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By T. M. Barczak, S. C. Tadolini

Pumpable roof supports provide an alternative approach to secondary support in underground mining. Unlike all other supports that are either partially or fully prefabricated prior to being transported into the mine, the pumpable support is fabricated in place in the mine entry. This reduces the underground material handling efforts and thus the injuries historically associated with in-mine support construction. On-site fabrication also facilitates application of the support in areas that are inaccessible to transportation equipment such as scoops or rail cars, making it ideal for many bleeder applications. One of the main advantages of the pumpable support is that it fully bridges from the mine floor to the roof, thereby eliminating the requirement of “topping off” the support with wooden wedges or crib blocks that soften most other support responses. This report examines the development of modern pumpable roof support technology and provides a full description of the performance capabilities of each of the support products now on the market.

By R. Luhrman, E. Christ, B. Gores, S. Fischer, E. Johanning

North American railroad locomotive operators (engineers and conductors) are exposed to multi-axis vibration and shocks (1, 2). A recent epidemiological survey showed a prevalence of serious type of neck and lower back disorders nearly double that of a control group (3). Ergonomic working conditions are important co-factors in a vibration and shock exposure risk assessment (4, 5). The goal of this study is to illustrate typical work stations (cabs and seats) in US/Canadian type locomotives and assess shock related exposure risk by calculations of the new proposed shock risk indicators according to the new ISO 2631-5 (2004) (6). Methods Locomotive cab and seat inspections were conducted and operators’ activities were assessed by a trained observer. Field measurements (n=50) were obtained during normal revue service following generally accepted guidelines (ISO 2631 (1)). A sub-sample of n=20 locomotives were selected for the calculation of proposed shock indicators (ISO 2631 (5)). Results There has been little change in basic locomotive cab and seat design in the U.S.. Two locomotive cab design concepts are used: the Association of American Railroad (AAR) Control Stand and in newer series wide-body locomotives the “Control Consol” (Figures 1-2), with varying seating conditions, but frequently subjecting the operator to an awkward body posture in addition to the vibration and shock exposure. [ ]

Jan 6, 2006

By Gabriel Esterhuizen, Tom Goodwin, Scott Schilling, Anthony T. Iannacchione

The Roof Fall Risk Index (RFRI) is a new method introduced by the National Institute for Occupational Safety and Health (NIOSH) to assist the underground stone mine operator in 1) assessing defects the mine strata and 2) rating the relative roof fall risk these defects pose. The RFRI utilizes observational techniques to identify defects in the roof strata caused by local geologic, stress, and mining conditions. Assessment values for ten defined defect categories provides the foundation for estimating a range of risk conditions between 0 and 100 that define the potential for a roof fall. This paper examines how the defect information is collected using two field verification sites and proposes methods to analyze the RFRI data. These examples provide information on how well the method replicates observed conditions and how it might be applied in practice.

By Kenneth B. Higbie

METALLURGICAL ACTIVITY in 1963 was again dominated by the insatiate demands of research and development conducted in conjunction with the nation's defense and aerospace programs. An increasing effort was noticeable throughout the year, however, to apply to the commercial field many of the processes and techniques that have been developed by government-sponsored research. Particularly effective has been the Industrial Applications Program of the National Aeronautic and Space Agency through which many of the technological advancements made during the course of NASA research and development have been published and released to the public. POWDER TECHNOLOGY Powder metallurgy techniques for fabricating metals, not long ago declared outmoded because of improved casting and shaping methods, have since made an astonishing comeback. Traditionally mechanical pressing of powder shapes has been employed when melting and casting was difficult or impossible, when phase relationships needed to be sidestepped, or when machining costs could be avoided. Hence, it has long been used for producing relatively small special shapes of high-melting metals and alloys. Small iron parts produced with a punch and die have been common for many years, but powder metallurgy techniques are now applicable to a wide range of materials and items. Hard-to-handle materials including refractory metals and their alloys are now rolled, forged, or extruded from billets made by sintering isostatically compacted powders. The major element of the powder metallurgy industry still comprises iron shapes, however, and two-thirds of the annual 100,000 tons of powder metallurgy products are made of iron. The largest single user of powder-forming techniques is the automobile industry which currently consumes 14,000 to 16,000 tons of iron powder per year. A typical 1963 model auto contained more than 100 pressed powder parts (e.g., transmission gears, timing gears, sprockets, ball joint suspensions) totaling 5 to 7 pounds per car. Some of these powders are used in self-lubricating parts of porous copper and copper alloys containing as much as 20 volume-percent lubricating oil. The expanded use of powder techniques, coupled with

Jan 1, 1964

By Charles L. Kimbell

Although virtually every available indicator of world mineral industry activity demonstrated a gain in 1983 relative to the 2 very poor years of 1981 and 1982, the overall prospects for future years seemed far from bright. There were significant upturns in the quantity and value of mineral commodities produced, traded, and consumed in 1983, and many nonfuel mineral prices advanced, although the price advances in current dollars in most instances barely compensated for inflation. The pattern of investment in exploration and development of new mining ventures and new plant construction reflected virtual industry-wide concern that substantial upturns in demand for mineral commodities in the near future were unlikely, at least for most large volume products. The world oil glut continued despite cutbacks in production, and substantial stocks of many other mineral commodities mitigated against growth in total productive capacity, at least among market economy nations. In these countries, development activity at both mines and plants was confined largely to programs aimed at substituting new, more efficient installations for old, uneconomic or marginally economic plants. Among the centrally planned economy countries, the pattern was somewhat different on the whole, but even there, growth in total productive capacity was evidently somewhat restrained, although it seemed questionable whether the restraint was a function of intentional planning or simply an inability to accomplish planned programs on schedule. International political events, particularly the Iran-Iraq war and the unstable situation in the eastern Mediterranean countries (Lebanon, Israel, and Syria), continued to adversely affect mineral industry activities in those areas. Similarly, the internal and international conflicts in Central America negatively influenced mineral industry operations there. In Afghanistan, it appeared that there was some upturn in the very modest mineral industry operations, but industry activities there undoubtedly continued to be affected by confrontations between the Soviets and the local citizenry.

Jan 1, 1985

By J. M. Davidson, F. Fraas, J. E. Conley

"A number of Reports of Investigations pertaining to the extraction of potash from cal¬cined polyhalite have been made by various members of the Nonmetallic Minerals Experiment Station of the United States Bureau of Mines. These reports describe results obtained in the study of samples of polyhalite (2CaS04.K2S04.MgS04.2H20) from deposits of possible com¬mercial importance in Texas and New Mexico.3Storch and Clarke6 in their initial paper presenting data on the properties of Texas polyhalite demonstrated the desirability of calcination and subsequent hot extraction with water as a satisfactory pronedure for treatment of this potash-bearing salt. Their preliminary data have been supplemented by an additional report7 dealing more particularly with the leaching of raw and calcined polyhalite with water and with saturated sodium chloride solu¬tions. Further data8 have been reported as a result of experiments made in a small labora¬tory rotary-tube furnace under various calcination and extraction conditions. Hot water was used as the leaching solution in all of these tests.In addition to the data on calcination and extraction, two processes as proposed by Storch and Clarke have been published by Wroth,9 and more recently a number of very promising processes have been proposed by Storoh and Fragen.10"

Apr 1, 1932

By G. L. Oldright, F. S. Wartman

"In the process of smelting copper ores and secondaries in the reverberatory furnace to produce a copper matte and a slag low enough in copper content to be discarded on the dump, it is essential to the best functioning of the process that most of the iron in the material charged into the furnace be at the end in the form of sulphide in the matte or ferrous oxide in the slag. Ferric oxide and magnetite present in the charged material should be reduced to ferrous sulphide or oxide. Ferric oxide offers no difficulty in reduction, at least to the magnetite stage, because it reacts very readily with sulphides at quite low temperatures. Magnetite is less reactive and consequently more resistant to slagging, so that the furnace man must take advantage of all factors favoring its reduction in order to prevent accumulations in the furnace.In order to determine these factors more definitely, the Bureau of Mines in cooperation with the Department of Metallurgy, University of Arizona, has undertaken at the Southwest Experiment Station an investigation of the effect of various factors upon the rate of reduction of magnetite by ferrous sulphide. A previous paper's reported the nature of the reactions taking place and the effect of various physical factors when only pure sulphide and oxide were present. Since in the actual smelting operation, many other substances are also present, it seemed desirable to make a study of the effect of their presence upon the rate of reduction of magnetite by ferrous sulphide. Such a study has been made; the work done and the results obtained are described herewith.As will be shown later, it has been found that of the substances usually present in the smelting charge, silica and magnesia accelerate, whereas lime, alumina, and cuprous sulphide hinder the reduction of magnetite by ferrous sulphide.No report of a previous laboratory investigation of this subject has been found. Almost all furnace operators have made at one time or another at least qualitative ccmparisons of the effect of various changes in operating oonditions upon the behavior of magnetite in the furnace, but the conclusions derived from the experiments have never been published."

Mar 1, 1931

By E. C. Perkins

As part of a program for developing methods of using domestic titanium deposits, the Bureau of Mines investigated methods for chlorinating titanium slags prepared from titaniferous minerals by electrosmelting. Titaniferous slags were made from ilmenites in the following deposits: Valley County, Idaho; Trail Ridge, Fla.; Aiken, S. C.; and Maclntyre, N. Y.; titaniferous magnetite from Iron Mountain, Wyo., were also evaluated. The tests were made in two chlorinators, a 4-inch and a 36-inch unit. Preliminary testing was done in a 40-millimeter bench-type unit. Chlorine gas was contacted with a loose mixture of titaniferous slag and carbon at a high temperature to form titanium tetrachloride. The moving-bed system used in this work involved a downward movement of feed countercurrent to the chlorine flow, and residues continuously removed from the bottom of the reactor. The performance characteristics of these slags depended on their composition, which varied widely according to the geographic source of the ore. The results showed that all but two of the slags could be chlorinated as effectively as rutile, converting 70 to 80 percent of the titanium to the tetra-, chloride. The two slags that proved difficult were made from New York ilmenite and Wyoming titaniferous magnetite. These slags contained enough magnesium to cause clinkering, which necessitated that the bed be prematurely withdrawn before more than 70 percent of it could react. The iron content of the slags did not interfere with operating the chlorinators. The data from the 4-inch and the 36-inch units were in agreement on the relative amenability of the slags to chlorination.

Jan 1, 1962

By Gerald G. Johnson

The use of the Scanning Electron Microscope to characterize Coal Mine Dust has been possible because of two circumstances. First, the imaging process of the SEM allows multiple signals (secondary electrons, back scattered electrons, x-ray emission, etc.) to be viewed. Second, the use of a computer to analyze the signals and perform statistical tests on the results. The parameters described are size, shape, chemical composition, mass distributions, and particle thickness. Although the system is intended for particular systems, those of agglomerates (whether tile same or not) are handled by special aspects of the computer programs. The work on fibers is not completed at the time of this report. This work discusses the hardware (developed especially for this process) and software (both on an IBM 360/370 and a PDP 11/20). The latter system allows direct interaction between the operator of the SEM and computer for maximum information at the least time.

Jan 1, 1979

By George J. Conroy

To provide data as a basis for proposed acceptance standards and procedures covering permanent splices in trailing cables, the Bureau of Mines conducted testing programs on the flexure life in flat types W and G dc trailing cable splices and ground conductors. Primary reliance was placed on laboratory testing, although some cross comparisons were made at manufacturers' plants and mine operations Besides providing data for acceptance standards and procedures, results of the program should promote the general improvement of commercially available splice kits.

Jan 1, 1977

By Robert J. Timko, Charles D. Taylor, Edward D. Thimons, Tom Mal

A test system was developed for measuring airflow in the National Institute for Occupational Safety and Health (NIOSH) ventilation gallery using a three-axis ultrasonic anemometer. The gallery was used to simulate face airflow conditions in underground mines having a blowing curtain. Airflow data collected at multiple sampling locations between the face and the end of the curtain were used to draw airflow profiles for different curtain setback distances, intake flow quantities and entry widths. In addition, methane was released at the face, measured at the sampling locations, and displayed as methane distribution in the area between the curtain and the face. Entry geometry had a significant effect on airflow patterns, and the flow patterns affected the distribution of methane in the entry. Flow measured at and parallel to the face was a good predictor of methane dilution and removal within two feet of the face.

The U.S. Code of Federal Regulations (Title 30) requires that a methane monitor be placed on every mining machine to continuously observe and record methane levels at the face. The monitor must provide a warning whenever methane levels are 1.0 percent or higher. An effective monitoring system will indicate a methane concentration of 1.0 percent on the mining machine before methane levels at the mining face reach 5.0 percent. Where the methane monitor is located on the mining machine is one of the most important factors that determines how effectively face methane levels can be predicted. Any change in the sampling location will result in a change in measured methane concentration. To protect the methanometer, it is usually located on the cutting boom at least 1 to 1.8 m (3 to 6 ft) outby the front cutting bits. A face ventilation system using blowing tubing was simulated in a full-scale test facility. Methane released from the face area was monitored at multiple locations on a model mining machine as well as locations near the face. Based on the relationship between concentrations measured on the machine and at the face, criteria were developed for selecting the best machine locations for monitoring methane. Recommendations are given for revising methane action levels for alternative sampling locations.

By John D. Sullivan, Alfred P. Towne

"In copper percolation-leaching plants the ore is usually crushed to a maximum size of about three-eighths inch. Ordinarily an ore is crushed as finely as feasible since the rate of extraction of copper is increased with decreasing size of particles owing to the greater surface exposed and. the shorter path required for solutions to come into contact with the minerals to be dissolved. However, greater degree of crushing also increases the amount of fines. When ores are charged into leaching vats the coarse and fine material tend to segregate, resulting in channeling of solutions and leaving the areas where fines predominate only partly leached. An improvement in the method of charging the ore into vats that would minimize the deleterious effects of the segregations of fines would increase the percentage extraction of copper.The Inspiration Consolidated Copper Co.4 recently installed classifiers to remove the primary slimes from the ore, before charging it into the leaching vats. This necessitates a separate agitation treatment for the slimes.Recent publications5 of the bureau have shown the advantages of agglomeration followed by trickle leaching to extract copper from concentrator tailings. It was shown that when equal parts of ore crushed to about 1/4-inch size and concentrator tailings were agglomerated with approximately 10 per cent of moisture, either in the form of water or leaching solution, and the mass was charred into a leaching vat the ore could be treated successfully by open-drainage trickle leaching. Even with 30 or 35 per cent of minus 200-mesh material present the ore could be leached, if it was not flooded with solution.The results obtained in agglomerating ores and slimes suggested the possible advantages to be gained by wetting the crushed ore for standard percolation-leaching plants before charging it into the vats. Wetting the ore whould make the fine material and slime cohere to the larger pieces of ore thus tend to prevent segregation when the ore is charged into the vats. The bureau, at its southwest Experiment Station and in cooperation with the Department of Mining and University of Arizona, Tucson Ariz., therefore made a study to work: out A way in which slimes could be handled in percolation leaching. The study showed that the method of charging ore into the leaching vats governed the distribution the fines and consequently the rate extraction of copper. The results of the study reported in this paper."

Feb 1, 1931

By Fredrick L. Johnson

In deposits of the John Muir Wilderness, tungsten is the principal metallic element. Gold, silver, copper, and molybdenum could be recovered as by-products from most of the tungsten deposits. More than 1 million tons (0.9 million t) of tungsten resources are estimated to be along the fringes of metasedimentary roof pendants. Gold-silver deposits and silver-copper-lead-zinc deposits with small resources are found at several localities. The association of metal deposits with the intrusive-metasedimentary rock contacts and the widespread existence of these contacts, suggests additional resources exist. The area has no known potential for coal, oil, gas, or geothermal energy.

Jan 1, 1981

By S. J. Schatzel, W. P. Diamond

Longwall mining alters the fluid-flow-related reservoir properties of the rocks overlying and underlying an extracted panel due to fracturing and relaxation of the strata. These mining-related disturbances create new pressure depletion zones and new flow paths for gas migration and may cause unexpected or uncontrolled migration of gas into the underground workplace. One common technique to control methane emissions in longwall mines is to drill vertical gob gas vent holes into each longwall panel to capture the methane within the overlying fractured strata before it enters the work environment. Thus, it is important to optimize the well parameters, e.g., the borehole diameter, and the length and position of the slotted casing interval relative to the fractured gas-bearing zones. This paper presents the development and results of a comprehensive, "dynamic," three-dimensional reservoir model of a typical multipanel Pittsburgh coalbed longwall mine. The alteration of permeability fields in and above the panels as a result of the mining- induced disturbances has been estimated from mechanical modeling of the overlying rock mass. Model calibration was performed through history matching the gas production from gob gas ventholes in the study area. Results presented in this paper include a simulation of gas flow patterns from the gas-bearing zones in the overlying strata to the mine environment, as well as the influence of completion practices on optimizing gas production from gob gas ventholes.

By H. M. Lawrence, E. Roca

"INTRODUCTION Of the phosphate rock deposits of the United States that are being exploited actively at present, the land-pebble area in Florida is the largest producer. In recent years the land-pebble district, in Polk and Hillsborough Counties, has produced about 80 per cent of the raw phosphate rock that has supplied the requirements of the several national industries based on this essential commodity.In the land-pebble deposits sizes finer than 16 to 22 mesh are below the commercial limit in phosphate content, and washing-plant practice has been directed to the recovery of the coarser material. Recently, more extensive control of the washery plan has resulted in the saving of additional amounts of phosphate, the loss of which had been considered unavoidable. However, strict requirements of the trade regarding the lowest acceptable grade of phosphate rock prevent the inclusion of more than a very small proportion of the low-grade phosphatic sands with the washery output of phosphate roe:. Further advances in practice resulting in larger recoveries of phosphate can only be effected by the application of processes that are based on other principles than merely a difference of particle size. Research is be conducted actively along these lines by the industry and by cooperating agencies.Flotation has been studied for several years by the International Agricultural Corporation and its allied company, the Phosphate Recovery Corporation. J. T. Burrows, vice-president of the International Agricultural Corporation, in a letter dated July 10, 1929, states:"

Aug 1, 1931

By H. H. Schrenk, W. P. Yant, F. A. Patty

"INTRODUCTION In accordance with the outline of investigation described in a previous report 5 of the Bureau of Mines dealing with the use of acrolein for detecting leakage of methyl chloride from unit--type refrigerating systems, the work has been extended to include an investigation of its use in a multiple system, This report gives the results of analysis of samples of the gas from representative units of a multiple system charged with methyl chloride containing approximately 0.9 per cent acrolein by volume, The results furnish a basis for estimating the Warning that would be given in event of leakage. The properties and warning intensity of acrolein have been described in a previous report. 5 ACKNOWLEDGMENTSThis investigation was made at the combined request-of Several Inc., Manufacturers of refrigerating, appliances, and the Roeasler Hasslacher Chemical Co., manufacturers of methyl chloride. Acknowledgment is given to R. M. Major, ,chief chemist of the former firm for arranging the experimental site and equipment; to Arthur O. Haseeneall, owner of the apartment building where the investigation was conducted, for his courtesy in permitting the investigation; and to R. R. Sayers, chief surgeon, Bureau of Mines, and surgeon., U. S. Public Health Service, for suggestions and advice."

Sep 1, 1930

By N. Kumar Kittusamy

A field study was conducted to evaluate seat designs on shuttle cars. Eight operators participated in evaluating seat designs on the basis of perceived levels of vehicle jarring/jolting and discomfort. Researchers also measured the levels of vehicle jarring/jolting. Four basic seat designs were compared on low and mid-coal seam shuttle cars during production operations at two underground coal mines. Two seats were currently used on the shuttle cars and another two were NIOSH designs. Objective data were collected using accelerometers with pre-amplifiers and filters connected to a data recorder; whereas subjective data were gathered with a visual analog scale (VAS) and a questionnaire. Results from measured levels of jarring/jolting showed that the NIOSH Seat L2A smoothed out bumps better than any other seats. Using the VAS, mid-seam and low-seam shuttle car operators rated the levels of jarring/jolting and discomfort lower with the NIOSH seat than the other seats. Questionnaire responses indicated that operators rated NIOSH seat designs as more comfortable. This research will provide the industry with better seat designs for isolating jarring/jolting in vehicles. Furthermore, researchers plan to improve the NIOSH seats using information gathered in this study.

Jan 1, 2003

By R. V. Ramani, J. M. Mutmansky, P. C. Luna, V. A. Marple, Honglin He, B. A. Olson

The development of a sampling instrument for the assessment of an underground coal miner’s exposure to airborne respirable coal mine dust on a continuous and real-time basis has been long identified as essential for timely initiation of control actions. A respirable dust dosimeter (RDD) which operates on the principle of increasing pressure across a filter media with increasing dust mass on the filter has been developed by the National Institute for Occupational Safety and Health. Comparisons of the performance of the RDD with an U.S. approved gravimetric respirable dust sampler (GRD) have shown that the RDD may meet the requirements for measuring miners’ exposures on a cumulative, near real-time basis such as mid-shift and end of shift exposures. Recently, the performances of the RDD and GRD were compared by conducting side-by-side area sampling experiments in a controlled experimental environment in the laboratory and in underground coal mines under normal operating conditions. In this paper, the results from the in-mine study are presented and discussed. The experimental design for the in-mine study included two mines in different coal seams in different geographic coal regions. To ensure a wide range of concentrations, the experiments were conducted in a continuous miner section in Mine 1, and a longwall face in Mine 2. Airborne dust sampling was conducted for four different shifts at each mine. In each shift, two samples of different exposure durations were collected from two different locations. Each sample consisted of the readings of three dosimeters and the exposed filters from the three paired GRD samplers. As a result, a total of 96 comparative samples were obtained, 48 for each mine. The data were analyzed for the precision of the RDD and GRD measurements and for the relationships between the differential pressure of the RDD and the mass of dust on the paired GRD filter. The analyses indicate that, on the average, the RDD and the GRD track the airborne respirable dust concentrations well, exhibiting both a high correlation between the two measurements and a reliable predictive relationship of one from the other. Details of the experimental design, data analyses procedures, results, conclusions and recommendations of the underground experiments are presented in this paper.

By James C. Barker

A uniquely mineralized area extends from northwestern Canada through Alaska into eastern Siberia. Some of the metals found there are relatively rare in the conterminous United Stales. Among these are cobalt, the platinum-group metals, and chromite. Geologic evidence suggests that cobalt and the platinum-group metals may be present in deposits that could constitute nationally important reserves. Chromite in potentially minable deposits is known, but it may be relatively less abundant. Limited reserves of these metals have been delineated, but most of the favorable terranes and reported occurrences throughout the vast expanse of Alaska remain unexplored. As part of the mineral studies mandated under the Alaska National Interest Lands Conservation Act, the Bureau of Mines' Alaska Field Operations Center and the Bureau's research centers at Albany, Oreg., and Reno, Nev., are cooperating in a long- range program to investigate occurrences and delineate reserves of cobalt, the platinum-group metals, and chromite in Alaska. Studies of other critical and strategic minerals will be phased in during succeeding years, as ongoing projects are completed. This first in a series of annual reports summarizes available information about deposits and past production of cobalt, the platinum-group metals, and chromite, and describes current and planned Bureau investigations of these minerals.

Jan 1, 1981