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Blastine <br />Colowyo usually engages in blasting of overburden and coal before its removal. A general sequence for drilling <br />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 in any 8- <br />millisecond period ,this will determine the size of the blast pattern and the maximum amount of <br />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 design <br />exceeds the criterion of the "scale distance formula," then we will revise the design until <br />compliance is met. <br />(4) Blast pattem design will then be sent to the field for implementation by the blasters. <br />(5) Drill blasting pattem. <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) thm (18) for surface <br />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. Experienced, trained, <br />certified and competent persons conduct al] blasting operations. <br />Because of the inherent complexities of the Colowyo mining operation, the surface blasting program has been <br />developed to conform with a variety of coal seams and the diverse overburden handling techniques. The coal <br />blasting will vary from coal seam to coal seam because of the different thicloaess encountered. Three general <br />types of overburden blasting will be required: one for blasting overburden, one for the pre-spliting of <br />overburden to provide for safer highwalls and one for blasting coal. <br />Approximate blasting patterns for coal and overburden are shown in Table 2,05-5, Blasting Parameters - <br />Overburden (Typical); Table 2.05-Sa Blasting parameters -Overburden pre-Split Shot (Typical) and Table <br />2.05-6, Blasting Parameters -Coal (Typical). <br />Colowyo will conduct a timing analysis through various methods for each overburden shot utilizing the down <br />hole delay timing, hole-to-hole delay timing, and row to row timing as applicable to verify the maximum <br />number of holes and thereby pounds of explosive detonated per 8 ms time period. This analysis can be <br />conducted by hand or with computer software that predicts the timing of each hole and the maximum number of <br />holes that will initiate within the prescribed time period. <br />Examples of the maximum pounds of explosives per Sms period of time versus the distance to local residences <br />and dwellings of concern is reflected on Map 26 -Blasting Analysis Map. Colowyo has historically calculated <br />the maximum weight of explosives detonated with any 8 ms time period by the following means: <br />(Max. no. of holes in an 8-ms) x (Max. lbs. of explosives put in any one hole) <br />Revision Date: 12/19/03 <br />2.05-28 Revision No.: MR-61 <br />