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By Steven J. Knoll, Theodore J. Williams, Douglas F. Scott

Highly stressed rock in stopes continues to be a primary safety risk for miners in underground mines because it can result in failures of ground that lead to both injuries and death. Spokane Research Laboratory personnel investigated electromagnetic (EM) emissions in a deep underground mine in an effort to determine if these emissions could be used as indicators of impending catastrophic ground failure. Results suggest that (1) there is no increase in the number of EM emissions prior to recorded seismic activity, (2) some EM signals are generated during blasting, (3) interference from mine electrical sources mask seismic-generated EM signals, (4) EM emissions do not give enough warning (compared to seismic monitoring) to permit miners to leave a stope, (5) the distance an EM signal can travel in the rock is between 18 and 40 m, and (6) current data acquisition systems do not differentiate between EM signals generated from seismic activity and random mine electrical noise. These results preclude monitoring EM emissions as precursors of impending catastrophic ground failure.

In 2006, a total of 2,113 coal mining operations reported employment to the Mine Safety and Health Administration (MSHA).1 Coal mines comprised 14.2% of all mining operations. ? Bituminous mines comprised 92.5% (n=1,955) and anthracite mines 7.5% (n=158) of coal mining operations. ? Approximately 71.0% of all coal mines were located in three states: Kentucky (29.2%), West Virginia (21.8%), and Pennsylvania (20.3%).

Jan 1, 2008

By G. L. Oldright

As a rule, the usual zinc retort smelter fired with natural gas made its own burners, of which there might be 300 per block, out of standard pipe fit-tings. The gas was discharged through a feeder pipe at various distances into a cylindrical horizontal "blow hole" through a pillar block and thence into the furnace; the best location of this gas-feeder pipe was at the horizontal central axis of the blow hole; the side entry into the blow hole usually was used. The air entered the same blow hole behind the gas, through a short nipple, in the inner end of which was a constructing orifice in a clay plug; in this ,work cone-shaped funnels of various lengths also were used. Even with the air and gas correctly proportioned to each burner, small differences in their dimensions were found to influence greatly the temperatures reached, their uniformity, and consequently the percentage of zinc extracted. This fourth paper of a series on cooperative work in the zinc retort plants of the Eagle-Picher Mining & Smelting Company discloses the methods and principles followed in approximating closely the optimum dimensions for various burners, with examples from experimental and commercial furnaces showing the interrelation of such dimensions with combustion and temperatures in the furnace.

Jan 1, 1948

In This Chapter [Finding the dust source Ventilation and dust collector malfunctions Upgrading the dust controls Design stage ventilation planning ] This chapter explains how to reduce respirable dust76 in hard-rock tunnels during excavation by using tunnel boring machines (TBMs). The first steps in combating a dust problem are to take dust samples to pinpoint the source, check the ventilation system, and check the dust collector. If the ventilation system and dust collector are operating properly, then other dust controls such as water sprays and conveyor belt scrapers must be upgraded. For tunnels in the design stage, recommended air quantities are provided. FINDING THE DUST SOURCE AND LOOKING FOR VENTILATION MALFUNCTIONS [The first steps in fighting a dust problem are to take dust samples to pinpoint the source, check the ventilation system, and check the dust collector. Without knowing the exact source, efforts to reduce dust are hit-and-miss (mostly miss).] Taking samples to pinpoint the dust source. In tunnels with high levels of airborne dust, the first task is to pinpoint where the dust enters the airstream. Most dust originates from rock breakage at the tunnel face, but the location where this dust enters the airstream can vary. Dust can leak from behind the TBM face shield, from gaps in the ventilation duct, or from a mal-functioning dust collector. It can be entrained into the air from the muck on a moving conveyor belt. It can even be shaken loose from the underside of the belt as it passes over the idlers. As a start, to locate the dust source, dust samples and air quantity measurements should be taken at the following locations:

Jan 6, 2003

By C. W. Morris

This study was performed for the U.S. Bureau of Mines. An existing computer simulation of a dragline was modified to simulate a dragline dumping into the hopper portion of a cross-pit conveyor system. This revised computer model was then used to study four proposed cross-pit conveyor systems. Parameters such as dragline position, hopper position, and digging procedure were varied to maximize the dragline production. This performance was compared with the conventional side-casting spoil method. I t was concluded that the cross-pit conveyor systems were competitive with the conventional side-casting technique.

Jan 1, 1977

By T. E. Swigart, C. E. Beecher

The Federal Government, as the largest lessor of oil and gas lands in the United States, is vitally interested in the conservation of those resources. This manual has been prepared at the direction of the Secretary of the Interior to call the attention of lessees of public oil and gas lands to the most common oil and gas field wastes and the best methods of preventing them; to outline the policies of the Interior Department on field operations; and to give information as to how the "Operating Regulations" of the department will be interpreted by the Bureau of Mines. The oil industry has progressed steadily. Present operating methods are much more efficient-and less wasteful-than those of a few years ago; moreover, the art of producing oil and gas is continually advancing. Public interest requires that improved methods, which will result in obtaining the greatest possible amounts of oil and gas from the natural deposits, shall be developed and used. Part I of this manual points out types of oil and gas wastes and suggests, in detail or by reference, the most practical and effective methods in current practice for stopping these wastes. Throughout Part I the department's operating policy is given, with interpretations of the "Operating Regulations" for enforcing every practical measure of conservation. Part II comprises the revised "Operating Regula-tions" which supersede all previous regulations and will govern future operations on public lands; it will be found in the pocket in the back cover of this bulletin.

Jan 1, 1923

By Michael Schmitz, John A. Organiscak

ABSTRACT: A method (patent pending) has been developed to determine the quality of environmental cab filtration systems. This method utilizes specially configured filter cartridges to remove carbon dioxide from the ambient air with the environmental cab’s air filtration system. A real-time gas monitor is placed inside an unoccupied cab with the filtration system running to time decay the carbon dioxide to its lowest concentration or equilibrium level. The outside carbon dioxide concentration level can be measured concurrently with another gas monitor or with the same inside cab gas monitor during a representative period before and after the inside sampling is conducted. Cab filtration system leakage is comparatively deduced from the difference between the special cartridge filter efficiency and overall cab efficiency. Laboratory trials have illustrated that desirable high efficiency test filter configurations (greater than 99 % efficiency) can be devised, but have air quantity and test time limitations. These trials also demonstrated that CO2 penetration was reflective of controlled air leaks around a high efficiency filter under equilibrium conditions. This report examines the elements of this patent pending method.

By K. C. McMahon

This report is the result of the engineering efforts performed by the Mining Equipment Operations of FMC to develop methods of automating a continuous miner. This work was done as part of modification number three of the contract for the development of a miner/bolter system. As the demand for energy places an ever-increasing pressure on the coal mining industry to produce more coal, methods for underground mining which will increase productivity with a con-current increase in safety are being actively sought. Removing the machine operator from his station on the continuous miner and placing him at a safer location behind the machine while retaining his control functions via an umbilical cable or a radio link was an important first step. However, the problems of poor visibility, no control "feel", and the judgmental problems of controlling the sump distance and the shear limits have not been conducive to the productivity increase that is desired.

Jan 1, 1975

By James H. Rowland

The Mine Improvement and New Emergency Response Act of 2006 (MINER ACT) established a Technical Study Panel (The Panel) to provide recommendations on the utilization of belt air and new technology that may be available for increasing the fire resistance properties of conveyor belt used in underground coal mines. The Panel Report recommended use of the Belt Evaluation Laboratory Test (BELT) as the method for testing and approval of flame resistant conveyor belts used in underground coal mines. The research conducted to establish the correlation of the BELT with large-scale belt fire flammability tests was done using 36- to 42-in wide conveyor belt. Due to today?s coal haulage capacity, the mining industry is using 72-in and wider conveyor belts. The National Institute for Occupational Safety and Health (NIOSH) conducted a study to determine if the BELT will also qualify wider belts as fire resistant for use in underground coal mines. This paper describes the results of recent experiments comparing results from using the BELT and the large-scale tests for six different belts.

Jan 1, 2010

By Britt H. Hatfield, Jiu-Chiuan Chen, Wen-Ruey Chang, David C. Christiani

Occupational exposures to whole-body vibration (WBV) at different frequency domains may differentially affect human comfort and the musculoskeletal system. Under this presumption, a frequency-based weighting scheme has been adapted in many widely accepted standards for WBV measurement. However, there is very little human data showing a direct link between WBV frequency and musculoskeletal disorders. We conducted an epidemiologic study to examine the association between WBV frequency and prevalence of low back pain (LBP) and to identify determinants of specific frequencies associated with LBP in urban taxi drivers. Methods The WBV frequency data were collected from 247 professional drivers (aged 44.6±8.3) who participated in an exposure validation study 1 of the Taxi Drivers’ Health Study (TDHS) in 2000. 2 In accordance with the ISO 2631-1 (1997) methods, we measured the frequency-weighted acceleration over drivers’ seat surface, under conditions representing randomly assigned destinations. We developed a WBV record-replay system at the Liberty Mutual Research Institute (LMRI) in Hopkinton, MA, USA. This system includes two tri-axial accelerometers (PCB Piezotronics, NY, USA), one RD-130T PCM data recorder (TEAC, Tokyo, Japan), and one LMWBV meter 2.0 (LMRI, MA, USA). Only the vertical axis of seat-surface WBV frequency was used in this study. To characterize the WBV frequency curve, we manually identified the presence of any peak within each of the following frequency range: <4, 4-10, 10-20, and >20 Hz. Information about the operating vehicles and driving environment was either collected from the vehicle registration record (manufacturer, year of make, transmission, engine size, etc.) or directly measured (wheel-base length, seat inclination, etc.). Structured interviews were conducted by an occupational physician to gather information on LBP that had led to medical attention or absence from driving in past year. We used multiple logistic regression to estimate the prevalence odds ratio (OR) associated with the presence of each index peak frequency, adjusting for age, body mass index, professional seniority, daily driving hours, seat inclination, and the intensity of predicted root-mean-square WBV exposure in m/sec2. For any revealed WBV frequency that was associated with LBP, we constructed a multiple logistic regression model to identify the personal and vehicle characteristics associated with the presence of WBV peak within the indicated frequency range.

Jan 6, 2006

By Paul S. Goodman

This report examines absenteeism and accidents. The first section provides some background information on absenteeism. The second section examines trends in absenteeism in underground coal mines over time. The third section examines causes of absenteeism. Models were examined. The first model looks at self-report reasons for absenteeism. The second examines demographic correlates of absenteeism. The third model includes demographic and attitudinal predictors of absenteeism. The next section of the report examines the effect of absenteeism on accidents. The last section contains strategies for reducing absenteeism.

Jan 1, 1985

By C. A. Kumke

The Korean crisis and the cessation of Russian manganese-ore shipments to the United States in 1950 reemphasized the almost total dependence of the domestic steel industry on foreign supplies for metallurgical-grade manganese ore. In this emergency, Congress authorized the Bureau of Mines to undertake experimental mine and process development work on the known large reserves of low-grade manganese ore in the Artillery Mountains region in Mohave County, Ariz. The objective of the work was to obtain the basic mining and metallurgical data needed to make specific plans for initiating exploitation of the deposits within 3 years if high-grade foreign ore could not be obtained during the emergency. The manganese deposits of the Artillery Mountains region are in an area of about 25 square miles on the north side of the Bill Williams River in southern Mohave County. Lasky, of the Federal Geological Survey, has estimated reserves at 175 million tons of manganiferous material assaying 3.5 to 4 percent Mn. Although the man¬ganese occurs in various Tertiary and Quaternary formations as both bedded and fissure vein deposits, the more important syngenetic deposits are found in upper and lower manganiferous zones in the sedimentary beds of playa and alluvial fan origin that constitute the Chapin Wash formation.

Jan 1, 1957

By James R. Boyle

The value of mineral production increased 6.2% in 1976. With the exception of coal, practically all commodities registered an increase in production and value; most had an increase in unit value. Total value exceeded $1 billion for the first time. The increase in nearly all nonmetallic mineral production was a complete reversal of the 1975 experience. Alabama led the Nation in the production of crushed marble and was second in bauxite and scrap mica, third in oystershell, third in kaolin, and fifth in dimension limes-tone and dimension marble. International Trade.-The international trade passing through the Mobile customs district was valued at $2,524 minion in fiscal year 1976, up 20% from that of the previous year. Of the total value of trade passing through the district, 52% of the value of experts and 89% of the value of imports were handled through the port at Mobile. The major export Commodity was coal through McDuffie Coal Terminal which amounted to nearly 2.9 million tons, up from 2.4 million tons in 1975. Coal exports were to Japan, Italy, Turkey, the United Kingdom, and Brazil. Other exports were cement (114,000 tons) and [ ]

Jan 1, 1979

By David A. Summers

Coal is increasingly viewed as one of the major fuel resources of this country for the remainder of this century. The need to extract a greater percentage of the coal in a given seam, together with advantages of improved safety, indicates that longwall mining will become more widely used within this time frame. A novel method of mining coal on a longwall face, utilizing high pressure water jets, is herein described. The mining machine proposed will exploit the stress conditions which exist on a longwall panel in order to achieve the required productivity while at the same time reducing respirable dust and methane ignition hazards. The water jets will excavate only the boundary of the extracted seam section, and thus the energy requirement of the machine will be minimized. The action of the machine is similar to that of an existing coal plow, except in that the wedge teeth of the plow are replaced by oscillating high pressure water jets. The machine can, therefore, cut to the depth and at the speed of existing shearer units at equivalent power levels. The removal of impact stresses from the machine will reduce downtime required for maintenance and replacement of picks and lower the load on the haulage motor of the system. The ability of the machine to increase the depth of cut without an increase in horsepower will further improve productivity when transportation systems to remove the greater production are in operation.

Jan 1, 1974

By R. F. Zaffarano

Intergrated energy balances and energy flows were constructed and quantified for State, regional, and national levels from four separate supply and demand commodity balances for coal, dry natural gas, petroleum and natural gas liquids, and utility electricity. These commodity balances were integrated by source and sectors through conversion and aggregation of their components to energy equivalents expressed in British thermal units (Btu). A summarization of the total gross energy components of supply and demand for commercial energy derived from direct fuels, hydropower and nuclear power, based on individual States and regions, is tabulated for 1960 and 1965. Pertinent computerization details and more than 500 individual State and regional printout tables, in both original commodity units and Btu&apos;s, are shown. Using these data, energy flows between States and regions were calculated to identify surplus and deficit energy areas. Report emphasis is on the conceptual aspects of integrated energy balances, rather than on the development of missing State energy data.

Jan 1, 1969

By B. H. Clemmons, B. G. Saunders, R. H. Stacy

"INTRODUCTION This investigation was undertaken to determine the response of Birmingham (Alabama) red-iron ore to heavy-medium concentration. Specifically, the work involved a study of the efficiency of the process in separating coarse gangue diluents from the ore and an endeavor to evaluate the potential economic results. The investigative work was not intended, nor is it to be construed, to be adequately exhaustive in scope to enable immediate plant construction. Rather, the primary objective was to determine the grade of ore that could be produced by heavy-medium treatment and the resulting indicative or tentative benefits to be derived from such treatment. The latter, in turn, would determine the merits of the more exhaustive study that would be required for an ultimate decision on the heavy-medium treatment of the ores.The problem of avoiding excessive contamination of red-iron ores by shale and/or ferruginous sandstone has been before the operators of the iron mining industry of the Birmingham, Alabama, district for many years. Within the last two decades, increased mechanization of mining methods has increased this contamination to a considerable degree. In fact, general utilization of scraper loading and other mechanical methods of mining, in conjunction with small increases in the natural insoluble content of the ores, in some cases has actually resulted in the production of ""acid"" or excessively insoluble ore, where ""basic"" or excessively lime ores were produced formerly.The contaminating materials are derived largely from roof spells and natural parting seams in the ore, a condition that to some extent has been aggravated by the irregularity of the ore beds. The latter have been subjected to both primary and secondary folding in many places. Considerable faulting has taken place, also. In many localities these conditions render virtually impossible complete avoidance of ore contamination from the over and underlying sandstones and shales. However, in a few localities, where the ore beds are less disturbed and shale partings are absent, mining can and is being accomplished with relatively little dilution."

May 1, 1948

By W. L. Cooley

Electrical accidents occurring in coal mines from 1975 through 1979 were categorized and analyzed. The data was searched for common electrical hazards, common activities on the part of those injured, and common negligent or careless behavior. The most common electrical hazard was abnormal arcs or sparks, the most common injured activity was handling energized trailing cables, and the most common careless behavior was failure to de-energize circuits before working on them. The accident data was combined with mine production statistics to form a normalized electrical accident rate. It was found that some mines have consistently more lost workdays per man-hour worked than do other mines. Bureau of Mines electrical safety research contract expenditures were reviewed to judge whether the research effort was directed to those areas which are related to the most accidents. In some cases it was not. A method was devised and utilized to estimate the relative cost to the mining industry to implement certain safety measures developed through Bureau research, and also to estimate the potential safety benefits. Some safety changes are recommended, others are not. MSHA regulations were reviewed for effectiveness in preventing electrical accidents, and suggestions were made for discontinuing, clarifying, or otherwise modifying the regulations.

Jan 1, 1981

Objective: Improve the dust control effectiveness of enclosed operator cabs on surface mining equipment.

Oct 1, 2007

By Gergely Markos

Uranium mill tailings represent a potential threat to the human habitat by containing large amounts of radioactive and chemically toxic substances in high concentrations. These: undesired components enter the human habitat in various pathways such as by erosion and water or air transport. The main objective of this investigation was to evaluate the actual movement and model the potential movement of contaminants by seepage of water from the tailings into the subtailings soil. This report represents various models of the movement of contaminants using both theoretical approaches and empirical evaluation of data available from other investigations. The data consist of field measurements and laboratory determi¬nations of major and trace cations, the dominant anions, pH, and Eh of moist solids, extracts, and waters from the tailings and surroundings. Evaluation and interpre¬tation of data were accomplished by using Eh-pH diagrams, various statistical methods and the WATEQFC computer program. Data analyses show that the critical area of investigating movement- is the interfaces between tailings and the external environment. The chemical differences at interfaces seem to result in a sink system for contaminants. The tailings-soil¬-water system shows extreme complexities because of chemical and physical hetero¬geneity of the system preventing the use of a single comprehensive model to represent real conditions. The validity of the simplifying assumption used has been shown and increasing complexity has been built into the models. Analogs of these models can be used for evaluation of similar systems.

Jan 1, 1981

By E. A. Mevissen

With the ever increasing consumption of mineral commodities, the vital question is not whether sufficient mineral quantities will be available, but rather can the known existing low grade resources be mined economically. Conventional conveyor systems are being used in some open pit mines to decrease haulage costs. n an effort, to take this concept one stop further, this contract study examines the use of a high angle conveying system in an open pit mine. It identifies available high angle conveying equipment and examines the haulage and crushing costs associated with both a conventional truck and shovel mining operation and a high angle conveyor operation. These costs analyses were performed on a hypothetical copper, taconite and phosphate mine. Information was gathered from a series of high angle conveying equipment and open pit mining operations in the U.S. Volume I includes a detailed review of the state-of-the-art in high angle conveying concepts, the, hypothetical mine development, and the cost analyses. Volume II includes the appendices.

Jan 1, 1981