REV01248

• Permit No: C1981008
• IBM Index Class Name: Revision
• Doc Date: 8/27/2004
• Doc Name: Summary of Adequacy Review ‎(Memo)‎
• From: Tom Kaldenbach
• To: File
• Type & Sequence: TR51
• 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]
MEMO
From: Tom Kaldenbacb~
To: File -New Horizon Mine, Permit C-81-008, TR-51
Re: Summary of Adequacy Review
COLORADO
DIVISION O F
MIN&RALS
GEOLOGY
0.ECLAMATIO N•NINING
SAf ETY•SQ ENCE
eil! Owens
Governor
Russell George
Executive Director
Ronald W. Cottony
Division Director
Natural Resource Trustee
TR-51 designates a topographic depression in New Horizon's reclamation as pond
014. This location was apre-mining topographic depression. This depression serves
as sediment control for a few acres of reclaimed land. The depression is an
impoundment [impoundment definition 1.04(64)] because it impounds water (even
though that may not have been the original intention). The rationale for approving
TR-51 is summarized below.
Pond 014's location next to a public road requires it to control the 100-year, 24-
hour event [4.05.9(2)(e)(ii)].
2. Pond 014 relies on storage to control runoff from the 100-year event.
3. The submittal demonstrates the storage capacity of Pond 014 is sufficient to safely
control the runoff from the 100-year event [4.05.9(2)(e)].
4. Pond 014 does not need a spillway because it relies primarily on storage to control
runoff [DMG interpretation of 4.05.9(2)(e)].
5. Pond 014 will need annual certified inspections [4.05.9(14)(a)].
6. Pond 014 will not need quarterly inspections because it is incised [4.05.9(18)(a)],
and because the permittee has demonstrated in writing that failure of the
impoundment will not create a threat to public safety [4.05.9(18)(a)].
7. The submittal provides an embankment stability analysis [2.05.3(4)(ii)(B)]
consisting of a written statement explaining how there is no embankment to fail
due to the incised nature of the pond.
8. To fulfill the reclamation plan requirement of 2.05.3(4)(ii)(D), the submitted
permit text explains that pond 014 is to remain a permanent topographic
depression on the reclamation landscape (along with an adjacent contour ditch),
after the pond removal requirements of 4.05.2(2) are met.
9. No additional reclamation bond is required because pond 014 is to remain as a
permanent topographic depression (as it was a premining depression), and there is
no spillway structure to remove.
Office of Office of Colorado
Mined Land Reclamation Active and Inactive Mines Geological Survey