2004-10-04_REVISION - M1989029

• Permit No: M1989029
• IBM Index Class Name: Revision
• Doc Date: 10/4/2004
• Doc Name: Adequacy Review
• From: DMG
• To: Hart Environmental
• Type & Sequence: TR4
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY ~~
Department of Natural Resources
1313 Sherman St., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
October 4, 2004
Michael J. Hart /
Hart Environmental v
2255 Meadow Ave.
Boulder, CO 80306
L/
RE: Aggregate Industries - WCR, Inc. File No. M-1989-029 ,/
Longmont Distel Operations 112(c) Technical Revision Application (TR- 4) Adequacy Review
Deaz Mr. Hart,
COLORADO
DIVISION O F
MINE6RALS
GEOLOGY
RECLAM ATION•M INING
SAFE TY•SCIENCE
Bill Owens
Governor
Russell George
Executive DIIeQnf
Ronald W. Cottony
Division Director
Natural Resource Trustee
Listed below aze the adequacy review comments for the Longmont Distel Operntions 112(c) Technical Revision
Application (TR-04), File No. M-1989-029. The Division of Minerals and Geology ("Division") is required to make a
decision no later than October 11, 2004, therefore, your response to the following adequacy review concerns should be
submitted to the Division as soon as possible.
1. The cover letter included with the application indicates that "The revised permit area is 712 acres, which is a net
reduction of six (6) acres, and includes the Longmont, Distel, Bigelow, Sherwood and Peschel properties." Please
be awaze that the current, approved permit contains 530.3 acres. Please clarify this discrepancy. Also be awaze
that in the event that the acreage in the permit is to be reduced, acreage has to be removed from the permit through
an application for acreage reduction.
Rule 6.4.5 Exhibit E- Reclamation Plan
The Reclamation Plan refers to numerous water flow control structures:
a) The Coffin-Davis Ditch diversion structure is located on the Bigelow properly and includes a bypass to St.
Vrain Creek, along the original irrigation ditch, that will allow the flow into the wetlands to be controlled
during periods of high flow. An additional flow control box may be constructed on the coffin-Davis ditch to
supply a lateral ditch that will be used to feed the post-mining pond on the Bigelow property (pg. 4);
b) As previously mentioned, in case of severe flooding of St. Vrain Creek, water may spill over the south bank of
the creek and flood the reclaimed pits, causing potential erosion of the slope between St. Vrain Creek and the
reclaimed areas. This could potentially lead to channeling of St. Vrain Creek through the reclaimed area. In
order to prevent washout of the slopes and creek bank, the points where floodwater will likely enter the pits
(the low points along the St. Vrain bank) will be protected with trenches constructed along the pit crest,
parallel to the creek. These trenches will be filled with rip rap covered and revegetated. In the event of
flooding, the trenches will act as energy dissipaters and aid in preventing erosion of the slopes. The locations
of the trenches will be determined by the topography at the completion of mining (pg. 5).
2. With regazd to item a), please indicate what pazameters would lead to the installation of an additional flow control
box on the Coffin-Davis Ditch.
3. W"ith regazd to item b), please indicate what parameters would identify a "low point" along the St. Vrain bank that
Office of
Mined Land Reclamation
Office of
Active and Inactive Mines
Colorado
Geological Survey