1993-10-01_GENERAL DOCUMENTS - C1984067 ‎(2)‎

• Permit No: C1984067
• IBM Index Class Name: General Documents
• Doc Date: 10/1/1993
• Doc Name: Amendment No. 1 to RM-Mines-320
• From: DMG
• To: All Contractors Bidding on Project
• Permit Index Doc Type: Reclamation Projects
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources pf,cl_,�;,__ =�.p
Hc'f�O
1313 Sherman St.,Room 215
Denver,CO 80203 " +
Phone:[phone] r1876«
FAX:[phone]
Roy Romer
Governor
DATE: October 1 1993 Michael Long
� D Division Director
TO: All Contractors Bidding on the Coal Gulch Bond
Forfeiture Project, RN-MINES-320
FROM: Paul Krabacher, Project Manager, Division of Minerals
and Geology
RE: Amendment No. 1 to RN-MINES-320
1. Standing structures and/or remaining equipment left on-site will be the contractor's
responsibility for removal at the commencement of the project as described on the
bottom of page 5 in the Invitation and Bid.
2. Sufficient fill quantities are calculated to leave the borrow area at a maximum
2H:1 V slope versus a 3H:1 V as stated in the bid.
3. The upper wetland will remain intact. The 4"d schedule 40 PVC drain pipe will be
extended 100 feet to enter the wetland pond directly. The outflow from the existing
wetland will be directed through a spillway to one constructed basin with dimensions
as described on page 7. It is estimated that 126 cubic yards of sand and 53 cubic
yards of manure will be required. The constructed basin will have a spillway
constructed with positive outflow directed into a surface drainage channel.
4. The contractor will choose between lining the intermittent drainages, having 2H:l V
slopes with riprap or erosion control fabric. Erosion control fabric will be
documented to resist a minimum sustained channel flow velocity rate of 8 feet per
second and/or a tractive force of 2 pounds per square foot during a 48 hour period
in a non-vegetated condition. When fully vegetated, the material will be
documented to resist a sustained channel flow velocity rate of up to 14 feet per
second and/or a tractive force of 5 pounds per square foot during a 48 hour period.
The material after a 24 hour saturation period will also have a tensile strength of
220 lb./ft. by 165 lb./ft. (per ASTM D-5035). A known material which exhibits these
characteristics is Landlok TRM 1060 supplied by Bowman Construction, Denver,
phone [phone]. Installation will be per manufacturer's installation guidelines.
Regardless of the erosion-control material used, the final channel cross-section shall
be constructed as portrayed on the attached drawing (A). Rock used for placement
as drainage riprap will consist of material as described in the drawing. A 6" layer of