2013-05-30_HYDROLOGY - M1983090

• Permit No: M1983090
• IBM Index Class Name: HYDROLOGY
• Doc Date: 5/30/2013
• Doc Name: SWSP
• From: OSE
• To: DRMS
• Permit Index Doc Type: Hydrology Report
• Email Name: ECS
• Media Type: D
• Archive: No

Mr. Andy Rodriguez
Poudre Pits Aggregate Mine SWSP
May 29, 2013
Depletions
Page 2
Evaporation and Operational Losses
The depletions resulting from evaporation, water lost in product, concrete batching, dust control, and
post pumping depletions from past dewatering activities are shown in Table B below:
TABLE B - 2013 DEPLETIONS*
* Depletions shown do not include those from dewatering operations.
The Firestein/Tigges /Roberts Aggregate Mine is comprised of three adjacent properties; the
Firestein, Tigges and Roberts parcels. Based on the information provided, the exposed water surface area
at the Firestein/Tigges /Roberts site totals 48.83 acres. Mining of the Roberts Pit was completed in May
2006 and the pit has been reclaimed and a plan for augmentation was approved in case no.
2002CW331. It is anticipated that operations at the Firestein/Tigges site during 2013 will consume 1.68
acre -feet of water for dust control, 5.52 acre -feet of water with the production of 45,000 cubic yards of
concrete (assumes 40 gallons of water per cubic yard of concrete), and 3.90 acre -feet of water lost with
132,500 tons of washed product (assessed a 4% by weight water loss).
Based on the information provided, there are 31.66 acres of groundwater exposed at the La
Poudre site and 8.51 acres at the North La Poudre site. The previous SWSP did not allow for any
aggregate production at the La Poudre and North La Poudre Pits as the operator had ceased mining
operations at these locations. However, the 2012 submitted accounting shows a total of 212,135.15 tons
of aggregate was mined at a water loss of 6.24 acre -feet. The mining that occurred in 2012 at the North
La Poudre site occurred in an old footprint and that mined area was partially backfilled in 2012. This
2013 SWSP again assumes that no other mining will occur at these site but to be conservative an
allowance of up to 47,000 tons (1.38 acre -feet) was included in the projected depletions. It is anticipated
that operations at the La Poudre /North La Poudre site during 2013 will consume 2.20 acre -feet of water
for dust control, 7.37 acre -feet of water for concrete batching (assumes 40 gallons of water per cubic
yard of concrete) and 1.38 acre -feet of water with the production of 47,000 tons of aggregate.
Dewatering Operations
Dewatering operations for all sites within this SWSP had been assumed to occur at a rate of 500
gpm with all water released directly to the river. For this SWSP, all operations were reanalyzed based on
the assumption of a dewatering rate of 100 gpm where 75% of the water was recharged in the adjacent
pits and 25% was discharged directly to the river. This is based on a reevaluation of historic operations
by the operator's consultant and a December 20, 2012 letter from Mark Johnson, Compliance Manager
Product
Water
Evaporation
Moisture
Consumed in`
Dust
Total
Total Lagged
Site Name
Losses
Loss
Concrete
Control
Depletions
Depletions
(ac -ft)
(ac -ft)
Batching
(ac -ft)
(ac -ft)
(ac -ft)
ac -ft
3.90
5.52
Firestein /Tigges /Roberts
116.87
(132,500
(45,000
1.68
127.97
126.12
Pit
cubic
cubic yards)
yards)
1.38
La Poudre Pit
75.76
(47,000
7.37
cubic
(60,000
2.20
107.09
109.37
North La Poudre Pit
20.38
yards)
cubic yards)
Total
213.01
5.28
12.89
3.88
235.06
235.49
* Depletions shown do not include those from dewatering operations.
The Firestein/Tigges /Roberts Aggregate Mine is comprised of three adjacent properties; the
Firestein, Tigges and Roberts parcels. Based on the information provided, the exposed water surface area
at the Firestein/Tigges /Roberts site totals 48.83 acres. Mining of the Roberts Pit was completed in May
2006 and the pit has been reclaimed and a plan for augmentation was approved in case no.
2002CW331. It is anticipated that operations at the Firestein/Tigges site during 2013 will consume 1.68
acre -feet of water for dust control, 5.52 acre -feet of water with the production of 45,000 cubic yards of
concrete (assumes 40 gallons of water per cubic yard of concrete), and 3.90 acre -feet of water lost with
132,500 tons of washed product (assessed a 4% by weight water loss).
Based on the information provided, there are 31.66 acres of groundwater exposed at the La
Poudre site and 8.51 acres at the North La Poudre site. The previous SWSP did not allow for any
aggregate production at the La Poudre and North La Poudre Pits as the operator had ceased mining
operations at these locations. However, the 2012 submitted accounting shows a total of 212,135.15 tons
of aggregate was mined at a water loss of 6.24 acre -feet. The mining that occurred in 2012 at the North
La Poudre site occurred in an old footprint and that mined area was partially backfilled in 2012. This
2013 SWSP again assumes that no other mining will occur at these site but to be conservative an
allowance of up to 47,000 tons (1.38 acre -feet) was included in the projected depletions. It is anticipated
that operations at the La Poudre /North La Poudre site during 2013 will consume 2.20 acre -feet of water
for dust control, 7.37 acre -feet of water for concrete batching (assumes 40 gallons of water per cubic
yard of concrete) and 1.38 acre -feet of water with the production of 47,000 tons of aggregate.
Dewatering Operations
Dewatering operations for all sites within this SWSP had been assumed to occur at a rate of 500
gpm with all water released directly to the river. For this SWSP, all operations were reanalyzed based on
the assumption of a dewatering rate of 100 gpm where 75% of the water was recharged in the adjacent
pits and 25% was discharged directly to the river. This is based on a reevaluation of historic operations
by the operator's consultant and a December 20, 2012 letter from Mark Johnson, Compliance Manager