GENERAL45187

• Permit No: C1981013
• IBM Index Class Name: General Documents
• Doc Date: 4/24/2006
• Doc Name: Review Memo on 2005 Bond Release Vegetation Report
• From: Dan Mathews
• To: Kent Gorham, Sandy Brown
• Permit Index Doc Type: Vegetation
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
C)eparbnent of Na[ural Resources
1313 Sherman 5[., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: (303) 832$106
DATE: Apri124, 2006
TO: Kent Gorham and Sandy Brown
FROM: Dan Mathews
RE: 2005 Golden Eagle Mine Bond Release Vegetation Data/Report
Permit No. C-81-013
COLORADO
DIVISION O F
MIN SRALS
GEOLOGY
shFETY•SCIENCE
Bill Owens
Governor
Russell George
EaeMive Director
Ronald W. Cottony
Division Director
Natural Resource Trustee
At Sandy's request, I looked over the referenced report, submitted by Greystone Consultants, for
Basin Resources, Inc. The report presented 2005 sampling data, which represents the first year of
sampling for demonstration of Phase III bond release revegetation success. The focus of my review
was on production sampling data, which was the issue of concern that Sandy brought to my attention.
It may be appropriate to request that the operator submit an amended sampling plan for 2006, based
on the following recommendations.
Production SamDline Recommendations for 2006
I agree with Sandy's suggestion regarding quadrat size. The 0.1 square meter quadrat size
is very small. Typically a 1/4 square meter plot size is recommended, even in relatively
uniform grassland communities. Larger plot sizes are more efficient when production is
relatively sparse and/or variable (as appears to have been the case in the rangeland
reclaimed arld reference communities). New DMG rules that became effective November
30, 2005 require minimum quadrat size of/< square meter. The new rules also require
that multiple quadrats along a single transect be treated as subsamples (i.e. the quadrat
values are averaged or totaled to produce a single value for each transect, which is the
'`sample observation" for calculation of sample statistics). See Rule 4.15.11(1)(b)(i). So,
for the 2006 sampling, a minimum quadrat size of r/a square meter will be required.
A quadrat size of r/: square meter or 1 square meter may be more efficient for the
rangeland communities. Also, the 2006 sample data will need to treat multiple
quadrats along a transect as subsamples (as was done for the 2005 AVF reclaimed
and reference communities). If larger quadrat sizes are used, the sampler may be able to
use fewer quadrats per transect to obtain a sufficient sample size for success
demonstration, as compared to use of smaller quadrats.
2. A minimum sample size of 30 (transects) should be run in the rangeland reference
and reclaimed areas. Even with use of larger quadrat sizes, the high variability and data
distributions associated with the rangeland communities may make it unlikely to achieve
sample size adequacy with a "reasonable" number of samples. However, it appears from
1
Office of Office of Colorado
Mined Land Reclamation Active and Inactive Mines Geological Survey