GENERAL32617

• Permit No: C1981020
• IBM Index Class Name: General Documents
• Doc Date: 9/7/1982
• Doc Name: PROPOSED DECISION AND FINDINGS OF COMPLIANCE
• Permit Index Doc Type: Findings
• Media Type: D
• Archive: No

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The collector ditch for the pond at the waste disposal site will be stable under
flows from the 10-year, 24-hour event and the emergency spillway will be stable
during flows resulting from the 25-year, 24-hour event. As in the case for the
pond at the mine bench, no mechanical installation is proposed for the dewatering
of the pond down to the maximum sediment storage level.
The following stipulation is required fora finding of compliance:
Stipulation No. 2
WITHIN SIX MONTHS OF PERMIT ISSUANCE AND PRIOR TO CONSTRUCTION OF
THE SEDIMENT PONDS AT THE MINE BENCH AND RT THE WASTE DISPOSAL SITE,
THE PERMITTEE MUST INSTALL APPROVED DEWATERING DEVICES TO DEWATER
THE PONDS TO THE MAXIMUM SEDIMENT STORAGE LEVEL. ALSO, THE
PERMITTEE MUST COMMIT TO INSTALLING MARKERS TO INDICATE THE 60~
SEDIMENT STORAGE LEVEL AT BOTH SEDIMENT PONDS.
The bypass culvert conveying undisturbed flow beneath the mine bench fill is
sufficient to pass the required 10-year, 24-hour peak flow. Velocities of
water discharged from the culvert during the 10-year, 24-hour event will be
moderate. Since the applicant proposes to install a dumped rock gutter at the
discharge end of the culvert, the energy should be properly dissipated.
The bypass culvert will discharge into a riprap-lined temporary diversion which
will convey the flow into the natural drainage. Because of the high slope of
the channel, flow velocities during the 10-year, 29-hour event could be as
high as 16 feet per second. The applicant has committed to the installation
of adequate channel lining to inhibit erosion of the diversion and appropriate
measures to dissipate flow energy prior to discharge into the receiving
drainage,
The collection ditches and culverts conveying runoff From the disturbed area
at the mine bench will adequately carry the flow resulting from the IO-year,
29-hour event. Ditches collecting disturbed flow and diverting undisturbed
flow at the waste disposal site will also be stable under the 10-year, 24-hour
peak flow conditions. These components of the surface drainage system are in
compliance with the Rules and Regulations.
VI. Hydrologic Balance: Ground Water - Rules 2.04.5, 2.09.7,
2.05.6(3) and 4.05
Information provided by the applicant with respect to ground water in the permit
area can be found in Sections 2.3.2, 2.6, and 4.9 in Volume I of the appli-
cation. Based on an analysis of these data and information, the following
determinations have been made by the Division.
Drilling in the area indicates the presence of a saturated zone within the
Cameo seam (Figure 4.4-1). This saturated zone occurs outside of the permit
area within the McClane Canyon Mine plan area and will not be encountered by
projected mining within the Munger Canyon Mine. Data indicates that the
Carbonera seam, which overlies the Cameo seam, also becomes progressively