This GIS layer was produced in association with other layers showing locations of coal-preparation plants in Indiana (COAL_PREPARATION_PLANTS_IN.SHP), locations of points where coal slurry was introduced (through pipelines or ditches) into disposal cells (COAL_SLURRY_DISCHARGE_IN.SHP), and locations of samples of coal slurry that were collected and analyzed by the Indiana Geological Survey (COAL_SLURRY_SAMPLES_IGS_IN.SHP).
Using the shapefile of approximate locations to identify areas of interest, about 160 historical aerial photographs taken in those areas between 1937 and 1981 were then obtained from the archives of the IGS and georeferenced. Other imagery that was utilized included Digital Ortho Quarter Quads (DOQQs) of the U.S. Geological Survey (1998) and imagery of the National Agricultural Imagery Program (2003) and the Indiana Orthophotography Project (2005).
CSDs were identified on the historical aerial photographs and other imagery, and their boundaries were digitized directly from the imagery using ESRI ArcMap to create this polygon shapefile (COAL_SLURRY_DEPOSITS_IN.SHP). The historical development of some CSDs was complex. Wherever possible, imagery taken on various dates ranging from 1937 to 2005 was used to identify and map different stages in a CSDs development.
CSDs were emplaced in a variety of different settings. At underground mines, disposal cells were specially constructed, but at many surface mines, preexisting features such as final-cut pits and spoil deposits were utilized for slurry disposal. Disposal cells sometimes consisted of impoundments ("slurry ponds") that were bounded by berms constructed of gob (coarse-grained refuse from coal preparation) or spoil (disturbed and displaced overburden from surface mining). Boundaries of various features (e.g., berms, final-cut pits, spoil deposits) that were visible at the times when the photographs were taken were then digitized directly from historical aerial photographs or other imagery.
The identification of CSDs on imagery involved the evaluation of several factors. CSDs are typically situated close to preparation plants, although in some locations, slurry is pumped or flows for considerable distances through pipes or ditches before entering a disposal cell. Other factors indicating the existence of a CSD include the presence of berms, a generally dark gray or black appearance (except where the deposit is highly oxidized or where salts have formed on the surface), the existence of braided or meandering stream channels (indicating a flay-lying deposit), and an absence of shadows indicating that the deposit is elevated.
Older, unreclaimed CSDs may exhibit erosional features that typically have relatively low relief, in contrast to coarse-grained gob deposits, which were created by dumping refuse in a large pile. Unreclaimed gob deposits are also typically dark gray to black in color, but they may also exhibit steep-sided, eroded edges that cast long shadows. Gob deposits may also show evidence of straight travelways on their upper surfaces where dump trucks traversed the deposit. Although both CSDs and gob deposits are typically dark gray to black, the more elevated (and drier) portions of CSDs are often light-colored to white because of more pronounced weathering or the formation of salts on the surface.
Historical aerial photographs are typically black-and-white and may be of poor resolution, and CSDs are sometimes difficult to differentiate from gob deposits or other disturbed or barren areas associated with active mining, so that the recognition of CSDs invariably requires subjective interpretations by the investigator.
After the CSDs were identified and mapped, estimates were made of their thicknesses, and volumes were then calculated.
This data set was compiled by Indiana University, Indiana Geological Survey, using data believed to be accurate; however, a degree of error is inherent in all data. This product is distributed "AS-IS" without warranties of any kind, either expressed or implied, including but not limited to warranties of suitability to a particular purpose or use. No attempt has been made in either the design or production of these data to define the limits or jurisdiction of any federal, state, or local government. These data are intended for use only at the published scale or smaller and are for reference purposes only. They are not to be construed as a legal document or survey instrument. A detailed on-the- ground survey and historical analysis of a single site may differ from these data.
CREDIT:
It is requested that the Indiana Geological Survey be cited in any products generated from this data. The following source citation should be included: [COAL_SLURRY_DEPOSITS_IN: Coal Slurry Deposits in Indiana (Indiana Geological Survey, 1:21,000, Polygon Shapefile)].
WARRANTY:
Indiana University, Indiana Geological Survey warrants that the media on which this product is stored will be free from defect in materials and workmanship for ninety (90) days from the date of acquisition. If such a defect is found, return the media to Publication Sales, Indiana Geological Survey, 611 North Walnut Grove, Bloomington, Indiana 47405 2208, and it will be replaced free of charge.
LIMITATION OF WARRANTIES AND LIABILITY:
Except for the expressed warranty above, the product is provided "AS IS", without any other warranties or conditions, expressed or implied, including, but not limited to, warranties for product quality, or suitability to a particular purpose or use. The risk or liability resulting from the use of this product is assumed by the user. Indiana University, Indiana Geological Survey shares no liability with product users indirect, incidental, special, or consequential damages whatsoever, including, but not limited to, loss of revenue or profit, lost or damaged data or other commercial or economic loss. Indiana University, Indiana Geological Survey is not responsible for claims by a third party. The maximum aggregate liability to the original purchaser shall not exceed the amount paid by you for the product.
In order to provide volumetric estimates of the CSDs that were mapped, it was necessary to make assumptions regarding the thicknesses of the deposits. The following simplifying assumptions were made: (1) The thickness of a CSD emplaced in a final-cut pit ("FCP") was assumed to be equal to the depth of the coalbed that was mined. Also, the cross-sectional area of such a CSD was assumed to be rectangular. NOTE: This assumption does not take into account any slurry that was emplaced by overflow above the tops of final-cut pits. Also, for the purposes of this preliminary evaluation, inclined haul roads and haul roads that transected spoil ridges are also included in the category of "final-cut pit" at some mine sites. (2) The thickness of a CSD emplaced behind a berm ("GND") is assumed to be equal to the height of the berm. It is assumed that the CSD was emplaced on undisturbed ground (rather than an excavated pit). The cross-sectional area of such a CSD is assumed to be rectangular. (3) A CSD emplaced within a deposit of ungraded spoil ("SPL") is assumed to completely fill the troughs between parallel ridges. Spoil ridges are assumed to have an angle of draw of 30 degrees on both sides, so that the troughs between them are assumed to have cross-sectional areas that are isosceles triangles. Consequently, the maximum thickness of a CSD within any given trough is assumed to be approximately equal to one-fourth of the average spacing between ridges, and the average thickness is assumed to be approximately equal to one-eighth of the average spacing. NOTE: This assumption does not take into account any slurry that was emplaced above the tops of spoil ridges.
For a few features, site-specific drilling data exists regarding the thicknesses of individual CSDs. For most features, however, thicknesses of deposits were estimated using various preexisting datasets, as follows: (1) Final-Cut Pits ("FCP"). Depths to coalbeds in the vicinity of CSDs emplaced in final-cut pits were obtained from two sources: (a) Information on surface mines contained in the Coal Mine Information System (CMIS). (b) Drilling-log data that are tabulated in the National Coal Resource Data System (NCRDS). In general, the approximate elevation of the coalbed was determined from the drill hole that is geographically closest to the CSD feature. The depth of the coalbed at the feature was then calculated by subtracting the coalbed's approximate elevation from the elevation of ground at or near the feature. Where data are available from both the CMIS and the NCRDS, preference was given to the NCRDS data. For many features, a range of ground elevations exists, so that values for a "minimum" and "maximum" thickness were determined. (2) Undisturbed Ground ("GND"). The heights of berms associated with CSDs emplaced on undisturbed ground were estimated from topographic contour data contained in digital line graphs (DLGs) derived from 1:24,000-scale quadrangle maps of the U.S. Geological Survey. (3) Ungraded Spoil ("SPL"). The average spacing of spoil ridges associated with CSDs emplaced in troughs between such ridges was determined by measurements made directly from georeferenced historical aerial photographs and other imagery. Wherever possible, the measurements were made on the spoil ridges where slurry was later emplaced; where slurry was already present in all available imagery, measurements were made on nearby spoil deposits that were presumably associated with the same coalbed. (NOTE: Typically, georeferenced historical aerial photos have not been orthorectified.) As described above, the average thickness of the deposit was then assumed to be equal to one-eighth of the average spacing between ridges.
Of the deposits that are categorized as FCP, GND, and SPL, there are several situations for which thickness estimates are not possible in the absence of site-specific field data. These include: (1) Graded spoil deposits. (2) Active areas where slurry emplacement (or removal) has recently been occurring, as indicated by changes that are evident by comparison of aerial photography taken in 2003 and 2005. (3) Excavated pits, other than final-cut pits and impoundments on undisturbed ground.
Using the shapefile of approximate locations to identify areas of interest, about 160 historical aerial photographs taken in those areas between 1937 and 1981 were then obtained from the archives of the IGS and georeferenced. Other imagery that was utilized included Digital Ortho Quarter Quads (DOQQs) of the U.S. Geological Survey (1998) and imagery of the National Agricultural Imagery Program (2003) and the Indiana Orthophotography Project (2005).
CSDs were identified on the historical aerial photographs and other imagery, and their boundaries were digitized directly from the imagery using ESRI ArcMap to create a polygon shapefile.
It is requested that the Indiana Geological Survey be cited in any products generated from this data. The following source citation should be included: [COAL_SLURRY_DEPOSITS_IN: Coal Slurry Deposits in Indiana (Indiana Geological Survey, 1:21,000, Polygon Shapefile)].
WARRANTY:
Indiana University, Indiana Geological Survey warrants that the media on which this product is stored will be free from defect in materials and workmanship for ninety (90) days from the date of acquisition. If such a defect is found, return the media to Publication Sales, Indiana Geological Survey, 611 North Walnut Grove, Bloomington, Indiana 47405 2208, and it will be replaced free of charge.
LIMITATION OF WARRANTIES AND LIABILITY:
Except for the expressed warranty above, the product is provided "AS IS", without any other warranties or conditions, expressed or implied, including, but not limited to, warranties for product quality, or suitability to a particular purpose or use. The risk or liability resulting from the use of this product is assumed by the user. Indiana University, Indiana Geological Survey shares no liability with product users indirect, incidental, special, or consequential damages whatsoever, including, but not limited to, loss of revenue or profit, lost or damaged data or other commercial or economic loss. Indiana University, Indiana Geological Survey is not responsible for claims by a third party. The maximum aggregate liability to the original purchaser shall not exceed the amount paid by you for the product.