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MqY-01-06 11:25 qM DOUG CONGER 970 565 8394 P. 02 <br />Fora 3'/cinch diameter drill-hole, Dynomix explosive, at 3.5ti q/foot, will fill about 16 feat of the 24-Foot <br />deep hole, leaving S feet of ~/-inch gravel stemming at the top of the hole to wntrol fly-rock and sortie shock <br />with a visually undamaging ... <br />a} less than Vl-inch per second per second acceleration, <br />b) frequencies of around Z00 cycles per second, and <br />c) nomeasurabtepeakpartidevelocity. <br />[Note: Structural damage begins occurring at accelerations of 2 inches/seclsec and above, in the <br />neighborhood of 10 cycles/sec and less, and with discernable peak part/Cle ve{ocity. ] <br />Colorado lawt requires no monitoring For a scaled distance (D~ of 55 or more, where scaler! dn.•tance <br />equals the actual distance (>300 feet) from the blast in feet (D) divided by the square root of the weight in <br />pounds of the explosive (W) per delayed hole, when fired with delays of more than 8milli-seconds <br />1Ds'n-~'] <br />At a straight line distance of 820 feet from the blast site to the nearest structure (the Plateau Creek Bridge Q <br />Forest Road 514) a 59 pound load per hole, fired at a greater than Bmilli-second delay, produces a scaled <br />distance of Ds = 109 feet (...Hearty two times better than the minimum required monitoring threshold). <br />Dy - 820 Ft ' X57 = 820 _ 7.5 = 109.33 Ft <br />It would take 2 t 1 pounds/hole/delay of explosive under the same specifications to produce a Colorado- <br />measurable scaled distance of Ds = 55 feet. <br />Ds = 8x0 Ft + X21 I = 820 ~ 14.5 = 56.55 Ft <br />At an explosives load of fifty-two percent (52%) of that delay hole-load limit, we consider the safety factor <br />for this blasting plan to be more than adequate. <br />Adea_ t_ e~cv llfm k2l <br />~. The appllcaHon lndlcatea that the nna/ alope o-the benched hJphwall shsll epproxJmate <br />O.tieH:1 V. Pursuant to Rule 3.1.10(3), Ilnal slopes must support ranyeland poet-minlnp land <br />use sntl shat! not be too steep to ba traversed by Ilvestoek. DMG recommends $H.1 V slopes <br />for renpeland poat•minlnp lend use. Please clerlfy how the propoattd 0.58H:1V alopea <br />address the requlrementa of Rule 3.1.10(3). <br />McStone RBSDanae #2: <br />Per Kt~lr 3.1.!0(9) the proposed slopes of the vast majority of the disturbed extraction area are to be <br />essentially Flat and nearly level. The steep perimeter headwalls and their protective crest-fencing ere an <br />intentional significant livestock and wildlife barrier at the west, north, and east property boundaries Access <br />is to be provided via the remaining entrance road ramp at the north edge of the extraction area. A solitary <br />near-vertical barrier wall will be left separating the extracted areas from the Plateau Creek gorge. Of note is <br />t}tat steep highwalls allow not only efficient extraction of the majority of the available resource, but also <br />allow for a greater portion of the remaining extracted disturbed area for a more rangeland--compatible, nearly <br />level plain. Slopes of even 3:1 and 4:1 are marginally useful for livestock due to their steepness, and are <br />much more difficult to re-vegetate. (A boils a much more e((icierR and ax(uf esnta/ner t/ran a cone.) A <br />naturally occurring near-vertical slope makes up the canyon walls of the Plateau Creek gorge immediately <br />west of the extraction areas, demonstrating compatibility with existing terrain. <br />®,Q,4guacv Item H31 <br />1. Pursuant to Rule 9.1.6(3), the epplJcet/on must demonatrete how the final confJpuretlon <br />or the hlphwall will be aufrlclently atab/e to protect areas outalde dre affected land from aNdea <br />end other demaye, P/esas au6mh an approprlari angrnaerl»p sbburey sna/yaes, described <br />untler Rule 8. b, for the hlyhuvall conflquraHon proposed In the epplleatlon, <br />CfR 30, SecNaru 776AS(oX21(9p(c)(r), d1e.e7(tl(SXp. ands17.a7(o~(3)(q <br />