_GENERAL DOCUMENTS - C1981017 ‎(293)‎

• Permit No: C1981017
• IBM Index Class Name: GENERAL DOCUMENTS
• Doc Name: Bid Documents ‎(IMP)‎
• Media Type: D
• Archive: No

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STATE OF COLORAD0
DIVISION OF MINERALS AND GEOLOGY
Department of.Natural Resources
1313 Sherman St.,Room 215
Denver,Colorado 80203 DIVISION OF
Phone:[phone] M I N E RA L S
FAX:[phone] &
GEOLOGY
DATE: August 6, 1999 RECLAMATION
MINING-SAFETY
TO: Steve Renner
Bill Owens
rGovernor
FROM: Dan Mathews
Greg E.Walther
Executive Director
RE: Coal Basin Noxious Weed Sampling Michael B.Long
Division Director
Enclosed are vegetation data summaries from the noxious weed"reference areas"at Coal Basin,sampled
on June 30,and July 1, 1999. The reference areas were established,and initially sampled last year.
1998/1999 data comparisons are also included. Sampling was conducted by a crew from the OSM Denver
office(Barbara Bowerman,Becci Siegle,Larry Kline,and Randy Pair),along with Sandy Brown,Byron
Walker and myself from DMG. Weed spraying had been conducted in the summer of 1998,subsequent to
the 1998 sampling,and a second spraying effort was scheduled for early July, 1999. The reference sites
will be sampled again next year.
Reference area locations,dimensions,and sampling methodologies are as described in my memo of July
23, 1998. Unless otherwise noted,sampling methods were identical to those employed in 1998. One
general recommendation is that the wood stakes I used as corner markers on the reference areas should be
replaced with more permanent metal stakes or roof bolts. Several of the wood stakes I hammered in last
year had been dislodged by clumsy or malicious cows or elk.
Reference Area No. 1(flat area adjacent to Sutey Refuse Pile)
The site had been heavily grazed by cattle shortly prior to sampling,and vegetation cover was no doubt
lower than would have otherwise been the case. If this site was sprayed in 1998,no effect was evident on
the target species. There was no statistically significant difference between 1998 and 1999 with respect to
either cover or density of noxious weeds. The dominant noxious plant both years was plumeless thistle
(Carduus acanthoides).
Reference Area No.2(on west slope of Sutev Refuse Pile)
Effects of spraying here were visually apparent,with frequent patches of dead weed litter and bare ground
which contained no current year weed growth. There was a statistically significant reduction in both cover
and density of noxious plants. Over-all reduction of noxious plant cover and density was on the order of SO
to 60 percent. Treatment appeared to be most effective on plumeless thistle,which had been the dominant
weed in 1998. Effectiveness of treatment on the less abundant noxious species was not evident from the
cover data,although there appeared to be some reduction in density of houndstongue(Cynoglossum
oJfrcinale). As might be expected,cover of desirable forts and total vegetation cover was also reduced.
Upon completion of the weed control program on the refuse pile slopes(and likely other sites as well);
reseeding with aggressive forage species such as smooth brome,orchardgrass,timothy,western
wheatgrass,intermediate wheatgrass,and cicer milkvetch is recommended. Supplemental seeding is
warranted both for erosion control and to reduce the potential for re-invasion by the noxious species.
Success of treatment on the topsoil pile adjacent to the Sutey Refuse Area appeared to be spotty,with some
patches of essentially complete weed kill,and other patches of dense,apparently vigorous Canada thistle
(Bria arvense).