This U.S. Geological Survey (USGS) data release provides the descriptions of 10 U.S. sites that include mineral regions, mineral occurrences, and mine features that contain enrichments of graphite. To be included in this data release, sites must have a contained resource and (or) past production of more than 1,000 metric tons of graphite, which is approximately 3 percent of the average annual U.S. consumption of graphite from 2016 through 2020. Sites in this dataset occur in Alaska, Alabama, Colorado, Montana, New York, Pennsylvania, and Texas. There are known graphite occurrences in California, Connecticut, Georgia, Michigan, New Hampshire, New Jersey, North Carolina, Rhode Island, and Wyoming that have not been included in this database because contained resource and (or) production of graphite were not found above our cutoff in the public domain for these areas.
Graphite is considered a critical and strategic mineral because of its essential applications in the aerospace and energy sectors (Robinson and others, 2017). Graphite is used in batteries, brake linings, lubricants, powdered metals, refractory applications, and steelmaking (U.S. Geological Survey, 2021). In 2020, the U.S. was 100 percent net import reliant on graphite from countries that included China, Mexico, Canada, and India (U.S. Geological Survey, 2021). Graphite has not been produced in the U.S. since the 1950s.
Graphite occurs in the U.S. as disseminated flake graphite deposits and as graphite veins. Globally, most currently mined flake graphite deposits contain at least 8 to 12 percent graphitic carbon in deposits larger than 0.5 million metric tons (Robinson and others, 2017). In comparison, the Graphite Creek deposit in Alaska contains a measured and indicated resource of more than 10 million metric tons with 7.8 percent graphite plus an inferred resource of more than 90 million metric tons with 8 percent graphite (King and others, 2019). Graphite One Inc. plans to decide whether to move the Graphite Creek deposit into production after an updated prefeasibility study is completed in early 2022.
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. 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). The presence of a graphite mineral deposit in this database is not meant to imply that the deposit is currently economic. Rather, these deposits were included to capture the characteristics of the largest graphite deposits in the United States. Inclusion of material in the database is for descriptive purposes only and does not imply endorsement by the U.S. Government. The authors welcome additional published information in order to continually update and refine this dataset.
King, N., Valorose, C., and Ellis, W., 2019, 2019 NI 43-101 mineral resource update for Graphite Creek, Seward Peninsula, Alaska, USA, prepared for Graphite One Inc. [Filing date March 26, 2019]: Alaska Earth Sciences, Inc., 258 p., accessed February 6, 2020, at http://www.sedar.com
Robinson, G.R., Jr., Hammarstrom, J.M., and Olson, D.W., 2017, Graphite, chap. J of Schulz, K.J., DeYoung, J.H., Jr., Seal, R.R., II, and Bradley, D.C., eds., Critical mineral resources of the United States - Economic and environmental geology and prospects for future supply: U.S. Geological Survey Professional Paper 1802, p. J1-J24, https://doi.org/10.3133/pp1802J
U.S. Geological Survey, 2021, Mineral commodity summaries 2021: U.S. Geological Survey, 200 p., https://doi.org/10.3133/mcs2021
The Esri ArcGIS 10.8.1 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 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. Metadata is provided in extensible markup language (XML), hypertext markup language (HTML), and text-formatted (TXT) formats.
DATABASE LAYERS AND TABLES
The Loc_Pt feature class contains point locations of mineral regions, mineral occurrences (deposits), and mine features, and 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 point locations, except for surface workings.
The Loc_Poly feature class contains footprints or polygons of areas, deposits, and mining districts. 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 (Loc_Poly_Sw) layer.
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 (ft) (300 meters[m]) in one dimension to be digitized, and multiple workings that are 500 ft (150 m) 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. No surface workings were delineated in this data release.
The Dep_Model table contains mineral deposit model and geoenvironmental model classifications that are models established and used by the USGS for the deposit types included in the database.
The Descr_Sum table contains relevant descriptions found in source reports. These descriptions are attributed according to the type of description, such as Geology, History, Production, Resources, etc. Descriptions pertain to individual features or to larger sites. The authors do not paraphrase or combine descriptions, and therefore, when a database feature is described in multiple reports, the feature will have multiple entries.
The GeolMinOcc table contains information about the geology of mineral deposits and prospects. Every attempt was made to compile information as reported in the source report. For example, if one source report states the valuable material as "graphite, and another reports "sphalerite", 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, "King and others (2019)". All information in the record comes from the primary source report unless an attribute field value contains a number in parentheses. This number denotes another source report whose Ref_ID is given in the Remarks field. Full citations for source reports are provided in the References table and adhere to USGS citation style.
The History table contains information derived from publicly available sources regarding the status of a mineral region, mineral occurrence, or mine feature 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 1912 and 1916 respectively, the mine was active from 1912 and 1916; 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 Production table contains published production data for mines. Production is listed by commodity and reported as shown in the source reports. Reported production values are totaled by the USGS authors for the time period defined by the Year_From and Year_To fields. 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 on the Site table. The contained SI commodity amount (CntSIComAm) for the contained SI commodity (CntSICom) has been provided in one consistent unit (metric tons) for the user; these conversions are typically calculated by USGS authors. 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. Conversion factors used by USGS authors can be found on the Conversions.csv file. Decimal trailers are not reported in the Entity and Attribute section for ranges. 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.
The References table contains the citation of the map or report(s) from which the point, polygon, or attribute information is obtained. The table also assigns a short reference (Ref_ID) that is used throughout the database. This table does not have a relationship class allowing the user to relate to other tables because Ref_IDs from tables such as the Production table may have multiple references.
The Resources table contains reported resource data for mineral deposits. Data are compiled for the most recent mineral resource estimate when available. 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 NI 43-101 or the Joint Ore Reserves Committee Code (JORC Code). The way the resource is reported dictates the number of records for each deposit. For example, if data from a single deposit are reported for an inferred resource and a proven reserve, data from both classifications will be reported as separate records, unless it is stated that the proven reserve is inclusive of the inferred resource. If resource data are reported for a group of features rather than an individual deposit, the Ftr_ID will show "-1111" and the resource is assigned to the "site" or Site_ID that groups those deposits on the Site table. The attribute field CntSIComAm has been provided in one consistent unit (metric tons) for the user; these conversions are typically calculated by USGS authors. A value ending with "111" as a decimal trailer indicates the value was calculated by USGS authors. For example, if a value in the Grade field is calculated by USGS authors to be 0.05 percent, then the value recorded in the database will be 0.05111. Conversion factors used by the USGS authors can be found on the Conversions.csv file. Decimal trailers are not reported in the Entity and Attribute section for ranges. 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 SI units by the USGS authors. Inclusion of material in the database is for descriptive purposes only and does not imply endorsement by the U.S. Government.
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. A Site_ID is also assigned to mineral regions, such as mining districts, which are represented as a single polygon or point feature in the database. The Site_ID is used in all tables except the References table and Loc_Poly_Sw feature class. 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.
Mineral regions may be a mineralized area, a mineral district, or a mining district. Mineral areas have similar geology and deposit types. Mineral districts are usually named and are 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. Mining district polygons may overlap.
Mine features are man-made features associated with the process of extracting, processing, or concentrating ore materials. In this database, mine features 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 such as pits, dumps, tailings, etc. within the surface workings outline.
Mineral occurrences, defined as a concentration of a mineral considered potentially valuable, can be deposits, prospects, or showings in USGS mineral deposit databases (USMIN). Mineral deposits have a defined size and may have a grade indicated by current and (or) past production, and (or) a resource estimate.
The locations of mineral regions, mine features, and mineral occurrences 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 Loc_Pt feature class. Otherwise, for points that have polygonal boundaries, the Loc_Pt feature class attribute field Loc_Poly contains the value "Yes" and the boundary definition is described in the field Poly_Def field. For example, "Approximate extent of the inferred and indicated resource polygons from map", or "Approximate extent of polygon no. 1 from map".
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 that summarize 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 data are derived from publicly available sources. The Last_Updt field shows the date that the record was last updated by the USGS 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. Except for 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. As an example, one Commodity record shows "graphite; lead (1)". This indicates the commodity "graphite" was derived from the primary reference denoted in the Ref_ID field as "King and others (2019)" and "lead" was derived from a secondary reference denoted in the Remarks field as "(1) Amato and Wright (1998)".
In the GeolMinOcc table, lists in different fields may not correspond. For example, if the Commodity field shows "graphite; lead", the Value_Mat field may list the associated ore minerals in a different order. The data in lists are alphabetized to prevent duplication of values as authors compile the dataset, with individual values separated by semicolons. 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, and the report also provides production data for underground "Mine X" that is associated with 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 feature classes and tables 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 that the attribute field Mat_Amnt occurs in the Production table and in the Resources table.