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By Amitava Ghosh

A new analytical formula for predicting ground vibrations induced by blasting is proposed. One factor accounts for geometrical spreading. One factor corresponds to inelastic attenuation. The geometrical spreading function is based on likely source geometries, idealized as either square-root, cube-root or site-specific scaling, and on the propagation characteristics of predominant wave types. The inelastic attenuation is approximated by an exponential function. The empirical constants in these functions are backcalculated from field measurements. Regression analysis has been performed on twenty-three sets of measured data in order to determine the validity and the effectiveness of the proposed method. In many cases, the proposed method gives better correlation than the conventional method. In most of the remaining cases, there was no difference between the two methods. Best-fit lines given by the proposed method fit the data trend very well, especially at large scaled distances. At large distances the proposed method gives a prediction much closer to the actual values than the conventional methods. The statistical analysis shows not much difference between square-root, cube-root or site-specific scalings.

Jan 1, 1983

By L. C. IlsLey

A list of permissible mine equipment approved by the Bureau of Mines before January 1, 1940, was published in Bureau of Mines Information Circu- lar 71103. Information Circular 71584, published as a supplement thereto, listed equipment approved during the calendar year 1940. The present list contains the information given in those two circulars, as well as approvals issued during the calendar year 1941. It embraces electrically operated air compressors, coal drills, conveyors and loading machines, electrical equipment for mine fans, mining machines and trucks, mine pumps, rock- dust distributors, room hoists, storage-battery gathering and haulage locomotives, storage-battery power trucks and shuttle cars, mine telephones, junction and distribution boxes, electric cap lamps, flame safety lamps, electric hand and trip lamps, electric flood lamps, flashlights, methane detectors, and single- and multiple-shot blasting units. The equipment listed is not approved by the Bureau of Mines until found by inspection and test to comply with minimum standards of safety as outlined in "schedules" prepared upon the basis of many years of ex- perience in dealing with safety problems confronting the coal-mining in- dustry. The use of such equipment in mines that are known to be gassy,. as well as in those that may become so, is earnestly recommended in the interests of safety. This circular is published so that the industry may be kept informed as to the many types of machines, devices, and lamps that are available for reducing explosion and other hazards incidental to coal mining.

Apr 1, 1942

By Walter I. Enderlin

To economically extract ore from great depths in the earth while sustaining an acceptable working environment will require the development of new technology and equipment, involving large capital expenditures. Moreover, careful analysis and advance planning will be required. But, the literature is lacking in data pertaining; to the thermal properties of various host rocks and to quantities of heat generated by various underground heat sources. This types, of data is required to forecast nine heat loads during advanced planning and design. This thesis sets forth a practical method for evaluating underground sources of heat in deep mines and provides an improved information base. Moreover, seven topics for further research are recommended. The heat sources considered are: wall-rock, ground water, adiabatic compression, equipment, service lines, blasting, metabolism, curing of cement, and oxidation of sulfides and timber. Seven deep metal mines with high production rates and high heat loads were visited to obtain data necessary to assess their thermal environments. Mine records were examined, wall-roc:, temperatures were measured and a survey of the mine ventilating air and mine drainage was performed. Also, the thermal conductivity of wet and dry specimens of the host rock were measured in the laboratory. Data analysis disclosed that rock heat and adiabatic compression account for stout 60 per cent of the mine heat load at depth. Equipment currently contributes approximately 20 per cent; however, to offset increasing costs with depth, increased mechanization is anticipated. The treat from ground water averages 19 per cent and the contribution from blasting, metabolism and cement is negligible. Also, approximately [0] per cent of the increase in the enthalpy of the ventilation air is in the form of latent heat. Moisture, however, did not significantly affect the thermal conductivity of the rock specimens measured in the laboratory. Also, from the data, it is evident that a negative correlation exists between the thermal conductivity of the host rocks and the per cent of the heat load derived from the wail-rock. Furthemore, steady state heat flow renditions may be assumed in airways where there has been no major changes in the ventilation system for a period of two years or more. Under these conditions, the author found it more convenient and reliable to compute heat influx using the steady state equation for heat flow into a cylinder, rather than Carrier's method for transient heat flow, which is so often used.

Jan 1, 1973

By Ruth F. Brinkley

This report is the 16th of a series of reports originally issued annually and more recently biennially to acquaint the reader with the work of the Explosives and Physical Sciences Division, Region VIII.3/ In the majority of instances the results of the investigations are made available to the public through Government publications and journal articles. In certain instances (specifically as regards security-classified research, investigations of a confidential nature, and short-range programs of very limited scope) results are reported only to those immediately concerned.

Jan 1, 1957

In 2007, a total of 4,639 stone mining operations reported employment to the Mine Safety and Health Administration (MSHA).1 Stone mines comprised 31.2% of all mining operations. ? Mines producing the primary commodity of limestone (crushed and broken) comprised the largest number of operations (n=2,051; 44.2%). ? Stone mining operations were located in all states and territories except Delaware and North Dakota. ? Pennsylvania had the most stone mines (n=373; 8.0%), followed by Texas (n=352; 7.6%).

Aug 1, 2009

By By Staff

"These proceedings consist of papers presented at a Bureau of Mines Technology Transfer Seminar on postdisaster survival and rescue research. Several seminars are held each year to bring the latest results of Bureau research to the attention of the mining industry as quickly as possible.INTRODUCTIONThe postdisaster research program is directed toward research and development of technology and equipment that increases the chances of a miner surviving or being rescued after an underground mine disaster. A disaster is an accident of major proportions, and it may result in the entrapment of miners whose normal egress from the mine is cut off. This often necessitates a rescue operation and a means of keeping the trapped miners alive while they await rescue. The Bureau is currently pursuing research to develop the technology that will enhance the ability of miners to survive such an occurrence. The research is divided into two basic problem areas, survival and rescue. Both areas are concerned with the inability of miners and rescue teams to cope with the postaisaster environment, such as toxic gases, unstable roof conditions, water flooding, and lack of oxygen. In addition, research is also conducted to find ways of locating and quickly reaching trapped miners. Most of the research conducted by the Bureau has been directed toward the postdisaster problems associated with coal mines. However, most of the research results are also applicable to noncoal mines as well.The papers presented in these proceedings address some of the recent research conducted by the Bureau of Mines that has been directed toward the postdisaster problems outlined above. The topics covered range from an overview of the technology developed for oxygen selfrescuers to training programs for mine rescue. Any questions or comments pertaining to this research are encouraged and appreciated. Open file report (OFR) references in the proceedings listed as available from NTIS may be obtained from the National Technical Information Service, Springfield, Va. 22161, and are also available for reference at Bureau of Mines facilities in Denver, Colo., Twin Cities, Minn., l3ruceton and Pittsburgh, Pa., and Spokane, Wash.; the Department of Energy facility in Morgantown, W. Va.; the National Mine Health and Safety Academy, Beckley, W. Va., and the National Library of Natural Resources, U.S. Department of the Interior, Washington, D.C."

Jan 1, 1982

By L. A. Stinnett

An investigation of hazardous surface openings of abandoned and inactive underground mines in the Black Hills area of South Dakota has revealed: (1) tracing legal ownership of mineral claims via county courthouses is confusing, complex, and oftentimes misleading, (2) in general, the selected mine openings in this investigation are to be considered relatively high in risks and hazard potential which poses a threat to the general public, (3) mine closure procedures and designs can generally be categorically implemented depending on the overall situation of the particular mine opening with subsequent unit costs estimates, (4) few preventive state or federal legal measures exist to date concerning mine closures, and (5) liability damages relating to mine opening accidents usually involve expensive and complex common law cases.

Jan 1, 1979

By K. L. Williams

The Bureau of Mines laboratory tested the response of a commercially available real-time aerosol monitor (GCA RAM-1) to various dusts. Monitor measurements were recorded, averaged, and compared with simultaneous gravimtric measurements of each test dust. Tests usually lasted several hours. The test dusts of various particle size distributions used included coal, limestone, and a commercially available test dust. For each particular dust, the monitor response was linear and correlated well with mass concentration over the range of about 0.5 to 10 mg/m3. The monitor can estimate a 2.0-/m3 respirable coal dust concentration within as little as 26 pct with 95 pct confidence. The monitor must, however, be calibrated with the dust to be measured because the instrument response is affected by the type of dust particle. The average monitor response to same mass concentration of coal dust was approximately twice the average monitor response to the same mass concentration of limestone dust.

Jan 1, 1984

By David W. Houseknecht

Probabilities of encountering coalbed discontinuities during vertical or horizontal drilling in a specific coalbed can be estimated based on analysis of mined-out areas of the coalbed where the size, shape, orientation, and distribution of discontinuities are known. The result- ant probability estimates can be applied to cost-risk evaluations of drilling programs proposed for exploratory, developmental, or methane drainage purposes in undeveloped areas of that coalbed. Data compiled from mine maps of the Beckley Coalbed in southern West Virginia were used to estimate the probabilities that discontinuities would be encountered in two illustrative hypothetical drilling programs--one for drilling vertical boreholes and the other for drilling horizontal boreholes. Analysis based on a mined-out area of the Beckley Coalbed indicated that vertical methane drainage boreholes spaced 1,000 feet apart in a square grid pattern would each have a 29 percent probability of encountering a discontinuity in a geologically unexplored area of the coalbed. It was also determined that exploratory vertical drilling could locate most of the discontinuities if a borehole spacing of 2,500 feet were used. For horizontal drainage boreholes in the Beck- ley Coalbed, the analysis indicated a linear relationship between hole length and the probability of encountering a discontinuity.

Jan 1, 1982

Reduce well construction and operation costs associated with in situ leach mining while increasing mineral recovery. Approach To accommodate the size of centrifugal pumps presently in use, in situ leaching production wells are typically drilled to 6 inches in diameter, while monitor wells are drilled to measure 4 inches in diameter. However, in order to reduce the cost of drilling these larger diameter wells and to increase recovery, the Bureau has developed jet pumps which have smaller diameters than centrifugal pumps of the same capacity. This allows both production and monitor wells to be drilled smaller. Bureau estimates indicate that the cost of drilling a 3-inch-diameter production well at in situ leaching operations would be about 35 percent less than the cost of a 6-inch well. Similarly, the cost of drilling a 2-inch-diameter monitor well would be about 26 percent less than the cost of a 4-inch well. Such significant savings in the cost of drilling these wells would effect a substantial reduction in total capital cost. Use of the new jet pumps can also increase the percentage of recovery because less costly wells allow closer well spacings, improving the distribution of the leach solution. How the System Works After the borehole is cased, the new small-diameter jet pump, along with piping and accessories, is installed and connected to a centrifugal pumping unit on the surface. High-pressure water from the surface pump is forced through a nozzle into the venturi of the jet type pump injector. This jet action lifts the leach and mineral-bearing solution to the surface.

Jan 1, 1984

By T. H. Jeffers

Significant amounts of cobalt are present in readily accessible spent copper leach solutions. The Bureau of Mines investigated the feasibility of extracting cobalt from these solutions in a multiple-compartment ion-exchange (MCIX) column. The effects of aqueous flow rate, resin flow rate, column height, and compartment height on cobalt extraction were determined. Cobalt extractions of 92 pct or higher were achieved at solution flow rates of up to 5.5 gpm/ft of column cross-sectional area and an aqueous-to-resin flow ratio of 40:1. Overall cobalt extraction increased as the column height increased, but cobalt extraction per unit of length was more efficient in 8-and 12-ftco1umns than in an 18-ft column. Solvent extraction procedures were utilized to purify and concentrate the MCIX column eluates and produce a cobalt sulfate solution containing 70 to 80 giL Co. Metallic cathodes containing over 99 pct Co were e1ectrowon from this solution. Zinc, nickel, and copper byproducts were also recovered during processing of the ion-exchange eluates. Estimated total capital cost for a commercial-scale 10,000 gpm of a spent leach solution containing 26 million. With credits for zinc, nickel, and copper estimated net operating cost was $9.36/lb Co.

Jan 1, 1987

By E. Chin

The countries of Asia and the Pacific, with their large mineral resource base, are significant suppliers of a wide variety of minerals to both regional and world markets. Australia, China, and India dominate the commercial mineral exploitation in the region. Australia has known reserves of major minerals, which are adequate for both domestic demand, and for exports, and is a significant producer of bauxite; copper; diamond; gold; iron ore; lead; manganese; mineral sands (titaniferrous minerals, monazite, and zircon); nickel; salt; silver; tin; uranium; and zinc. China is the world leader in proven reserves of antimony, barite, ilmenite (titanium), magnesite (magnesium), molybdenum, rare earths, and tungsten. China also has large resources of low-grade iron ore and significant resources of other mineral commodities, such as coal, based on its production and export capabilities. India has significant resources of bauxite, barite, graphite, iron ore, and mineral sands.

Jan 1, 1995

By Richard D. Miller

This Bureau of Mines publication contains analyses and related source data for 271 natural gas samples from 22 States collected during calendar year 1982. All samples were obtained and analyzed as part of Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted since 1917. The analyses published herein were made by the mass spectrometer and chromatograph. The results of the investigation of the occurrences of helium are published annually to make the information available to the petroleum industry and the general public. Twenty-six publications have presented the results of 13,051 gas analyses vide prior to 1982. The first 3 bulletins (1-3)3 contain analyses and related source data on 5,218 gas samples collected from 1917 through 1960; these bulletins have been supplemented annually by information circulars (4-17, 19-24, 26) containing 7,833 analyses of samples collected since 1960.

Jan 1, 1983

By N. E. Hanna

To be approved for use in underground coal mines in the United States, explosives and blasting devices must pass certain safety tests prescribed by the Federal Bureau of Mines. These tests are described in Schedule 1-G4/ (explosives) and Schedule 26A5/ (blasting devices). An explosive or blasting device that passes the appropriate tests is placed on the active permissible list. As this list is subject to continuous revision, it has been the practice of the Bureau of Mines to publish periodically the names of explosives and blasting devices that have been added to the active list, as well as those that have been transferred to the inactive list; changes in brand names also are reported. The present circular gives all explosives and blasting devices on the active permissible list as of December 31, 1957, and shows all changes, additions, and transfers in that list between December 31, 1951,6/ and December 31, 1957.

Jan 1, 1958

By Richard A. Walker

This report describes the development and performance of a multi-level, multi-function Calibration Light Source designed for field-calibration of a group of specific photometers. The Calibration Source is capable of providing ±35% accuracy calibrations at all of the following levels: 0. 05 foot-Lamberts, 6 foot-Lamberts, 6 foot-candles and 20 foot-candles. The Source was found to provide constant light output to within 1% over 50 hours of lamp operation and for line voltage variations of ±25%. It is compact and light-weight (11 pounds), and can be easily transported and used by one man in normal office environments (without requiring a darkroom).

Jan 1, 1976

By Alexander L. Peyton

The Magruder and Chambers copper deposits in the Little River gold district, on the border line of Lincoln and Wilkes Counties, Georgia, have been known for a number of years (fig. 1). The Magruder deposit was first opened as a gold mine but has produced mostly copper and load. Records show that about 50 cars of concentrates were shipped from this property. No record of any production at the Chambers deposit is available. The Bureau of Mines, in its program of investigation of strategic minerals deposits, diamond drilled 10 holes, totaling 3,784 feet, on the two properties between December 3, 1948, and June 23, 1949. Eighty-eight core samples were analyzed, and the analyses and drill-hole data are presented in this report.

Jan 1, 1950

By R. Hogg, J. M. Mutmansky, E. Kaya

"Characterization of the size, shape, chemical composition, and mineralogical content of mine airborne dusts generally requires a larger mass of dust particles than is typically collected using traditional sampling devices. In this paper, the general design of a passive dust collector is described and the field results are presented. The collector was constructed of galvanized sheet metal duct with a resin-coated honeycomb to provide an elutriation-type system for particle collection. Several versions of the collector were used in the field portions of the research.The dust samples collected from underground coal mines were found to possess angular particle shapes, relatively consistent size distributions, and elemental compositions that showed relatively little variation, at least for the more prevalent elements. In addition, the distributions of particles sizes obtained from the passive dust collector appear to be similar to those of samples collected at the same time in a conventional personal sampler except that the passive device seems to collect a larger quantity of coarse, nonrespirable particles. Conclusions on the suitability of this dust collector for collecting characterization samples are presented. In addition, the potential for using such a dust collection system for supplying dusts for biomedical research is discussed.INTRODUCTIONRecently, a considerable amount of research effort has been directed toward better understanding of the characteristics of the coal dust generated during the mining process. It is generally believed that dust characteristics play a significant role in the development of Coal Workers' Pneumoconiosis (CWP). In order to effectively protect coal workers from coal dust, it is important to understand the properties of dust, the mechanisms of generation and dust-lung reaction. Conducting research on dust characterization, dust control and the biomedical aspects of dust toxicology generally requires a large sample of airborne coal dust. Unfortunately, current dust sampling instruments are not able to meet this demand because only a few milligrams of dust are collected."

Nov 1, 1995

By R. V. Ramani

In this report, the application of the Open Pit Materials Handling Simulator (OPMHS) to a mine located in Illinois using bucket wheel excavator (BWE) and a stripping shovel in tandem for overburden removal is described. The specific objective of the study is to demonstrate the application of the simulator to analyze mine planning and scheduling problems and to generate and analyze alternatives for increased production. On the basis of the simulations it was concluded that the maximum productive capacity of the system in raw coal was around 3000 tons per shift. At this production level, the equipment combination and availability also satisfy the match requirements for the stripping shovel and the BWE, and the overburden and coal removal systems. Several alternatives requiring new equipment are proposed and analyzed for increasing production. However, no economic analyses of these proposals were done.

Jan 1, 1977

By Robert W. Freedman

Vacutainers are employed by the Bureau of Mines and the Mining Enforcement and Safety Administration for sampling mine air and other atmospheres containing fixed gases, low-molecular-weight hydrocarbons, and products of combustion. Tests were conducted to study shelf life of evacuated samplers prior to sampling and also to check the stability of sampled gases prior to analysis. An unexplained phenomenon, slow accumulation of carbon monoxide in evacuated samplers, occurred after a few weeks' storage; levels were low but increased with time and could pose a problem for critical applications. Accordingly, attempts to halt CO release by additional means of treatment were made, and storage at low temperature was found to be effective.

Jan 1, 1978

By Christopher J. Bise

The objectives for the research project, "Coal Mine Injury Analysis: A Model for Reduction Through Training," were to identify and develop a means to indicate deficiences in human performance, job skills, and/or knowledge at a given mine site that are amenable to alleviation through training or job redesign, and to provide ;I set of analytical tools and training resources that will enable mine training personnel to effectively incorporate the noted deficiencies into a personalized model training program. The findings of this research project are contained in Light separate volumes. Volume I represents the Executive Summary of the study and provides a broad overview of the project's individual areas of emphasis and deliverables. The additional eight volumes provide greater detail on the development of a Model Mine Training Program based upon Professional Database Analysis, Incident Reporting, Loss Control, Job Safety Analysis, Risk Assessment, Cost/Benefit Analysis, and Mine Safety Management.

Jan 1, 1993