gene R. Reid

The contract objective is the development of an Automatic Fire Control System for Mobile Underground Metal Mining Equipment. The Phase I Report, which described the projected data handling plan, was published on July 24, 1975. The Phase II effort covered the period from July 24 through December 2 and accomplished the following objectives: ? Acquisition of data in accordance with the project data handling plan. Data were acquired through visits to twenty mine sites in ten states and Canada; visits to Bureau of Mines and MESA facilities; visits to mobile equipment manufacturers; and an extensive literature search. ? Analysis of accumulated data which provided the following specific types of design inputs: selection of the type of mobile underground equipment found to represent the greatest overall fire hazard; typical operating conditions for the vehicle; characteristics of the reported fire experiences; and performance, cost and maintenance factors affecting potential purchases of automatic fire control systems for underground mining equipment. ? Development of the AFCS design concept. Utilizing the data analysis results and considering the state-of-the-art of fire control system components, a recommended design concept was developed with particular emphasis placed on the need for a low cost and reliable system. Design trade-off studies are provided for the recommended system and for four alternate system concepts.

Jan 1, 1975

By Danny Riley, Brian Curry, Sandya Govindaraju, James Bain

Acute vibration causes vasoconstriction in naïve human subjects1. Vibration-induced decrease in skin perfusion has also been reported in the rat-tail vibration model 2. After vibration exposure, rat-tail arteries demonstrate vacuoles in smooth muscle cells, similar to that caused by pharmacological vasoconstrictors3. This study addressed the effects of different frequencies, durations and patterns of vibration on lumen size and vacuole formation using the rat-tail vibration model in male Sprague-Dawley rats (~300 g). Methods The different groups were: 4-hr continuous vibration at 30, 60, 120 and 800 Hz; continuous exposure durations of 5 min, 1 hr and 4 hr at 60 Hz; and 4-hr cumulative exposure of 60 Hz delivered intermittently in cycles of 10 min on and 5 min off. Acceleration was set at 49 m/s2 r.m.s. for all frequencies. Unanesthetized rats were restrained in cages on a nonvibrating platform with their tails placed on a vibrating stage driven by a B&K motor (4809). The sham control animals were also placed in the vibration apparatus but not vibrated. Room temperature was controlled at 25 ± 1°C. Ventral arteries from proximal tail segments 7 were immersion fixed in aldehydes, embedded in epon-araldite and sectioned (0.5 µm) for morphological analysis. Vascular lumen sizes were measured as the percent ratio of the lumen perimeter to internal elastic membrane length using Image J software (NIH). The number of vacuoles in the smooth muscle layer of each artery section was counted. Results Fig 1: Semithin sections of arteries. A. Sham control. B. 4-hr vibration 60 Hz. In vibrated arteries, the lumen decreases in size, and smooth muscle cells (SMC) exhibit vacuoles (arrow). Bar equals 40 µm for each panel. [ ]

Jan 6, 2006

By D. D. Bush

Based on the results of this study, the underhand cut and fill stoping method, with mass destressing, is an effective method for controlling rock bursts and falls of ground for deep mining in the Coeur d'Alene Mining District. The procedure can be utilized to pull highly stressed pillars by converting from conventional overhand stoping methods or used as a primary recovery system. During the demonstration, only one minor rock burst occurred, with no injuries. The system facilitates accurate placement of vertical boreholes for effective mass destressing. Each mining cut is filled with cemented sandfill overlying a timbered mat that forms the back for the succeeding cut. For this demonstration, a cemented fill was mixed on the surface and piped to the stone. Costs for pillar recovery by this method are comparable and are considered cost effective over conventionally timbered overhand mining as a pillar recovery method.

Jan 1, 1982

By John C. Machisak

THIS CHAPTER of the Minerals Yearbook (volume III) contains overall injury experience and employment data at bituminous-coal, lignite, and anthracite mines, coking plants, metal and nonmetal mines, metallurgical plants, and stone quarries in the United States for the calendar year 1956. Volume I of the Yearbook includes injury experiences and related employment data in the metal, nonmetal, and quarrying industries, and in the milling operations connected with the mining of those commodities. Volume II contains the injury and related employment experience of the coal mining, coking, and oil and gas industries. Reporting is voluntary on the surveys conducted by the Bureau of Mines to collect injury and employment data in the mineral industries, except in the coal-mining industry, where operators are required by Federal law to furnish the information requested.

Jan 1, 1958

By Martin D. Conyac

A 1984 Bureau of Mines investigation identified ho mineral resources in the Wilderness Study Area (WSA). However, four prospects in the WSA contain anomalous amounts of copper and silver minerals; one had traces of gold. Stratabound copper-silver occurrences appear to be prevalent. Quartz veins in the WSA locally contain trace gold, and one mine adjacent to the area produced some gold in the late 1800's. The WSA is underlain principally by Precambrian and early to middle Paleozoic quartzites, argillites, dolomites and limestones that have been complicated by faulting, generally tilted northeastward, and thrust southeastward over sequences of late Paleozoic sedimentary rocks. The stratabound copper-silver occurrences and gold-quartz veins are in Precambrian and Cambrian rocks in the western part of the WSA, as are similar deposits regionally. Sand and gravel, and limestone are abundant, but plentiful resources of these commodities are nearer established markets. In November 1983 there were 5 small groups of current claims oh the WSA boundary; none are patented claims. Probably less than 35 claims have been located within the WSA, mostly in the northwestern portion; hut over 100 claims have been located outside, near the northwestern boundary. Oil and gas leases nearly surround the boundary and 6 extend up to 1 mile into the study area. There has been no recorded mineral production from within the WSA. From 3 to 5 miles to the west, several lode nines in the Johnnie district have produced several million dollars worth of gold from quartz veins, and some silver and lead from galena-calcite veins. These veins generally trend northeasterly and dip northwesterly and probably do hot extend into the study area.

Jan 1, 1985

By Robert L. Lagace

This report describes the results of a system study of the factors influencing mine rescue attempts based on the use of electromagnetic VF rescue transmitters by trapped miners and helicopterborne search receivers by mine rescue personnel. The findings cover four main task areas. The first - mine emergency/disaster considerations - concentrates on characterizing the events and key parameters of mine fires and explosions related to trapped miner location and rescue activities. The parameters include critical time periods, affected areas, survival times, response and rescue times, and survival rates. The second - hardware considerations - concentrates on characterizing the relevant properties of VF rescue transmitters, oxygen-type self-rescuers, VF search receivers, helicopter performance, and signal detectability and sensor sweepwidths for helicopterborne sensors. The third - search theory probabilistic model develops a method to identify the most important regions to be searched, and to allocate helicopter-based search effort so as to maximize the number of miners detected in time to be rescued. The fourth - sensitivity analyses and application of the search model - exercises the search model on representative mine emergency/disaster scenarios to assess the impact and effectiveness of helicopter-based searches. Conclusions and recommendations are presented, together with a set of search scenario planning guidelines.

Jan 1, 1982

By Charles E. Whieldon

Data on the oilfields in Mahoning, Columbiana, Carroll, Jefferson, and Harrison Counties, Ohio, were collected from scattered sources and compiled to make the information readily available to operators who may be interested in conducting secondary-recovery operations in the area. General geology, oil production, oil-productive acreage, core data, reservoir calculations by townships, and miscellaneous data and reference material are presented.

Jan 1, 1965

By Terry R. Neumann

A mineral survey of the 23,760-acre Abert Rim Wilderness Study Area (OR-1-101) was conducted by the U.S. Bureau of Mines in 1986 at the request of the Bureau of land Management in order to evaluate its identified mineral resources. The study area is located in south-central Oregon, 26 mi north-northeast of Lakeview, OR. Federal and Lake County mining records indicate no mining claims, geothermal leases, or oil and gas leases within the study area as of January 1, 1987. No economic concentrations of minerals were found in the study area. The Wilderness Study Area is dominated by Abert Rim, a north-trending Basin and Range fault scarp that parallels the study area's western boundary. Exposed on the scarp is an approximately 2,000-ft-thick volcanic sequence consisting of Oligocene-Miocene basalts, tuffs, and tuffaceous sedimentary rocks.

Jan 1, 1987

By G. L. Gates

The waters used to waterflood the Wilmington oilfield were studied by the Bureau of Mines, in cooperation with the city of Long Beach, Calif. Increases in the pressure of the injection wells indicated that they were being plugged by materials suspended in the waters. This study was made to identify the suspended materials, determine their origin, and find methods of preventing their formation. The suspended oil-coated materials were iron sulfide, barium sulfate, calcium carbonate, clay, and sand (or silica). Results indicated that the sulfide, which was as high as 90 milligrams per liter, was the product of sulfate-reducing bacteria. The injection of ocean water increased the sulfate content of the waters in the petroleum reservoirs from 3 to 250 milligrams per liter, thereby furnishing sulfate for growth of the bacteria. The waters were supersaturated with barium sulfate. Laboratory tests showed that sulfide could be removed from the waters by adding iron at a cost of 1 to 2 mills per barrel. The solubility of iron sulfide and calcium orthophosphate in the injection waters was also determined.

Jan 1, 1975

By P. A. Rey

Water recycle is an important part of the coal preparation process. This study was directed toward: (1) a survey of current practice and an evaluation of both the solid and liquid components of blackwater, (2) an experimental study of blackwater flocculation, and (3) a fundamental analysis of the flocculation process. The solids contained in the blackwater discharge to the fine refuse thickener of a coal preparation plant were found to contain, on average, 56% coal and 44% mineral matter. The mineral matter was largely illitic clay, while the water phase contained relatively large amounts of S04 and Ca++. Detailed studies were made of both natural and synthetic flocculants and the influence of polymer type and pH on the settling rate, turbidity of the supernatent liquid and sludge volume of the settled solids. More tundamental studies were made that clearly indicate the need for controlled mixing of polymer into the suspension to be flocculated, and the need to evaluate, more closely, the structure of the flocs formed during the process. Research recommendations are given.

Jan 1, 1983

By David C. Benson

This Bureau of Mines report is an update of IC 8725 and comprises tables listing the name, location, and other pertinent data concerning certain fuel-related projects. The tables include information on projects involving the proposed or planned development of fuel resources, as well as the development of storage, transportation, and conversion facilities; the report covers the 26 States east of the Mississippi River. Of the total 535 projects for which information is provided, 429 concern coal mines and electric generating plants (including Energy Supply and Environmental Coordination Act (ESECA) coal conversion notices).

Jan 1, 1978

Mining men and State officials in their efforts to make mining safer are confronted from time to time with various complicated questions. In recent gears these questions have tended to increase with the use of mechanical appliances. Twenty-five years ago electricity had been used but little in mires; today there is practically no other means of transmitting power employed in American mines, except that in metal mines compressed air is used, chiefly for drilling and for operating small portable hoists. In coal mines there has been a great increase in mechanization, which tends to concentrate the work of production in small areas and to increase the local difficulties of ventilation; also, it has intensified locally the hazard from coal dust as well as firedamp in bituminous and subbituminous mines. The answers to the questions that arise are not always obvious, as is shown by the fact that even able, experienced men differ in their opinions of the best, way to overcome a particular mining hazard. The difficulty of .solving the problems is also demonstrated by the varying provisions in mine-safety rules, both in official regulations and in the rules of those mining companies that are endeavoring to do more than follow the letter of the law. Such differences of opinion as to the best way of meeting a difficult situation are often found within the same mining organization, and, similarly, varying opinions are held by different members of the Bureau of Mines staff.

Jan 1, 1937

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

By D. A. Stanley

The Bureau of Mines conducted laboratory-scale experiments to determine whether or not surface waters with a high organic content could be purified sufficiently to be used to replace the natural high-quality deep well water currently being used in the silica flotation step of phosphate rock beneficiation. Waters abundant in organic matter were collected from two central Florida streams, flocculated with a cationic polyethylenimine polymer, and processed in a sand filter. This treatment removed most of the organic materials from the water. Untreated surface water, treated surface water, and distilled water were used to compare the flotation response of the acid insolubles in an amine flotation circuit. Surface water treated with PEI-1000 was shown to be as effective as distilled water for the acid-insoluble-flotation step. Flocculation and filtration can therefore produce water suitable for amine flotation of quartz, which would permit substitution of surface water for deep well water.

Jan 1, 1981

By R. L. Balmer

This information circular, which describes the methods and costs of sinking a small underground shaft with steel supports at the Keystone mine of American Smelting and Refining Co., near Crested Butte, Colo., is one of a series being prepared by the Bureau of Mines on current shaft-sinking practices in various mining districts of the United States. Preparations for sinking a combined exploration, development, and production shaft from the lowest level of the Keystone mine began early in 1957. This vertical, three-compartment, 6-1/4-by 16-foot rectangular shaft was to be sunk in separate stages or lifts so as to correspond with the progress of an associated lateral exploration and development program. The first section of the shaft was collared and sunk to a depth of 209 feet between September 1957 and April 1958. Because of the depressed base-metal market, the mine was shut down as soon as the initial phase of the exploration and development program had been completed and before any deeper sinking could be attempted.

Jan 1, 1962

By Howard B. Hamilton

Laboratory performance of mercury filled current limiting devices (CLD) used for high speed switching of DC circuits (600 volts and below, up to 1000 amperes) using a system involving a parallel connected vacuum switch with CLD and an additional series connected vacuum switch was verified in USBM Contract #HO 357079. This report details analytical work and field experimental tests to predict and control voltage surges associated with the high switching speed associated with the switching system. It also details tests conducted to demonstrate the fault current limiting ability of the CLD. Problems associated with designing a fault current limiting system are discussed.

Jan 1, 1978

By H. A. Doerner

"The pure mineral chromite, FeO.Cr203, consists of ferrous and chromic oxides, chemically united in equal molecular proportions. Unfortunately, pure chromite as defined above appears to be a rare exception. In most chrome ores the mineral may be considered a combination of spinel, MgO.Al203, and chromite, with the latter predominating. The ratios between the four common constituents Fe0, Mg0, Cr203 and A203 vary greatly, and other minor constituents such as TiO2 and. Fe203 may also be present.In the mechanical concentration of chromite ores the maximum grade of concentrates that can be produced is thus limited by the composition of the chrome minerals present. Pure chromite contains 68 per cent Cr203, but the Cr203 content of the chrome minerals in commercial ores varies between 45 and 60 per cent and the average is not far from 55 per cent.Chromite is usually associated with serpentine. Other silicates, quartz, dolomite, magnetite, ilmenite and other iron Minerals are frequently present.The amenability of a chrome ore to concentration, depends upon the kind and amount of the various gangue minerals present and the amount .of crushing necessary to separate the chromite from them.A relatively small amount of chrome ore is concentrated by milling. In most cases the mine product is simply hand-sorted. Such chrome deposits as are known in the United. States can not be worked in this way on account of one or both of the following conditions: High cost of labor and finely disseminated impurities. There are, however, several deposits in the United States, Canada, and Alaska which may be able to compete with imported or by efficiently utilizing modern ore-dressing and milling methods."

Nov 1, 1930

This chapter presents an overview of fatal and nonfatal injuries reported to MSHA during 1986-1995. Reportable injuries follow the criteria for reporting specified in 30 CFR 50. These criteria are listed in appendix A. The data used for these analyses came from the MSHA accident, injury, and illness data closeout files for the years 1986-1995. The MSHA data are described in appendix A and methods used in data analysis in appendix B. There may be slight discrepancies between the figures presented here and other presentations of MSHA data for the following reasons: (1) injuries to nonemployees have been excluded from analysis; and (2) injuries identified by MSHA after the files were closed out are not included. Within the MSHA data, there are differences in reporting requirements for operators and contractors. Contractors are required to report only those injuries that occur during certain categories of work (described in appendix A). For this reason, data on injuries among employees of operators and contractors in the MSHA database should not be considered directly comparable. As discussed in the "Introduction," the MSHA data on fatal injuries differ from the CFOI data (chapter 1) because of varying definitions used for the mining industry. As compared to the CFOI data, MSHA data exclude injuries that occurred off of mine property and include injuries occurring at mills and processing plants on mine property. Tables 4-1 through 4-9 and figure 4-1 provide comparisons of injury frequencies and rates among the commodities. These comparisons are followed by sections 4A through 4E, which provide more detailed tables and figures for each commodity separately. The method used to calculate injury rates is described in appendix B. Since denominator data for occupations (lob titles) were available for 1986 only, estimates of rates by occupation for the entire 10 year period are based on extrapolation from 1986 data. For this reason, estimates of injury by occupation should be interpreted with caution. Fatal Injuries A total of 1,078 fatal on-the-job injuries were reported to MSHA during the 10-year period 1986- 1995. The average annual fatal injury rate for all commodities combined during this period was 30.9 per 100,000 full-time equivalent workers. Mine operators accounted for 908 (84%) of the fatalities and had an average annual fatal injury rate of 28.2 per 100,000. While mine contractors comprised only 16% (n = 170) of the total number of fatalities, their average annual fatal injury rate was 2.3 times higher than that of mine operators (65.0 per 100,000). Table 4-1 presents the number and rates of fatal injuries by commodity for operators and contractors. Contractors in metal, nonmetal, stone, and sand and gravel are grouped together, since MSHA data on employment were not available for rate calculations for these commodities separately. The highest average annual fatality rate for the period, 66.5 per 100,000, occurred among metal and nonmetallic mineral mining contractors, followed closely by coal contractors (63.1 per 100,000). Among mine operators, the highest average annual fatal injury rate was in coal (38.9 per 100,000); the lowest was in nonmetal (14.3 per 100,000). Table 4-2 shows the average annual fatal injury rate by type of operation for each commodity for mine operators only. Of commodities with underground mines, all except stone had higher fatality rates at underground than at surface operations of these mines. The highest fatality rate for any operation occurred in surface operations at underground stone mines (124.5 fatal injuries per 100,000 workers). Stone had the second highest fatality rate for underground operations at underground mines (77.9 per 100,000). The highest rate for underground operations at underground mines occurred in metal (87.6 per 100,000). Table 4-3 shows the number and rate of fatal injuries by U.S. Bureau of the Census occupational groups (described in appendix D) for the 10 occupation-commodity groups with the highest fatal injury rates. These data should be interpreted with caution because the denominator used in calculating the rates was based on an extrapolation from data for the year 1986 only, as described in appendix B. Extractive occupations are represented in this group for three commodities: coal, metal, and sand and gravel. Construction trades are included for coal, sand and gravel, and nonmetal. The distribution of fatal injuries by commodity and work activity for mine operators is presented in table 4-4. A description of the work activity categories is in appendix C. Overall, the leading work activity at the time of injury was using or operating tools and machinery (26.4%) followed by constructing, repairing, and cleaning (24.0%), vehicular operations (18.8%), and materials handling (12.6%). The distribution varied by commodity. The largest percentage of fatal injuries occurred while operating tools and machinery in both coal and stone; during vehicular operations in metal; and during constructing, repairing, and cleaning activities in nonmetal and sand and gravel. Table 4-5 shows the distribution of fatal injuries by commodity and MSHA accident classification for mine operators. A description of the MSHA accident classifications appears in appendix E. The largest proportion of injuries overall occurred during powered haulage (28.5%). The

Jan 5, 2000

By S. J. Rodgers

This report presents guidelines on methods of dust control in conventional coal mining operations. The normal mining cycle and equipment used in a room and pillar conventional section are described. Main ventilation, section ventilation and face ventilation are discussed in detail. Proper installation of line brattice, maintenance of proper air flows at the face and split ventilation are stressed. The effects of maintaining the end of the line brattice near the face are described. The advantages and disadvantages of blowing and exhausting face ventilation are presented. The use of water sprays on cutter bars and loading machines is described. The design of a nonclogging water spray system developed under a Bureau of Mines contract is presented. Other methods of reducing dust exposure are discussed and include alternative procedures for shot firing and administrative controls.

Jan 1, 1983