2004-07-16_REVISION - M2001054

• Permit No: M2001054
• IBM Index Class Name: Revision
• Doc Date: 7/16/2004
• Doc Name: Preliminary Adequacy Review Ltr.
• From: DMG
• To: Forsgren Associates Inc.
• Type & Sequence: TR1
• Media Type: D
• Archive: No

DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources
1313 Sherman St., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
t July 16, 2004
COLORADO
DIVISION O F
MINERALS
GEOLOGY
REC LAM ATION•MINING
$A FEt Y•SCIEN<E
Bill Owens
Governor
Russell George
' SCDtt .Steffens Executive Direttor
POISgren ASSOCIateS, IIIC. Ronald W. Cottony
PO Box 738 Division Director
Onray, CO c41427 / Natural Resource Trustee
\A 1. 1
Re: Bridal Veil Pit, Permit M-2001-054, Technical Revision TR-01, Preliminary Adequacy Review Letter.
Dear Mr. Steffens,
I have reviewed the information in the above-named request for technical revision, and f nd the text and drawing to
bewell-presented. The technical revision involves changes to the basic bench configuration, while leaving other
aspects of the mining and reclamation plans unchanged. The information provided appears to explain the changes
fairly well, but I have a few questions about some of the other aspects of the plans, that were not covered in your
submittal. Please address these following items:
I. The lower bench elevation is to be raised by placement of backfill materials. Please confirm that such backfill
will only include materials generated onsite. L` offsite-generated materials aze to be used, please refer to
Construction Materials Rule 3.1.5(9), and provide all additional pertinent information.
2. There will be a significant depth of fill to be placed in raising the lower bench, and its stability must be ensured.
Please describe the depth of the lifts to be used during backfill placement, and the method(s) of compaction. Please
state what, if any, ASTM specification will be used to measure the compaction.
3. Please describe the slope gradient of the (west-facing) outslope of the fill to be placed. Will the fill be graded to
blend with the unaffected native surface in the 50-foot buffer? The new outslope gradient should be labeled on the
map.
4. It appears from the new map that the northern road has been "eliminated," which I assume to mean that certain
earthwork (fill or grading) was performed. Since this revision primarily involves changes to the final configuration
of the site surface, information about reclamation of the old road should be provided. Please describe the closure
and reclamation performed for the old road. This should include fill, compaction, grading, drainage control,
seeding, eta (Additionally, thank you fot including a copy of the new CDOT access pemut for the new road.)
5. The wall between the two benches is labeled on the map as having a slope gradient of 60°, which is much
steeper than the currently-approved slope gradient of 1.5:1 (equivalent to about 34°). Past discussion of the
instability of the steeper slope gradient resulted in the permit requirement for the gentler slope. Please commit to
the gentler slope gradient as part of this revision. Also, this should be changed on the map.
6. The original plan included a culverted crossing of the road over the stormwater drainage channel, which was
later modified to a gentle swaie in the road through the drainage channel. The new map depicts the new road
alignment and stormwater channel though the swaie, if it to stiA be part of the plan, is not clearly shown nor
labeled. Please clarify if the swaie is still part of the plan, and modify the map accordingly.
STATE OF COLORADO
Office of Office of Colorado