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~ III IIIIIIIIIIIII III <br />P.O. Box 1887, 702 Gregg Drive, Buena Vista, CO 81211 <br />Ph. 17191 395-3790 Fax (7191 395-3794 <br />TROUT CREEK QUARRY -BLASTING INFORMATION <br />In order to begin the quarrying of riprap at the proposed site, the pioneering of access to the top of the rock <br />out crop will requ've some minor blasting. During this phase, we will be obtaining valuable seismographic <br />data with the use of seismograph rewrders positioned et the base and crest of the Roller Compacted <br />Conttete (RCC) dam. 'These blasts will be smaller in size, but will utilize the same pattern, and hole <br />loading that is expected to produce the desired products of the quarrying operation. <br />It is important to understand that it is not the size of the blast or overall quantity of explosives that <br />determine the vibrations that can cause damage, but rather the amount of explosives that is detonated at one <br />point in time. On page 426 of the attached portions of the Blasters' Handbook, it states that the Peak <br />Particle Velocity, V, depends on the maximum charge-weight per delay and not the total charge weight, <br />orovidin¢ that the delay interval is eight milliseconds or more. We will be utilizing nine millisecond delays <br />at the very minimum. Therefore, it is only relevant that we discuss the maximum weight per delay that will <br />be detonated. _ - ~^ <br />Another important factor to consider is the correlation of vibration levels to observed damage. This can be <br />seen in Figure 26-D on page 429 of the attached portions of the Blasters' Handbook. A Bureau of Mines <br />safe blasting aiteria for residential structures is 2.0 inches per second. <br />At our worst case, we are orooosin¢ a maximum of 42 pounds of explosives per delay at a distance of I50 <br />on page 426 of the Blasters' Handbook, we arrive at <br />tis equates to approximately a 2:1 safety ctor for re <br />SLNChAeS. <br />A drawing and calculations of the bore hole and loading is attached. This was developed by Lawrence <br />Nerenburg, Business Development Manager for Orica USA (formerly ICI Explosives). Mr. Neroburg, <br />who is a licensed blaster in many western states including Colorado and California, was contacted at a <br />remote project site and we developed the plan by phone. Also included is additional blasting information <br />provided by Gordon Revey of Revey and Associates, a blasting and vibration consultant. Mr. Revey has <br />provided the vibration analysis for the RCC dam, which is also attached. <br />°° Aa~U~aOk, ~~mat¢ratt®, Arggr®gait~a " <br />