2008-08-11_PERMIT FILE - C1992080 ‎(3)‎

• Permit No: C1992080
• IBM Index Class Name: Permit File
• Doc Date: 8/11/2008
• Section_Exhibit Name: APPENDIX 5-2 SEDIMENT POND CONTROL DESIGN
• Media Type: D
• Archive: No

the 90% confidence level. Comparisons between sample mean parameter values assume
that the sample mean value accurately represents the population mean in all cases. The
following formula was used for sample adequacy calculations:
nmin
(t)2 (S)2
(d Xbar)2
where: nmin -minimum sample size
s =sample standard deviation
t =the Student's t distribution value at the 90% level (one-sided)
d =percent acceptable deviation from the mean (10%)
Xbar =sample mean
2.3 STATISTICAL ANALYSIS
Statistical analysis for the revegetation success criterion of total vegetation cover is
required if the value of the sample mean from the reclaimed area is less than 90 percent of
the value of the final revegetation success criterion standard of 35 percent.
Sampling revealed that the mean total vegetation cover of the reclaimed area was greater
than that of the final revegetation cover success standard. The mean total vegetation
cover value from the reclaimed areas (63.60%) was greater than the value of the
revegetation success standard (40.00%); therefore no statistical analysis was required.
3.0 RESULTS AND ANALYSIS
Three vegetative lifeforms were encountered during the sampling of the reclaimed area.
They included perennial graminoids, biennial, and perennial forbs. A total of twelve
individual flowering plant species were encountered during cover sampling. The plant
species encountered and their characteristics are presented in Table 2.
3.1 RECLAIMED AREA
The reclaimed areas of the Carbon Junction Mine include the former North Pit, North Pit
Haul Road, Topsoil Stockpile #2, South Pit Drill Pad, Previously Reclaimed Spoils Area,
and Equipment Area. These areas were reclaimed to match the adjacent topographic
features, whether it is the deeply dipping sandstone slope of the North Pit or flat
agricultural field adjacent to the Equipment Area. The replaced soils are generally silty
clays. The reclaimed area has been revegetated to a mixed graminoid and forb
herbaceous community grassland with no significant woody plant component. The
visually dominant species are Agropyron intermedium (intermediate wheatgrass), Bromus
marginatus (mountain brome), Agropyron smithii (western wheatgrass), and Onobrychis
viciaefolia (sanfoin). Other significant species include Melilotus officinalis (yellow
Oakridge Energy Carbon Junction Mine Page 4
2008 Vegetation Sampling ReporC