PERMFILE62477

• Permit No: M1997014
• IBM Index Class Name: Permit File
• Doc Date: 6/16/1997
• Doc Name: FAX COVER
• From: DMG
• To: KJ HAMMER CO
• Media Type: D
• Archive: No

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(Page 2)
MINE ID # OR PROSPECTING ID #
INSPfiCTION DATfi 4 21 7
This inspection was conducted
management plan approved by the
1997. The Operator was represe

M-79 -214IiR
INSPECTOR'S INITIALS GSC
_«,
OBSERVATIONS
to determine the status of the storm water and sediment
Division of Minerals and Geology (Division) on February 26,
nted by Leela Rajasekar of Tuttle Applegate, Inc.
The sediment control plan is referenced in Exhibit I of the February 27, 1997 agreement
between the Colorado Mined Land Board (Board), the Division, and Rocky Mountain Rock Products
(Operator). Pursuant to the agreement, the runoff control plan was to have been implemented
to the Division's satisfaction by April 15, 1997. The Operator revised this plan on March
28, 1997, the Division issued a list of concerns with the revised plan on April 1, 1997 and
the Operator responded to the Division's issues on April 9, 1997. In subsequent discussions
with the Operator and the Operator's representative, Tuttle Applegate, Inc., the Division
verbally approved various elements of the April 9, 1997 plan. A diversion structure near the
entrance gate has not been approved. On April 18, 1997, the Operator submitted a schematic
for this structure, the Division needs additional information regarding depth and width of
the structure which was not clear from the schematic.
With the exception of the entrance gate diversion structure, the revised sediment control
plan has been implemented in the field. Some of the structures do not, however, meet the
design criteria. These are as follows:
Upper Basin Channel: Runoff collects in Pond UBl, flows through a 29" concrete culvert
into a small rip-rap armored stilling basin, and into Pond UB2. Runoff from sub-basins
B and B1 and overflow from the Pond UB1 emergency spillway is intercepted in a separate
rip-rap lined channel which runs into the north side of Pond UB2. In the area where the
channel should turn southward to enter Pond UB2, the rip-rap is not aligned with the
channel. The channel in this area needs to be adequately re-routed into Pond UB2 and
armored with properly aligned rip-rap. See Problem PB-1 on page 4 of this report.
Entrance Gate Sediment Pond: This pond contained water at the level of the discharge
culvert. The outside of the south pond embankment is wet and soft. Since this pond is
fed by a perennial spring, the south embankment will need to be buttressed with coarse
material which allows for free drainage. See Problem PB-2 on page 4 of this inspection
report.
Culvert Diameters: The Drainage Basin Map received on April 14, 1997 called for discharge
culvert diameters as listed below. The culvert diameters measured in the field are
listed for comparison.
POND ID DISCHARGE CULVERT DIAMETER FIELD MEASURED
(in) (in)
UB1 24 24
UB2 24 18
MB1 24 22
LB1 24 22
LB3 24 22
Except for Pond UB1, the culvert diameters measured in the field are smaller than called
for in the design. Required corrective actions will be to either install the appropriate
sized culverts or demonstrate that the existing ones will be adequate. The adequacy
of the existing culverts can be demonstrated by modelling the design 10 year-24 hour
hydrograph through the ponds using culvert diameters measured in the field. Properly
sized culverts must be installed as soon as possible or a new runoff model which
demonstrates that the existing culverts are adequate must be submitted and approved by
the Division as soon as possible. See Possible Violation PV-1 on page 4 of this report.
Emeraencv Soillwavs• The emergency spillway cross sections were field checked with 100'
an 25' tape measures. The spillways for UB1, UB2, MB1, LB1 and LB3 were found to be