Procedures to conduct Fuel Stockpile Inventories

1. ARIPPA 19th Annual Technical Convention Procedures to conduct Fuel Stockpile Inventories August 26, 2009

2. Items Covered • Coal Pile Maintenance in Preparation for Stockpile Surveys • Coal Pile Density Procedures • Coal Pile Volume Procedures • Summary and Questions

3. Efficient Management of Stockpiles • Provide easy access to material • Maximize load distance efficiency factor • Attain stack/reclaim rates • Meet blending requirements • Maintain or improve uniformity, integrity, and quality • Minimize manpower or equipment • Safety • Be able to deal with stockpile fires • Reduce environmental impacts

4. Stockpile Delivery Methods • Truck dump • Rail dump • Ship or barge unload

5. Coal on stockpile • Delivered and stacked as cone • Rate of delivery determines number or shape of cones • Kidney shape with moving stackout • Or multiple cones • All cones need to be moved • For more deliveries • Safety improvement • Segregation reduction to preserve quality

6. Kidney Stackout

7. Multiple cone stackout

8. Effects of Pile Conditions on Accuracy • Windrows • Gullies • Inconsistent • Uncompacted • Compacted • Coal quality • Excessive cones

9. Working on pile

10. Methods to avoid so moisture not increased • Large flat stockpiles that allow little, if any, runoff • Possibility of ponding on surface • Pushing coal through low areas that have standing water while unloading/reclaiming • Ground water levels higher than the pile or pile base

11. Beneficial Practices in controlling moisture • Keep stable side slopes, while increasing maximum height over smallest area • Avoid flat tops • Enhance runoff by compacting surface AND side slopes • Allow good drainage of the pile • Reduce moisture content of incoming coal

12. Pile construction by Rubber-tired

13. Improved conditions=improved accuracy • More consistent density • Less moisture variability • Less water means easier to move and easier to burn • Consistent quality • Less chance for fire • Smoother surface easier for volumetric calculations • Better burn rates

14. What to do for improving pile conditions • Work the pile in consistent pattern • Don’t rush due to time or amount of delivery • Eliminate gullies from erosion • Eliminate windrows • Compact consistently across the pile • Reduce amount of loose coal in cones • Keep berms to minimum

15. Conclusions - Questions

16. Coal Pile Density Procedures • ASTM D6347 – Standard Test Method for Determination of Bulk Density of Coal Using Nuclear Backscatter Depth Density Methods

17. Methods for Stockpile Densities • Nuclear Methods • Depth Density • Surface • Direct Density Methods • Shelby Tube • Water-displacement Method • Continuous Auger Sampling Method

18. Depth Density Procedures • Nuclear Density Procedures • Calibration Procedures • CAST Method Procedures

19. Preparation of Access Holes • Small – diameter Augers • Split – spoon / hollow-stem augers • Hydraulic Push

20. Installation of Access Pipe • PVC Pipe • small – diameter augers • split – spoon / hollow-stem augers • Steel Pipe • hydraulic Push

21. Nuclear – depth density gauge • Troxler Model 1351 • Troxler Model 1352 • CPN 501

22. Recording density counts • Gamma readings • Set of 2 each elevation • Not a density YET!

23. Calibration of Nuclear gauge • Same process • Gamma readings • Minimum 4 points • ASTM is 8 points • Linear regression • Forcing curve to a line

25. Direct Density Methods • Sampler • Different problems

26. Direct Density Methods • Sampling interval • Recovery of sample • Weighing the sample • Calculating the density

28. Factors that effect density • Calculations • Stockpile condition • Moisture • Quality • Pile construction • Access • Sampling interval • Recovery of sample • Gauge stability • Scale accuracy • Calibration

30. Coal Pile Volume Procedures • ASTM D6172-98 (reapproved 2004) Standard Test Method for Determining the Volume of Bulk Materials Using Contours or Cross Sections Created by Direct Operator Compilation using Photogrammetric Procedures.

31. Introduction • On a continuing basis, coal companies, power generating stations, quarries, aggregate suppliers, and other entities need to know how much material is contained in stockpiles at facilities such as mines, quarries, processing plants, generating stations, landfills and other storage sites. • Through the use of aerial photography, ground control surveys, and photogrammetric processes, stockpiles can be mapped and the volume of an inventory area can be determined.

32. Introduction • This work usually requires a quick turnaround from the initial flight until the final volumes are calculated. Many times the photography must occur on a certain date or within a specified period. • Coal stockpiles are usually needed within a short period of time, since they may be needed on an end of month and a mid-month basis. • Landfills and quarries are usually needed within a month of aerial acquisition. • Weather is always a concern.

33. What is Topographic Mapping? • All mapping techniques use data collection points to approximate the mapped surface. • Aerial mapping uses photographic pairs to determine data collection points. • Conventional surveying uses horizontal angles, vertical angles, and distances to determine data collection points.

34. What is Topographic Mapping? (continued) • The more data points and the selection of the data points used, the greater the accuracy. • It is therefore important to have a system that allows for a rapid collection of many data points and coverage for the entire mapped surface.

35. Using the data points collected • Creating a digital terrain model (DTM) • DTM is actually the collection of mass data points which include spot elevations, and break/fault lines. • From this a triangulated irregular network (TIN) is generated. • The TIN is then used to create contours.

36. Calculating the volume • To calculate the volume of data points collected you need to compare the base TIN file with the new TIN file. • The base contour map is a digital file of the surface below the stockpile. • The new contour map is a digital file of the data collected and calculated by the TIN. • The difference of these two digital files is the volume of the stockpile.

40. Basic Needs • Aerial Imagery • Horizontal and Vertical Ground Control • Delineated Limits of Stockpile • Base Map Data

41. Aerial Imagery

42. Ground Control

43. Stockpile Limits

44. Base Map

45. Base and Control Map

46. Control Map

47. Standards • American Society of Testing and Material Standards • American Society for Photogrammetry and Remote Sensing Standards • National Map Accuracy Standards • National Coal Weighing and Sampling Association Needs

48. Aerial Photography Needs Aerial Photography • USGS Calibrated Aerial Camera • Black and White or Color Film • Contact Prints or Digital Files • Film Diapositives or Digital Scans • Photo Enlargements Rockwell Shrike Commander

49. Aerial photography camera

50. Photogrammetry • The illustration showshow an aircraft fliesalong a flight line(represented on theground by a dashedline in the illustration)and takes overlappingphotographs. Thedark gray area showsthe overlap area.