GENERAL41307

• Permit No: C1981041
• IBM Index Class Name: General Documents
• Doc Date: 1/17/1983
• Doc Name: ROADSIDE REFUSE PILE FIELD TRIALS FN C-81-041
• From: MLRD
• To: POWDERHORN COAL CO
• Permit Index Doc Type: STIPULATIONS
• Media Type: D
• Archive: No

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Ricnaro D Lamm
Governor
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DEPARTMENT OF NATL. _ 999 ...._„
D Monte Pascoe. E.ecutive Dnector
MINED LAND RECLAMATION DIVISION
DAVID C. SHELTON Director
January 17, 1983
Mr. Henry Barbe
Powderhorn Coal Company
P. O. Box 1430
Palisade, Colorado 81526
Re
Dear Mr. Barbe:
Roadside Refuse Pile Field Trials
File No. C-041-81
The Division has completed its review of Powderhorn Coal Company's plan
for field trials and temporary revegetation of the Roadside refuse pile.
The following are the Division's comments and suggestions on that plan.
1) Powderhorn Coal Company has proposed to test the effects of sail depth -
and exposure in a randomized, replicated plot design. The Division is
concerned with the small size of the subplots (3m x 3m). This size does
not allow for production sampling more than once during the course of
the study, therefore, valuable production trend data is not obtained. In
addition, the applicability of data from small subplots of this size may
be limited because of an increased probability of interference by other
factors such as differing soils and refuse characteristics.
The Division feels that the minimum subplot size should be 50 feet x 50 feet.
2) The length of time that the field trials are proposed to be maintained is
five years. This length of time will not be sufficient to adequately
evaluate revegetation success, given that the liability period is ten years.
3) Powderhorn proposes to test three soil depths (6", 12", and 18") with no
control plot. A control must be included. There are two types of controls
which could be used; a four foot soil depth treatment or a treatment on
natural sails with similar slope and aspect.
As has been discussed, it appears that the treatment on natural soils would
be preferred by Powderhorn. If this option is chosen, the site chosen
for each of the three different exposures would have to be similar in slope
and aspect. The subplot size would have to be the same size (50' x 50'
minimum) and there would have to be three replications at each site. All
existing vegetation would have to be eliminated on each plot and at least
one inch of the topsoil would have to be removed to minimize the amount of
inherent seed. Following that the cultural treatments would be the same for
all plots.
423 Centennial Building, 1313 Sherman Street Denver, Colorado 80203 Tel. [phone]