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6.4.4 Exhibit D—Mining Plan <br /> 4. The Mining Plan specifies that explosives are being used in the mining operation. The <br /> Division reviewed the permit file and could not find a record of a blasting plan. In <br /> accordance with rule 6.5(4), the Operator must demonstrate that the offsite areas will not <br /> be adversely impacted by blasting. If the Operator has already submitted a blasting plan <br /> to the Division for approval, then please provide a copy of the approved blasting plan. <br /> Otherwise, the blasting plan shall include the following information: <br /> a) How frequently does blasting occur? <br /> b) Specify the blast pattern <br /> c) Provide a cross section of a typical hole profile <br /> d) Specify the delay timing <br /> e) Specify the air overpressure <br /> 0 Specify the peak particle velocity <br /> g) Specify the maximum weight of explosives detonated in an 8 millisecond period <br /> PLS Response: The blasting is conducted by Buckley Powder Company. The Owl Canyon <br /> Quarry blasting plan is enclosed. a)Blasting occurs between 0 and 2 times per week, with the <br /> average being a blast a week. b) There are two blast patterns that may be used. This may be a <br /> 9'x 9'or 10'x 10'pattern. c) Please refer to enclosed plan. d) The hole delay is 350MS, <br /> surface delay is 25MS between holes in a row, and 42 to 84MS from row to row. e) The air <br /> overpressure is from 80 to 120 DBL. J) The peak particle velocity is measured in three areas. <br /> The Transverse is between 0.15 and 0.70, the vertical is between 0.14 and 0.50, and the <br /> longitudinal is between 0.20 and 0.50. g) A hole that is 20'deep with 5'of stemming leaves a <br /> 15'x 4"diameter hole to be filled with 5.81bs/ft ofANFO. This hole would then allow for 87 <br /> pounds ofANFO per hole with a maximum of 3 holes detonated at the same time. This is 261 <br /> pounds maximum in the 8 millisecond period. <br /> 5. Please specify when mining will progress into Mining Area B and D. <br /> PLS Response: Mining Area DI has a planned start date upon obtaining all necessary <br /> approvals to allow for continued mining. Mining Area D2 would commence after mining in <br /> DI is complete, and D3 to follow D2 in the same fashion. The remaining area in Mining Area <br /> D and the Mining Area Bare slated as possible reserves. If this material is determined to of <br /> sufficient grade to warrant mining,Mining Area D would begin upon completion of Mining <br /> Area D3 sometime around the year 2054. Mining Area B would begin after mining in is <br /> complete in Mining Area D, which would be around the year 2074. Please refer to Mine Plan <br /> Map for further sequencing details for Mining Areas DI-D3. <br /> 6. The Mining Plan Map indicates that backfilling will occur within Mining Area D1-3 prior to <br /> mining of the phases. Please clarify the sequence in which backfilling and mining of area D <br /> will occur. <br /> PLS Response: The years provided in DI-3 are ranges in which mining in those mining Areas <br /> are planned to occur. Backfilling will occur in the mining Areas that were mined prior to <br /> current activity and no timeframes were provided on the map acknowledging the backfilling <br />