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Variability of Subsurface Structure and Infiltration Hydrology among Surface Coal Mine Valley Fills


Authors: Erich Hester Kathryn L. Little Joseph D. Buckwalter Carl E. Zipper Thomas J. Burbey
Owners: Erich Hester
Resource type: Composite Resource
Storage: The size of this resource is 151.7 MB
Created: Sep 29, 2018 at 3:22 p.m.
Last updated: Oct 13, 2018 at 9:54 a.m. by Erich Hester
DOI: 10.4211/hs.b1d5fd2c2d3e49878d86cb7c2d483d2a
Citation: See how to cite this resource
Sharing Status: Published
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Abstract

This is the data repository for the journal article entitled "Variability of Subsurface Structure and Infiltration Hydrology among Surface Coal Mine Valley Fills" published in Science of the Total Environment in 2018 by Erich T. Hester, Kathryn L. Little, Joseph D. Buckwalter, Carl E. Zipper, and Thomas J. Burbey. The data themselves, as well as information about the data, for example geographic location and date, can be found in several locations:

1) Many data are in the journal article or the associated supplementary information, which are available at the journal website or can be requested by emailing Erich Hester at ehester@vt.edu
2) Many data are available in the files associated with this Hydroshare resource, which are described in the readme.txt file
3) Any questions that are not answered by the above methods can be directed to Erich Hester at ehester@vt.edu

Note that the data included in this Hydroshare resource are for the electrical resistivity imaging (ERI). The other data collected for the published article (e.g., bore logs) are solely within the article itself and the associated supplementary information published with the article at the journal website.

Content

readme.txt

This document describes the process we used to produce and utilize the files in this dataset, as well as the organization and naming conventions of the files.

The SuperSting R8 and EarthImager 2D manuals by Advanced Geosciences, Inc. (AGI) contain detailed information about the procedure. The links in the following citations require AGI customer access.
Advanced Geosciences, Inc. (2009). Instruction Manual for EarthImager 2D Version 2.4.0 Resistivity and IP Inversion Software. Retrieved March 21, 2017, from http://www.advancedgeosciences.com/files/eicust/earthimageruser.shtml.
Advanced Geosciences, Inc. (2017). SuperStingTM Earth Resistivity, IP & SP System With Wi-Fi® Instruction Manual. Retrieved January 20, 2018, from http://www.advancedgeosciences.com/files/cust/superstinguser.shtml.


Folder Structure & File Names

The file fillsummary.csv contains general information about each of the field sites.

Each of the four (4) .zip files contains the data for one valley fill. Within each .zip file, file names use two-character fill abbreviations: BH for Barton Hollow, BW for Bearwallow, EF for End Fill, and OF for Office Fill. For descriptions within this readme file, we use XX to represent these two-character fill abbreviations.

Each of the .zip files includes folders and basic files for each ERI survey at the valley fill, organized by survey. The naming system is:
	- XXLONG - survey of most/all of the valley fill, involving no artificial rainfall.
	- XXSHORTA - survey of the artificial rainfall plot while dry
	- XXSHORTB - survey of the artificial rainfall plot after 1 hour of sprinkling
	- XXSHORTC - survey of the artificial rainfall plot after 2 hours of sprinkling
	- XXSHORTD - survey of the artificial rainfall plot after 3 hours of sprinkling
	- XXSHORTE - survey of the artificial rainfall plot after 4 hours of sprinkling

For each survey, there are four basic files that are downloaded from the resistivity meter prior to data processing:
	- .cmd (command file) - contains the code provided by the user to the resistivity meter to perform the survey.
	- .crs (contact resistance file) - contains the contact resistance values at each electrode for the survey.
	- .stg (Sting file) - contains the raw data results of the survey.
	- .zip (zip file) - contains various other survey information. We did not need to use the .zip files during data processing.

Each survey folder (e.g. XXLONG) contains one or more trial folders, which in turn contain files associated with one data inversion, i.e., one run of the EarthImager 2D software. EarthImager automatically creates the hierarchy of the trial folders. The automatic contents of these folders include five files:
	- .trn (terrain file) - contains topographic data provided by the user to EarthImager for use during inversion.
	- .jpg (image file) - visually depicts the results of the inversion.
	- .ini (initial settings file) - contains the user-specified initial and inversion settings used by EarthImager during inversion.
	- .out (inversion output file) - contains the numerical results of the inversion.
	- .stg (Sting file) - contains the raw data points processed during inversion. This may differ from the original .stg file downloaded from the resistivity meter if noisy data points or electrodes have been removed from the raw dataset.
	- The final trial folder of each XXLONG survey also includes a .lvl file (XXLONG_trialX_AllRes.lvl) that defines the color scale for the visual depiction of the results, overriding the automatic scaling on EarthImager so that the results of the four long surveys can be compared. The images produced with this user-defined scale are found in the same folders (XXLONG_trialX_AllResX scaled.jpg).


Files Associated with Time Lapse Inversion

Outside of the survey folders, there are a few files used during the time-lapse inversion process.
	- XXTimeLapse.bch - contains the file path for the base-case inversion output (.out) file, followed by the file paths for all subsequent Sting (.stg) files to be compared to the base case. The exact file paths will differ depending on where you save your files.
	- whiteout_XX2.lvl - contains the custom color scale for the time-lapse inversion results, such that areas with little to no change in conductivity appear white rather than the default green.
	- XX time lapse inversion notes.txt - details the maximum percent differences in conductivity in each artificial rainfall survey, and notes the final values used for the custom color scales. 

The folders for surveys involving artificial rainfall  (XXSHORTB, XXSHORTC, XXSHORTD, XXSHORTE) include additional files.
	- .bmp and .jpg - In addition to the ordinary inversion results, there are images showing the differences in electrical resistivity and conductivity as compared to the dry survey (XXSHORTA).
	- .dat (output data file) - numerical data of the differences in electrical resistivity and conductivity as compared to the dry survey (XXSHORTA).
	- .bln (blanking file) - produced by EarthImager during the time-lapse inversion process.
	- .lvl (level file) - contains the custom color scale to optimize the visibility of conductivity differences in the time-lapse results.
	- "whiteout" .jpg files (XXSHORTX_trialX_DiffCond1 whiteout2.jpg) - recreate the time-lapse conductivity results, with areas with little to no difference in conductivity appearing as white instead of green. Produced using whiteout_XX2.lvl.

Procedure & Associated File Types
Note: the details of how to perform each data processing task are found in the EarthImager 2D manual, unless stated otherwise.

Prior to data processing
	1) Create .cmd file and upload it to the SuperSting, as described in the SuperSting manual. This will be used for the ERI surveys. The .cmd files we used appear in each fill's .zip file.
	2) Field work: perform ERI surveys as described in the SuperSting manual. Gather topographic data of the sites.
	3) Create .trn files based on the topographic data of the field sites.
	4) Download survey data from resistivity meter to computer, in the form of four files: .cmd, .crs, .stg, .zip. You will mostly be working with the .stg file, but the others are good records to have.

Basic data processing
	5) Adjust initial settings and inversion settings in EarthImager as necessary. These can later be found in .ini files.
	6) Read raw data (.stg files) into EarthImager. Check data editing statistics, which are based on the initial settings and the raw data.
	7) Read the appropriate .trn file into the program.
	8) Run the inversion. EarthImager will automatically organize the files in a folder system of inversion trials, as described above and in the EarthImager manual.
	9) Save images of the resulting tomogram, if desired.
	10) Remove noisy data and rerun inversion if necessary. We removed above 50% data misfit using the data misfit histogram.

Time-lapse data processing
	11) Perform the above steps on the base case survey. 
	12) Open the time-lapse inversion window in EarthImager. Select the base case survey's .out file and the subsequent surveys' .stg files. Save the resulting .bch file.
	13) Select comparison criteria and scale. We compared surveys based on conductivity changes. We ran the initial time-lapse inversion using a scale of -100% to 100% difference.
	14) Run the inversion. Save the resulting .avi file if desired.
	15) Examine the resulting .dat files containing the conductivity differences. (File will be named SurveyName_trialX_DiffCondX.dat.) Note the minimum and maximum percent differences in conductivity (i.e., greatest absolute values) for each survey comparison.
	16) Rerun the time-lapse inversion with the tomograms' percent difference bounds adjusted to the greatest percent differences observed in the .dat files. This helps visually emphasize the changes observed.
	17) If desired, save the .avi file.
	18) Adjust the color scale if desired using the color and contour properties window. We adjusted the color scale such that blues and greens represented increases in conductivity over time; reds and yellows represented conductivity decreases (or inversion artifacts, as is more likely); and white represented little to no change in conductivity from the base case survey. We saved these custom color scales as .lvl files.
	19) Save inversion image results as desired.

Credits

Funding Agencies

This resource was created using funding from the following sources:
Agency Name Award Title Award Number
United States Office of Surface Mining Reclamation and Enforcement Using novel geophysical techniques to relate surface coal mining fill characteristics to effluent stream water quality OSM Cooperative Agreement # S16AC20076

How to Cite

Hester, E., K. L. Little, J. D. Buckwalter, C. E. Zipper, T. J. Burbey (2018). Variability of Subsurface Structure and Infiltration Hydrology among Surface Coal Mine Valley Fills, HydroShare, https://doi.org/10.4211/hs.b1d5fd2c2d3e49878d86cb7c2d483d2a

This resource is shared under the Creative Commons Attribution CC BY.

 http://creativecommons.org/licenses/by/4.0/
CC-BY

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