20210430_Permit_07-01_ESC_Narrative_FS

NCDEQ DEW MINE PERMIT U /-U I MODIFICATION
EROSION AND SEDIMENT CONTROL PLAN
FOR
SOUTH OF 33 R 17/R 18
FOR
PCS PHOSPHATE COMPANY, INC
ENGINEERS
1530 NC HWY 306 S
AURORA, NC 27806
�lutrien
April 23, 2021
Prepared by:
ROBERT
CHILES
ENGINEERING
CONSULTANTS MARINE SURVEYORS
NC BELS FIRM # 1392
417 A Broad St
PO BOX 3496
New Bern, NC, 28564
[phone] Office

PURPOSE
This modification adds 1,232 acres to the permitted Mine Permit 07-01 boundary. This
submission presents Erosion and Sediment Control measures for the development of the
South of 33 R17/R18 Area. The area covered by this erosion and sediment control plan is
shown on SHEET 1.
The purpose of this plan is to direct the work to maintain control of runoff and prevent offsite
sediment release.
TERMS USED THROUGHOUT NARRATIVE:
Mine Corridor [SEE SHEETS 6.0 — 6.3]
The Mine Corridor includes the Offsite Stormwater Diversion Berm and Canal, the Light
Vehicle Road, Berms, the Internal Water System Canal, the Outfall Water from the
depressurization wells, mine power, and the mine haul road as shown in section views on
Sheet 6.3.
Offsite Drainage Canal [SEE SHEETS 5.0 & 5.1]
The Offsite Stormwater Outlet Canal is to be excavated and stabilized as part of the Highway
33/306 Overpass and Relocation project. The canal is sized to carry the flow from the Offsite
Stormwater Diversion to the west during a 1,000 year rainfall event, and flow towards an
existing double box culvert under Highway 33/306 into Bailey Creek.
Offsite Stormwater Diversion [SEE SHEETS 5.0 & 5.2]
The Offsite Stormwater Diversion serves to redirect offsite stormwater from the west areas
outside the proposed mine block towards the existing outlets. The Diversion is sized to retain
and convey the 1,000 year rainfall event, and minimize offsite stormwater entering the mine
area.
The above features are utilized to segregate and control the drainage from undisturbed,
offsite areas ahead of the mine development to prevent the flow of water from areas outside
the mine into the mine area. This Offsite Diversion and canal will be constructed prior to land
disturbing activities in adjacent areas and direct the water to maintain the approximate
watershed flowing to Bailey Creek throughout the life of the mine.
Internal Water System
The Internal Water System serves to collect and contain water from inside the mine activities
area and convey this water to the onsite settlement and treatment areas.
Once the mine corridor is constructed, mine site runoff will be contained in the Internal Water
System and conveyed to onsite settling areas. This plan provides a controlled transition from
initial land disturbance until the enclosure of the disturbed area within the mine corridor.
We are proposing a work sequence designed to be protective of the surrounding internal and
external areas during development, that is achievable through field practices of mine
operations during construction.

Site Description
The portion of the site which is subject to this plan is bounded to the not by Highway
33/306, with two areas crossing the highway to support Mine activity; the Dragline Walk Path
[SHEET 5.3] and the Mine Corridor Crossing [SHEET 5.4]. These two areas tie the South of
33 R17/R18 areas to the existing 07-01 Permit as shown on SHEET 1. The areas to the west
are undeveloped and outside the existing mine permit. The areas to the south and east of the
site are inside the existing 404 and 401 permits, but outside of this modification.
The site terrain slopes from the west along a sand ridge that has a crest location
approximately along NC Highway 306, and a toe approximately at the Modified Alternative L
Corps 404 permit boundary. Once the terrain is past the toe of the ridge, the site slopes very
slightly east, with grades of approximately 0.1 %. The existing land contours are shown on
SHEET 2.
Stormwater run-off from the area being added in this plan and the adjacent areas currently
drain as shown on SHEET 3. Since the areas excluded from this 07-01 Permit modification
will not have been disturbed by mine activities, they will not generate excess sediment
movement and should remain stable. Areas to the west of the permit boundary will be
diverted with the Offsite Diversion and continue outside the working mine area through the
Offsite Drainage Canal.
Ground cover is a mixture of softwood plantation, agricultural fields, cut -over woodland which
is partially in a state of regrowth with small volunteer tree seedlings and patchy weed growth,
and heavily vegetated hardwood bottom lands.
The soils are predominately classified as sandy loam or loam as shown in SHEET 4.

Watershed and Drainage Area Description and Control Measures
For analysis and for convenience, the subject area is divided into three drainage areas.
Sheet 3 shows the existing drainage patterns for the proposed and future mining areas.
® Offsite Watershed - West of the mine along the sand ridge. Sheet 5.0 shows the
discrete watersheds flowing westward towards the mine permit boundary.
® Bailey Creek - Drains to Bailey Creek via the Bailey Creek Field Ditch through the
concrete double box culvert under Highway 33/306.
• tual
North Broomfield Field Area —Drains the North Broomfield Field Ditch to the even
outlet at Broomfield Swamp Creek.
The total onsite area included in this plan is approximately 1,232 acres within the
R17/R18 Mine Blocks.
OFFSITE WATERSHED DIVERSION AND OUTLET CANAL
This plan utilizes the planned Offsite Stormwater Diversion and Outlet Canal to control offsite
stormwater that currently flows through the proposed mine blocks. The canal will be
constructed as part of the Highway 33/306 Overpass and Relocation project and will be
vegetated and stabilized prior to the introduction of flow from the diversion.
The diversion will be constructed ahead of the mine corridor construction activities to allow
for the relocation of the overhead powerlines that currently transect the proposed R17/R18
mine blocks. The diversion will primarily be a filled berm, constructed in lifts from onsite
soils. The side slopes, access ramps [Typical Detail SHEET 5.2] will be topsoiled, seeded,
and stabilized as construction advances. The Diversion will be constructed in segments
ranging between 300 to 600 feet in length, with soil plugs at the end of each phase. Any
accumulated water in the diversion will be pumped into the Internal Water System for
treatment and eventual discharge. Once the section is vegetated and stabilized, the plug will
be removed, and allowed to flow to the Offsite Stormwater Outlet Canal.
BAILEY CREEK WATERSHED
The Bailey Creek Watershed will be consumed by the mining activity in the R17/R18 Mine
block. This watershed will be contained by the corridor and stormwater transferred to the
Internal Water System.
NORTH BROOMFIELD FIELD AREA
The North Broomfield Field Area will be consumed by the mining activity in the R17/R18 Mine
block. This watershed will be contained by the corridor and stormwater transferred to the
Internal Water System.

Design Criteria and Focus
All erosion control features are designed to provide control for the 25-year design storm. The
plan provides for control of stormwater runoff during development within South of 33
R17/R18 Mine Blocks. The construction sequences below show the methodology for
containing, controlling, and managing the volume of runoff that must be controlled at any
given time. Construction will be in sections, based upon soils, grade, and other factors to
accomplish the following control measures of offsite sediment movement or erosion. The
plan includes:
• Establishment of sediment barriers to control sheet flow.
• Use of redirection swales, diversion berms, and canals to reduce the amount of water
reporting to disturbed areas.
• Sequencing the work to reduce the total disturbed area at any given time.
• Seeding and mulching to stabilize disturbed areas.
EROSION AND SEDIMENT CONTROL PLAN SEQUENCE
SHEET
5.0 Shows Proposed R17/R18 Mine Block and highlights different areas of the plan.
5.1 Offsite Stormwater Outlet Canal for the Offsite Stormwater Diversion in plan and
profile view.
5.2 Offsite Stormwater Diversion in plan and profile with sections for accessing
powerlines and a typical section.
5.3 Dragline Walk Path from South Bonnerton to the South of 33 R17/R18 mine block
area. This will be a temporary crossing of the railroad, powerlines, and highway to
allow the draglines access to the mine area.
5.4 Mine Corridor crossing at the proposed Highway 33/306 re-route. This sheet shows
the traffic and mine systems as they cross under the proposed UVtfl and back to
the existing mine area.
5.5 Interim Staging Area will serve as a staging area for equipment and mine material
during the Diversion and corridor construction. This area will eventually be replaced
by the Mine Facilities area as it is developed and constructed.
5.6 Mine Facilities Area will serve as the mine operation center once completed. The
Facilities area will contain employee parking, offices, change rooms, and equipment
and material staging for mine operati ons.

MINE CORRIDOR PLAN SEQUENCE
SHEET
6.0 An overall plan of the mine corridor surrounding the South of 33 R17/R18 mine
blocks.
6.1 Shows the Corridor along the West Cl" North sides of the mine blocks with enlarged
plan details.
6.2 Shows the Corridor along the South and East sides of the mine blocks with enlarged
plan details.
C®nstructi®n Sequences
Offsite Stormwater Diversion and Outlet Canal
1. The Outlet canal will be consfiructed as part of the Highway 33/306 Overpass and
Relocation Project and should be stabilized and complete prior to the beginning of mining
activities in the R17/R18 Mine Blocks.
2. Offsite Stormwater Diversion - Clear for and begin roll filling Offsite Stormwater Diversion
berm from north to south. Excavate and install the Diversion Outlet into the Offsite
Stormwater Outlet Canal. Continue roll filling of the Offsite Stormwater Diversion to the
Facilities area at the southern end of the project, tying the raised berm into the ridge per
the plan.
3. Install Diversion outlets at the north end per plan.
4. Construct access ramps for the powerline relocation project and drainage pipes under the
access ramps per plan [SHEET5.2]
Mine Corridor
1. Install security fence in appropriate locations.
2. Install silt fence along the South and East perimeter of the R17/R18 Mine Block. The
North and West sides will be contained with the berm along the Offsite Stormwater Outlet
Canal and the Offsite Stormwater Diversion berm.
3. Construct Internal Water System sump as shown [SHEET 5.4] and install pumps and
pipelines to transfer the Internal Water to the Treatment system.
4. Construct Outfall Water sump as shown [SHEET 5.4] and install pumps and pipelines to
transfer the water to the outfall system.
5. Construct topsoil berm and seed along the East and South perimeter [SHEET 6.3]
6. Excavate and stabilize within 14 days the Internal Water System canal and the Outfall
Water canal. Divert any internal drainage to the Internal Water System.

Vegetative Plan
1. Vegetative cover will be placed in accordance with the DEMLR Erosion and Sediment
Control Planning and Design Manual section 6.11.
2. Erosion control measures shall be checked after every significant rainfall event and
repaired, as necessary.
APPENDIX
Specifications See Attachment A
Vicinity, Clearing Blocks &General Site Features See Sheet 1
Existing Topography Contour Lines See Sheet 2*
it " with Aerial Photo See Sheet 2A*
Site Drainage Features See Sheet 3
Soil Types See Sheet 4*
Watershed Stormwater Control Measures See Sheet 5.0-5.2
Discrete Mine Erosion Control Areas See Sheet
Mine Corridor Overall Plan See Sheet 6.0
West and North Corridor with enlarged plan See Sheet 6.1
South and West Corridor with enlarged plan See Sheet 6.2
Corridor Cross Sections See Sheet 6.2
Sheets with asterisk (*) denote Sheets prepared by Nutrien Mine Planning.