This file is a digital point representation of the locations of abandoned airshafts used to help ventilate historical coal mines in the Boulder-Weld coal field, Denver Basin, Colorado. This file was created as part of the Front Range Infrastructure Resources Project (FRIRP) of the USGS, and provides information pertaining to energy resource issues within the Colorado Front Range urban corridor in and near the Denver metro area. These data contributed to the publication titled as follows: Maps showing the extent of mining, locations of mine shafts, adits, airshafts, and bedrock faults, and thickness of overburden above abandoned coal mines in the Boulder-Weld coal field, Boulder, Weld, and Adams counties, Colorado: U.S. Geological Survey Geologic Investigations Map I-2735, 1:48000-scale.
In 1996, the U.S. Geological Survey (USGS) initiated a Front Range Infrastructure Resources Project (FRIRP) to provide relevant information to the public, land-use planners, and decision makers regarding the location and characteristics of water, mineral, and energy resources along the Front Range corridor in Colorado. Energy resource issues within the FRIRP project area include the impacts of historic coal mining, particularly in regard to the potential for subsidence over abandoned mines in recently developed areas or in areas currently being evaluated as residential, commercial, and (or) industrial building sites. In order to address this issue, the USGS and the Colorado Geological Survey (CGS) jointly undertook the development of digital data (coverages) based on previously published maps showing the location and depth to abandoned underground coal mines in the Boulder-Weld coal field north and northwest of Denver, Colorado. Mining in the coal field began in the early 1860s and continued into the 1970s with the last mine closing in 1979 because of fire. Although much of the surface expression of mine development has been removed or masked by increasing urban and residential development, subsurface features of underground mining, such as airshafts, hoisting shafts, and open mine rooms, are still present. Because of this, there continues to be a potential for subsidence in abandoned mine areas. The primary purpose for compiling the Boulder-Weld coal field coverages is to provide the public and land-use planners with some basic digital data necessary for an initial GIS assessment of areas that have been impacted by coal mining. Such areas may require special considerations with regard to development and surface subsidence potential. It should be noted, however, that these data do not in any way provide the information necessary for a complete and accurate estimation of the subsidence potential in any specific area of the coal field. For this reason, users requiring more detailed information regarding subsidence potential should consult with the Colorado Geological Survey, 1313 Sherman Street, Room 715, Denver, Colo., 80203; 303-866-2611; http://geosurvey.state.co.us.
The digital coverage of the locations of abandoned airshafts is based on a previously published map compiled by the consulting firm of Amuedo and Ivey for the Colorado Geological Survey in the early 1970s (see Myers and others, 1975, in reference section of metadata). The primary intent of coverage is to show historic airshaft locations within abandoned mine workings in the Boulder-Weld coal field.
publication date
These data are considered more accurate at scales of 1:48,000 or smaller. It should be noted that these data do not in any way provide the information necessary for a complete and accurate estimation of the subsidence potential in any specific area of the coal field. For this reason, users requiring more detailed information regarding subsidence potential should consult with the Colorado Geological Survey, 1313 Sherman Street, Room 715, Denver, Colo., 80203; 303-866-2611; http://geosurvey.state.co.us.
U.S. Geological Survey, Box 25046, MS 939, Denver Federal Center
No measured x,y coordinates (for example, latitude and longitude) were available for the airshaft locations. These locations were digitized visually from TIFF images of a map showing the extent of abandoned underground coal mines and related features (including airshafts) compiled by Myers and others (1975) at a scale of 1:24,000. In the Myers and others map, symbols used to designate the locations of the airshafts consisted of circles ("o") that covered a map area diameter of about 150 ft. The visually estimated center point of each circle was digitized as the point location for airshafts depicted in this coverage. The user is cautioned to use this coverage only as a "first cut" for GIS analysis, and should seek more detailed information concerning abandoned airshaft locations if this information is critical to the user's evaluation for a specific study. Additionally, no information is provided here detailing the condition or stability of any given airshaft at the present time.
coal mine subsidence and land use in the Boulder-Weld coalfield
The digital point data representing abandoned airshaft locations were compiled from analog data plotted on a 1:24,000-scale composite base map (clear film) representing all or parts of nine USGS 7.5' topographic quadrangles within the coal field boundary. To facilitate the scanning and digitization procedures required to create the coverage, photographic reproductions were made on scale-stable mylar for each 7.5'quadrangle area within the coal field area rather than creating a single photographic reproduction of the entire composite map. Each 7.5' segment was then electronically scanned, and converted to a Tagged Image File Format (TIFF) image that could be imported into Environmental Systems Research Institute (ESRI) ArcInfo software for coverage development. The abandoned airshaft location point coverage was developed from the "on-screen" digitization of each airshaft location as delineated in the 7.5' quadrangle TIFF images. In the TIFF images, symbols used to designate the locations of the airshafts consisted of circles ("o") that covered a map area diameter of about 150 ft. The visually estimated center point of each circle was digitized as the point location for airshafts depicted in this coverage. The user is cautioned to use this coverage only as a "first cut" for GIS analysis, and should seek more detailed information concerning abandoned airshaft locations if this information is critical to the user's evaluation for a specific study. Additionally, no information is provided here detailing the condition or stability of any given airshaft at the present time.
There are 95 airshaft locations in the coverage. Other than ArcInfo identifiers generated during the digital capture of the data, there are no additional attributes in the airshaft coverage.
Box 25286 Denver Federal Center
This publication was prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Although all data and software published are used by the U.S. Geological Survey, no warranty, expressed or implied, is made by the U.S. Geological Survey as to the accuracy of the data and related materials and (or) the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of these data, software, or related materials.
Depth to coal mining geographic features and attribute data for the Colorado Front Range
ArcIMS Image Map Service
A web-based interactive mapping system that accesses an ArcIMS Map Service running on certmapper.cr.usgs.gov.
This product can be downloaded individually using any one of the digit form, Network_Resource_Name URLs above. Each of these URLs may provide access to various formats of the same product.
U.S. Geological Survey, Box 25046, MS 939, Denver Federal Center
For inquiries regarding this document, please include the metadata contact person's name, dataset name, and publication series and number.