DOCSLIB.ORG

Uranium Mining in Virginia

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Uranium Mining in Virginia Nontechnical Summary Uranium Mining in Virginia In recent years, there has been renewed interest in mining uranium in the Common- wealth of Virginia. However, before any mining can begin, Virginia’s General Assembly would have to rescind a statewide moratorium on uranium mining that has been in effect since 1982. The National Research Council was commissioned to provide an independent review of the scientific, environmental, human health and safety, and regulatory aspects of uranium mining, processing, and reclamation in Virginia to help inform the public discussion about uranium mining and to assist Virginia’s lawmakers in their deliberations. eneath Virginia’s convene an independent rolling hills, there committee of experts to Bare occurrences of write a report that described uranium—a naturally occur- the scientific, environmental, ring radioactive element that human health and safety, and can be used to make fuel for regulatory aspects of mining nuclear power plants. In the and processing Virginia’s 1970s and early 1980s, work to uranium resources. Addi- explore these resources led to tional letters supporting this the discovery of a request were received from large uranium deposit at Coles U.S. Senators Mark Warner Hill, which is located in and Jim Webb and from Pittsylvania County in southern Governor Kaine. The Virginia. However, in 1982 the National Research Council Commonwealth of Virginia study was funded under a enacted a moratorium on contract with the Virginia uranium mining, and interest in Center for Coal and Energy further exploring the Coles Hill Research at Virginia deposit waned. Polytechnic Institute and In 2007, two families living in the vicinity of State University (Virginia Tech). Funding for Coles Hill formed a company called Virginia the study was provided to Virginia Tech by Uranium, Inc. to begin exploring the uranium Virginia Uranium, Inc. The expert members of deposit once again. Since then, there have been the National Research Council committee calls for the Virginia legislature to lift the served as volunteers, without payment for their uranium mining moratorium statewide. time, for the 18-month period during which the To help inform deliberations on the possi- study was conducted. bility of future uranium mining in Virginia, the The resulting report is intended to provide Virginia Coal and Energy Commission an independent scientific and technical review requested that the National Research Council to inform the public and the Virginia legislature. The report does not focus on the Coles Hill deposit, but instead considers uranium mining, processing, What Is Uranium? and reclamation in the Commonwealth of Virginia Uranium is a radioactive element found at low as a whole. The committee was not asked to consider concentrations in virtually all rock, soil, and the benefits of uranium mining either to the nation seawater. Significant concentrations of uranium or to the local economy, nor was it asked to assess can occur in phosphate rock deposits and the relative risks of uranium mining compared with minerals such as pitchblende and uraninite. the mining and processing of other fuels, for example coal. The committee was also not asked to make any recommendations about whether or not uranium mining should be permitted in the Commonwealth of Virginia. What is Uranium Used For? The main commercial use of uranium is to make fuel for nuclear power reactors, which provide 20 percent of electricity generation in the United States. As with power stations fueled by fossil fuels Figure 1. A sample of the uranium-containing mineral uraninite. such as coal or natural gas, nuclear power stations Photograph by Andrew Silver, Brigham heat water to produce steam that in turn drives Young University. Image courtesy of turbines to generate electricity. In a nuclear power the United States Geological Survey. station, the nuclear fission of uranium atoms replaces the burning of coal or gas. shown in Figure 2) of concentrated uranium. Projections for future energy use by the Nuclear Predicting Future Demand for Uranium Energy Agency and the International Atomic Energy The market for uranium is driven by the electric Agency show that by 2035, reactors in the United power industry’s need for nuclear power. As of States are expected to require 12,000 – 25,000 short November 2011, the United States has 104 nuclear tons (10886 – 22680 metric tonnes) of uranium per reactors in operation, and in 2011 these reactors year. In 2010, the United States imported 92 percent required 20,256 short tons (18,376 metric tonnes, as of the uranium that it needed to fuel its nuclear power stations. Understanding future uranium demand is diffi- cult because it is hard to predict when aging reac- tors will be retired, and when new reactors will be constructed. Also, unan- ticipated events at nuclear power plants, such as the Chernobyl or Fukushima accidents, could affect how people and governments plan for and utilize nuclear power. This impacts demand for nuclear energy Figure 2. Projections for uranium requirements to fuel nuclear reactors in the United States and, therefore, uranium. through 2035. Source: Compiled from data in NEA/IAEA (2010). – 2 – Where does the Supply of Uranium Come From? Uranium comes from mining uranium ore deposits, from existing stockpiles held by government and commercial entities, and from recycling uranium from sources such as nuclear warheads. In 2009, world uranium mining fulfilled 74 percent of world reactor requirements, and the remaining 26 percent came from secondary sources such as stockpiles and decommissioned warheads. Uranium was produced in 20 countries in 2010, but eight countries accounted for more than 92 percent of the world’s Figure 3. World uranium production in 2010. Eight countries accounted for more than uranium production (see 92 percent of global uranium production. Figure 3). The United States Source: WNA (2011) produced 3 percent of global uranium. Overall, world uranium primary production production increased markedly from 2003 to 2006, increased steadily between 2000 and 2009, with but then slowed due to operational challenges and Kazakhstan, Namibia, Australia, Russia, and Brazil lower uranium prices. showing marked increases between 2006 and 2009 to Geological exploration has identified more offset decreased production in Canada, Niger, United than 55 occurrences of uranium in Virginia (see States, and the Czech Republic. In the United States, Figure 4). These are located primarily in the Figure 4. Uranium occurrences (not necessarily uranium ore deposits) identified in Virginia so far. The red square in the lower, central portion of the map indicates the Coles Hill deposit. Source: Adapted from Lassetter (2010). – 3 – Piedmont and Blue Ridge regions. In order for a uranium occurrence to be considered a commer- What Are Tailings? cially exploitable source of uranium ore, it must The solid waste remaining after recovery of be of sufficient size, appropriate grade (have uranium from uranium ore in a processing plant enough uranium compared to the other rock in the are the ‘tailings.’ Tailings consist of everything deposit) and be amenable to mining and processing. that was in the ore except the extracted uranium. Of the sites explored in Virginia so far, only the Tailings from uranium mining and processing deposit at Coles Hill is large enough, and of a high operations contain radioactive materials enough grade, to be potentially economically viable. remaining from the radioactive decay of uranium, such as thorium and radium. Tailings are The Lifecycle of a Uranium Mine and typically neutralized and compacted to reduce Processing Facility water content, and then stored in tailings impoundment facilities either above or below the The process of taking uranium ore out of the local ground surface; modern best practice is for ground and transforming it into yellowcake—as storage below the ground surface. well as the cleanup and reclamation of the site during mining and processing operations as well as after operations have ceased—includes several remove impurities and produce yellowcake. This components: involves both physical processes (such as crushing and/or grinding) and chemical processes (i.e., Mining: There are three types of mining that could dissolving uranium from ore using acids or bases, be used to extract uranium ore from the ground. called leaching). Separation, drying, and packaging These are open pit mining, underground mining, are also part of the sequence of uranium processing and in situ (‘in place’) leaching/in situ recovery steps. The choice of the type of processing depends (ISL/ISR—the process of recovering the uranium on the nature of the uranium ore and its host rock from the ground by dissolving the uranium minerals as well as environmental, safety, and economic in liquid underground and then pumping that liquid factors. During uranium ore processing, several to the surface, where the uranium is then taken waste products are created, including tailings or out of the solution). In effect, ISL/ISR combines leached residue (the solid waste remaining after mining and some of the processing steps. The recovery of uranium in a processing plant, see box), choice of mining method depends on many factors, and waste water. including the quality and quantity of the ore, the shape and depth of the ore deposit, the type of rock Reclamation: Reclamation and cleanup to return surrounding the ore deposit, and a wide range of the site to as close as possible to its pre-mining site-specific environmental conditions. Because of state can occur either while the site is being the geology in the Commonwealth of Virginia, it is mined, or after mining and processing operations very unlikely that ISL/ISR can be used to extract are complete. Reclamation includes decontamina- uranium anywhere in the state. Accordingly, the tion and cleanup, such as demolition of buildings report focuses on conventional mining—open pit and other structures, to prepare the area of the mining and underground mining, and the processing mining site and processing facility for other of the ore that comes from conventional mines.
Load more

Recommended publications
  • Environmental Impacts of Uranium Mining in Australia History, Progress and Current Practice
    A policy paper commissioned MAY 2017 by the Minerals Council of Australia Environmental impacts of uranium mining in Australia History, progress and current practice Ben Heard POLICY PAPER Environmental impacts of uranium mining in Australia History, progress and current practice Ben Heard is a doctoral researcher at the University of Adelaide, focusing on clean energy systems and the potential role of nuclear technologies. He holds a Masters in Corporate Environmental and Sustainability Management from Monash University and was an environmental sustainability consultant from 2005-2016. He has taught several units of the Masters of Sustainability at the University of Adelaide and is an honourary member of the Leaders Institute of South Australia. His most recent research paper Burden of proof: A comprehensive review of the feasibility of 100% renewable-electricity systems was published in the journal Renewable and Sustainable Energy Reviews. The Minerals Council of Australia is the peak national body representing Australia’s exploration, mining and minerals processing industry, nationally and internationally, in its contribution to sustainable economic, and social development. This publication is part of the overall program of the MCA, as endorsed by its Board of Directors, but does not necessarily reflect the views of individual members of the Board. Minerals Council of Australia Level 3, 44 Sydney Ave, Forrest ACT 2603 (PO Box 4497, Kingston ACT Australia 2604) P. + 61 2 6233 0600 | F. + 61 2 6233 0699 www.minerals.org.au | [email protected] Copyright © 2017 Minerals Council of Australia. All rights reserved. Apart from any use permitted under the Copyright Act 1968 and subsequent amendments, no part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior written permission of the publisher and copyright holders.
    [Show full text]
  • THESIS URANIUM CONTAMINATION VALUES and LIMITS Submitted By
    THESIS URANIUM CONTAMINATION VALUES AND LIMITS Submitted by Aaron Paul Miaullis Department of Environmental and Radiological Health Sciences In partial fulfillment of the requirements For the Degree of Master of Science Colorado State University Fort Collins, Colorado Summer 2012 Master’s Committee: Advisor: Thomas Johnson Co-Advisor: Alexander Brandl Thomas Borch Copyright by Aaron Paul Miaullis, 2012 All Rights Reserved ABSTRACT URANIUM CONTAMINATION VALUES AND LIMITS Hypothesis: Current soil contamination limits for non-enriched uranium are not consistent and are not optimized to allow the beneficial use of uranium while protecting the health of the public. Objective: Assess available health impact data regarding non-enriched uranium ingestion and inhalation as well as past soil contamination recommendations to determine if the regulatory limits for uranium are optimized, as recommended by the ICRP. Provide supporting data for keeping current soil contamination limits for non-enriched uranium, or suggest new limits based upon chemical uptake ratios. ii ACKNOWLEDGEMENTS I would like to thank the following persons for their help, guidance, mentoring, and support during the research and compilation of this paper: The Lord God My family: Maureen, Nicholas, Caitlin and Helena Miaullis My parents: J. Bart Miaullis and Laura White The United States Army Dr. Tom Johnson Dr. Alexander Brandl An additional thank you to the following people for providing their time and effort in obtaining and providing much needed reference material: LTC Andrew Scott, PhD, US Army MAJ(R) Carlos Corredor Steve Brown The Armour Archive Finally, thanks to the significant number of other individuals with whom I have conversed and discussed many additional points within this paper.
    [Show full text]
  • Nuclear Power
    FEBRUARY 28, 2013 | No. 757 NUCLEAR POWER: LOOKING BACK, LOOKING FORWARD (NM757.4292) Last year marked the 20th anniversary of the fi rst edition of the World Nuclear Industry Status Report (WNISR). For two decades the reports have punctu- red the lies of the nuclear industry. Mycle Schneider and Antony Froggatt wrote the 2012 edition and both contributed to the 1992 edition − congratulations Mycle and NUCLEAR POWER: LOOKING Antony! BACK, LOOKING FORWARD 1 FUKUSHIMA PROPAGANDA 4 The predictions made in WNISR-1992 stack up well. After a 20-year period of signi- fi cant growth, the report correctly predicted that nuclear expansion would "slow to a URANIUM MINING ISSUES: trickle". From 1992 to 2012, worldwide nuclear power capacity increased from 326 2012 REVIEW 8 gigawatts (GW) to 374 GW − a 15% increase in 20 years. IN BRIEF 18 The nuclear industry is fi nally catching up with Mycle and Antony. The International Atomic Energy Agency's 'low' estimates have become a more reliable guide over the years, and the Agency's current 'low' estimate of 456 GW capacity in 2030 suggests very slow annual growth of around 1.5% (IAEA, 2012). Nuclear power's proportional contribution to world electricity production will certainly decline. Nuclear's contribution peaked at 17% in 1993, fell to 12.3% in 2011, and the IAEA estimates just 4.7−6.2% in 2030 (IAEA, 2012, p.17). By 2030, a majority of the world's reactors will be nearing the end of their operating lives and the nuclear industry will need to run just to stand still.
    [Show full text]
  • Geology of U Rani Urn Deposits in Triassic Rocks of the Colorado Plateau Region
    Geology of U rani urn Deposits in Triassic Rocks of the Colorado Plateau Region By W. I. FINCH CONTRIBUTIONS TO THE GEOLOGY OF URANIUM GEOLOGICAL SURVEY BULLETIN 1074-D This report concerns work done on behalf ~1 the U. S. Atomic Energy Commission -Jnd is published with the permission of ~he Commission NITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1959 UNITED STATES DEPARTMENT OF THE INTERIOR FRED A. SEATON, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director For sale by the Superintendent of Documents, U. S. Government Printin~ Office Washin~ton 25, D. C. CONTENTS Page Abstract---------------------------------------------------------- 125 Introduction__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 125 History of mining and production ____ ------------------------------- 127 Geologic setting___________________________________________________ 128 StratigraphY-------------------------------------------------- 129 ~oenkopiformation_______________________________________ ~29 Middle Triassic unconformity_______________________________ 131 Chinle formation__________________________________________ 131 Shinarump Inernber____________________________________ 133 ~udstone member------------------------------------- 136 ~oss Back member____________________________________ 136 Upper part of the Chinle formation______________________ 138 Wingate sandstone_________________________________________ 138 lgneousrocks_________________________________________________ 139 Structure_____________________________________________________
    [Show full text]
  • Uranium Fact Sheet
    Fact Sheet Adopted: December 2018 Health Physics Society Specialists in Radiation Safety 1 Uranium What is uranium? Uranium is a naturally occurring metallic element that has been present in the Earth’s crust since formation of the planet. Like many other minerals, uranium was deposited on land by volcanic action, dissolved by rainfall, and in some places, carried into underground formations. In some cases, geochemical conditions resulted in its concentration into “ore bodies.” Uranium is a common element in Earth’s crust (soil, rock) and in seawater and groundwater. Uranium has 92 protons in its nucleus. The isotope2 238U has 146 neutrons, for a total atomic weight of approximately 238, making it the highest atomic weight of any naturally occurring element. It is not the most dense of elements, but its density is almost twice that of lead. Uranium is radioactive and in nature has three primary isotopes with different numbers of neutrons. Natural uranium, 238U, constitutes over 99% of the total mass or weight, with 0.72% 235U, and a very small amount of 234U. An unstable nucleus that emits some form of radiation is defined as radioactive. The emitted radiation is called radioactivity, which in this case is ionizing radiation—meaning it can interact with other atoms to create charged atoms known as ions. Uranium emits alpha particles, which are ejected from the nucleus of the unstable uranium atom. When an atom emits radiation such as alpha or beta particles or photons such as x rays or gamma rays, the material is said to be undergoing radioactive decay (also called radioactive transformation).
    [Show full text]
  • A Prospector's Guide to URANIUM Deposits in Newfoundland and Labrador
    A Prospector's guide to URANIUM deposits In Newfoundland and labrador Matty mitchell prospectors resource room Information circular number 4 First Floor • Natural Resources Building Geological Survey of Newfoundland and Labrador 50 Elizabeth Avenue • PO Box 8700 • A1B 4J6 St. John’s • Newfoundland • Canada pros pec tor s Telephone: 709-729-2120, 709-729-6193 • e-mail: [email protected] resource room Website: http://www.nr.gov.nl.ca/mines&en/geosurvey/matty_mitchell/ September, 2007 INTRODUCTION Why Uranium? • Uranium is an abundant source of concentrated energy. • One pellet of uranium fuel (following enrichment of the U235 component), weighing approximately 7 grams (g), is capable of generating as much energy as 3.5 barrels of oil, 17,000 cubic feet of natural gas or 807 kilograms (kg) of coal. • One kilogram of uranium235 contains 2 to 3 million times the energy equivalent of the same amount of oil or coal. • A one thousand megawatt nuclear power station requiring 27 tonnes of fuel per year, needs an average of about 74 kg per day. An equivalent sized coal-fired station needs 8600 tonnes of coal to be delivered every day. Why PROSPECT FOR IT? • At the time of writing (September, 2007), the price of uranium is US$90 a pound - a “hot” commodity, in more ways than one! Junior exploration companies and major producers are keen to find more of this valuable resource. As is the case with other commodities, the prospector’s role in the search for uranium is always of key importance. What is Uranium? • Uranium is a metal; its chemical symbol is U.
    [Show full text]
  • Tailings and Their Component Radionuclides from the Biosphere-Some Earth Science Perspectives
    Tailings and Their Component Radionuclides From the Biosphere-Some Earth Science Perspectives Isolation of Uranium Mill Tailings and Their Component Radionuclides From the Biosphere-Some Earth Science Perspectives By Edward Landa GEOLOGICAL SURVEY CIRCULAR 814 A critical review of the literature dealing with uranium mill tailings, with emphasis on the geologic and geochemical processes affecting the long-term containment of radionuclides 1980 United States Department of the Interior CECIL D. ANDRUS, Secretary Geological Survey H. William Menard, Director Library of Congress catalog-card No. 79-600148 Free on application to Branch of Distribution, U.S. Geological Survey 1200 South Eads Street, Arlington, VA 22202 CONTENTS Page Abstract 1 Introduction ------------------------------------------------------------­ 1 Acknowledginents ---------_----------------------------------------------- 2 Quantity and location of the tailings --------------------------------------­ 2 Radioactivity in tailings --------------------------------------------------­ 4 Sources of potential human radiation exposure from uranium mill tailings ------ 6 Radon emanation ----------------------------------------------------- 6 VVind transport ------------------------------------------------------- 6 Surface water transport and leaching ----------------------------------- 7 External gamma radiation -------------------------------------------­ 8 Contamination of terrestrial and aquatic vegetation ---------------------- 8 Seepage ----------------------------------------------------~--------
    [Show full text]
  • The Nuclear Fuel Cycle
    THE COLLECTION > From the uranium mine> toI wNTasRtOeD dUisCpToIsOaN l 1 > The atom 2 > Radioactivity 3 > Radiation and man 4 > Energy 5 > Nuclear energy: fusion and fission 6 > How a nuclear reactor works 7 > The nuclear fuel cycle 7 > The nuclear fuel cycle FROM RESEARCH 8 > Microelectronics 9 > The laser: a concentrate of light TO INDUSTRY 10 > Medical imaging 11 > Nuclear astrophysics 12 > Hydrogen 7 >>TThhee nnuucclleeaarr ffuueell ccyyccllee UPSTREAM THE REACTOR: PREPARING THE FUEL IN THE REACTOR: FUEL CONSUMPTION DOWNSTREAM THE REACTOR: REPROCESSING NUCLEAR WASTE NUCLEAR WASTE © Commissariat à l’’Énergie Atomique et aux Energies Alternatives, 2005 Communication Division Bâtiment Siège - 91191 Gif-sur-Yvette cedex www.cea.fr ISSN 1637-5408. From the uranium mine to waste disposal 7 > The nuclear fuel cycle From the uranium mine to waste disposal 7 > The nuclear fuel cycle 2 > CONTENTS > INTRODUCTION 3 Uranium ore is extracted from open-pit mines – such as the McClear mines in Canada seen here – or underground workings. a m e g o C © “The nuclear fuel cycle includes an erray UPSTREAM THE REACTOR: of industrial operations, from uranium PREPARING THE FUEL 4 e mining to the disposal of radioactive l Extracting uranium from the ore 5 waste.” c Concentrating and refining uranium 6 y Enriching uranium 6 c Enrichment methods 8 l introduction uel is a material that can be burnt to pro - IN THE REACTOR: FUEL CONSUMPTION 9 Fvide heat. The most familiar fuels are wood, e Preparing fuel assemblies 10 coal, natural gas and oil. By analogy, the ura - e g a nium used in nuclear power plants is called Per unit or mass (e.g.
    [Show full text]
  • Measurement and Calculation of Radon Releases from Uranium Mill Tailings
    I I I I I I I I I io-1 ^*"^^-dL ^-. : tfl ^^ ^-----^_ • . w 2 E 10- _o^ Q • " ^N^^v +-*m "•'•^^N• ^«Nr \ S 10-3 0 • •• VN V it; 0 . • •• *>*v* * O • ^* \ O 10 vV\ \ • 1 ^ • Measured diffusion coefficients # X\ >« CO 3 p = 0.41 • ,\v i\N TJ P - 0.55 (top), 0.26 (bottom) N C 0 10-5 ~ Fitted function: r -, • *• 2 5 QC D = 0.07 exp -4 (m - mn + m ) • • • 10-6 ! I I 1 I I I I I c ) 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Moisture saturation, m TECHNICAL REPORTS SERIES No 333 Measurement and Calculation of Radon Releases from Uranium Mill Tailings if sk\ \ %}$?J INTERNATIONAL ATOMIC ENERGY AGENCY, VIENNA, 1992 MEASUREMENT AND CALCULATION OF RADON RELEASES FROM URANIUM MILL TAILINGS The following States are Members of the Internationa! Atomic Energy Agency: AFGHANISTAN HAITI PANAMA ALBANIA HOLY SEE PARAGUAY ALGERIA HUNGARY PERU ARGENTINA ICELAND PHILIPPINES AUSTRALIA INDIA POLAND AUSTRIA INDONESIA PORTUGAL BANGLADESH IRAN, ISLAMIC REPUBLIC OF QATAR BELARUS IRAQ ROMANIA BELGIUM IRELAND RUSSIAN FEDERATION BOLIVIA ISRAEL SAUDI ARABIA BRAZIL ITALY SENEGAL BULGARIA JAMAICA SIERRA LEONE CAMEROON JAPAN SINGAPORE CANADA JORDAN SOUTH AFRICA CHILE KENYA SPAIN CHINA KOREA, REPUBLIC OF SRI LANKA COLOMBIA KUWAIT SUDAN COSTA RICA LEBANON SWEDEN COTE D'lVOIRE LIBERIA SWITZERLAND CUBA LIBYAN ARAB JAMAHIRIYA SYRIAN ARAB REPUBLIC CYPRUS LIECHTENSTEIN THAILAND CZECHOSLOVAKIA LUXEMBOURG TUNISIA DEMOCRATIC KAMPUCHEA MADAGASCAR TURKEY DEMOCRATIC PEOPLE'S MALAYSIA UGANDA REPUBLIC OF KOREA MALI UKRAINE DENMARK MAURITIUS UNITED ARAB EMIRATES DOMINICAN REPUBLIC MEXICO
    [Show full text]
  • Regional Geology and Ore-Deposit Styles of the Trans-Border Region, Southwestern North America
    Arizona Geological Society Digest 22 2008 Regional geology and ore-deposit styles of the trans-border region, southwestern North America Spencer R. Titley and Lukas Zürcher Department of Geosciences, University of Arizona, Tucson, AZ, 85721, USA ABSTRACT Nearly a century of independent geological work in Arizona and adjoining Mexico resulted in a seam in the recognized geological architecture and in the mineralization style and distribution at the border. However, through the latter part of the 20th century, workers, driven in great part by economic-resource considerations, have enhanced the understanding of the geological framework in both directions with synergistic results. The ore deposits of Arizona represent a sampling of resource potential that serves as a basis for defining expectations for enhanced discovery rates in contiguous Mexico. The assessment presented here is premised on the habits of occurrence of the Arizona ores. For the most part, these deposits occur in terranes that reveal distinctive forma- tional ages, metal compositions, and lithologies, which identify and otherwise constrain the components for search of comparable ores in adjacent crustal blocks. Three basic geological and metallogenic properties are integrated here to iden- tify the diagnostic features of ore genesis across the region. These properties comprise: (a) the type and age of basement as identified by tectono-stratigraphic and geochemi- cal studies; (b) consideration of a major structural discontinuity, the Mojave-Sonora megashear, which adds a regional structural component to the study and search for ore deposits; and (c) integration of points (a) and (b) with the tectono-magmatic events over time that are superimposed across terranes and that have added an age component to differing cycles of rock and ore formation.
    [Show full text]
  • 1 Introduction
    1 Introduction WHO commissions reviews and undertakes health risk assessments associated with exposure to potentially hazardous physical, chemical and biological agents in the home, work place and environment. This monograph on the chemical and radiological hazards associated with exposure to depleted uranium is one such assessment. The purpose of this monograph is to provide generic information on any risks to health from depleted uranium from all avenues of exposure to the body and from any activity where human exposure could likely occur. Such activities include those involved with fabrication and use of DU products in industrial, commercial and military settings. While this monograph is primarily on DU, reference is also made to the health effects and behaviour of uranium, since uranium acts on body organs and tissues in the same way as DU and the results and conclusions from uranium studies are considered to be broadly applicable to DU. However, in the case of effects due to ionizing radiation, DU is less radioactive than uranium. This review is structured as broadly indicated in Figure 1.1, with individual chapters focussing on the identification of environmental and man-made sources of uranium and DU, exposure pathways and scenarios, likely chemical and radiological hazards and where data is available commenting on exposure-response relationships. HAZARD IDENTIFICATION PROPERTIES PHYSICAL CHEMICAL BIOLOGICAL DOSE RESPONSE RISK EVALUATION CHARACTERISATION BACKGROUND EXPOSURE LEVELS EXPOSURE ASSESSMENT Figure 1.1 Schematic diagram, depicting areas covered by this monograph. It is expected that the monograph could be used as a reference for health risk assessments in any application where DU is used and human exposure or contact could result.
    [Show full text]
  • REGULATORY GUIDE 3.59 (Task WM 407-4)
    0 U.S. NUCLEAR REGULATORY COMMISSION March 1987 )0C REGULATORY GUIDE 11-1 , ****41r' OFFICE OF NUCLEAR REGULATORY RESEARCH REGULATORY GUIDE 3.59 (Task WM 407-4) METHODS FOR ESTIMATING RADIOACTIVE AND TOXIC AIRBORNE SOURCE TERMS FOR URANIUM MILLING OPERATIONS USNRC REGULATORY GUIDES The guides are issued in the following ten broad divisions: Regulatory Guides are issued to describe and make available to the public methods acceptable to the NRC staff of Implementing 1. Power Reactors 6. Products specific parts of the Commission's regulations, to delineate tech 2. Research and Test Reactors 7. Transportation niques used by the staff In evaluating specific problems or postu 3. Fuels and Materials Facilities 8. Occupational Health lated accidents or to provide guidance to applicants. Regulatory 4. Environmental and Siting 9. Antitrust and Financial Review Guides are not substitutes for regulations, and compliance with 5. Materials and Plant Protection 10. General them is not required. Methods and solutions different from those set out in the guides will be acceptable if they provide a basis for the findings requisite to the issuance or continuance of a permit or Copies of issued guides may be purchased from the Government license by the Commission. Printing Office at the current GPO price. Information on current GPO prices may be obtained by contacting the Superintendent of -This guide was issued after consideration of comments received from Documents, U.S. Government Printing Office, Post Office Box the public. Comments and suggestions for improvements in these 37082, Washington, DC 20013-7082, telephone (202)275-2060 or guides are encouraged at all times, and guides will be revised, as (202)275-2171.
    [Show full text]