PERMFILE67186

• Permit No: C1981028
• IBM Index Class Name: Permit File
• Doc Date: 6/15/2006
• Doc Name: Revegetation Success Criteria
• Section_Exhibit Name: Appendix TR-37
• Media Type: D
• Archive: No

. 2.0 METHODS
In looking for another method of evaluating revegetation success at the mine, four criteria
need to be satisfied, first the reclamation success criteria must be quantitative (cover,
production), second the criteria must be based on a known biologic relationship, third the
criteria must be simple to establish and calculate, and fourth the criteria must be predictive
so the criteria can be established prior to sampling and analysis.
2.1 Vegetation Cover and Production
For cover and production this meant searching for criteria that could be based on a known
physical or biological factor (preferably only one) with a strong direct relationship to both
cover and production whose data collection would be simple, and provide a predictive
criterion value that accounted for the variability in the ambient environmental conditions
on a yearly basis. Biological predictive factors appeazed too difficult to define, let alone
collect meaningful data for. Which left physical pazameters. Precipitation immediately
came to mind, and the mine has along-term record of precipitation from on-site. This
parameter appeazed to satisfy the four criteria above.
Coors Energy Company has collected precipitation data at the mine for a number of yeazs.
This data represents the most complete record of precipitation from the mine azea.
Table 7. presents a summary of precipitation data collected from 1993 through 2001,
• corresponding with the most recent vegetation monitoring. A review of the data
illustrates that precipitation is lowest during the autumn and winter months (October
through March) and higher from spring through late summer. The months with the
highest average precipitation are May and June. The majority of the precipitation at the
mine occurs during the period between January and July. A second precipitation period,
representing the entire period between the end of the normal growing season and the
middle of the next (September-July) was also identified for evaluation.
Precipitation sums for the two periods were plotted against the total vegetation cover and
total herbaceous production values from the Osgood sand reference azea and the
reclamation areas. From the resulting data plots, curves were fitted for each of the
precipitation regimes, sampling locations, and pazameters. Plots and curves were
undertaken for the reference area and each of the reclamation azeas, as well as
combinations of similarly aged reclamation areas for each precipitation period and
pazameter (cover and production). Curves tested for each plot included lineaz, natural
logarithmic, power, exponential, and polynomial. R-values for closest fit were calculated
for each curve and the curve with the best-fit and R-value is presented on each initial plot.
In several instances, the increase in order of the polynomial curve brought increased values
to the R-value, however, the increased order curves (generally above trinomial or quartic)
produced curves that could not be justified in real world terms.
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