Search Documents

By V. A. Leach, J. R. Johnson

The calculation of the dose to the bronchial epithelium, lungs and other body tissues from exposures to airborne radon and thoron daughters requires a knowledge of the pattern of deposition in the respiratory system and clearance from it. Exposure to radon or thoron daughters is measured in units of Working Level Months (WLM), which is independent of the aerosol particle size, the fraction of daughters that are attached to the aerosol and the degree of disequilibria between the daughters, and age and breathing rate of the subject. These factors will influence the deposition and clearance, and hence dose. It is therefore of interest to find the relationship between WLM and calculated dose as a function of aerosol size, unattached fraction, and disequilibria, and of age and breathing rate, and to define ranges for these parameters for which WLM is an acceptable measure of the risk. This presentation briefly reviews the two dosimetry models being considered by a current Nuclear Energy Agency (OECD) Working Group, and using these models, defines limits on parameters for which the WLM is applicable.

Jan 1, 1981

By Kenneth H. Johnston

Records show that waterflooding was tried in Osage County as early as 1934, but it was not economically important until a large unitized flood in the North Burbank field was begun in 1950. Development was rapid and by the end of 1960, there were 70 active water flood projects and 16 active pressure-maintenance projects in the County. The locations and status of the water-flood and pressure-maintenance projects in Osage County on December 31, 1960 are shown in figure 1, and information pertaining to these projects as of July 1, 1960 is given in table 1. For the past several years, Bureau of Mines petroleum engineers have arranged tours of selected waterflooding projects for the spring meeting of the Kansas-Oklahoma Water flood Association. These tours are conducted to demonstrate unique operating methods and new field equipment and to provide additional opportunities for exchanging information. Each of these tours has been supplemented by a published report describing in detail the projects visited. This report has been prepared for distribution during the 1961 spring tour of three waterflooding projects and a pressure-maintenance project in Osage County, Okla. (fig. 2).

Jan 1, 1961

By Marcin Borecki

Una de las condiciones para aumentar los efectos económicos y la seguridad del trabajo consiste en la mejora de la preparación de los licenciados de escuelas mineras, la profundización de sus conocimientos de especialidades determinadas, la introducción de disciplinas básicas para el trabajo en la industria minera y el perfeccionamiento permanente del sobrestante en servicio. En ese sentido, el presente texto señala el uso de métodos analíticos y operacionales que se adecúen al modelo tecnológico y moderno a través del empleo de la técnica electrónica de cálculo, de forma que ayude a tomar decisiones óptimas en el proceso de gestión.

Jul 1, 1974

By A. R. T. Denues

"INTRODUCTION The orienting phases of the current investigation of cushioned blasting in the Explosives Division of the Bureau of Mines were indicated in a previous publication (5) 3/. Pertinent literature reviewed therein indicated a highly controversial field. This emphasized the need for experimental studies of many factors that affect the health and safety of miners and the efficiency of mining operations. Results of some orienting tests showed marked effects on practical hazards. Further, they emphasized the necessity and importance of the contemplated investigation. The scope and general plan of these practical inquiries into the safety of cushioned blasting were indicated.This investigation of cushioned blasting relates to the various means employed to reduce the intensity of application of energy from explosive actions in boreholes. It has been suggested (from p. 19 of reference 5) that the divisions of this work would correspond to the salient hazards affected by cushioned blasting. These include the ignition hazard, hazards from poisonous gases, and other practical hazards in the blasting technique. The ignition hazard was resolved into two components of approximately equal weight. These include studies of effects upon (1) the incendivity of blown-out shots and upon (2) the occurrence of such shots. Experimental studies of effects on the incendivity of blown-out shots were first undertaken. Questions of the best procedure for making these evaluations have been adduced, and the interpretation and utilization of the results of gallery testing seemed to require detailed attention; some preliminary general considerations of such testing were therefore necessary."

Jan 1, 1943

By Mark A. Williams

"This paper was originally intended to be a presentation of a case study of two surface bituminouscoal mines in the southern Appalachian coal fields located within five miles of each other. These mines were nearly identical in every aspect from geologic setting to equipment application. Althoughrepresentatives from each mine desired to participate in the preparation of this paper through support in providing background information and in review and editing, it was later concluded that, due to the environmental sensitivity associated with each mine, it may not have been a good decision to present this case study in a public forum."

Jan 1, 1994

By Alexis Echevarría

El presente texto describe el programa de sostenimiento, aplicación, optimización aplicado en los recursos de la mina Cobriza de Doe Run Perú. La base filosófica de dicha minera radica en la seguridad por lo que el programa debe adecuarse a las características del terreno. Paralelamente a esto, se realiza otros sistemas de sostenimiento como: "shotcrete" por vía húmeda con equipo robotizado, arcos de acero, pernos de roca y muros de sostenimiento, así como se cuenta con los instrumentos de control de desplazamientos de terrenos instalados en diversas zonas de la mina (extensómetros). Asimismo, el control de calidad de los sistemas de sostenimiento es importante porque permite optmizar los recursos y mantiene la calidad de los mismos.

Jul 31, 2003

In the Broken Hill South mine tile practice of issuing to the miner a quantity of fuse and a box of caps from which he made up the "rods" required for a particular blast, has been abandoned. Instead, capping stations have been established, and the miner can now obtain, from the magazines, fuses cut to accurate lengths with the detonators attached.Various types of fuse-cutting machines and crimping devices are available, but only those used by the Broken Hill South Mine Ltd. are described in this paper.The fuse-cutting machine, designed by the engineering staff, is an electrically driven unit fitted with a gear box for the purpose of adjusting the rate at which the fuse is fed to the cutting device, thereby enabling fuses of various lengths to be accurately severed from the main coil of fuse.The machine in question is designed to cut 4, 6, and 8-ft. fuses, but no difficulty should be experienced in designing a machine to cut fuses to any required lengths.

Jan 1, 1932

By D. Komljenovic

This paper presents the use of queuing theory in truck fleet sizing in open pit mining operations. In the first part, a methodology is developed by which an optimal ratio between the size of shovels and trucks may be determined. The second part gives the fundamentals of the queuing theory and its application in analyzing shovel and trucks. The stochastic character of involved times (loading, truck cycle, etc.) is taken into consideration. Using the above theory, the optimal truck fleet size in actual conditions may be estimated. Minimal operating cost of the working system (shovels-trucks) represents the basic requirement of the analyzed process. The methodology was validated on Caterpillar front-shovel ? truck combinations.

Sep 1, 2004

By John J. Baz-Dresch, Kenneth L. Bickel, Winthrop F. Watts

Catalyzed diesel particulate filters (CDPF's) reduce the concentration of diesel particulate matter (DPM) and may reduce the emissions of carbon monoxide (CO) and hydrocarbons (HC) in diesel exhaust. Asamera Minerals' Cannon Mine first installed CDPF's in 1987, and currently has 12 diesel- powered vehicles equipped with CDPF's. The Cannon Mine and the U.S. Bureau of Mines collaborated to evaluate the durability and performance of a CDPF. One of the CDPF's used at the mine was periodically evaluated in the USBM's diesel emissions laboratory after 839, 1,584, and 2,881 h of in-mine service. The objectives of this report are to present results from the USBM's evaluation of this CDPF, to describe the Cannon Mine's experience and cost analysis of using CDPF's, and to make recommendations for the future use of CDPF's. CDPF's improve air quality at the Cannon Mine, but they frequently become plugged and are subject to excessive mechanical shocks and stress, shortening their useful life. Mine records indicate that CDPF's account for 0.8 to 4.9 pct of the vehicles' operating cost at the mine. CDPF life to date has ranged from 1,671 h to more than 5,992 h. Laboratory tests of the CDPF determined that DPM removal efficiency decreased and regeneration temperature increased over time.

Jan 1, 1994

By A. D. Davis, J. L. Sorensen, C. J. Webb

Environmental impacts from acidic mine drainage are growing national concerns that are particularly acute in the headwaters of the Rocky Mountain region. In the Black Hills of South Dakota, approximately one thousand mines are inactive or abandoned, most of them in the headwaters of major drainages. This paper examines the Bear Butte Creek basin, a heavily mineralized watershed with significant historical mining impacts and a surface gold mine permitted in 1997. The watershed loses its surface discharge to swallow holes in the karstic Madison Limestone. The integrity of the aquatic ecosystem was monitored with a suite of sitespecific bio-indicators. Stream surveys covered the entire reach of Bear Butte Creek from near its headwaters to the swallow holes in the Madison aquifer. Data from the stream surveys, water-quality sampling, and bio-indicator surveys clearly showed that water-quality impacts are limited mainly to Strawberry Creek and to the area of Bear Butte Creek near and downstream of the town of Galena.

Jan 1, 1999

By P. Mbele

Iron ore concentrate is not easily transported to, or processed in, ironmaking plants, therefore it is necessary to agglomerate. This paper will determine the possibility of agglomerating Sishen concentrate into suitable ironmaking feedstock. Pelletizing is one of the conventional and preferred agglomeration processes for iron ore concentrate investigated at Kumba Value-In-Use Laboratories. Sishen concentrate was mixed with binder, and then pelletized using a laboratory pelletizing disc; afterwards the green pellets were indurated at high temperatures to give strength high enough to survive handling and lessen disintegration in the shaft during ironmaking. Sishen pellets have satisfactory physical and metallurgical properties which make them suitable feedstock for the direct reduction processes. These were tested under Midrex shaft operational conditions and performed well, with a metallization of 94.47% being attained.

Jan 1, 2012

By Harry Perry

One of the most notable achievements of the iron and steel industry in the United States in this century has been the general increase in productivity of individual blast furnaces and the reduction in coke rate. Most of the improvement in furnace operations has occurred within the past decade. During this time the output of the average furnace increased about one-third, while fuel rates decreased from 15 to 20 percent. For example, in 1949, the iron and steel industry produced 811.2 short tons of pig iron per blast-furnace day with a coke rate of 1,870.4 pounds per ton of pig iron, By 1960, the average production of pig iron per blast-furnace day had risen to 1,182.4 tons, while the coke rate had decreased to 1,497 pounds per ton of pig iron. These figures are averages for the entire industry; many furnaces produced over 2,000 tons per day and one furnace, operating on pellets, reached 2,700 tons of pig iron per day, Coke rates of individual furnaces varied, but some furnaces operated on less than 1,200 pounds per ton of pig iron. The significance of this decrease in coke rate is shown clearly when data on pig-iron production and coke consumption in 1959 are compared with 1948. In 1948, 57.3 million short tons of coke was charged into blast furnaces to produce 60.1 million tons of pig iron; in 1959 only 47.6 million tons of coke was needed to produce 60.2 million tons of pig iron. Thus, in 1959, nearly 10 million tons less coke was required to produce about the same amount of pig iron as was produced in 1948.

Jan 1, 1962

By Cesar Ccorahua, Pabel Alvarado

Los diseños de Open Pit con la Linea Media Del Banco, son la forma más eficaz de construir diseños de Open Pit. El diseño de un Pit puede cambiar en función de los precios de los metales, los costos y otras restricciones económicas, geológicas y ambientales; Estas restricciones deben establecerse en el modelo de bloque y debe establecerse una variable numérica y categórica específica. Los profesionales deben informar lo que está en el diseño basado en el Modelo de Bloques. Aunque el diseño se considera lento en software 3D, el diseño de la línea media del banco ejemplifica la flexibilidad y la eficiencia.

Sep 1, 2017

By Victor F. Paterno

In December of 2007, a joint venture of J.F Shea, Skanska and Schiavone referred to as S-3II, was awarded a $1.15 billion (? 886,880,000) contract to construct the run-ning tunnels and station structures for the Number 7 Line Extension Project in New York City by the Metropolitan Transportation Authority Capital Construction (MTACC) and New York City Transit (NYCT). As part of the contract, a technically complex and critical connection of the new tunnel to the existing, operational 7 Line subway was required. This paper describes the innovative design approach that was conceived to carry out the underpinning and excavation works both within the east-west 7 Line subway tunnel and beneath the north-south, 4 track, 2 level Times Square Station for the A, C & E trains. This underpinning provided temporary support to the subway substructure as the grade of the tunnel invert was lowered up to 10 feet (3 meters) into the rock sub-grade to allow the future subway to pass under the basement of the world?s busiest bus terminal. In addition, the creation of a new portal connecting the existing subway tunnel and the subterranean level of the Port Authority Bus Terminal by means of underpinning structural footings and horizontal spiling/poling of existing ground will be discussed.

Jan 1, 1961

By Paul Swatkowski

A Note About Copyrighted Material ??Permission to Use? has been granted ?Teachthe7habits ?Think win/win (4thHabit) ?Don?t stop here ?i.e., buy the book

Jan 1, 2009

By L. P. Lamprecht

Traditionally, South African shaft sinking operations have used electric detonators for the initiation of blastholes. Globally, the trend in shaft sinking is to use the shock tube and detonating cord (STDC) initiation system, with value adding benefits. In pursuing this global trend, Cementation Mining of South Africa in partnership with SMX have ventured the STDC route. This paper explores the work carried out to date, and identifies a number of benefits to be gained by using the system.

Jan 1, 1999

By Francisco Grimaldo

La minera de Cerro de Pasco cuenta con una mina polimetálica de plomo, zinc y plata con mineralogía compleja, cuyo yacimiento principal se desarrolla en los cuerpos mineralizados de Sílica-Pirita, generador de aguas ácidas. Sin embargo, las filtraciones, el minado y los minerales acumulados en stock piles de diferente composición mineralógica han generado aguas ácidas subterráneas y superficiales que se caracterizanpor su alto contenido de metales pesados (hierro y zinc). En ese sentido, el presente texto señala dos proyectos contenidos en el PAMA que buscan reducir el problema ambiental generado por las aguas ácidas y abastecer las necesidades de agua de sus procesos industriales. El primer proyecto comprende la separación de aguas neutras del interior de la mina subterránea, mientras que el segundo, la construcción de la planta de neutralización de alta densidad.

Jul 31, 2003

By Philip E. Niebuhr

A procedure, which can be performed in the field by nonanalytical personnel, is given for sensitive spot tests for detecting tellurium or selenium. The expressed need of a field test for detecting small amounts of tellurium, which may be accompanied by relatively large amounts of selenium, has led to the development of this method. Tellurium search has been impeded by the lack of a satisfactory test from the standpoint of sensitivity and specificity. A quantitative laboratory method exists, but it is expensive and relatively laborious. Several other qualitative tests are known, but they require unstable solutions, which must be freshly prepared for use, and a greater variety of laboratory equipment. The particular advantages of the test described are its simplicity and the stability of the reagents required, there-fore is is well adapted for field use. Also, this test was found to be of practical use in the analytical laboratory when screening samples, thereby reducing analytical costs. The roughly quantitative interpretation of the results can save time by indicating the approximate size of the sample taken for a quantitative determination.

Jan 1, 1962

By S. Dalton

The use of coal for power generation is being questioned in many developed countries, as a result of ever-tightening environmental restrictions and concerns about the potential impact of CO2emissions on climate. Coal will continue to be the fuel of choice for new power plants for many developing countries with large percentages of the world?s population, because of its relatively low cost and broad availability. Even in many of the developed countries that are under pressure, coal will continue to fuel large percentages of power due to the installed base. Using coal efficiently and in an environmentally responsible manner will be a challenge for technology and politics in this new century, with the politics played out on the world stage. Coal use will vary in the next few decades, including short-term changes such as the use of more diverse coals and the increased use of efficient ultra-supercritical boilers to longer term ?refining? of coal to produce a range of energy and chemical outputs. This paper outlines EPRI?s Global Coal Initiative aimed at needed developments and demonstrations that support the long-term vision of environmentally sound and economical coal use for power generation, and discusses some of the forces that are driving this development effort.

Jan 1, 2001