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• Production patterns will vary in burden and spacing dimensions. Burden spacing will range <br />from 6 to 25 plus feet. Spacing will vary from 6 to 25 plus feet. Burden and spacing dimensions <br />are governed on drill bit size (5.25 to 7 inch diameter), hardness of rock and degree of <br />fragmentation desired. Normal production blasting will be a rectangular pattern with on-echelon <br />delays. Staggered patterns have been used in the past with success and will be used in the <br />future as conditions warrant. Stemming will be washed gravel to contain the pressures. <br />Typically, six to eight holes per row and six to twenty rows per shot will be used. Smaller or <br />larger patterns may be used or tried to make the shot more economical or to fragment the <br />overburden better. <br />Standard on-echelon delay sequencing in normal production shots will use appropriate delays <br />in order not to exceed the peak particle velocity of 1 inch per second. WFC will vary from this <br />design some what to reduce ground vibrations and increase fragmentation. <br />Normal production blasting breaks to two faces and delays will all be non-electric. Non-electric <br />delays will be located on the surface and down each borehole to minimize the number of holes <br />• detonating in any given 8ms time period. Use of non-electric delays reduces noise and <br />increases safety in a region of frequent thunderstorms. <br />A typical production, decked production and parting blast design can be examined in <br />Attachment 2.05.3(6)(a)-5. These blast designs have been approved by a certified blaster. <br />Explosive Selection and Poundage <br />Actual field experience at the New Horizon Mine indicates a high percentage of the blast-holes <br />contain some amount of water. Since the startup of the mine, various water resistant products <br />and loading techniques have been examined and tried. New Horizon Mine has settled upon the <br />use of: a) water resistant slurry for the extremely wet holes, b) bagged gel products in <br />conjunction with ANFO in plastic sleeved holes for slightly wet holes, c) de-watering pumping of <br />the wet holes in conjunction with lined ANFO for moderately wet holes d) straight ANFO for the <br />dry holes.. Typical poundage of explosives used per hole will range from 0-1420 pounds of <br />ANFO/slurry for full bench production blast, 0-700 pounds of ANFO/slurry for deck shots and 0- <br /> <br />(Revised July 2006) 2.05.3(6)(a)-7 <br />