A data search by state was conducted to ascertain where digital, geospatial mine feature information from 7.5 and 15-minute topographic maps were available. Geospatial mine feature data, available for Nevada and California at 1;24,000-scale, were acquired and used as a starting point for those states. For remaining states, historical 7.5- and 15-minute topographic maps were acquired from the USGS Historical Topographic Map Collection/topoView website (https://ngmdb.usgs.gov/topoview/) as geoPDF files. In the 7.5-minute series, about 60 percent of the quadrangles had multiple versions. In the 15-minute, 1:48,000-scale series, about 10 percent of the maps had multiple versions, and in the 15-minute, 1:62,500-scale series, about 20 percent of the maps had multiple versions. For quadrangles with two map versions at the same scale, both maps were acquired. For quadrangles with more than two versions at the same scale, the oldest map, and versions at approximately 10-year intervals up to the most recent were acquired. Using Global Mapper software, acquired maps were converted from geoPDF to geoTIF format to make them accessible in ArcGIS. Capture of mine features was accomplished at each scale by visually inspecting the maps for mine symbols and digitizing points and/or polygons into an ArcGIS file geodatabase. No reconciliation between these data from different map scales was done. For example, if a mine feature occurred on a 7.5-minute map and a similar feature occurred on a 15-minute map, the feature was digitized twice. Information describing the feature type (prospect pits, mines, adits, dumps, tailings, etc.) and the map date, name, and Geospatial Data Architecture (GDA) and Scan identification number was compiled in the corresponding attribute table. Where mine symbols occurred on multiple versions (dates) of a map of the same scale, the first occurrence of the symbol was digitized. If subsequent versions of the map showed the same symbol within a permissible tolerance of the original location, the symbol was not re-digitized. The permissible tolerance for point symbols was roughly the area of a "box" which completely enclosed the map symbol. In the case of polygonal features, if the shape of the feature changed between map versions, the entire polygon was re-digitized. Slight shifts between versions of a map were common and reflected map scanning and georegistration variance. When mine symbols were located within a topographic depression but no explicit pit outline was shown on the map, the depression was assumed to be a pit related to mining activity and the outermost depression contour was digitized as a polygon. The polygon was then attributed according to the mine symbol and/or the label contained on the map. When a map label name was surrounded by numerous symbols, the closest major symbol received the name. For example, if a name was surrounded by prospect pit and adit symbols on the map, the name would be applied to the closest adit symbol. Pre-existing, 1:24,000-scale mine feature data for the states of Nevada and California were checked for locational accuracy; attribute table schema were modified and updated for consistency; and mine features (point and polygon) from older versions of maps were captured. Data inspection and checks were performed by the individual digitizing the maps (first-level review), by team members reviewing a random selection of maps in a state (second-level review), by a project lead who reviewed data compiled at the state level (third-level review), and a final spot check of the merged data for the western US by USGS colleagues (fourth-level review). In each case, reviews addressed the accuracy and completeness of mine feature capture, completeness and consistency of attributes, adherence to established project schema, and representation of mine features through time.
Similar to the initial process step, mine symbols on 7.5- and 15-minute topographic maps for the states of Arkansas (AR), Iowa (IA), Louisiana (LA), Minnesota (MN), Missouri (MO), and Texas (TX) were digitized and appended to the existing source data. Some notable changes were made to some of the database attribute values. Terms in the attribute field Ftr_Type were modified as follows: 1) added "Iron Pit" and "Shell Pit"; 2) changed "Ore Storage Pond" to "Ore Stockpile/Storage"; moved "Ore Storage Pond" to Ftr_Name; 3) changed "Tailings - Thickener" to "Tailings - Undifferentiated"; moved "Tailing Thickeners" to Ftr_Name; 4) changed "Pumice Mine" to "Pumice Pit"; moved "Pumice Mine" to Ftr_Name; 5) changed "Unidentified Feature" to "Disturbed Surface" or "Disturbed Surface - Pit"; and 6) changed "Gravel/Borrow pit - Undifferentiated" to "Gravel/Borrow Pit - Undifferentiated". Terms removed from the Remarks field include: 1) "Unidentified - generic disturbed ground symbol"; 2) "Unidentified - generic disturbed ground symbol. Labeled as Pit only"; 3) "Photorevised"; 4) "Revised"; and 5) "Coincident feature labeled as <Ftr_Type> on 19xx map" (changed to "Feature designated as <Ftr_Type> from feature on 19xx map"). Unlabeled features attributed as Ftr_Type "Disturbed Surface" or "Disturbed Surface - Pit" (previously attributed as "Unidentified Feature"), were re-evaluated to identify some of these features. A buffer was applied to identify other nearby labeled features within approximately 1 kilometer. If it was reasonable to assume that a nearby labeled feature could be used to infer the Ftr_Type of the unlabeled "Disturbed Surface" feature, then the Ftr_Type was changed and the Remark "Inferred <Ftr_Type> from adjacent feature" was entered in the Remarks field. For example, several polygons labeled as "gravel pits" are present on a map dated 1950. A 1980 version of the map contains some pink, photorevised unlabeled disturbed surface polygons near the 1950 polygons. The 1980 disturbed surface polygons were assigned the Ftr_Type "Gravel Pit" and "Inferred Gravel Pit from adjacent feature." was entered in the Remarks field. This was not done when multiple Ftr_Types surrounded an unlabeled feature or if it was not reasonable to infer the Ftr_Type based on geographic factors. The field "Topo_Date" has been changed from a text field type to an integer field type to facilitate numeric analysis. Some features included in the original source dataset may have been added, deleted or otherwise modified if errors were discovered while performing these updates.
Version 2.0 - Similar to the initial process step, mine symbols on 7.5- and 15-minute topographic maps for the states of Michigan (MI), Wisconsin (WI), Indiana (IN), and Illinois (IL) were digitized and appended to the existing source data. The terms "Tipple" and "Mine" have been added to the Ftr_Type field domain. Some features included in the original source dataset may have been added, deleted or otherwise modified if errors were discovered while performing these updates.
Version 3.0 - Similar to the initial process step, mine symbols on 7.5- and 15-minute topographic maps for the states of Kentucky (KY), Ohio (OH), and Tennessee (TN) were digitized and appended to the existing source data. Some features included in the original source dataset may have been added, deleted or otherwise modified if errors were discovered while performing these updates.
Version 4.0 - Similar to the initial process step, mine symbols on 7.5- and 15-minute topographic maps for the states of Alabama (AL), Florida (FL), Georgia (GA), North Carolina (NC), Mississippi (MS) and South Carolina (SC) were digitized and appended to the existing source data. The feature type (Ftr_Type) "Pumice Pit" has been merged into the existing Ftr_Type "Quarry - Pumice" for simplification. "Chert Pit" and "Marl Pit" have been added to the Ftr_Type domain. Some features included in the original source dataset may have been added, deleted or otherwise modified if errors were discovered while performing these updates.
Version 5.0 - Similar to the initial process step, mine symbols on 7.5- and 15-minute topographic maps for the states of Delaware (DE), Maryland (MD), New Jersey (NJ), and Virginia (VA) were digitized and appended to the existing source data. Some features included in the original source dataset may have been added, deleted or otherwise modified if errors were discovered while performing these updates.
Version 6.0 - Similar to the initial process step, mine symbols on 7.5- and 15-minute topographic maps for the states of Connecticut (CT), Maine (ME), Massachusetts (MA), New Hampshire (NH), Rhode Island (RI), and Vermont (VT) were digitized and appended to the existing source data. Some features included in the original source dataset may have been added, deleted or otherwise modified if errors were discovered while performing these updates.
Version 7.0 - Similar to the initial process step, mine symbols on 7.5- and 15-minute topographic maps for the state of Pennsylvania (PA) were digitized and appended to the existing source data. Some features included in the original source dataset may have been added, deleted or otherwise modified if errors were discovered while performing these updates.
Version 8.0 - Similar to the initial process step, mine symbols on 7.5- and 15-minute topographic maps for the state of New York (NY) were digitized and appended to the existing source data. Some features included in the original source dataset may have been added, deleted or otherwise modified if errors were discovered while performing these updates.
Version 9.0 - Similar to the initial process step, mine symbols on 7.5- and 15-minute topographic maps for the state of West Virginia (WV) were digitized and appended to the existing source data. Some portions of the West Virginia 1:24,000-scale polygons were supplemented with work done by Aaron Maxwell (Assistant Professor in the Department of Geology and Geography at West Virginia University) and his lab group at the West Virginia View consortium (Maxwell, 2020). They used a previously published version of this dataset for the state of Kentucky to train deep learning models. These were then applied to ~1300 historic 1:24,000-scale topographic map quadrangles in West Virginia to extract the land disturbance extents. These rasters were vectorized into shapefiles and shared with the USGS team. The rasterized vector polygons were smoothed using Esri geoprocessing tools and a 40-meter PAEK generalization. They were simplified further by removing extra vertices within a 1-meter tolerance. The data was then reprojected from the native topographic map datum of NAD 1927 to WGS 1984. The polygons were cleaned up further by removal of raster artifacts by comparing each feature to the symbology on the georeferenced topographic maps. Attribution of the USGS data tables and the capture of point features for these maps used the same process as previous versions of this dataset. Some features included in the original source dataset may have been added, deleted or otherwise modified if errors were discovered while performing these updates.
Version 10.0 - Similar to the initial process step, mine symbols on 7.5- and 15-minute topographic maps for the state of Alaska, Hawaii, and the Commonwealth of Puerto Rico were digitized and appended to the existing source data. Alaska map scales of 1:63,360 are included in the 1:62,500-scale datasets. Puerto Rico scales (1:10,000, 1:20,000, and 1:30,000) are included in the 1:24,000-scale datasets. Some features included in the original source dataset may have been added, deleted or otherwise modified if errors were discovered while performing these updates.
The entity and attribute information provided here describes the tabular data associated with the six point and polygon feature classes in the file geodatabase (see "Supplemental Information" for details). The structure of the attribute table was generated by the USGS authors of this dataset. 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 dataset.