_INSPECTION - C1981019 ‎(55)‎

• Permit No: C1981019
• IBM Index Class Name: INSPECTION
• Doc Name: Inspection Report
• Inspection Date: 8/13/2008
• Email Name: JRS
• Media Type: D
• Archive: No

IV. ENFORCEMENT ACTIONS
Colowyo C-1981-019
13 August 2008 '
Page 1/5
The following identifies enforcement actions taken during this inspection, the required
abatement and date of abatement for the violation, previous violations still requiring
abatement and the termination of violations cited during previous inspections.
Notice of Violation CV-2008-004 was issued as a result of this inspection. The violation
was issued for failure to minimize disturbance to the hydrologic balance in the mine
and associated off-site areas, failure to construct a channel so as to not increase the
potential for downstream flooding and minimize adverse impacts to the hydrologic
balance, failure to construct a permanent diversion to safely pass the peak runoff
from a 10-year storm event, failure to construct a permanent diversion to prevent
additional contribution of suspended solids to stream flow and runoff outside the
permit area, failure to provide adequate pond capacity to contain or treat the runoff
from a 10-year, 24-hour precipitation event, failure to provide a nonclogging
dewatering device on a pond to remove water storage resulting from inflow, failure
to prevent outflow through the pond's emergency spillway during the passage of
runoff resulting from the 10-year, 24-hour precipitation event and failure to provide
adequate freeboard to prevent overtopping of the pond's embankment by sudden
increases in volume.
The abatement for the violation, which is due on or before 15 October 2008, is as
follows:
1 . Clean the Prospect Pond to remove the sediment to restore the proper pond
volume and function.
2. Complete an inspection of the Prospect Pond embankment to ensure stability. This
needs to be performed by a registered, professional engineer. A report of the
findings needs to be forwarded to the Division for review by the abatement date
below.
3. Complete the Prospect Ditch, including the necessary riprap, as designed. Repair
the Prospect Ditch, as required, to fix erosional problems that have occurred.
4. Repair both of the large gullies to the north and south of the prospect ditch which
are contributing a great deal of sediment to the Prospect Pond.
5. Submit to the Division a complete Technical Revision detailing methods that will be
immediately implemented to reduce the peak flow into the Prospect Pond from
storm events. These methods have been discussed in detail in the Permit Renewal 05
correspondence.
On 13 August 2008, at approximately 13:00, the Prospect Pond was inspected. The
mine site had received a large rain storm over the previous weekend with
approximately 1 .66 inches of rain in the Prospect drainage. Of this rain, 0.8 inches fell
in 15 minutes and a total of 1 .19 inches of rain fell in 45 minutes (according to
Colowyo's rainfall data. This large inflow into the Prospect Pond caused the trash
rack and primary spillway to clog and ultimately led to discharge through the
emergency spillway and over the top of the embankment. The 10-year, 24-hour