HYDRO22573

• Permit No: M1977129
• IBM Index Class Name: Hydrology
• Doc Date: 1/28/2005
• Doc Name: Review of As-Built Drawings Stage I Inlet/Outlet Channels
• From: DMG-acs
• To: DMG-sss
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources
1313 Sherman 8[., Room 215
Denver, Colorado 80203
Phone: [phone]
PAX: [phone]
DATE: January 28, 2005
TO: Steve Shuey /)
FROM: Allen Sorenson /i/ l~"
COLORADO
DIVISION OF
MINERALS
GEOLOGY
iECLAMATION•MIN ING
SA FETY•SOENCE
Bill Owens
Governor
Russell George
Executive Director
Ronald W. Cattany
Division Director
Natural Resource Trustee
RE: Review of As-Built Drawings, Stage Ilnlet/Outlet Channels, Whitewater Building
Materials Corporation, Whitewater Pit 500, Permit No. M-1977-129
The Division of Minerals and Geology (DMG) engineering staff has reviewed the design drawings
approved in technical revision TR-02 for the inlet and outlet channels in the stage I pond perimeter and
the as-built drawings for these channels that were subsequently provided by the Operator. The purpose
of these channels is to allow flow from the adjacent Gunnison River into and out of the pond during
high stream flows. The drawings designate these channels as U/S notch for the upstream channel and
D/S notch for the downstream channel.
Based on the review of the drawings, DMG has determined that the channels were constructed in
genera] accordance with the approved plans and that the channels will function in accordance with the
intent of the design. The as-bunts show some variances from the design plans. For example, the side
slopes of the notches were built at slopes much flatter than the 2.5:1 (typ.) slopes shown on the design
drawings, but this will actually result in greater channel stability. Also the channel bottom widths are
narrower than shown in the design, but because the channel side slopes are flatter the cross sectional
areas are about the same and flow capacity will not be much diminished. Finally, the D/S notch invert
was constructed 1.25 feet higher than shown in the drawings; this will not appreciably impact the
operation of the channels or pond.
The only problem identified on the as-built drawings is a typographical error on drawing C-1 as-built,
where notch D/S is inadvertently labeled as notch U/S.
cc: Carl Mount, DMG (via email)
c:~acs\LOANER MACHINEVvty Documents\whitewater as builts.doc
Office of Office of Colorado
Mined Land Reclamation Active and Inactive Mines Geological Survey