20090243 Ver 2_More Info Received_20110111

HAL OWEN & ASSOCIATES, INC.
SOIL & ENVIRONMENTAL SCIENTISTS
P.O. Box 400, 266 Old Caats Road
Lillington, NC 27546-0400
Phone [phone] /Fax [phone]
www.halowensoil.com
11 January 2011
Mrs. Crystal Amschier
Wilmington Regulatory Field Office
US Army Corps of Engineers
69 Darlington Avenue
Wilmington, NC 28403-1343
Reference: Womble Mine (226 Acresl. ST Wooten Corps. Harnett County. NC
i1SAC:F. ATTT# SAW-7(?AR-(12377
Dear Mrs. Amschler,
We received your email dated 3 January 2011 requesting clarification and additional
information (items listed in italics below) for the Pre-Construction Notification submitted for the
above referenced project. The following responses are provided for your consideration.
1) The cover sheet and the plans indicate that the current culvert is 22,~t in length but pg 3 of
the PCN indicates it is a I8' culvert. Please clarify the correct len~2th ofthe existing culvert.
The existing culvert is 22 feet long and 18 inches in diameter.
2) Previously issued plans proposed the road slopes to be at a 2:1 and discussed using a lower
elevation to reduce impacts. The current proposal is for 3:1 slopes and doesn`t discuss efl`orts
to minimize impacts by reducing elevation of'the roan Can you please provide additional
information on this.
The previously proposed haul road (Location A) crossed the stream where the banks were
steeper and the wetlands and floodplain were narrower. The haul road elevation was high
(~lOtt above the stmambed) requiring minimal cutting into the streambanks, and as a result
fill slopes were wide. The road was redesigned to reduce the fill slopes by lowering the road
elevation and steepening the slope. At proposed Location B, the haul road has already been
designed with a lower profile requiring the road to be cut into the banks as it approaches the
stream. The proposed road elevation is approximately 6 feet above the streambed which
allows a 4-foot diameter pipe to be placed in the stream with about 2 '/2 feet of fill over the
pine. The mining eauinment using the haul road will be laden with mined materials and
heavy. and at least one foot of fill is required by the manufacturer to protect the structural
intesJrity of the flue. lslsa. the proposed road elevation 1:294.66 ft) is at the 100 year
headwater elevation and about 1 toot above the 2s year headwater elevation. Lowering the
road would greatly increase the chance that the road evould be at~ertanBed d•.z^nL a starrn
event, and wash out the road especially given that the primary fill material would be sand.
Therefore, furtaer reducing the road elevation is not recommended.
Soil Science Investigations • Wetland Delineations, Permitting, and Consulting

HAL OWEN & ASSOCIATES, INC.
Using a 2:1 road slope was considered and would result in five feet less stream impact and
172 square feet less wetland impact. However, given that sediment concentration and soil
loss decrease as slope percent decreases and slope length increases; a 3:1 slope is preferred
for stability, ease of maintenance, and to provide better overall environmental integrity for
the site over the long term. _In other words, shorter, steeper road slopes will make stabilizing
the slopes more difficult, greatly increase the difficulty of maintenance and the potential for
formation of erosional features, and will very likely shed more sediment into the
drainageway over time. The safety issues discussed below are also considerations here.
3) During the processing of the previously issued permit, we requested justification on the 30'
width of the road and you responded citing that [aJ narrower road would be insu, fJicient to
support the volume of trucks an[d] equipment expected to cross safely. Please expand on why
a narrower road would not meet the needs of this project.
The proposed facility is a mining operation and the use of the internal xoads is not necessarily
limited to on road vehicles. Much larger mining related equipment needs to be able to meet
and pass on the road. A large off road dump truck needs to be able to meet and successfully
negotiate past another large off tad dump thick while staying entirely on the improved road
surface. Pulling to the shoulder with a loaded dump truck is simply not safe due to the
potential far roll-over. The plans for this operation need to be established in a way that will
allow vehicle and equipment movemerrts within the mine and not jeopardize the safety of the
employees.
I would also like to mention that as part of the mining permit, a 75-100 foot buffer has
been left along all streams to prated water quality. Also, this property consists of 22S acres of
land, of which slightly greater than 30 acres of wetlands and 10.375 feet of streams have been
identified. This pen~nit request is to impact 0.3 % of the wetlands and 0.6 % of the streams.
We trust that this provides the additional information that you requested and that the
permitting process can proceed as soon as possible. If you have any questions or need additional
information, please feel free to contact us at your convenience.
~~
Sincerely,
Krissina B. Newcomb
Pr~oj~jec't Environmental Scientist I
Hal Owen
Senior Environmental Consultant
CC: Butch Lawter, ST Wooten
DWQ 401 Wetlands Unit
Soil Science Investigations • Wetland Delineations, Permitting, and Consulting