2008-03-13_REPORT - C1981019 ‎(2)‎

• Permit No: C1981019
• IBM Index Class Name: REPORT
• Doc Date: 3/13/2008
• Doc Name: 2007 AHR 2007 Revegetation Monitoring Report
• From: Colowyo Coal Company
• To: DRMS
• Annual Report Year: 2007
• Permit Index Doc Type: Hydrology Report
• Email Name: SB1
• Media Type: D
• Archive: No

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Contrary to the aforementioned three variables, woody plant density at Colowyo remains somewhat
problematic. Perusal of Chart 5 in comparison to the current success standard of 1000 stems per acre
reveals that all monitored areas fall short. As stated in the 2003 report, it is Cedar Creek's
recommendation that Colowyo pursue a program of modification. This program would provide several
avenues for correction of the woody plant density issue (see Appendix AA -Section 6.3) by modifying
both the success criterion (which has been set too high for the short-duration bond responsibility period
of ten years) as well as "in-the-field" revegetation efforts (which have not adequately addressed metrics
necessary to encourage emergence by woody taxa, especially sagebrush).
Considering the 2007 monitoring effort as a whole, observed revegetation at the Colowyo mine is
generally in good condition and well onto the path of successional advancement. An occasional unit that
exhibits elevated levels of annual grasses or early sera) weeds and may or may not need remediation
(herbicide treatment) depending on future precipitation patterns that should favor planted perennials. As
revegetated communities continue to mature, the majority should meet both land use goals and bond
release success criteria with regard to ground cover, diversity, and current annual production. However,
woody plant densities in most units with at least two growing seasons are below, and occasionally well
below, the current standard of 1,000 shrubs per acre. This difficulty must be addressed, and two of the
options are presently being developed for submittal to CDRMS.
Sections that follow (Sections 2.2 and 2.3) provide a brief narrative of the results from each
individual unit evaluated by Cedar Creek. Also included for each unit is a map of the 2007 sample points
and aone-page summary (compendium) of all pertinent data collected within the unit and revegetation
specifications applicable to the unit*. Section 2.4 provides a data summary by area (East Pit and West
Pit), Section 2.5 provides a discussion of the results from the sampling of the two established and three
proposed reference areas. The seeding success analysis is presented in Section 2.6 and a discussion of
the results from sampling of the CSU shrub plots in East Pit is presented in Section 2.7. Finally, Section
2.8 and 2.9 provide data collected from the permanent shrub plots established in 2007 and information
collected in Section 16 for informational purposes, respectively. Raw data tables for cover, production,
and woody plant density are presented in Appendix AB.
* Data and specifications are limited to that information collected by, or known to, Cedar Creek as of 2007. Past data
and information could be added to these compendia at any time. Future data can be added as it becomes available.
Rio Tinto Energy America/Colowyo Mine Page 7 Revegetation Monitoring - 2007