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Blasting <br />C <br />l <br />f <br />ll <br />bl <br />i <br />f <br />d <br />d <br />l b <br />i <br />l <br />A <br />i <br />b <br />l <br />o <br />owyo over <br />e <br />y engages <br />ast <br />ng o <br />ur <br />en an <br />coa <br />ore <br />ts remova <br />. <br />genera <br />usua <br />n <br />sequence for drilling and blasting ofoverburden 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 <br /> ignite in any 8-millisecond period, this will determine the size of the blast pattern <br /> and the 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 [he <br /> blast design exceeds the criterion of the "scale distance formula," then we will <br /> revise the 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 (I) thru <br /> (18) 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 />(l2) 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 <br />overburden handling techniques. The coal blasting will vary from coal seam to coal seam <br />because of the different thickness encountered. Three general types of overburden blasting <br />will be required: one for blasting overburden, one for the pre-spliting of overburden to <br />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 <br />Parameters -Overburden (Typical); Table 2.05-Sa Blasting parameters -Overburden pre- <br />Split Shot (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 <br />detonated per 8 ms time period. This analysis can be conducted by hand or with computer <br />software that predicts the timing of each hole and the maximum number of holes that will <br />initiate within the prescribed time period. <br />Examples of the maximum pounds of explosives per 8ms period of time versus the distance <br />to local residences and dwellings of concern is reflected on Map 26 -Blasting Analysis Map. <br />• Colowyo has historically calculated the maximum weight of explosives detonated with any 8 <br />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 />2.05-28 Revision Date: 12/19/03 <br />Revision No.: MR-61 <br />