2013-01-30_HYDROLOGY - M1978052

• Permit No: M1978052
• IBM Index Class Name: HYDROLOGY
• Doc Date: 1/30/2013
• Doc Name: Combined Replacement Plan
• From: OSE
• To: Bishop-Brogden Associates
• Permit Index Doc Type: Hydrology Report
• Email Name: BMK
• Media Type: D
• Archive: No

Point of
Replacement
Distance From
Replacement Source
(miles)
Transit Loss From
Replacement Source
( %)
Projected Pit Depletions
for Plan period (WY 2013
2014)
and 2014
(Acre -Feet)
Howe Pit
8
4%
2.1
Riverbend West
25
11.5%
53.9
Riverbend East
21
11 %
274.7
Mr. Heintz & Ms. Wynne
MMM South Platte Combined Replacement Plan
January 28, 2013
TABLE D — TRANSIT LOSS PER SITE
Page 4 of 7
For the purpose of this SWSP the proposed transit loss is accepted however, the transit loss is
subject to change if the division engineer or the water commissioner determines that a different transit
loss needs to be assessed to the Aurora leased water.
The total lagged mining depletions and replacements are shown on attached Table 5.
Dewatering
Dewatering will continue to occur at the Riverbend East Pit during WY 2013 & 2014. In WY
2012 MMM dewatered the site at approximately 3,000 gpm. MMM anticipates increasing this rate to
5,000 gpm, or approximately 674 acre -feet per month, due to the deeper levels of mining planned for
WY 2013 & 2014. The dewatering operation can pump directly to the river producing an instant credit
and a lagged depletion, or can pump to the north recharge pond producing a lagged credit and a
lagged depletion. Dewatering depletions will be lagged back to the river using the same parameters as
shown in Table C for Riverbend East and the recharge pond accretions will be similarly lagged back to
the river only using a value of 800 ft for the distance to the river (X). Totalizing flow meters are
installed at each discharge location and meter readings must continue to be reported on the submitted
accounting with actual credits /depletions determined in real time.
Long Term Augmentation
In accordance with the letter dated April 30, 2010 from the Colorado Division of Reclamation,
Mining, and Safety ( "DRMS "), all sand and gravel mining operators must comply with the requirements
of the Colorado Reclamation Act and the Mineral Rules and Regulations for the protection of water
resources. The April 30, 2010 letter from DRMS requires that you provide information to DRMS to
demonstrate you can replace long term injurious stream depletions that result from mining related
exposure of ground water. For Howe Pit and Riverbend East, Denver Water is the DRMS permit
holder. As municipal entities are not required to post bonds, these sites are not required to be bonded
to cover the cost of lining or backfilling the site. For Riverbend West, MMM has posted a bond to cover
the cost of backfilling or lining in accordance with approach # 1 and # 3 of the DRMS letter. As this site
will include unlined ponds that will permanently exposed ground water, an application to the water court
for a plan of augmentation to cover the long term depletions from the site must be filed at least three
years prior to the completion of mining. A summary of the final reclamation plans and the approach to
replace long term injurious stream depletions are shown in Table E.