2011-07-11_PERMIT FILE - M2011001 ‎(12)‎

• Permit No: M2011001
• IBM Index Class Name: PERMIT FILE
• Doc Date: 7/11/2011
• Doc Name: Third Adequacy Review Response
• From: Tetra Tech
• To: DRMS
• Media Type: D
• Archive: No

July 8, 2011
TETRA TECH
Mr. Peter S. Hays
Environmental Protection Specialist
Division of Reclamation, Mining and Safety
1313 Sherman Street, Room 215
Denver, CO 80203
f. ECE MAD
'JUL 1 1 2011
DI+Aaion of Reclamatiag,
Meng end S .'y
RE: Response to Iverson Mine (M 2011 - 001) Third Adequacy Review Comments
Dear Peter:
We received your Third Adequacy Review comments dated June 28, 2011 regarding the Iverson Mine
(M- 2011 -001). Following is a listing of each of your comments followed by our responses.
6.4.4 Exhibit D — Mining Plan
1. In response to Question #16 from the April 1, 2011 adequacy letter, Tetra Tech conducted a site visit
to reevaluate the impact flow of the Cache la Poudre River may have on the Iverson Mine. As a
result, the mining limits were revised to a 200 foot set back from the top of bank where the pit side of
the river is adjacent to the erosive side of the river and a 100 foot set back from the top of bank where
the pit side of the river is adjacent to the depositional side of the river. The revised mining offsets
from the Cache la Poudre River are acceptable to the Division, however the Applicant must indicate
on the Mining Plan Map where the 100/200 foot offset transition points begin and end.
We have added setback dimension lines to Exhibit C, the Mining Plan Map, to show where the 100
foot setback and transitions to a 200 foot setback. Attached is a revised version of Exhibit C
(Attachment 1).
6.4.5 Exhibit E — Reclamation Plan
2. The revised Reclamation Plan received on June 6, 2011 did not include the Applicant's commitment
to eradicate the Russian Olives at the site upon commencement of operations from the April 29, 2011
adequacy letter from Tetra Tech. Please revise Exhibit E to indicate the previous commitment by the
Applicant.
We apologize for this oversight; the version of Exhibit E submitted on June 6th was an update to the
original version of Exhibit E rather than the April 29, 2011 version of Exhibit E. Lafarge does still
commit to eradicating the Russian Olives upon commencement of operations. We deleted the
statement regarding Russian Olives from the attached version of Exhibit E (Attachment 2) so that it
matches the April 29 version of Exhibit E which you found to be acceptable.
3. Tetra Tech recommended inflow and outflow spillways be installed in conjunction with site
reclamation to control the matter in which high river flows impact the site. The installation of the
spillways during reclamation is acceptable to the Division as long as the proposed sequence of
mining and reclamation progressing from the southeast corner, center, north end and southwest
corner is followed. If the sequence is altered and the southwest portion is not mined last, the spillway
structures must be installed after the southern portions of the site have been mined and reclaimed.
Lafarge commits to mining the site in the sequence described in Exhibit E so that the southwest
portion is mined last.
1900 S. Sunset Street, Suite I -F, Longmont, CO 80501
Tel [phone] Fax [phone] www.tetratech.com