Contents
3A
Borrow Pit Dimensions
September 2010
Corriemoillie Wind Farm Environmental Statement
Appendix 3A – Borrow Pit Dimensions
Appendix 3A – Indicative Calculations of Rock and Peat
Requirements
Volume of Rock Required
Borrow Pit Dimensions
Borrow
Pit No.
1
2
3
4
5
Easting
Northing
233366
868054
233817
234553
234984
233941
867465
867342
866100
867243
New/
Existing
new
new
new
new
new
Dimensions
100m x 100m x
7m
50m x 50m x 7m
150m x 150m x
2.7m
70m x 70m x 3m
50m x 50m x 7m
Total Yield*
Total Volume
Required**
Potential Yield
(m3)
70,000
17,500
60,750
14,700
17,500
180,450
Reinstatement
Task
total length of
Wind Farm access
access track
track construction
11377m
Assumptions
Rock required (m3)
of which existing =
1646m
assume all roads etc are 1m depth
(worst case)
assume all requires widening/
upgrading at 1m depth x 2m width
x1646m
of which new (full
width)=9508m
assume 1m depth x 5m width x 9508m
(assume all types of road need approx
same amt of rock fill)
of which new (borrow
pits)=223m
assume 1m depth x 3m width x 223m
669
Turning area
construction
~64m x 10m x 10 dead ends - assume
1m depth
6400
Passing area
construction
~64m x 5m every 500m - so assume
22.7 on site, at 1m depth
7264
Crane hardstanding
construction
~50m x 25m - assume 1.3m depth - 19
in all
Culvert installation
~1 culvert/500m x 6m - assume built in
access track calculations
Water crossing 1
construction
~8m x 5m- assume built in access track
calculations
Water crossing 2
construction
~8m x 5m- assume built in access track
calculations
Water crossing 3
construction
~8m x 5m- assume built in access track
calculations
Water crossing 4
construction
~8m x 5m- assume built in access track
calculations
Water crossing 5
construction
~8m x 5m- assume built in access track
calculations
Tree felling
Tree felling access
track construction
assume incorporated into rest of access
track construction
Construction
compound
Parking area
installation
~40m x 10m - assume 0.6m depth
Concrete area for
refuelling installation
~10m x 10m - assume concrete - from
site batching
full
full
full
full
full
177,640
* approximate value takes into account projected wastage & bulking factor of 15% and 25%
respectively.
** approximate volume of rock required for on site works (internal tracks, upgrade of existing track
turbine foundations, hardstanding etc).
3292
51950
30875
Notes:
Coordinates – Easting and Northings, approximate location only. Exact location to be determined by
ground truing, and subject to limitations imposed by archaeological, ecological, landscape factors etc.
Borrow Pit Dimensions – these dimensions are estimated, require ground truthing and subject to
limitations imposed by archaeological, ecological, landscape factors etc.
Depth of Borrow Pit (approximate depth that material could practicably be won to, including depth of
overburden) – Pits 3 and 4 have been trial pitted – other depths are estimated based on ground
features and site visits
Potential Stone Quantity (approximate volume of material that may be won) – derived from estimated
values of borrow pit area and depth of borrow pit, with allowance made for overburden and other
losses. Significantly more or less materials may be excavated.
Corriemoillie Wind Farm Environmental Statement
240
Appendix 3A – Page 1
Appendix 3A – Borrow Pit Dimensions
Concrete batching
area installation
~15m x 50m - assume 0.6m depth
450
Laydown area
installation
~100m x 100m - assume 1m depth
10000
Substation
Turbine foundation
construction
15m x 10m x 0.4m
2208-3500 m 3 stone per turbine - from
carbon calc (assume 3500m3 as worst
case)
depth of peat over turbines=approx
1.3m x 419m3 area=545m3 peat
removed per turbine
Aggregate required
TOTAL ROCK
REQUIRED (m3)
Borrow pits
1
3
4
5
100m x 100m x 7m
50m x 50m x 7m
150m x 150m x2.7m
70m x 70m x 3m
50m x 50m x 7m
TOTAL ROCK
PRODUCED
(assuming no OB
etc)
Appendix 9A – Page 2
66500
177700
2
Additional vehicle
movements needed
60
70000
17500
60750
14700
17500
180450
Assume 1m3 aggregate is 4 tonnes
and wagons have a 29 tonne payload
0
Corriemoillie Wind Farm Environmental Statement
Appendix 3A – Borrow Pit Dimensions
Peat Depth Calculations
Peat Depth
Class - 0.2m
intervals
0-0.2
ID
Access tracks
0.2-0.4
0.4-0.6
0.6-0.8
0.8-1
1-1.2
1.2-1.4
1.4-1.6
1.6-1.8
1.8-2
2-2.2
2.2-2.4
2.4-2.6
>2.6
Assumed
depth (m)
Number
proposed
Volume of
peat
disturbed
(m3)
185.417
% of track in
depth or
shallower
1.63
1280.204
8145.357
8044.972
7906.795
9970.002
7473.368
5678.248
3061.152
1901.41
1052.271
751.116
1381.77
132.272
7.26
31.12
48.80
62.70
77.31
86.69
92.93
95.92
97.59
98.43
98.98
99.92
100.00
0.2
Length (m)
185.4
Width (m)
5
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
640.1
2715.1
2011.2
1581.4
1661.7
1067.6
709.8
340.1
190.1
95.7
62.6
106.3
9.4
5
5
5
5
5
5
5
5
5
5
5
5
5
1
64
10
10
6400
22.7
7264
1500
10000
Turning Areas
0.8-1
Passing Areas
Construction Compound
Laydown Area
Substation and Control
Building
Crane Hardstanding
Areas
0.8-1
0.4-0.6
0.6-1.4
1
0.6
1
64
50
100
5
50
100
0.2-0.4
0.4
15
10
60
0.4-0.6
0.4-0.6
0.8-1
0.8-1
0.4-0.6
1-1.2
1-1.2
1-1.2
0.4-0.6
2-2.2
0.4-0.6
>2.6
1.2-1.4
0.4-0.6
1-1.2
1.6-1.8
>2.6
1-1.2
1.2-1.4
0.6
0.6
1
1
0.6
1.2
1.2
1.2
0.6
2.2
0.6
2.8
1.4
0.6
1.2
1.8
2.8
1.2
1.4
50.0
50.0
50.0
50.0
50.0
50.0
50.0
50.0
50.0
50.0
50.0
50.0
50.0
50.0
50.0
50.0
50.0
50.0
50.0
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
750
750
1250
1250
750
1500
1500
1500
750
2750
750
3500
1750
750
1500
2250
3500
1500
1750
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Corriemoillie Wind Farm Environmental Statement
Assumptions/ comments
median track depth = 0.8-1m
Total length of track (existing, new and borrow pits - but not
Lochluichart)=11377m
Assume same average depth as tracks (1m) as locations
unknown
Assume same average depth as tracks as location unknown - one
every 500m, so 22.7 proposed
covers several depth classes
Assumed to be the same as turbine centre depths
Appendix 3A – Page 3
Appendix 3A – Borrow Pit Dimensions
Turbine foundations
Met mast
Borrow Pits
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
1
2
3
4
5
0.4-0.6
0.4-0.6
0.8-1
0.8-1
0.4-0.6
1-1.2
1-1.2
1-1.2
0.4-0.6
2-2.2
0.4-0.6
>2.6
1.2-1.4
0.4-0.6
1-1.2
1.6-1.8
>2.6
1-1.2
1.2-1.4
0.2-0.4
0.6-0.8
1-1.2
0-0.2
0-0.2
0.8-1
0.6
0.6
1
1
0.6
1.2
1.2
1.2
0.6
2.2
0.6
2.8
1.4
0.6
1.2
1.8
2.8
1.2
1.4
0.4
0.8
1.2
0.2
0.2
1
100
50
150
70
50
100
50
150
70
50
TOTAL PEAT
DISTURBED
251.4
251.4
419
419
251.4
502.8
502.8
502.8
251.4
921.8
251.4
1173.2
586.6
251.4
502.8
754.2
1173.2
502.8
586.6
167.6
8000
3000
4500
980
2500
each turbine requires a cylindrical foundation of 25m diameter 419m2
assume foundation is same as turbines
141391.954
Indicative Peat Use in Restoration
Reuse
Assumption
Amount Reused (m3)
Road edge dressing
assume peat is an average of 1m depth and 2m width on either
side of the 11,377m of roadway allowing for a 45o batter to the
roadway
22,754
Cable trenches
assume these will have no net effect on peat excavation as
they will be immediately backfilled with excavated peat
Restoration of passing areas
Replacement of excavated peat
7264
Restoration of construction compound
Replacement of excavated peat
1500
Appendix 9A – Page 4
Corriemoillie Wind Farm Environmental Statement
Appendix 3A – Borrow Pit Dimensions
Restoration of laydown area
Replacement of excavated peat
10,000
Covering turbine foundations with peat
Assume 400m2 per turbine can be covered (hardstanding
maintenance areas will be retained)
7600
Replacing excavated peat onto borrow pits
Replacing excavated peat
18980
Engineering borrow pits to accept 2m of
peat in total
Excluding originally excavated peat
65820
Additional
onsite
uses
(backfilling
excavations, drain blocking, habitat
restoration, further engineering of borrow
pits etc)
Unknown amounts
TOTAL
111,164
Excess not used on site (approx)
30,228
–.
Corriemoillie Wind Farm Environmental Statement
Appendix 9A – Page 5