Rare Earth Element Occurrences in the United States

Metadata also available as - [Outline] - [Parseable text] - [XML]

Frequently anticipated questions:


What does this data set describe?

Title: Rare Earth Element Occurrences in the United States
Abstract:
Version 4.0 of this data release provides descriptions of more than 200 mineral districts, mines, and mineral occurrences (deposits, prospects, and showings) within the United States that are reported to contain substantial enrichments of the rare earth elements (REEs). These mineral occurrences include mined deposits, exploration prospects, and other occurrences with notable concentrations of the REEs. The inclusion of a particular mineral occurrence in this database is not meant to imply that it has economic potential. Rather, these occurrences were included to capture the distribution and characteristics of the known, reported REEs deposits in the United States, which are diverse in their geology and resource potential.

Concentrated, mineable deposits of the REEs are rare, such that most of the sites within this data release are for unmined locations where the published information may not contain thorough descriptions (Van Gosen and others, 2014). Therefore, decisions had to be made by the authors regarding the addition or exclusion of specific REE occurrences in the dataset, based principally on the available descriptions of the REE concentrations and the apparent size of the mineralized body. The level of detail of this type of information varied widely amongst the occurrences, ranging from general descriptions to detailed sampling and analysis of some deposits.

The entries and descriptions in the database were derived from published papers, reports, data, and internet documents representing a variety of sources, including geologic and exploration studies described in State, Federal, and industry reports. Although an attempt was made to capture as many examples as possible, this dataset is a progress report that is part of an ongoing effort. The authors welcome additional published information in order to continually update and refine this dataset.

In addition to the conventional resources described in this report, every year approximately 56,000 metric tons of REEs are mined, beneficiated, and put into solution, but not recovered, by operations associated with the global phosphate fertilizer industry (Emsbo and others, 2015, 2016). As indicated by Emsbo and others (2015, 2016), recovery of byproduct REEs from the phosphate industry has the potential to substantially increase the supply of REEs to the market.

The significant increases in applications and demands for REEs has led to an increased interest in identifying new sources that include extraction not only from mineral deposits, but also the potential for REE extraction from coal-based resources, and recycling of products containing REEs. The Department of Energy is currently (2019) evaluating technologies to recover REEs and other critical minerals from coal and coal-based resources (https://www.netl.doe.gov/coal/rare-earth-elements). Recycling efforts have focused on recovering REEs from light bulbs and electronics. The dataset provided in this data release is restricted to non-fuel, REE-bearing mineral deposits and does not include energy resources (such as coal).

Van Gosen, B.S., Verplanck, P.L., Long, K.R., Gambogi, Joseph, and Seal, R.R., II, 2014, The rare-earth elements—Vital to modern technologies and lifestyles: U.S. Geological Survey Fact Sheet 2014–3078, 4 p., https://dx.doi.org/10.3133/fs20143078.

Emsbo, Poul, McLaughlin, P.I., Breit, G.N., du Bray, E.A., and Koenig, A.E., 2015, Rare earth elements in sedimentary phosphate deposits—Solution to the global REE crisis?: Gondwana Research, v. 27, p. 776–785, accessed March 13, 2019, at https://doi.org/10.1016/j.gr.2014.10.008.

Emsbo, Poul, McLaughlin, P.I., du Bray, E.A., Anderson, E.D., Vandenbroucke, T.R.A., and Zielinski, 2016, Rare earth elements in sedimentary phosphorite deposits—A global assessment, chap. 5 of Verplanck, P.L, and Hitzman, M.W., eds., Rare earth and critical elements in ore deposits: Reviews in Economic Geology, v. 18, p. 101–114, accessed March 13, 2019, at https://www.segweb.org/store/detail.aspx?id=EDOCREV18.
Supplemental_Information:
The Esri ArcGIS 10.6 geodatabase contains 1 point and 2 polygon feature classes, 8 attribute tables, and 15 relationship classes. Relationship classes link tables using the Ftr_ID or Site_ID fields. Feature classes are also provided as Esri shapefiles; attribute tables are provided as Excel and comma-separated values (CSV) files. The description of each database layer (feature class) and attribute table is provided below, followed by general information about concepts and terms used in the development of the database.

DATABASE LAYERS AND TABLES

The Loc_Pt feature class contains point locations of mines, mineral occurrences (which includes deposits, prospects, and showings), and mineral regions, and the attribute information describing the location, source report, scale of the map used to obtain the location, and if the location has a polygonal footprint in the Loc_Poly feature class. In the database, all features have a point location, except for surface workings.

The Loc_Poly feature class contains footprints or polygons of areas, deposits, mineral districts, mining districts, placer districts, and prospects. If a source report shows a location as a polygon, the polygon is digitized, and the approximate centroid of the polygon is added to the Loc_Pt layer. Attribute information about the location is provided in the Loc_Pt layer. Mines are represented as points in the database, even when footprints are presented in source reports. Where possible, the approximate extent of the mining operation area, determined from imagery, is presented in the surface workings layer (see Loc_Poly_Sw).

The Loc_Poly_Sw feature class contains the approximate area of mining-related activity, or “surface workings” as shown on Esri imagery. These polygonal outlines have no corresponding point location in the database, nor do they have links to other tables. The attribute information for surface workings contains the date of the imagery and basic location information including state and county names. Surface workings must be at least 1,000 feet (300 meters) in one dimension to be digitized, and multiple workings that are 500 feet (150 meters) or less apart are combined into one outline. No attempt is made to distinguish between the types of surface workings (for example, roads, pits, leach pads, waste piles, etc.), even when presented in source reports.

The Site table is used to identify related features, such as a deposit and the mine(s) operating on it, or a mine and its related deposits. Each site has a unique identification value in the Site_ID field. The Site_ID is used in all tables except the References table. The Site table also indicates where information about a site occurs within the database. For example, if the Resources field in the Site table contains the value “Yes”, resource information is available in the Resources table.

The GeolMinOcc table contains information about the geology of mineral deposits, prospects, and showings. Every attempt is made to compile information as reported in the source report. For example, if one source report states the valuable material as "thorite and monazite" and another reports "cenosite", the attribute field Value_Mat will contain all values. The value in the Ref_ID field is the primary source report for the record, for example, Jackson and Christiansen (1993). All information in the record comes from the primary source report unless an attribute field value contains a footnote denoted as a number in parentheses. If a record value is followed by a footnote, the Ref_ID is given in the Remarks field. Full citations for source reports are provided in the References table.

The Resources table contains reported resource and reserve information for mineral deposits. Initial (or earliest resource data found by authors) and current resource data were compiled, even if information from intervening years was reported. Resource values were recorded as shown in source reports, including year reported, resource amount, units, and classification system(s). The definition of terms (for example, inferred, proven, probable, etc.) used in various resource classification systems may change through time. Resources extracted from older sources might not be compliant with current rules and guidelines in minerals industry standards such as National Instrument 43-101 (NI 43-101) or the Joint Ore Reserves Committee Code (JORC Code). Inclusion of material in the database is for descriptive purposes only and does not imply endorsement by the U.S. Government. If resources or reserves are reported for a group of features rather than an individual deposit, the Ftr_ID will show “-1111” and the resource or reserve is assigned to the “site” or Site_ID that groups those deposits in the Site table. A value ending with “111” as a decimal trailer indicates the value was calculated by USGS authors. For example, if a grade is calculated by USGS authors to be 0.05 percent, the value recorded in the database will be 0.05111. Where a range in values is provided for attribute fields such as Mat_Amnt, Grade Contained, etc., the average of the range is reported within the field and the range of values is noted within the Remarks field. For consistency, resource values are converted to the International System of Units (SI units) by the USGS authors. When gold and silver values are reported in ounces in the source report, troy ounces were assumed when converting to SI units.

The Production table contains published production data for mines. Production is listed by commodity and reported as shown in the source reports. If production is reported annually, production is totaled by the USGS authors for the time period defined by the Year_From and Year_To values. If production is reported for a group of features, the Ftr_ID will show “-1111” and the production is assigned to the “site” or Site_ID that groups those mines in the Site table. A value ending with “111” as a decimal trailer indicates the value was calculated by USGS authors. For example, if a grade is calculated by USGS authors to be 0.05 percent, the value recorded in the database will be 0.05111. Where a range in values are provided for attribute fields such as Mat_Amnt, Grade Contained, etc., the average of the range is reported within the field and the range of values are noted within the Remarks field. For consistency, production values are converted to the International System of Units (SI units) by the USGS authors. When gold and silver values are reported in ounces in the source report, troy ounces were assumed when converting to SI units.

The History table contains information derived from publicly available sources regarding the status of a mine, prospect, deposit, or mineral region through time. Values in the Status field indicate a condition or phase for the time period stated in the Year_From and Year_To fields. This information may not reflect the current status of a feature. For example, if the attribute record shows the status of a mine is “Active” and the Year_From and Year_To dates are 1963 and 2001 respectively, the mine was active from 1963 to 2001; it is unknown if the mine is still active. The Last_Updt field shows the date that the record was last updated by the authors.

The Dep_Model table contains mineral deposit model and geoenvironmental model classifications for a deposit. When deposit model classifications could not be determined from published sources, the deposit model was assigned based on available geologic information and denoted as “USGS Authors (2018)” in the DpMD_RefID field.

The Descr_Sum table contains relevant descriptions found in source reports. These descriptions are attributed according to the type of description, such as Geology, Resource, Production, History, etc. Descriptions pertain to individual features or to larger sites. The authors do not paraphrase or combine descriptions, therefore, when a database feature is described in multiple reports, the feature will have multiple entries.

The References table contains the citation of the map or report(s) from which the point, polygon, or attribute information was obtained. The table also assigns a short reference Ref_ID which is used throughout the database.

GENERAL INFORMATION

Mines are a man-made feature associated with the process of extracting, processing, or concentrating ore materials. In this database, mines have a point location, and where possible, the polygon boundary showing the extent of surface workings identified from imagery. No attempt is made to distinguish specific mine features like pits, dumps, tailings, etc. within the surface workings outline.

Mineral occurrences, defined as a concentration of a mineral considered potentially valuable, are attributed as deposits, prospects, and showings in the database. Mineral deposits have defined size and grade indicated by current and (or) past production, and (or) a resource estimate. Prospects have sufficient data to describe at least two dimensions and the presence of useful or valuable minerals or materials. Showings have the occurrence of potentially valuable minerals as indicated by geological examination or analyses of samples.

Mineral regions are attributed as “areas”, mineral districts, mining districts, or placer districts. Areas have similar geology and deposit types. Mineral districts are areas, usually designated by name, defined by a group of deposits of similar type, origin, and/or commodity. Mining districts represent historic administrative areas organized by miners under the mining laws of the United States. Mining districts are typically an area containing a group of mines that exploited the same or related commodity. Placer districts are areas of placer mining operations. Placer district polygons were defined by the USGS authors. Mineral region polygons may overlap.

The locations of mines, mineral occurrences, and mineral regions are commonly represented as points in source maps and reports, and occasionally as footprints (polygon outlines). In this database, all features have a point location, and some have an additional polygonal footprint. Surface workings in the Loc_Poly_Sw feature class are the exception -- they do not have a corresponding point location or attribute information in the point layer. Otherwise, for points that have polygonal boundaries, the point attribute field Loc_Poly contains the value “Yes” and type of boundary is described in the field Poly_Def (for example, “Trace of placer districts” or “Outline of Indicated and Inferred Resource”).

Each point and polygon feature is uniquely identified by a Ftr_ID. The Site_ID is used to indicate groups of related features, or “sites”. Tables are linked (related) using the Ftr_ID or the Site_ID fields. Some tables have more than one record describing a feature. For example, a point denoting a mine location may have many records in the Production table summarizing the dates and amounts of material produced. The database is designed to allow the user to navigate from the point or polygon layers to the linked table information or from the tables to the point and polygon layers.

All database information is derived from publicly available sources. The Last_Updt field shows the date that the record information was last updated by the authors. Full citations are listed in the References table, and each citation is assigned a short citation, REF_ID that is used for identification in the database. With the exception of the Loc_Poly feature class, the primary reference(s) is noted in the Ref_ID field. Additional references are enumerated after attribute field values, and the corresponding short reference is in the Remarks field. For example, the Commodity field shows “rare earth elements; iron (1)”. This indicates the commodity “rare earth elements” was derived from the primary reference denoted in the Ref_ID field as “McKeown and Klemic (1956)” and “iron” was derived from a secondary reference denoted in the Remarks field as “(1) Jackson and Christiansen (1993)”.

There is no relevance to the order of data presented in lists. For example, if the Commodity field shows “rare earth elements; thorium; uranium”, that is the order in which those commodities were compiled by the authors and does not represent the order of importance. Additionally, in the GeolMinOcc table, lists in different fields do not relate. For example, if the Commodity field shows “rare earth elements; thorium; uranium”, the Value_Mat field may list related ore minerals in a different order. Similarly, the data lists reflect the order in which the information was compiled. Listed fields are present in the Site, Loc_Pt, and GeolMinOcc tables.

Field or attribute records that contain "Null" values in the file geodatabase, were checked for available data, and no data were found. In some cases, an entire field may contain no information. These "Null" fields are maintained in the database structure for consistency with related USGS products and for possible future use if information becomes available.

Two points may occupy the same location. This occurs when there is a deposit with a mine, and the location of either the mine or the deposit is unknown. For example, a report provides a map showing the location of a deposit. The report also provides production data for underground “Mine X” that is mining the deposit, but does not provide the location of “Mine X”. In this case, a second point representing “Mine X” is placed at the point location of the deposit.

Polygon features may overlap. Viewing polygons as outlines without color fills will show where polygon overlap occurs.

In the attribute section of this metadata, attribute fields from all tables and feature classes are listed in alphabetic order; corresponding feature classes and tables are listed in parentheses after the field name in the ‘Attribute_Label’. For example, “Mat_Amnt (Production, Resources)” indicates the attribute field Mat_Amnt (material amount) occurs in the Production table and in the Resources table.
  1. How might this data set be cited?
    Bellora, Jesse D, Burger, Meredith H, Bradley S Van Gosen, Long, Keith R, Carroll, Thomas R, Schmeda, German, and Giles, Stuart A, 20190618, Rare Earth Element Occurrences in the United States: USGS ScienceBase, Denver, CO.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Bellora, J.D., Burger, M.H., Van Gosen, B.S., Long, K.R., Carroll, T.R., Schmeda, Germán, and Giles, S.A., 2019, Rare Earth Element Occurrences in the United States (ver. 4.0, June 2019): U.S. Geological Survey data release, https://doi.org/10.5066/F7FN15D1.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -162.91886276
    East_Bounding_Coordinate: -73.452801511
    North_Bounding_Coordinate: 69.529824019
    South_Bounding_Coordinate: 27.638399615
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date:
    Ending_Date: 2018
    Currentness_Reference:
    publication date
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: Vector Digital Data Set
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • Entity point (267)
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000000001. Longitudes are given to the nearest 0.000000001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257223563.
  7. How does the data set describe geographic features?
    Attribute Fields
    Fields containing attribute information associated with the data set. Attribute fields occur in data layer(s) noted in parentheses. (Source: Producer defined)
    Alteration (GeolMinOcc)
    Alteration associated with the mineralization in the mineral occurrence. (Source: USGS Authors) Values may include albitization, hydrothermal, silicification, etc.
    Approx_Lat (Site)
    Approximate latitude (WGS84) of the approximate center of the site area. (Source: USGS Authors)
    Range of values
    Minimum:27.6359
    Maximum:69.53
    Units:decimal degrees
    Approx_Lon (Site)
    Approximate longitude (WGS84) of the approximate center of the site area. (Source: USGS Authors)
    Range of values
    Minimum:-162.92
    Maximum:-73.4529
    Units:decimal degrees
    Assoc_Dep (Production)
    Deposit(s) associated with the production. (Source: USGS Authors) Ftr_ID(s) for deposits from which production occurred.
    Assoc_Mat (GeolMinOcc)
    Associated materials occurring with the valuable material(s). (Source: USGS Authors) A list of materials that occur with the valuable materials, but are not considered ore or valuable. Same as gangue for metallic mineral deposits.
    CntSICom (Production, Resources)
    Contained commodity reported by the source, converted to its elemental form where appropriate (Source: USGS Authors) Commodity in elemental form that is contained within the valuable material(s). If the commodity occurs as a compound, USGS authors convert the compound to its elemental form. For example, if the material is reported by the source document as zircon (ZrSiO4), elemental Zr is calculated and reported by USGS Authors. The quantity of CntSICom is reported in the CntSIComAm field, and the associated units are reported in the CntSIComUt field.
    CntSIComAm (Production, Resources)
    Contained commodity amount reported by the source, converted to the International System of Units (SI units). The minimum and maximum values listed below are from the field in the Resource table. The values in this field for the Production table range from 0.00022 – 15,700,000. Contained Commodity Amount units vary by commodity and deposit, and are listed in the field CntSIComUt. (Source: USGS Authors)
    Range of values
    Minimum:0.35
    Maximum:154,000,000
    Units:See CntSIComUt.
    CntSIComUt (Production, Resources)
    Contained commodity amount unit reported by the source, converted to the International System of Units (SI units), metric tons. These units apply to values listed in the field CntSIComAm. (Source: USGS Authors) metric tons
    COG_SI (Production, Resources)
    Cut-off grade (CutOffGrad) reported by the source, converted to International System of Units (SI). The minimum and maximum values are for resources; no cut-off grade information was available for production values. Cut-off grade units vary by commodity and deposit, and are listed in the field COU_SI. (Source: USGS Authors)
    Range of values
    Minimum:0.4
    Maximum:1,000
    Units:See COU_SI.
    Commodity (GeolMinOcc, Loc_Pt, Site)
    Commodity(s) present or associated with the feature. (Source: USGS Authors) Commodity(s) reported for a mine, mineral occurrence, mineral region, or estimated resource and production.
    Cont_Units (Production, Resources)
    The units of weight reported for the contained commodity. (Source: USGS Authors) Values may include kilograms, metric tons, pounds, etc.
    Contained (Production, Resources)
    The amount of contained commodity present in the ore. The minimum and maximum values listed below are from the Resource table. The values for this field in the Production table range from 1 – 44,400,000 with variable units. (Source: USGS Authors)
    Range of values
    Minimum:0.352
    Maximum:5,660,000,000
    Units:See Cont_Units.
    COU_SI (Production, Resources)
    Reported resource or production cutoff grade units (CutOffUnit) converted to International System of Units (SI). (Source: USGS Authors) Values include: dollars per metric ton NSR (net smelter return), parts per million ThO2, percent TREO, etc.
    County (Loc_Pt, Loc_Poly_Sw)
    U.S. county name. (Source: USGS Authors) Name of the county where the feature is located. If the mine, mineral occurrence, or mineral region occurs in multiple counties, all county names are listed, separated by semicolons.
    CutOffGrad (Production, Resources)
    Reported resource or production cutoff grade. The minimum and maximum values listed below are for resources, no cut-off grade information was available for production values. (Source: USGS Authors)
    Range of values
    Minimum:0.4
    Maximum:1,000
    Units:See CutOffUnit.
    CutOffUnit (Production, Resources)
    Reported resource or production cutoff grade units. (Source: USGS Authors) Values include: dollars per tonne NSR (net smelter return), grams per tonne, percent TREO, etc.
    Dep_Model (Site)
    Indicates whether the deposit(s) on the site has been classified in the Dep_Model table. (Source: USGS Authors) A "Yes" or "No" value indicating which corresponding tables contain attribute information related to the site.
    Descr (Descr_Sum)
    Provides a brief description of a feature identified by the Ftr_ID or Site_ID. (Source: USGS Authors) Description reported by the source reference.
    Descr_Sum (Site)
    Indicates whether descriptions have been captured for the site in the Descr_Sum table. (Source: USGS Authors) A "Yes" or "No" value indicating which corresponding tables contain attribute information related to the site.
    Descr_Type (Descr_Sum)
    Indicates the topic of the description. (Source: USGS Authors) Values include Exploration, Geology, History, Production, Resources, and Site.
    DpMd_NoNm (Dep_Model)
    Deposit model number and (or) name. (Source: USGS Authors) The deposit model classification assigned to a deposit.
    DpMd_RefID (Dep_Model)
    The deposit model classification reference. (Source: USGS Authors) The short reference of the source report that provides geologic descriptions that help classify the mineral deposit model.
    Ftr_Group (Loc_Pt)
    A group to which a feature belongs, such as mine feature, mineral occurrence, or mineral region. (Source: USGS Authors)
    ValueDefinition
    Mine FeatureA man-made entity associated with the process of extracting, processing, or concentrating ore materials.
    Mineral OccurrenceConcentration of useful minerals or materials in sufficient quantity that it has been (or might be) exploited.
    Mineral RegionAn area defined by a grouping of mines or mineral deposits or a geological environment permissive for mineral deposits.
    Ftr_ID (Dep_Model, Descr_Sum, GeolMinOcc, History, Loc_Poly, Loc_Poly_Sw, Loc_Pt, Production, Resources)
    An identification assigned to a feature. A “-1111” value indicates that the record pertains to a group of related features. These features will have the same Site_ID but differing Ftr_IDs. (Source: USGS Authors) The format of the identification pertains to the type of feature followed by a number. The format is Mo (for mineral occurrences), Mr (for mineral regions), or Mf (for mine features) followed by a 5-digit number, for example, “Mo00001”.
    Ftr_Name (Dep_Model, GeolMinOcc, History, Loc_Poly, Loc_Poly_Sw, Loc_Pt, Production, Resources)
    Published name of a database feature. (Source: USGS Authors) Current (preferred) form of the name of the mine, mineral occurrence, or mineral region.
    Ftr_Type (GeolMinOcc, Loc_Pt)
    Type of mine, mineral occurrence, or mineral region feature. (Source: USGS Authors)
    ValueDefinition
    AditA horizontal passage from the surface into a mine.
    AreaArea of similar geology and deposit types.
    DepositA mineral occurrence with grade and size as determined by a reserve, or a resource estimate, or by production history.
    Mine ShaftA vertical or inclined excavation through which a mine is worked.
    Mineral DistrictAn area, usually designated by name, defined by a group of deposits of similar type, origin, or commodity.
    Mining DistrictA section of country usually designated by name, having described or understood boundaries within which minerals are found and worked under rules and regulations prescribed by the miners therein. There is no limit to its territorial extent and its boundaries may be changed if vested rights are not thereby interfered with.
    Open Pit MineSurficial mine, in which the valuable rock is exposed by removal of overburden.
    Placer DistrictArea of placer mining operation.
    Placer MineThe extraction and concentration of heavy metals or minerals from placer deposits by various methods, generally using running water.
    Portal MineA mine in which the main entry or access is by means of the mouth of an adit or tunnel.
    Processing PlantA facility/plant where processing occurs (The methods employed to clean, process, and prepare coal and metallic ores into the final marketable product.
    ProspectA mineral occurrence that has at least two dimensions (area) and evidence that useful minerals or materials are present, as indicated by analyses or the presence of valuable minerals.
    Prospect PitA general term for a pit made for the purpose of prospecting mineral-bearing ground.
    Shaft MineA mine in which the main entry or access is by means of a shaft.
    ShowingA mineral occurrence where potentially useful minerals or rocks are present as indicated by geological examination or analyses of samples.
    Strip MineA surface mine in which ore is exposed by removal of overburden (barren material). Coal, numerous nonmetals, and metallic ore deposits may be mined in this manner. May also be referred to as open cast mines.
    Underground WorkingsA mine feature that is specified by the data source as 'underground workings', or a group of underground mine features such as drifts, stopes, winzes, levels, etc. These features are projected to the surface.
    Unspecified Mine FeatureA mine whose actual feature identity is unknown or not specified.
    GEM_Name (Dep_Model)
    Associated geoenvironmental model(s). (Source: USGS Authors) Geoenvironmental models are derived from the deposit model classifying the deposit.
    GEM_RefID (Dep_Model)
    The geoenvironmental model classification reference. (Source: USGS Authors) Short reference, or Ref_ID, of the source report that contains the information used to select the appropriate geoenvironmental model for a mineral occurrence.
    GeolMinOcc (Site)
    Indicates whether data have been captured in the GeolMinOcc table for the mineral occurrence(s) on the site. (Source: USGS Authors) A "Yes" or "No" value indicating which corresponding tables contain attribute information related to the site.
    Grade (Production, Resources)
    The reported numerical grade of the deposit. The minimum and maximum values listed below are from the Grade field in the Resources table. The values in this field for the Production table range from 0.00035 – 335 with variable units. Where the grade is reported as a range in values, the average of the range is listed within the field and the reported range is noted in the Remarks field. (Source: USGS Authors)
    Range of values
    Minimum:0.001
    Maximum:3103.090088
    Units:See Grade_Unit.
    Grade_Unit (Production, Resources)
    The units of the reported numerical grade. (Source: USGS Authors) Values may include grams per tonne, parts per million, percent, etc.
    GradeSI (Production, Resources)
    The reported numerical grade (Grade) converted to International System of Units (SI). The minimum and maximum values listed below are from the GradeSI field in the Resources table. The values in this field for the Production table range from 0.000118 – 45.6 with variable units. Where the grade is reported as a range in values, the average of the range is listed within the field and the reported range is noted in the Remarks field. (Source: USGS Authors)
    Range of values
    Minimum:0.001
    Maximum:3103.09
    Units:See GradUnitSI.
    GradUnitSI (Production, Resources)
    The units of the reported grade (Grade_Unit) converted to International System of Units (SI). (Source: USGS Authors) Values may include grams per metric ton, parts per million, percent, etc.
    History (Site)
    Indicates whether history data for the site have been captured in the History table. (Source: USGS Authors) A "Yes" or "No" value indicating which corresponding tables contain attribute information related to the site.
    Host_Age (GeolMinOcc)
    The age of the lithological unit(s) that host, that are in direct contact with, or cut across the mineral occurrence (Host_Litho). (Source: USGS Authors) Age is recorded as it was stated in the source, this age may be reported as numeric values or chronostratigraphic units.
    Host_Litho (GeolMinOcc)
    The lithological unit(s) that host, that are in direct contact with, or cut across the mineral occurrence. (Source: USGS Authors) Values may include breccia, granite, heavy-mineral sands, etc.
    Host_Name (GeolMinOcc)
    The formal name of lithological units that host the mineral occurrence. (Source: USGS Authors) Descriptive text, not abbreviated.
    Last_Updt (Dep_Model, Descr_Sum, GeolMinOcc, History, Loc_Poly, Loc_Poly_Sw, Loc_Pt, Production, References, Resources)
    The date that the record was last updated or revised by the USGS authors. (Source: USGS Authors) Format is YYYY-MM-DD.
    Lat_WGS84 (Loc_Pt)
    Latitude of the point location in decimal degrees (WGS84). The Pt_Def field indicates the type of location. (Source: USGS Authors)
    Range of values
    Minimum:27.6384
    Maximum:69.529824
    Units:decimal degrees
    Loc_Date (Loc_Poly_Sw, Loc_Pt)
    The publication year of the map used to obtain the feature location. (Source: USGS Authors) The year may differ from the publication date of the reference (identified by the Ref_ID). For example, the explanation for a location figure in a report states “Map from 2002”. The reference was published in 2003. In this case, “2002” is recorded in Loc_Date.
    Loc_Poly (Loc_Pt, Site)
    Indicates whether a polygon location(s) has been digitized for a corresponding point location. (Source: USGS Authors) A "Yes" or "No" value indicating which corresponding tables contain attribute information related to the site.
    Loc_Pt (Site)
    Indicates whether the point location(s) has been captured for features in the site. (Source: USGS Authors) A "Yes" or "No" value indicating which corresponding tables contain attribute information related to the site.
    Loc_Scale (Loc_Pt)
    Defines the accuracy of the location as Large, Medium, or Small depending on the scale of the map that the location was captured from. (Source: USGS Authors)
    ValueDefinition
    Small (less than 1:250,000)The representative fraction scale of the source map is 1:250,000 or smaller.
    Medium (1:24,000-1:250,000)The representative fraction scale of the source map is between 1:24,000 and 1:250,000.
    Large (greater than 1:24,000)The representative fraction scale of the source map is 1:24,000 or larger.
    Long_WGS84 (Loc_Pt)
    Longitude of the point location in decimal degrees (WGS84). The Pt_Def field indicates the type of location. (Source: USGS Authors)
    Range of values
    Minimum:-162.918863
    Maximum:-73.452802
    Units:decimal degrees
    Mat_Amnt (Production, Resources)
    The reported amount of the material. The minimum and maximum values listed here are from the Mat_Amnt field in the Resources table. The values in this field for the Production table range from 1 – 1,990,000,000 with variable units. Negative number values indicate that the amount value is listed for two different commodities. For example, if the source says that there were 900 metric tons of ore containing 0.15 percent thorium and 0.08 percent monazite, -900 would be entered in Mat_Amnt for each record (table row). (Source: USGS Authors)
    Range of values
    Minimum:85
    Maximum:16,700,000,000
    Units:See Mat_Units.
    Mat_Type (Production, Resources)
    Type of material in the resource or reserve estimate, or type of material produced from the mine. (Source: USGS Authors)
    ValueDefinition
    bulk materialUsually refers to industrial materials where estimates are given for weight or volumetric units.
    commodityThe final, valuable material that has been processed out of the ore material. The type of commodity is commonly represented in the final sales units such as ounces, pounds, etc.
    oreThe mixture of valuable materials along with gangue rocks and minerals. Ore is commonly represented in tons, metric tons, cubic yards, carloads, etc., and is usually associated with a grade(s) of valuable material(s) contained in a given amount of ore produced.
    Mat_Units (Production, Resources)
    The units of the material amount reported. (Source: USGS Authors) Values may include kilograms, metric tons, pounds, short tons, etc.
    MatAmntSI (Production, Resources)
    The reported amount of the material (Mat_Amnt) converted to International System of Units (SI). The minimum and maximum values listed here are from the MatAmntSI field in the Resources table. The values in this field for the Production table range from .007 – 241,723,000 with variable units. Negative number values indicate that the amount value is listed for two different commodities. For example, if the source says that there were 900 metric tons of ore containing 0.15 percent thorium and 0.08 percent monazite, -900 would be entered in Mat_Amnt for each record (table row). (Source: USGS Authors)
    Range of values
    Minimum:77
    Maximum:2,420,000,000
    Units:See MatUnitsSI.
    Material (Production, Resources)
    The material reported in the production value or resource estimate. (Source: USGS Authors) Values may include monazite, rare-earth elements (REE), rare-earth oxide (REO), etc.
    MatUnitsSI (Production, Resources)
    The units of the material amount reported (Mat_Units) after conversion to International System of Units (SI). (Source: USGS Authors) Values include cubic meters, metric tons, and metric ton unit (tungsten trioxide).
    Min_Age (GeolMinOcc)
    Age of mineralization. (Source: USGS Authors) Values may be numeric, descriptive text, or a combination.
    Min_Style (GeolMinOcc)
    Describes how the valuable materials occur. (Source: USGS Authors) Values may include dikes, disseminated, veins, etc.
    MinReg_ID (Site)
    Unique identification of a mineral region. MinReg_ID is the same as the Ftr_ID in the Loc_Pt table. (Source: USGS Authors) In this database, mineral region types include mineral districts, placer districts, areas, and mining districts, that contain one or more mine or mineral occurrence feature.
    Other_Name (Loc_Pt, Site)
    Other reported names of the mineral region, mineral occurrence, mine, or site. (Source: USGS Authors) Descriptive text, not abbreviated.
    Poly_Def (Loc_Pt)
    Type of polygonal boundary. (Source: USGS Authors) Definitions of polygons are typically derived from map legends or source descriptions, and may include outline of mining districts, ore body outline, etc.
    Prod_USD (Production)
    Gross value of production from the mine in U.S. dollars. Dollars amounts are those at the time of the publication. This version includes one value, though the database structure is set for a range domain to be used in other releases. (Source: USGS Authors)
    Range of values
    Minimum:12,000
    Maximum:12,000
    Units:U.S. Dollars
    Production (Site)
    Indicates whether the production data for the mine(s) on the site have been recorded in the Production table. (Source: USGS Authors) A "Yes" or "No" value indicating which corresponding tables contain attribute information related to the site.
    Pt_Def (Loc_Pt)
    Point definition from source report or approximated by authors. (Source: USGS Authors) Points can be captured from a source report figure or map, or approximated by the authors to show a location of a mine (for example, center of pit). In cases where a mineral occurrence or mineral region boundary was available, the polygon was digitized, and the point represents the approximate center of the polygon (centroid).
    Rcvry_Amt (Production)
    The amount of recovered material. This version includes one value, though the database structure is set for a range domain to be used in other releases. (Source: USGS Authors)
    Range of values
    Minimum:591
    Maximum:591
    Units:See Rcvry_Unit
    Rcvry_Unit (Production)
    Unit of weight of the recovered material. (Source: USGS Authors) Metric tons.
    RcvryAmtSI (Production)
    The amount of recovered material (Rcvry_Amt) converted to International System of Units (SI). This version includes one value, though the database structure is set for a range domain to be used in other releases. (Source: USGS Authors)
    Range of values
    Minimum:591
    Maximum:591
    Units:See RcvryUntSI
    RcvryUntSI (Production)
    Units of weight of the recovered material (Rcvry_Unit) converted to the International System of Units (SI). (Source: USGS Authors) Unit of weight converted to metric tons.
    Ref_Detail (Dep_Model, History, Loc_Poly_Sw, Loc_Pt, Production, Resources)
    The figure, page, map, etc. number that the data were recorded from. (Source: USGS Authors) If the data occurs in a table on a certain page, the table name or number and page number are captured, for example, “Page 10, Table 5".
    Ref_ID (Descr_Sum, GeolMinOcc, History, Loc_Poly_Sw, Loc_Pt, Production, References, Resources)
    Shortened reference identification of the source report. (Source: USGS Authors) Identification includes author name(s) and publication year.
    Reference (References)
    Full reference of the source report. (Source: USGS Authors) References are listed using USGS citation format.
    Remarks (Dep_Model, Descr_Sum, GeolMinOcc, History, Loc_Poly, Loc_Poly_Sw, Loc_Pt, Production, Resources, Site)
    Additional author comments, remarks, or information about the feature or data. (Source: USGS Authors) Descriptive text, not abbreviated.
    Resources (Site)
    Indicates whether the resource or reserve estimates for the deposit(s) on the site have been captured in the Resources table. (Source: USGS Authors) A "Yes" or "No" value indicating which corresponding tables contain attribute information related to the site.
    Rsrc_Class (Resources)
    Indicates how the resource or reserve was classified in the source report. Resources extracted from older sources might not be compliant with current rules and guidelines in minerals industry standards such as National Instrument 43-101 (NI 43-101) or the Joint Ore Reserves Committee Code (JORC Code). Inclusion of material in the database is for descriptive purposes only and does not imply endorsement by the U.S. Government. (Source: USGS Authors) Descriptive text, not abbreviated.
    Rsrc_Code (Resources)
    Standard classification system used to classify and report the estimate. (Source: USGS Authors)
    ValueDefinition
    CIMThe CIM Definition Standards on Mineral Resources and Reserves (CIM Definition Standards) establish definitions and guidance on the definitions for mineral resources, mineral reserves, and mining studies used in Canada. The Mineral Resource, Mineral Reserve, and Mining Study definitions are incorporated, by reference, into National Instrument 43-101 Standards of Disclosure for Mineral Projects (NI 43-101). The CIM Definition Standards can be viewed on the CIM website at www.cim.org.
    SECU.S. Securities and Exchange Commission filings. The most common SEC form used in this database is a 10-K Annual report pursuant to Section 13 or 15(d).
    Rsrc_Date (Resources)
    Year of the resource estimate. If the value is "Null", the date of the resource estimate is unknown and most likely does not equal the date of the resource source publication. (Source: USGS Authors) Format is YYYY.
    Rsrc_Descr (Resources)
    Indicates how the resource or reserve was reported in the source report. (Source: USGS Authors) Values include Reserve, Resource, and Unclassified.
    Site_ID (Dep_Model, Descr_Sum, GeolMinOcc, History, Loc_Poly, Loc_Pt, Production, Resources, Site)
    Unique identification assigned to a site. (Source: USGS Authors) Format is two-letter state abbreviation and a 5-digit number. For example, NV00001.
    Site_Name (Site)
    Site name assigned by authors. (Source: USGS Authors) Mine and mineral occurrence features are grouped into sites based on geological characteristics or location.
    StatDetail (History)
    Status detail that pertains to the type of activity that occurred during a specified time period, as shown in the Year_From and Year_To fields. (Source: USGS Authors) Additional information about the Status field. Values include descriptive text entry.
    State (Loc_Poly_Sw, Loc_Pt)
    U.S. state name abbreviation. (Source: USGS Authors) State name abbreviated using 2-letter codes.
    Status (History)
    Activity that took place during a specified time period, as shown in the Year_From and Year_To fields. (Source: USGS Authors)
    ValueDefinition
    ActiveIndicates a mine is in full-time or intermittent production, or is selling from stockpiles.
    Closed to Mineral EntryLand is closed to mineral exploration and activity.
    DevelopmentIndicates planning and studies are in progress or have been completed for the development of the mine, or that a mine is actively under development.
    DiscoveryThe actual finding of a valuable mineral, indicative of a deposit. Legally, a discovery is a prerequisite to making a mining claim on an area.
    EvaluationThe fixing of an evaluation, not an appraisal. Used in preference of the word valuation, which is often confused with appraisal.
    ExplorationThe search for deposits of useful minerals or fossil fuels. It may include geologic reconnaissance, e.g. remote sensing, photogeology, geophysical and geochemical methods, and both surface and underground investigations. Establishing the nature of a known mineral deposit, preparatory to development. In the sense that exploration goes beyond discovery, it is a broader term than prospecting.
    InactiveIndicates that a mine is not in production, is on care and maintenance, or is under reclamation.
    Intermittent ExplorationThe process of exploration that occurs at irregular intervals; not continuous or steady evaluation activity at the site.
    Value_Mat (GeolMinOcc)
    Valuable materials (minerals or rocks) that comprise the valuable constituents of a deposit. (Source: USGS Authors) Values may include monazite, thorite, yttrium, etc.
    Year_From (History, Production)
    First year of production or history. When mine production was intermittent, only the first and last year of reported production are shown. (Source: USGS Authors) See Last_Updt (last updated) field for the currency of the values.
    Year_To (History, Production)
    Last year of production or history. When mine production was intermittent, only the first and last year of reported production are shown. (Source: USGS Authors) See Last_Updt (last updated) field for the currency of the values.
    Entity_and_Attribute_Overview:
    The entity and attribute information provided describe the tabular data associated with the data set. Please review the detailed descriptions that are provided (the individual attribute descriptions) for information on the values that appear as fields/table entries of the data set.
    Entity_and_Attribute_Detail_Citation:
    The entity and attribute information was generated by the individual and (or) agency identified as the originator of the data set. Please review the rest of the metadata record for additional details and information.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Jesse D Bellora
    • Meredith H Burger
    • Bradley S Van Gosen
    • Keith R Long
    • Thomas R Carroll
    • German Schmeda
    • Stuart A Giles
  2. Who also contributed to the data set?
    The data sets were developed by the U.S. Geological Survey Geology, Geophysics, and Geochemistry Science Center (GGGSC) with support from the Bureau of Land Management Solid Minerals Program. Database reviews and contributions were made by USGS personnel Nick Karl and USGS student contractor Tyler Reyes.
  3. To whom should users address questions about the data?
    Bradley S Van Gosen
    U.S. Geological Survey, Southwest Region
    Research Geologist
    PO Box 25046, Mail Stop 973
    Lakewood, CO
    United States

    303-236-1566 (voice)
    303-236-1425 (FAX)
    bvangose@usgs.gov

Why was the data set created?

This dataset is part of an ongoing effort by the U.S. Geological Survey (USGS) to understand the attributes and geologic distribution of critical mineral resources, both globally, and in particular, in the United States. As described in USGS Professional Paper 1802, the United States continues to become more dependent on imports to meet the domestic demands for an increasing number of mineral commodities (Schulz and others, 2017). Many mineral commodities are now produced primarily or entirely outside of the United States, creating the potential for supply interruptions in the foreseeable future, or in the long term. These important but highly dependent mineral commodities are deemed critical and (or) strategic resources.

The rare earth elements (REEs) represent a prime example of a “critical mineral resource”. In the 21st century, the REEs have gained visibility due to: (1) the recognition of the essential, specialized properties that REEs contribute to modern technology, as well as (2) China's dominance in production and supply of the REEs, and (3) international dependence on China for the majority of the world's REE supply. Since the late 1990s, China has provided 85–95 percent of the world’s REEs, while the United States and other nations are highly dependent on REEs for their use in high technology devices, clean energy components, and defense technologies.

This dataset was compiled to provide base layers of information that identify and describe the known REE deposits, prospects, and showings in the United States. This compilation is intended to contribute to our geologic understanding of REE deposits in the United States, and to assist in evaluating their resource potential.

Schulz, K.J., DeYoung, J.H., Jr., Seal, R.R., II, and Bradley, D.C., eds., 2017, Critical mineral resources of the United States—Economic and environmental geology and prospects for future supply: U.S. Geological Survey Professional Paper 1802, 797 p., http://doi.org/10.3133/pp1802.

How was the data set created?

  1. From what previous works were the data drawn?
    CIM (2014) (source 1 of 3)
    Canadian Institute of Mining, Metallurgy and Petroleum, 2014, CIM Definition Standards for Mineral Resources and Mineral Reserves: Canadian Institute of Mining, Metallurgy and Petroleum, CIM Website.

    Online Links:

    Type_of_Source_Media: Digital and/or Hardcopy Resources
    Source_Contribution:
    Reference used by the authors to develop standardized vocabularies for the database and attribute tables. The use of this reference is denoted as CIM (2014) in this metadata.
    AGI (1997) (source 2 of 3)
    Institute, American Geological, 1997, Dictionary of Mining, Mineral, and Related Terms, Second Edition: American Geological Institute, Virginia.

    Type_of_Source_Media: Digital and/or Hardcopy Resources
    Source_Contribution:
    Reference used by the authors to develop standardized vocabularies for the database and attribute tables. The use of this reference is denoted as AGI (1997) in this metadata.
    AGI (2011) (source 3 of 3)
    Institute, American Geological, 2011, Glossary of Geology, Fifth Edition, Revised: American Geological Institute, Virginia.

    Type_of_Source_Media: Digital and/or Hardcopy Resources
    Source_Contribution:
    Reference used by the authors to develop standardized vocabularies for the database and attribute tables. The use of this reference is denoted as AGI (2011) in this metadata.
  2. How were the data generated, processed, and modified?
    Date: 2018 (process 1 of 4)
    A literature search of publicly available mineral resource information was conducted for rare earth element occurrences in the United States. Priority was given to identifying existing databases or compilations with high quality locations and data attributes that could be utilized directly in a geographic information system (GIS). The literature search identified sources of data on active mines, mineral occurrences, mineral regions, and resource and production data. Relevant information was acquired, reviewed for quality and geospatial information, and prioritized for digital data capture.

    Mines described in published reports were captured as point locations and attributed to show mining activity in the History table and mine production in the Production table. Where possible, the approximate extent of the mining operation area was captured from imagery and presented in the surface workings layer (see Loc_Poly_Sw). Surface workings were digitized if the ground disturbance was at least 1,000 feet in one dimension. The outlines of adjacent surface workings were merged if they were within 500 feet of one another.

    Mineral occurrences, defined as a concentration of a mineral considered potentially valuable, were compiled and attributed as deposits, prospects, and showings. Mineral deposits have defined size and grade indicated by current and (or) past production, and (or) a resource estimate; prospects have sufficient data to describe at least two dimensions and the presence of useful or valuable minerals or materials; showings have a surface occurrence of a potentially valuable mineral as indicated by geological examination or analyses of samples. Mineral occurrences were represented as points and also as polygons if the aerial extent or “footprint” of a prospect or deposit was available. Each polygon was attributed to describe the reported boundary type, such as the extent of the estimated resource, the grade limit or grade-thickness, or the limit of mineralization. The footprints of mineral deposits and prospects overlapped in some areas.

    Mineral regions were digitized as shown in the source reports, and thus may be represented as points or polygons. Mineral regions are attributed as areas, mineral districts, mining districts, or placer districts. Areas have similar geology and deposit types. Mineral districts are areas, usually designated by name, defined by a group of deposits of similar type, origin, and/or commodity. Mining districts represent historic administrative areas organized by miners under the mining laws of the United States. Mining districts are typically an area containing a group of mines that exploited the same or related commodity. Placer districts are areas of placer mining operations. Placer district polygons were defined by the USGS authors. Mineral region polygons may overlap.

    All data were spatially integrated using ArcGIS. All attribute data were compiled from publicly available sources published between 1889 and 2017. Standardized vocabularies were developed by USGS authors and include definitions from CIM (2014), AGI (1997), and AGI (2011). Data were checked throughout the compilation process for accuracy of locations; and completeness, accuracy, and consistency of attributes.
    Date: 13-Mar-2018 (process 2 of 4)
    Version 2.0: The data for the state of Alaska used in the Version 1.0 release was derived from the USGS Alaska Data Resource File (ARDF) (https://ardf.wr.usgs.gov/index.php). After release of Version 1.0, USGS Alaska personnel notified the authors that only the following ARDF occurrences should be included in the database: Ross-Adams mine, Cheri, Geiger, Geoduck Zone, I and L Zone, Ross-Adams, Sunday Lake Zone, Upper Cheri, Dotson Zone, Wennie, Unnamed (north shore, Stone Rock Bay), Unnamed (near Mallard Bay), I-L- and M, Little Jim and Little Joe, Boots, Shore, Eudialyte.

    The authors also included the following Alaska deposits because they contain substantial enrichments of REEs: Dora Bay, No Name Creek, Ray River, Unnamed (near Salmon Bay).

    All other Alaska features were removed from the Version 2.0 database. This included the spatial features (points, polygons) as well as all information in the attribute tables.

    Data from states other than Alaska remain unchanged between Version 1.0 and Version 2.0.
    Date: 22-Mar-2019 (process 3 of 4)
    Version 3.0 of the database includes modifications to the syntax of several field values, changes to the data structure, the addition of new records, flagging values calculated by the USGS authors, and the correction of minor errors. These changes are described below.

    The syntax of the field Ftr_Name was expanded to include the site name. The new syntax is "Site Name, Feature Name", for example, “Bokan Mountain, Ross-Adams Mine”.

    The syntax of the field "Material" in the Resources and Production tables was expanded to include the material and the known chemical formula. For example, the material uranium oxide is now presented as "uranium oxide (U3O8)".

    Previously resource and reserve classifications (e.g. inferred, measured, indicated) were aggregated in the field "Rsrc_Class". Resource classifications are now compiled as reported. For example, if a resource is reported as “measured plus indicated” and “inferred”, the values are entered as two attribute records rather than one.

    Fieldnames in the Resources and Production tables were changed from "Contain_SI" and "ContUnitSI" to "CntSIComAm" and "CntSIComUt" respectively. The field "CntSICom" was added.

    For sites that contained commodities in addition to rare earth elements, records were added to the Resource table as appropriate. For example, Bokan Mountain, AK now has records such as niobium oxide and zirconium dioxide in addition to rare-earth oxide.

    To better differentiate calculated versus reported values, an ending decimal trailer of "111" was added to all values calculated by USGS authors. Furthermore, in the Resource and Production tables, USGS authors attempt to provide the contained amount of the commodity which are typically estimated from material amount and grade.
    Date: 18-Jun-2019 (process 4 of 4)
    Version 4.0 of the database includes modifications to the “Contained” and the “Mat_Amnt” fields of the Resources table.

    Changes that were made were done for ObjectID 257, Pea Ridge resource record for rare-earth oxide (REO).

    These changes include: Mat_Amnt changed from 5,000,000.111 to 600,000, Contained changed from 600,000.111 to 72,000.111, Mat_AmntSI changed from 5,000,000.111 to 600,000, and CntSIComAm changed from 600,000.111 to 72,000.111.

    Reason for the changes was because the value entered for “Contained” was actually the “Mat_Amnt” so there was a misinterpretation of the text from the original data source.
  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    Unique values in attribute fields were checked through frequency analyses. The unique values in each attribute field were reviewed and checked for spelling, consistency of terms, accuracy, adherence to established vocabularies, and completeness. Values calculated by USGS authors were reviewed and verified. Further information regarding calculations can be obtained from the USGS authors. Floating-point numerical values may be reported to 8 decimal places. Default settings in the ArcGIS geodatabase, which typically show 6 decimal places, may be formatted to show the full numerical value. The full data value of the record is provided in the Remarks field.

    When converting from an ArcGIS file geodatabase attribute table to Excel, precision of numeric values may change. The values from the ArcGIS file geodatabase are accurate and should be used for any calculations or analyses.
  2. How accurate are the geographic locations?
    Locations of features were compiled from published coordinates and by digitizing from georeferenced raster images of maps or imagery. The locational accuracy of features is dependent on the accuracy of the source maps, which generally ranged in map scale from 1:10,000 to 1:1,000,000. The scale of the source maps was recorded as “Large” for 1:24,000 scale or larger, “Medium” for maps scales between 1:24,000 and 250,000; and “Small” for scales smaller than 1:250,000.
  3. How accurate are the heights or depths?
    Vertical accuracy in the data set is not applicable.
  4. Where are the gaps in the data? What is missing?
    Mine feature, mineral occurrence, and mineral region geospatial and attribute data were compiled for the United States. Data were limited to publicly available sources that span the time period from 1889 to 2018. Common literature sources include government and private industry annual reports, NI 43-101 reports, journal articles, company websites, and USGS publications. To more completely populate the Production and Resources tables, select values were calculated by USGS authors and are indicated by “111” as a decimal trailer.
  5. How consistent are the relationships among the observations, including topology?
    The locations of mine features, mineral occurrences (which includes deposits, prospects, and showings), and mineral regions are represented as points, and some of these point locations have corresponding “footprints” or polygonal outlines. The polygonal footprint may represent the approximate outline of a mineral occurrence or mineral region. The exceptions are areas disturbed by mining-related activity, or surface workings, which are derived from imagery rather than published reports. Surface working outlines have no corresponding point location, nor do they have links to other tables.

    Polygonal outlines, except for surface workings, may overlap. Overlapping surface workings are merged into a single outline. Surface workings do not distinguish different types of mine features, such as pits, tailings piles, dumps, etc.

    Two points may occupy the same location. This occurs when there is a deposit with a mine, and the location of either the mine or the deposit is unknown. For example, a report provides a map showing the central location of a deposit. The report also provides production data for underground “Mine X” that is mining the deposit but does not provide the location of “Mine X”. In this case, a second point representing “Mine X” is placed at the point location of the deposit.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None. Please see 'Distribution Info' for details.
Use_Constraints:
There is no guarantee concerning the accuracy of the data. Any user who modifies the data is obligated to describe the types of modifications they perform. Data have been checked to ensure accuracy. If any errors are detected, please notify the originating office. The U.S. Geological Survey strongly recommends that careful attention be paid to the metadata file associated with these data. Acknowledgment of the U.S. Geological Survey would be appreciated in products derived from these data. User specifically agrees not to misrepresent the data, nor to imply that changes made were approved or endorsed by the U.S. Geological Survey. Please refer to https://www2.usgs.gov/laws/privacy.html for the USGS disclaimer.
  1. Who distributes the data set? (Distributor 1 of 2)
    U.S. Geological Survey - ScienceBase
    Attn: USGS Information Services
    Building 810, Mail Stop 302
    Denver, CO
    United States of America

    1-888-ASK-USGS (1-888-275-8747) (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set?
  3. What legal disclaimers am I supposed to read?
    This database, Rare Earth Element Occurrences in the United States (https://doi.org/10.5066/F7FN15D1) has been approved for data release by the U.S. Geological Survey (USGS). Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the U.S. Government may be held liable for any damages resulting from its authorized or unauthorized use. Although these data have been processed successfully on a computer system at the USGS, no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The USGS shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also contains copyrighted materials as noted in the text. Permission to reproduce copyrighted items for other than personal use must be secured from the copyright owner.
  4. How can I download or order the data?
    • Availability in digital form:
      Data format: Digital Data
      Network links: https://doi.org/10.5066/F7FN15D1
    • Cost to order the data: None. No fees are applicable for obtaining the data set.


  1. Who distributes the data set? (Distributor 2 of 2)
    Peter N Schweitzer
    U.S. Geological Survey: Midwest Region: EASTERN MINERAL & ENVIRON RES SC
    Geologist
    Mail Stop 954
    12201 Sunrise Valley Dr
    Reston, VA
    USA

    703-648-6533 (voice)
    703-648-6252 (FAX)
    pschweitzer@usgs.gov
  2. What's the catalog number I need to order this data set?
  3. What legal disclaimers am I supposed to read?
    This database, Rare Earth Element Occurrences in the United States (https://doi.org/10.5066/F7FN15D1) has been approved for data release by the U.S. Geological Survey (USGS). Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the U.S. Government may be held liable for any damages resulting from its authorized or unauthorized use. Although these data have been processed successfully on a computer system at the USGS, no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The USGS shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also contains copyrighted materials as noted in the text. Permission to reproduce copyrighted items for other than personal use must be secured from the copyright owner.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 05-Jul-2019
Metadata author:
Carma A San Juan
U.S. Geological Survey, Southwest Region
Physical Scientist
PO Box 25046, Mail Stop 973
Lakewood, CO
United States

303-236-2450 (voice)
303-236-3200 (FAX)
csanjuan@usgs.gov
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://mrdata.usgs.gov/metadata/usree.faq.html>
Generated by mp version 2.9.50 on Fri Jul 5 15:23:20 2019