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Module 9: Treatment Facilities/Sedimentation Ponds/Dams and Impoundments
9.1
Discharge Information
a. Describe the source of the discharge. (Water pumped from mine workings, surface runoff, etc.)
b. Estimated gallons per minute flow rate of discharge.
c. Provide a representative chemical
“Background/Monitoring Report”.)
9.2
analysis
of
the
proposed
discharge.
(Use Form 11.4A
Treatment Facilities
a. Provide a plan for the collection and treatment of surface and groundwater discharges from areas
disturbed by mining activities. Include a description, detailed construction and maintenance plans, flow
diagram, detailed plan view and cross-section drawings, design criteria, and design calculations (which
include the proposed capacity) of the treatment facilities. Identify treatment chemicals to be used.
b. Explain how the mine will be sealed upon closure to prevent pollutional post mining discharges.
c. Show all mine drainage treatment facilities on the Operations Map, Module 14.
d. Show the location of the proposed discharge (where it enters a stream) on the Environmental Resources
Map, Module 14.
e. Submit the “NPDES Information” in Module 2 if the operation will have a point source discharge.
9.2
Sedimentation Ponds, Dams and Impoundments
Complete the following information if new structure(s) will be constructed or existing structures will be utilized in
the mining operation.
a. Identify the proposed use(s) for each structure.
b. Provide a unique label for each structure and show location (to scale including embankments and outlet
structures on Environmental Resources Map, Module 14 (and reference the structure in Module 14 if it will
remain as part of postmining land use.)
c.
Provide detailed cross sections and plan view scale drawings of the proposed structure which show: depth
of water, storage volume, principal spillway, dewatering devices, embankment details (including maximum
height, top width, and cutoff trench), crest of emergency spillway and existing ground.
d. Describe the materials, grading and compaction procedures that will be used for impoundment
construction.
e. Describe the potential effect on the structure from subsidence from underground mining, and any design
provisions made to offset potential impacts.
f.
If the detailed design plans are not included with the initial submittal of this application, identify when the
detailed design plans will be submitted. (Note: The detailed design plans must be approved by the
Department before construction of the structure begins.)
g. If the structure is located outside of the area covered by the geology and hydrology description contained
in Modules 10 and 11, include a preliminary geology and hydrology report.
9.3
Detailed Design and Construction Plans
Include a Sediment Impoundment data sheet for each dam, sediment pond, or impoundment
9.4
Class C Dams
a. A separate permit is required for impoundments that meet one or more of the following:
i.
a contributory drainage area exceeding 100 acres;
ii.
a depth of water measured by the upstream toe of the dam at maximum storage elevation exceeding
15 ft;
iii. an impounding capacity at maximum storage elevation exceeding 50 acre-feet.
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b. A permit processing fee of $1,500 should be included for structures that meet the above criteria. Permits
for impoundments that meet the above mentioned criteria and are to be left in place after mining will be
forwarded to the Division of Dam Safety, Bureau of Waterways Engineering and Wetlands.
9.5
Operation and Maintenance Requirements
Describe the operation and maintenance requirements for the structure, including a dewatering timetable.
9.6
Removal
Describe the timetable and plans for removal of the impoundment and reclamation of the area.
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SEDIMENT IMPOUNDMENT
Complete and submit.
Sedimentation impoundments and other impoundments must be constructed in accordance with the approved permit
before any disturbance of the area to be drained into the pond. Any enlargement, reduction in size, reconstruction,
or other modification, that may affect the stability or operation must be approved by the Department.
Pond No.
(Identify No. on Environmental Resources Map, Module 14)
U.S.G.S. Quadrangle:
Location (Point of discharge): Latitude:
Longitude:
Location from Bottom Right corner of U.S.G.S. Quadrangle:
inches North:
inches West
HYDROLOGY: Drainage Area
acre
Design Storm
Average Watershed Slope
Land Use
Soil Type
Curve Number
Peak Discharge
Embankment
Principal
Spillway
Top Width (Minimum)
Outside Slope (Maximum) (
H:
Inside Slope (Maximum)
Top Elevation
Bottom Elevation
Upstream Toe Elevation
Downstream Toe Elevation
Amount Allowed for Settlement
Type of Cover
Incised Slope (if any)
Inside Slope (Maximum) (
Top Elevation
Bottom Elevation
V)
H:
V)
Type
Conduit Diameter (if barrel/riser give both)
Inlet Elevation
Outlet Protection
Spillway Capacity
Dewatering
Device
Type/Size
Inlet Elevation
Discharge Regulation (i.e., self draining or valved)
Discharge Capacity (cubic feet/second)
Time to Dewater Full Pond
Emergency
Spillway
Type
Width
Depth (with 2 feet of freeboard
Length
Sideslopes
Crest Elevation
Slope
Type of Lining/Protection
Spillway Capacity (provide design calculations)
Storage
Capacity
Length @ Bottom
Width @ Bottom
Length @ Crest of Principal Spillway
Width @ Crest of Principal Spillway
Volume @ Crest of Principal Spillway
Length @ Crest of Emergency Spillway
Width @ Crest of Emergency Spillway
Volume @ Crest of Emergency Spillway
9-3
or