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By R. L. Grayson

In 1995, Congress abolished the Bureau of Mines in the Department of Interior but preserved the safety and health research functions being performed at the Pittsburgh and Spokane Research Centers. These functions were transitionally housed in the Department of Energy before permanently merging with the National Institute for Occupational Safety and Health (NIOSH), Department of Health and Human Services, in October 1996. Since the merger of the former Bureau with NIOSH, there has been an active evaluation of ongoing research activities, significant interaction with stakeholders, and the development of a process leading to "data informed" priority setting. This presentation will review current surveillance information concerning the level of injury and disease from mining work and will discuss how research priorities are evolving to improve the contribution of research to the prevention of injury and disease.

Jan 1, 1998

By Carl G. Bock

INTRODUCTION Rapid transit systems involving near surface tunneling in hard rock are becoming more numerous, especially along the northeast corridor of the East Coast. Tunneled systems are under construction in Washington, D.C. and are being planned for Atlanta, Buffalo and Baltimore. Near surface tunneling is defined for this paper as being that in which the crown is 100 feet or less below ground surface. For Rosslyn Station, the total cover ranged from 52 to 70 feet. The rock cover, however, ranged from 40 to 50 feet which is slightly less than the station height and about two-thirds of its width. Rosslyn Station (Fig. 1) is the only station excavated completely in hard rock in the Virginia portion of the 98.5 mile Washington Metropolitan Area Transit Authority's (WMATA) rapid transit system. The station site, oriented in a north-south direction beneath a main thoroughfare and flanked by multistory office buildings, was fixed by the need to serve a dense population center at a specific location and geologic conditions were a secondary consideration in siting. There was no previous underground rock excavation in the Washington Metropolitan Area of the size and scope of Rosslyn Station that offered a practical case history guide to the geologic conditions and excavation problems to be encountered. GEOLOGY The regional geology of the Washington Metropolitan Area is divided into two physiographic provinces by the northeast trending Fall Line (Fig. 2). Northwest of this boundary is the Piedmont Province

Jan 1, 1974

By Ray A. Rothrock

The in situ mining of uranium is the process whereby chemical lixiviant is injected by means of wells into, and flowed through, an ore body. The lixiviant reacts with uranium which has been previously oxidized making the uranium soluble. The solution is then brought to the surface by means of producing wells. In situ mining disturbs the ground-water quality in the immediate area. Since ground water is a natural resource used by man, care must be taken not to allow the lixiviant to escape the local mining area. Also, when the ore body is mined out, the area should be restored to as near its original state as is reasonably achievable. The return of ground-water quality to its original state can occur naturally over a long period of time or be enhanced using appropriate technological means.

Jan 1, 1981

By P. Rusin

Toxic substances in On solutions can retard biological leaching of copper sulfide dump ores. On solutions were analyzed for metals, organics, and chloride, and showed inhibitory concentrations of aluminum, manganese, and chloride. Inhibition of bacterial activity by the solid fraction of On solution, with and without the organic constituents, was evaluated. Toxicity to bacterial species was evaluated by monitoring bacterial numbers, pH, Eh, and rates of iron oxidation. The On solution solids were toxic at 50 -60% of their field concentration. Most of the toxicity of the On solution was due to the organic fraction. Different SX reagents show varying degrees of inhibition of T. ferrooxidans. Bacterial inhibitory effects of carriers and lixiviants used in the SX plant should be determined so that entrained SX reagents do not retard biological dump leach systems. The reagents used should be the most cost effective and the least toxic.

Jan 1, 1994

By A. L. Hornbaker

Management of mineral resources through land-use planning procedures is not a new concept, particularly at the local level of government. Colorado may well be one of the first states, however, to vigorously attempt to evaluate on both the state-wide and regional basis, mineral resource potential and to make certain that potential for mineral resources is included as one of the primary factors considered in the local land-use decision-making process. Less than a decade ago the only consideration given to mineral resource extraction, particularly aggregate resources, was whether or not they could be produced at the particular time they were needed. This attitude has now shifted to the other extreme, not only in Colorado, but other states as well, so that other interests, especially housing projects, mountain subdivisions, recreational and wilderness areas are gaining prime consideration in land-use decisions. Ideally, in a more acceptable median position, mineral resource potential would receive definite consideration at the local level.

Jan 1, 1977

By Qingwen Shi, Brijes Mishra

Laminated rock can delaminate and fail under certain stress states. Delamination-caused roof fall and cutter roof failure is a common failure mechanism in roadways in Pittsburgh coal seam due to the existence of laminated shale roof. Two-dimensional numerical models were developed at laboratory scale based on the bonded particle method in order to simulate the delamination with particle flow code. In these models, an assembly of bonded particles and parallel weak planes represents the laminated rock. This model calibrated the micro-parameters of the bonded particlematerial and weak planes with laboratory data. The mechanism of fracturing and delamination in a laminated specimen was investigated using unconfined and confined compression test and unsupported roof compression test. The numerical results show that, under a constant horizontal stress, delamination occurswhen the stress is much lower than its compressive strength. The confined compressive test indicates that delamination is restrained by applying confining stress since delamination-caused failure does not occur during any stage of the confined compressive test. Unsupported roof compression tests showed propagation of cutter roof failure with initiation of cracks and delamination at the intersections of the roof and ribs. An outer failed zone and inner failed zone form separately. The separated zones connect and form an opening in the roof. The presented numerical results provide additional insight into process of delamination.

Sep 14, 2020

By Zhiyuan Shen, Dan Zhao

The abstract discusses the importance of reliable mine monitoring systems for preventing accidents. It focuses on diagnosing ventilation system failures caused by roadway faults that alter airflow resistance. The paper proposes using an improved Support Vector Machine (SVM) method to identify the fault location based on changes in air volume detected by wind speed sensors. The approach involves building a sensitivity 0-1 matrix and establishing a roadway fault scope library. The improved SVM method is tested on the Daming coal mine, demonstrating its effectiveness in diagnosing fault locations, reducing training time, and improving accuracy compared to traditional SVM.

Apr 5, 2022

By P. S. Newall

As part of a much larger research project, factor analysis was employed to help interpret and compare the geochemical signatures produced by two different sample media; a traditional -80# soil fraction, and a coarse float. Both sample types were collected by hand auger from the extension zone of the Redmoor sheeted-vein complex and analyzed -for 19 major and trace elements. The rationale behind the study infers that the geochemical anomalies produced by wallrock alteration around such targets can be better detected in the lithogeochemical rather than the soil environment, sometimes at considerable distance from their source.

Jan 1, 1991

By Jon Bowler

Daw Mill Colliery, UK Coal, near Coventry in England, mines the Warwickshire Thick Seam at 800 m/2500 ft depth using longwall retreat with gateroads supported by rockbolts. Over the last eight years the mine has worked longer and wider panels with extraction heights of over 5 m. Recently the mine has experienced high deformation conditions principally from the rib sides resulting in operational issues and production delays. Investigation of rib deformation was undertaken using new inspection and measurement techniques, including systematic laser surveying, and improved rib support consumables were developed and introduced. A new rib trussing system using textile webbing has proved very successful.. A rib support management system was also developed and introduced for face retreat. This allowed rib support to be more effectively managed both for production and safety. For the current developments, new 28-mm-diameter roof and rib bolt systems have been introduced and rib bolt length has been increased to 3 m, with the aim of achieving gateroad stability over the life of the panel. Significant reductions in roof and rib deformation have been confirmed by the latest monitoring results. These ground control innovations are allowing Daw Mill?s potential to be realised. Production from 302?s face in 2008 set new UK and European records. However the support enhancement process continues and further innovations are planned.

Jan 1, 2009

By Eugene N. Cameron, Igor N. Sviatoslavsky, Harrison H. Schmitt, Gerald L. Kulcinski

The recent discovery of large amounts of helium-3, a valuable thermonuclear fuel, on the surface of the Moon has prompted engineers and scientists to examine the commercial attractiveness, thetechnological feasibility, and the environmental features of this important resource. The main feature of this fuel cycle is the low (˜ 1%) fraction of energy released in neutrons. Such low neutron fluxes result in important reductions in the amount of radioactivity, afterheat, and radiation damage in a fusion power plant. On the other hand, the high fraction of energy in charged particles and synchrotron radiation can be directly converted to electricity, resulting in very high efficiencies of electricity production (˜60.70%). It has been shown that there is 10 times more energy in He3 on the Moon than there ever was in fossil fuels (i.e., coal, oil, and gas) on the Earth. The techniques and equipment needed to extract the helium-3 have been examined and internationally acceptable mechanisms for the industrial development of this resource have been outlined. This paper expands on the financial, environmental, and technical aspects of the recovery of helium-3 for use in the 21st century.

Jan 1, 1990

By Yinan Zhang, Y. Luo

Most of the reported coal spontaneous combustion events occur in surface and underground mines where low rank coals (i.e., subbituminous and lower for this particular studies) are extracted indicating their high propensities for spontaneous combustion. Low rank coals have high moisture content (15 to 45%) and are capable of absorbing more moisture in dried condition. However, it is hard to induce the initial stage of self-heating process for the low rank coal using the current laboratory R70 testing method — a method widely used in the coal industry. Like a sponge, dry low rank coals can absorb water vapor in the air while the heat contained in the moist air is transferred to coal and served as the required activation energy to initiate the coal self-heating process. In order to prove this theorem and quantify the effects, the R70 adiabatic oxidation testing method has been improved to introduce a controlled moist flow into the coal reaction vessel. Tests using the new method and its setup on low rank coals showed that the initial self-heating process of coal sample can be greatly accelerated by the added water vapor — impossible with the regular R70 method. Once the self-heating is sustained, the removal of air moisture can further accelerate the process.

Sep 17, 2021

By J. A. Meech

An analysis of screen design options on the operating efficiency of secondary crushing plants has been conducted using a dynamic computer model. The model allows for the simulation of a wide variety of crushing circuits and can be run on either a microcomputer (IBM PC/XT) or a large time-sharing mainframe computer. Size reduction and separation characteristics of crushers and screens are based on standard manufacturer design and performance data. Input/output routines are available in tabular, alarm or strip chart recorder modes to facilitate operation of the program. A number of alternate circuit designs are compared to show the influence of surge capacity, screen size and area, screen deck location, and closed side crusher settings on the operation of a 10,000 ton per day plant. The program is currently in use at Queen's University to teach plant operations and control. It has potential to be a valuable tool for operator training.

Jan 1, 1985

By Frank E. Chase

Retreat mining is one of the most hazardous operations conducted underground. One of the keys to miner safety and an efficient recovery of the reserves is to design adequately sized production pillars to prevent pillar squeezes, excessive pillar spalling, severe floor heave, roof falls, and pillar bumps. Currently, few pillar design approaches are available which consider the abutment pressures generated by the gob. The Bureau of Mines is developing a method called Analysis of Retreat Mining Pillar Stability (ARMPS) to aid in the design of retreating sections. Back analysis of 42 case studies indicates that ARMPS can be helpful in predicting stability during retreat mining operations.

Jan 1, 1993

By A. Cecala, J. Noll, J. Hummer

The National Institute for Occupational Safety and Health has observed that many control rooms and operator compartments in the U.S. mining industry do not have filtration systems capable of maintaining low dust concentrations in these areas. In this study at a mineral processing plant, to reduce respirable dust concentrations in a control room that had no cleaning system for intake air, a filtration and pressurization system originally designed for enclosed cabs was modified and installed. This system was composed of two filtering units: one to filter outside air and one to filter and recirculate the air inside the control room. Eighty-seven percent of submicrometer particles were reduced by the system under static conditions. This means that greater than 87 percent of respirable dust particles should be reduced as the particle-size distribution of respirable dust particles is greater than that of submicrometer particles, and filtration systems usually are more efficient in capturing the larger particles. A positive pressure near 0.02 inches of water gauge was produced, which is an important component of an effective system and minimizes the entry of particles, such as dust, into the room. The intake airflow was around 118 cfm, greater than the airflow suggested by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) for acceptable indoor air quality. After one year, the loading of the filter caused the airflow to decrease to 80 cfm, which still produces acceptable indoor air quality. Due to the loading of the filters, the reduction efficiency for submicrometer particles under static conditions increased to 94 percent from 87 percent.

Jan 1, 2015

By S. D. F. Rocha

The influence of surfactants on the crystallization of calcium sulfate was investigated in both hatch and continuous systems. The investigation was per formed at the following conditions. 343 °K, 28% P205 and with a sulfate level of 2.0%. At concentrations of 5 and 200 µgig, respectively, dodecylbenzene sulfonic acid (DBSH) and sodium diisooctil sulosuccinate (SSNa) promoted both an increase in the size and a reduction in the length/width (L/W) ratio of the calcium sulfate hydrates produced in the hatch and continuous crystallizers. Unique effects were observed in the batch system at higher DBSH concentrations. At 10 µg/g, the precipitation of hemihydrate crystals with a distinct morphology and texture occurred under conditions where dihydrate precipitation was expected. Above 50 µg/g, the precipitation of calcium sulfate hydrates was completely inhibited.

Jan 1, 1996

By R. L. Loofbourow

Most wet mines face unquantified water costs as well as the obvious wing costs. Both kinds of cost are multiplied by work at greater depth and by higher unit prices. This intensified challenge merits renewed or perhaps altogether new response. Any practicable way to reduce inflow tackles both obvious and unquantified costs. Ten groups of possible ways to do it are cited. Most have been demonstrated. Two are known from work other than mining. Surely new means can be found. Here are opportunities for operators of wet mines!

Jan 1, 1980

By James J. Meadows, Jason D. Pampena, Emanuele G. Cauda, Lauren G. Chubb

Respirable crystalline silica (RCS) found in dust generated by various mining processes is an important occupational hazard in the underground coal-mining industry. Exposure can lead to disabling and incurable diseases, including coal workers’ pneumoconiosis (CWP), silicosis and lung cancer [1,2]. Clusters of rapidly progressive CWP have been observed in the Appalachian regions of eastern Kentucky and southwestern Virginia, and recent cases have been generally more severe and showing more rapid progression. CWP is approximately four times as common among long-tenured underground coal miners in central Appalachia than long-tenured underground miners in the rest of the United States, and 20.6 percent of long-tenured underground miners in central Appalachia were suffering from the disease as of 2017.

By N. Magdalinovic

Generally speaking, erosion, as a process which entails degradation of surface layers of earth under the influence of the mechanical energy of surface waters, and from the point of view of biosphere sustainability, is a harmful process. This is absolutely true when agricultural and forest areas are concerned. However, if erosion is viewed selectively, this general definition about its harm raises serious questions. In other words, the erosion which takes place in the terrains where there is no vegetation because of the geological composition of the soil, does no harm. On the contrary, if the mineralogical composition of such terrains is characterized by a presence of precious and rare metals, erosion can be very useful. It contributes to the creation of new alluvial deposits of these metals in the waters in the plain land. It is here that torrents from hills come down and cause erosion. And finally, if there were no erosion, there would be no renewable deposits of gravel and sand.

Jan 1, 2007

By M. J. Meulendyke

An extensive program of marked ball wear testing (MBWT), laboratory corrosion studies, and worn ball surface analyses has been used to gain insight about the role of corrosion in the overall wear process. In some environments, localized corrosion is observed; the actual wear mechanisms in such cases are pitting/spalling and abrasion. Factors affecting the occurrence of pitting include the abrasiveness of the ore, corrosivity of the slurry, corrosion resistance of the media, and galvanic coupling effects. Elimination of pitting substantially improves overall wear resistance. When pitting is not observed, the contributions of general corrosion are significantly less.

Jan 1, 1984

By Leonard B. Rothfeld

For many years, pulverized coal (PC) boilers in utility power plants have been the dominant market for domestic coal. Today, two new coal utilization technologies challenge the PC boiler's dominance. Atmospheric fluidized bed combustion (AFBC) and "coal gasification/combined cycle" (GCC) stand on the verge of commercial demonstration in the utility environment at a scale of 100 MW. Developed over the past decade, these technologies respond to the demands for cleaner ways to burn coal and for more flexibility in fuel supply. In the near term, these are the "clean coal" technologies most likely to have a significant impact, because they are ready for commercial application. As for environmental acceptability, consider that just a few years ago one of the environmental slogans was "no coal in California." Indeed, the only large quantities of coal above ground in California at that time were in transit on the way to Asia. Today, thanks to new technology, we can point to two operational coal-burning plants in California and one in the works: * Cool Water GCC demonstration plant (100 MW) * California Portland Cement AFBC commercial cogeneration, near Riverside (190 000 lb/hr steam) * Energy Factors AFBC commercial cogeneration at Stockton, to be operational 1988 (44 MW)

Jan 1, 1987