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2024-02-01_REVISION - M1973021 (2)
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2024-02-01_REVISION - M1973021 (2)
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Last modified
2/1/2024 12:43:10 PM
Creation date
2/1/2024 11:22:34 AM
Metadata
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Template:
DRMS Permit Index
Permit No
M1973021
IBM Index Class Name
Revision
Doc Date
2/1/2024
Doc Name Note
Adequacy Response 1
Doc Name
Adequacy Review Response
From
Holcim/HDR
To
DRMS
Type & Sequence
TR9
Archive
No
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AR7 <br />As you are aware, DRMS will be required to bond to backfill any areas <br />of exposed groundwater until an appropriate permanent <br />augmentation plan is approved. For the proposed Satellite South Pit, <br />this will result in a substantial bond increase, and as such <br />DRMS will require significant additional supporting information for the <br />reclamation cost estimates provided in TR9. <br />b. Please provide as much supporting information as possible to <br />support the Unit Price provided for the Dewatering task (estimated <br />volume, pumping equipment needed, duration of pumping, anticipated <br />pumping rate, etc). <br />The pump currently used for dewatering at the Morrison Quarry is a 6" Garmen- <br />Rupp PA Series Pump (Model: PA6c50-40450/51). Specifications include RPM: <br />1,700, GPM: 1,800. <br />As is discussed in Exhibit D - Mining Plan, Groundwater Management subsection, <br />the estimated dewatering requirement for groundwater inflow is 5 <br />gallons/minute. Therefore, when it is not raining, the dewatering system will only <br />be intermittently operated to maintain dry conditions in the pit during backfill <br />operations. It is assumed that dewatering and pumping will mostly be done <br />during and after rainfall and storm events when water collects in the South Pit. <br />This is similar to current dewatering operations during active mining. <br />For purposes of developing the cost estimate, the following assumptions were <br />used: <br />a. a similar diesel powered super vacuum assisted pump, 6", diesel powered costs <br />$30K-$50K to purchase. For purposes of estimating costs, the following <br />assumptions were made: <br />b. Due to the 16 month duration of the project, 2 pumps would be purchased <br />($100,000 cost). This is more cost effective than renting. <br />c. It was assumed that roughly $250/week of $1000/month was needed for diesel <br />to power the pump. This should be sufficient since dewatering will not be <br />continuous ($16,000 for 16 months of operation). <br />d. It was assumed that approximately $250/month would be needed for <br />miscellaneous repairs, etc. ($4,000) <br />e. Based on this analysis, total costs = $120,000 (Monthly costs = $7,500/month) <br />Exhibit E - Reclamation Plan has been updated to clarify the dewatering strategy. <br />Exhibit E - Reclamation Plan. Item <br />3.0. p. 13. <br />Exhibit L - Reclamation Cost. p. 21. <br />AR8 <br />As you are aware, DRMS will be required to bond to backfill any areas <br />of exposed groundwater until an appropriate permanent <br />augmentation plan is approved. For the proposed Satellite South Pit, <br />this will result in a substantial bond increase, and as such <br />DRMS will require significant additional supporting information for the <br />reclamation cost estimates provided in TR9. <br />c. Please provide a unit cost for processing the material blasted/mined <br />as backfill to meet the size requirements outlined in TR9 (max rock size <br />limited to 2/3 the proposed lift thickness of 30 inches.) <br />PDF of the drill and blasting cost estimate has been provided. <br />The drilling and blasting proposed in the reclamation plan is the same drilling and <br />blasting strategy used at the Morrison Quarry. Operations has indicated that <br />blasted rock is no larger than 30" therefore material processing will not be <br />needed before material is hauled to the satellite south pit for backfill. <br />1
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