Public Well Points for Rosebud-Robinson coal zone

Title: Public Well Points for Rosebud-Robinson coal zone
Abstract:: This ArcView shapefile contains a point representation of drill hole and outcrop data points in the coal resource assessment of the Rosebud-Robinson coal zone, Colstrip coalfield, Montana. This theme was created specifically for the National Coal Resources Assessment in the Northern Rocky Mountains and Great Plains Region.
Supplemental_Information:: This theme represents a digital point coverage showing the location of 108 non-confidential drill holes used in the assessment of total coal resources in the Rosebud-Robinson coal zone in the Colstrip coal field, Montana. Only drill holes penetrating the entire (or preserved) Rosebud-Robinson coal zone are included in the theme. Much of the drill hole data used in the Colstrip coal field study was previously compiled in the U.S. Geological Survey National Coal Resources Data System (NCRDS), although some additional drill hole data furnished by the operators of the Rosebud coal mine was also incorporated into this study. These data were all collated in a commercial relational database (Stratifact; GRG Corporation). Subsequently, a process of point data verification and editing was initiated, particularly for the NCRDS data. These data were cross-checked with published or unpublished drill hole records (when available) that included information on drill hole location and surface elevation with accompanying geophysical logs, cuttings descriptions and/or core logs from which coal thickness and depth could be determined. In the case of cuttings or core descriptions, coal thickness and depth were taken directly from the written reports. When geophysical logs were used, however, coal thickness and depth were measured from original analog prints or copies of the logs. Types of geophysical logs typically used for coal measurements include natural-gamma (gamma ray), gamma-gamma density (bulk density) and resistivity (or resistance) logs. Caliper logs, which measure variations in the drill hole diameter, were used in conjunction with density logs to verify that low density log deflections were in response to coal rather than drill hole washout. When no additional records other than those reported in NCRDS for a specific drill hole could be located, we compared the NCRDS information with data from wells nearby to determine the validity and usefulness of those data. Once the point data were collated and edited for stratigraphic and coal geologic content, the point data set was imported into ARCVIEW and converted to a shapefile for incorporation as a theme in the ARCVIEW project. Only public drill hole information is included in the theme. The point data theme is linked to a table that includes a USGS point identification number (internal designation); the source of the drill hole information (company or agency) and the published or alternative drill hole identification number; the surface elevation (in feet) of the drill hole; the total depth (in feet) of the drill hole; drill hole location reported by section, township and range; the total, net coal thickness (in feet) for coal beds in the Rosebud-Robinson coal zone in each drill hole; the number of beds within the coal zone; the 7.5' quadrangle in which the well was drilled; the well type (coal exploratory or oil and gas test); and the drill hole location in coordinates of latitude and longitude. Except for drill hole data furnished by the operators of the Rosebud coal mine, drill hole locations (x,y) in coordinates of latitude and longitude came directly from the National Coal Resources Data System (NCRDS), and thus, the accuracy of the well locations cannot be fully verified in all cases. Common abbreviations used in the sources of drill holes are as follows; USGS for the U.S. GeologicalSurvey; MBMG for the Montana Bureau of Mines and Geology; Bur of Rec or USBR for the U.S. Bureau of Reclamation; BLM for the Bureau of Land Management; and MMS for the Minerals Management Service.

Data format:	Geographic features and attributes in format Shapefile (version 1.0)
Network links:	<http://energy.cr.usgs.gov/coal/nca/rockiesgis.htm>
Media you can order:	CD-ROM (2 disc set) (format ISO 9660)

Data format:

Geographic features and attributes in format Shapefile (version 1.0)

Network links:

<http://energy.cr.usgs.gov/coal/nca/rockiesgis.htm>

Media you can order:

CD-ROM (2 disc set) (format ISO 9660)

Public Well Points for Rosebud-Robinson coal zone

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