PERMFILE54207

• Permit No: M2000113
• IBM Index Class Name: Permit File
• Doc Date: 1/3/2001
• Doc Name: MAMM CREEK SAND & GRAVEL PIT FINAL HYDROLOGIC ADEQUACY REVIEW COMMENTS FILE NO M-2000-113
• Media Type: D
• Archive: No

STATE III IIIIIIIIIIIII III
sss
OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources
1313 Sherman St., Room 215
DIVISION O F
Denver, Colorado 80203
Phone: [phone] MINERAL S
FAk: 1303) 832-8106 ~ &
GEOLOGY
RECLAMATION
Date: January 3, 2001 MINING•SAF ETY

To : Gregg Squire, Carl Mount, Allen Sorenson Bill Owens
governor

From :Tom Schreiner
~ Oren E Watcher
Enecuuve Director
Michael B. long
Divivon Director
RE : Mamm Creek Sand & Gravel Pit -Final Hydrologic Adequacy Review Comments
File No. M-2000-113
I have reviewed all adequacy responses for the "Mamm Creek" Regular 112 Application. I
recommend the following adequacy concerns be addressed to the satisfaction of the Division
prior to a recommendation of approval.
RULE ti.4.4 EXHIBIT D - Minintd Plan
1. Please clarify how [he granular bedding & filter, as depicted on Exhibit CS-2, will be
constructed and where the materials will come from. Also, the estimated material volumes and
costs will be needed and should be incorporated into the reclamation cost for the operation.
Please address.
2. The applicant will need to clarify how pit slopes, excavated at 0.40H: I V (near vertical) and up
to 25-30 feet in height, will be reclaimed to the desired 3: l and 2:1 configuration. Will the
reclaimed slopes be created via backfilling and grading during mining or will the slopes be
created underwater. (It appears that the pits will be allowed to fill in with water prior to
backfilling to reclamation contours. For example, the applicant states "when the West Property
Line to Horse Fence Area is mined out, the pit is expected to fill with water."). The applicant
should clarify if contemporaneous reclamation of pit slopes is planned ands the extent of 0.4:1
slopes to be left exposed during a maximum disturbance scenario. The Division recommends the
applicant consider maintaining the pit slopes at all times at a 2:1 or 1.5:1 slope while leaving
some rock in place to minimize chance of the Colorado River capturing the pit during a high
flow event and causing a slope failure. An alternative would be for the operator to maintain the
excavations in a "dry" condition until such time that all backfilling and grading to desired
reclamation contours is completed. Please address.
3. The applicant will need to provide a definate commitment to returning the renewable resource
area to an acceptable and stable condition at the end of each year's low flow mining season. An