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<br />~ i ~ ~ ~ ~1~ (~'(-1T nR A T1~1 <br />~J lL 11 L ~Jl ~.IJL~JI~! VL/U <br />DIVISION OF MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1317 Sherman 51., Room 215 <br />Denver, C080203 <br />Phone: (3031 866-3567 <br />FAX: 13031 832-8106 <br />DATE: November 17, 1992 <br />TO: Steve wath/e~a,q,,~/~~y~/p"'~ <br />FROM: Carl Mount!/ ~~ <br />RE: Colowyo Co\al Mine; C-81-019 <br />MR-22: Blasting Sketches and Blasting Reports <br />pF Cpl <br />,~F- 4 <br />u~~',diMiMr,~ <br />~~ .i <br />~ /8]6 ~ <br />~,unrr <br />Gnerno~ <br />Michael B. Long <br />Die ision D~~ector <br />The following is my opinion concerning the appropriateness of allowing Colowyo <br />to substitute a blasting report with keyed symbols for individual blasting <br />sketches. <br />The purpose of a blasting report is allow the Division to independently calculate <br />the amount of explosives firing during any 8 millisecond delay. In order to <br />accomplish this, the Division needs to know the following specifics for each <br />blast: <br />- type of blast <br />- point of initiation <br />- amount of surface delay between each charge <br />- amount of depth delay for each charge <br />- amount of explosive in each charge <br />- number of charges <br />- manner in which charges are laid out and the order of firing <br />it is the Division's responsibility to be able to figure the amount of explosives <br />used per 8 millisecond delay independent from the operator. Since the revised <br />blasting record submitted by Colowyo simply states the number of charges per <br />delay and the amount of explosives per charge, independent verification is <br />difficult or impossible. , <br />Independent verification can only be accomplished from a sketch, since the above <br />specifics may change with each blast. In my opinion, Colowyo should be required <br />to have a sketch for each blast ae specified in Rule 4.08.5 (7). - <br />M:\COAL\SFW\COLOWYO\MRBLAST.22 <br />