Open-File Report 06-19
Nevada Uranium and Thorium Occurrences
byThis database supersedes the occurrence descriptions in Nevada Bureau of Mines and Geology (NBMG) Bulletin 81 (Garside, 1973) and those in a partial update of that bulletin, NBMG Open-File Report 79-2 (Garside, 1979). However, Garside (1973) also included introductory text, figures, and descriptions of uranium and thorium minerals. With the occurrence descriptions from the bulletin and open-file report as a starting point, we added descriptions of new occurrences and made many additions, corrections, and improvements to the older descriptions. New information came mainly from geologic literature published after 1973, with some data from new field examinations.
NO.: Unique number assigned to each entry. The records are arranged by county, and commonly within counties alphabetically by the first-listed name.
NAME: This field contains the most commonly used name for the mine, prospect, or occurrence. In many cases, the name is that of the claims that were staked on the property when it was first examined. In some cases, the number of mining claims reported to have been staked is listed. The spelling is as reported in the reference(s); no attempt was made to indicate possible erroneous spellings (for example, by [sic]). If improved location data suggested that properties originally described together are actually separated by considerable distance (very generally, a kilometer or more), separate descriptions were made.
OTHER NAME: Any other, commonly less used, names are included in this field. Also included are alternative spellings. For properties for which there is doubt about the correlation to the primary name, the name is queried.
COUNTY: The county in which the property is located.
LOCATION: The Public Lands Survey location (Township, Range, Section, quarter or half section) is listed in this field. Some properties are described as being in parts of more than one section or township. In many cases, the location is given only to a section; the more exact location is given by the UTM (Universal Trans Mercator) coordinates. Quarter sections are described as ¼ and half sections as ½. Unsurveyed means the section corners in a particular township have not been located and were not shown on topographic maps. If the location is described as protracted, sections have not been surveyed in the area, and the location was estimated from protracted sections shown on the U.S. Geological Survey 1:100,000-scale topographic maps. Projected sections were estimated by projection of section lines from adjacent surveyed sections as shown on topographic maps. In general, “exact location unknown,” indicates less certainty of location than “exact location uncertain.”
MERIDIAN: Nevada has two meridians, Mt. Diablo Baseline and Meridian, and San Bernardino Baseline and Meridian. In Nevada, all but 7 townships are located in the Mt. Diablo Baseline and Meridian. All of the described radioactive occurrences are in townships of the Mt. Diablo Baseline and Meridian.
UTMN, UTME: The Universal Trans Mercator grid northing and easting. This was determined in a variety of ways: directly from U.S. Geological Survey 1:24,000-scale topographic maps, from digital topographic map software such as TOPO!, or by conversion from longitude-latitude geographic coordinates by use of conversion software (Blue Marble Geographics). The UTM 1000-m grid lines or map edge tics are on all USGS maps published since 1957. Comments on the certainty or method of determination may be found in the NOTES field.
ZONE: The UTM zone between 114º and 120º longitude is zone 11; this includes all of Nevada.
NAD: The datum for geographic coordinates in this report is the North American Datum of 1927 (NAD27). Although the use of this datum is gradually being replaced with the North American Datum of 1983 (NAD83), we use NAD27 because all printed Nevada 7.5’ topographic maps use it. The difference between datums is less than about 100 m, but the appropriate datum should be selected when using a GPS instrument to locate a point.
DISTRICT: The name of the mining district listed in this field is based on the principal names used by Tingley (1998a), and the inclusion in a particular district was based on the boundaries in Plate 1 of that report. If no district is listed, the occurrence is outside of known districts.
QUAD: The name and date of publication of the U.S. Geological Survey 7.5’-quadrangle topographic map used to locate the occurrence is listed here. The date is that of the map actually used, including revisions or photorevisions. Although the map was commonly the most recent available, we made no attempt to ascertain if there were more modern versions.
U PRODUCTION: The year (if known) and amount of any known or reported uranium production is listed in this field. Only a few of Nevada’s uranium mines have recorded production.
U RESOURCES/RESERVES: A few Nevada mines have published reserves or resources. No attempt was made to confirm the data, and unless otherwise noted, data are not Canadian NI 43-101 compliant.
OTHER PRODUCTION: If the uranium mineralization is found in association with other ore minerals, either as an occurrence or co-product/by-product, we report known production of other metals or materials. No attempt was made to be complete.
DEVELOPMENT: The descriptions in this field refer to the mine or prospect workings (shafts, adits, etc.), bulldozer cuts, prospect pits, or other mineral exploration excavations. In some cases, the presence of exploration drill holes is reported. We commonly used the measurement system of the data reference source; many measurements are reported in U.S. customary units (feet, inches), although the metric system was used by some sources.
RADIOACTIVITY: The radioactivity (background and high values) was commonly measured at the properties by scintillation counter. These instruments vary in their sensitivity and accuracy. Some older instruments are calibrated to read radiation levels in mR/hr (milliroentgen per hour). Most newer instruments report radiation in counts per second (cps). A more significant radioactivity value is the number of times the high readings are above the background. Many experts consider 2–3 times background an anomalous value worthy of further investigation. Some sources indicate that the average background on the Earth’s surface is 0.02-0.05 mR/hr. Uranium analyses are also reported, commonly as U3O8 (U3O8). Many older analyses were done by radiometric methods, and were reported as eU3O8 (equivalent U3O8); chemical analyses of that period were reported as cU3O8, commonly in percent. More recent analyses (for example, from the National Uranium Resource Evaluation program of the early 1980s) were done chemically, and are listed in this report without qualification, as ppm (parts per million) U3O8 (1 ppm = 0.0001 percent). A few sources report uranium as ppm U (or eU, for equivalent U); this can be converted to U3O8 by multiplying by 1.09. The radioactivity readings and analyzed samples were commonly collected at the most radioactive spot(s); these reading or analyses are not commonly representative of larger areas or blocks of rock. The highest reported analyses or radioactivity are important indications of uranium concentration. Some reports may have described chip samples across certain widths, or samples collected for background values. We have reported all these data.
GEOLOGY: A brief description of the geology is found in this field. For a large percentage of the descriptions we are entirely dependent on published and unpublished descriptions by other geologists. We may have applied our own knowledge of the property or area to emphasize certain characteristics.
RADIOACTIVE MINERALS: All uranium and thorium minerals that were reported from a property are listed. Additionally, some minerals are listed that have uranium adsorbed on or otherwise included in their structure. Minerals at a number of properties were identified visually in the 1950s and 1960s; their presence may not have been confirmed by later investigations. Some mineral names have been superseded or discredited; we just list the minerals as reported in the references.
HOST ROCK: The rock type or types that contain the mineralization are listed in this field. In some cases, the rock type was interpreted from regional geologic maps in addition to the main information source.
MAIN COMMODITIES: The main mineral commodities sought or mined are listed here. The radioactive element symbols U and Th are shown in bold.
OTHER COMMODITIES: Other mineral commodities that were recognized, mined, or explored for are listed. The radioactive element symbols U and Th are shown in bold.
NBMG SAMPLE: The numbers listed in this field are for samples collected during several mineral resource studies of Nevada lands done during the 1980s and early 1990s; the analyses of these samples were reported by Tingley (1998b).
OLD NO.: Unique number given in Garside (1973, 1979).
REFERENCES: Reference citations listed here commonly include those having any mention of the occurrence as well as references used for more general geologic information. In many cases, most of the geologic description and location information came from one or two references.
NOTES: In this field we list comments about the certainty of the location, including the source we used to determine the UTM locations (UTMs). Also listed are record numbers of property descriptions from the U.S. Geological Survey Mineral Resources Data System (MRDS; Mason and others, 1996) and the U. S. Bureau of Mines Minerals Availability System/Mineral Industry Location System (MAS/MILS; U. S. Bureau of Mines, 1995).
Many original references to relatively obscure uranium or thorium occurrences are referred to in this report as AEC Reports followed by a four-digit number. These reports, commonly called U.S. Atomic Energy Commission Preliminary Reconnaissance Reports, were the result of field examinations by geologists of the Resource Investigation Division of the U.S. Atomic Energy Commission (AEC) during the uranium boom of the 1950s. More than 300 radioactive localities and many other non-radioactive prospects were visited. About 600 one-page reports for Nevada were produced as a result of these investigations. These Preliminary Reconnaissance Reports were not released to the public until about 1968, when they were numbered sequentially and open filed on microfiche with the National Technical Information Service (NTIS), U.S. Department of Commerce (http://www.ntis.gov/). A set of these microfiche for the U.S. (describing a reported 7,700 localities in 42 states) is available at the DeLaMare Library at the University of Nevada, Reno (UNR). Reportedly, they can be ordered from NTIS, although their on-line database only contains listings for publications after 1990.
AEC geologists also compiled more detailed geologic reports on certain Nevada uranium deposits. Much of this information was published by the AEC or in cooperation with the U.S. Geological Survey, but unpublished material also exists. Published AEC Reports commonly had series prefixes such as RME or RMO. The Business and Government Information Center of the University of Nevada, Reno, Library has an extensive but incomplete collection of AEC documents. Also, a number of these reports on Nevada properties are available in paper, microfiche, or digital (pdf) format in the Information Office of NBMG.
Publications of the U.S. Geological Survey (USGS) are available at many libraries, including UNR’s DeLaMare Library. Some Trace Element Memorandums (TEM) and Trace Element Investigations (TEI) of the USGS contain descriptions of cooperative studies with the AEC. The DeLaMare Library has a nearly complete collection (paper) of these, and some of them are available as digital documents at the USGS Publications Warehouse ( http://infotrek.er.usgs.gov/pubs/) .
During the late 1970s and early 1980s the U.S. Department of Energy (DOE) published an enormous amount of material on uranium as part of the National Uranium Resource Evaluation (NURE) program. These reports, some with sections only in microfiche, are available for Nevada in the NBMG Information office. Descriptions of properties, commonly on microfiche, were an important source of data for this study.