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RULE 2 PERMITS <br />The planned coal production at the Colowyo operation is shown in Table 2.05-2. <br />Blasting <br />Colowyo usually engages in blasting of overburden and coal before its removal. A general <br />sequence for drilling and blasting of overburden and coal will proceed as follows: <br />(1) Establish a drill bench on the overburden. <br />(2) Utilize the timing model to determine the maximum number of blast holes that will ignite <br />in any 8 -millisecond period, this will determine the size of the blast pattern and the <br />maximum amount of explosive to ignite at any 8 ms time period. <br />(3) Compare this poundage of explosives to the "scale distance formula" result. If the blast <br />design exceeds the criterion of the "scale distance formula," then we will revise the <br />design until compliance is met. <br />(4) Blast pattern design will then be sent to the field for implementation by the blasters. <br />(5) Drill blasting pattern. <br />(6) Load drill holes with explosives. <br />(7) Blast reports will then be recorded to meet the criteria noted in Rule 4.08.5 (1) thru (18) <br />for surface coal mining operations. <br />(8) Blast overburden. <br />(9) Remove blasted overburden with shovel, front-end loader, or dragline. <br />(10) Clean coal seam. <br />(11) Drill blasting pattern. <br />(12) Load drill holes with explosives. <br />(13) Blast Coal Seam <br />(14) Remove blasted coal with front-end loaders. <br />Colowyo will comply with all applicable state and federal laws in its use of explosives. <br />Experienced, trained, certified and competent persons conduct all blasting operations. <br />Because of the inherent complexities of the Colowyo mining operation, the surface blasting <br />program has been developed to conform with a variety of coal seams and the diverse overburden <br />handling techniques. The coal blasting will vary from coal seam to coal seam because of the <br />different thickness encountered. Three general types of overburden blasting will be required: one <br />for blasting overburden, one for the pre -splitting of overburden to provide for safer highwalls and <br />one for blasting coal. <br />Approximate blasting patterns for coal and overburden are shown in Table 2.05-4, Blasting <br />Parameters — Overburden (Typical); Table 2.05-5 Blasting parameters — Overburden pre -Split Shot <br />(Typical) and Table 2.05-6, Blasting Parameters — Coal (Typical). <br />Colowyo will conduct a timing analysis through various methods for each overburden shot <br />utilizing the down hole delay timing, hole -to -hole delay timing, and row to row timing as <br />applicable to verify the maximum number of holes and thereby pounds of explosive detonated per <br />8 ms time period. This analysis can be conducted by hand or with computer software that predicts <br />Rule 2 Permits 2.05-13 Revision Date: 5/25/18 <br />Revision No.: RN -07 <br />