_INSPECTION - C1981008

• Permit No: C1981008
• IBM Index Class Name: Inspection
• Doc Name: Inspection Report
• From: DRMS
• To: Ross Gubka
• Inspection Date: 9/16/2013
• Email Name: MLT
• Email Name: SB1
• Media Type: D
• Archive: No

September 16,2013 C-1981-008/New Horizon Mine MLT
Ditches and Culverts
• Pre-mining and interim control features appear on Map 2.05.3(3)-1. Post-mining locations of
the various ditches and culverts are identified on Map 2.05.3(3)-2. Design details are
provided in Attachment 2.05.3(3)-1 of the permit.
• During the inspection,we observed some ditches and culverts were in need of maintenance.
A list of items follows:
• Ditch C9 flows into Pond 013 from the east. A culvert was installed beneath the two-track
that provides access to the pond's spillway. The inlet end of this culvert had become clogged
with tumbleweeds (Photo 11), forcing flow to overtop the two-track. This culvert does not
appear to be described in the permit, so it could not be determined whether the culvert has
been sized appropriately. Designs for this culvert need to be added to the permit.
• Ditch C7/ C31 flows into Pond 012 from the west. This ditch was filled with sediment,
requiring immediate maintenance (Photo 12). (The operator brought an excavator to the site
later that afternoon to commence with cleaning the ditch.) Designs for this ditch are
inconsistently portrayed in the permit. Map 2.05.3(3)-1 names it as C7 (5.8 Ac.),while Map
2.05.3(3)-2 labels it C31 (17.7 Ac.). Table 2.05.3(3)-1 in the Appendix says C31 has a DA
of 38.7 acres, and goes to Pond 011. The permit needs to be revised to show a single, final
design for this ditch.
• A cutoff ditch has been in place across the top of the reclaimed slope on Benson-West and
WFC (Lloyd)parcels. Now that portions of these parcels are being irrigated, the tail water is
also directed to the cutoff ditch. A rock-lined ditch installed recently by the operator to carry
flow from the cutoff ditch down to the collection ditches experienced failure during the Sept.
14 precipitation event (Photo 13). Although the 24-hour accumulation did not meet the 10-
year event of 2.0 inches, the shorter periods of concentrated precipitation appear to have had
an adverse impact on this structure. The permit does not appear to incorporate designs for
the cutoff ditch. Given the seasonal addition of irrigation tail water to this ditch, and the
increased combined flow that will result,the permit should be revised to incorporate this
ditch.
• Ditch C8/ C30 carries flow to Pond 012 from the east. As with C7/ C31, there are
discrepancies within the permit as to the ditch's location and drainage area. This ditch
appeared to have successfully handled the storm event, although there were locations where
accumulations of tumbleweeds (Photo 14)partially obstructed the flow.
• At Pond 011, a temporary collection ditch was installed earlier this year to collect surface
runoff from the backfilled area east and south of the pond and convey it to the pond's inlet in
the southwest corner. Construction of this ditch was required due to the delay in topsoil
redistribution brought about by the Morgans'judicial appeal of PR-06. (The top of backfill
is lower than the top of the pond embankment, so runoff must be intercepted at a higher
elevation, to the south.) This temporary ditch was breached in spots, allowing water to be
ponded in the area between the ditch and the pond (Photo 15). No environmental damage
appeared to have resulted as a result of the ditch's being breached.
REVEGETATION—Rule 4.15
Vegetative Cover; Timing:
• The second cutting of hay on all of the reclaimed Irrigated Pasture had been completed, and a
number of the fields were being irrigated using sideroll sprinklers.
Number of Partial Inspection this Fiscal Year: 3
Number of Complete Inspections this Fiscal Year: I Page 4 of 14