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Fora 3`/Z-inch diameter drill-hole, Dynomix explosive, at 3.56 #/foot, will fill about 16 feet of the 24-foot deep hole, leaving 8 feet of/4-inch gravel stemming at the top of the hole to control fly-rock and sonic shock with a virtually undamaging ... a) less than %:-inch per second per second acceleration, b) frequencies of azound 200 cycles per second, and c) no measurable peak particle velocity. [Note: Structural damage begins occurring at accelerations of 2 inches/sec/sec and above, in the neighborhood of 10 cycles/sec and less, and with discernable peak particle velocity. ] Colorado lawZ requires no monitoring for a scaled distance (Ds) of 55 or more, where scaled distance equals the actual distance (>300 feet) from the blast in feet (D) divided by the square root of the weight in pounds of the explosive (W) per delayed hole, when fired with delays of more than 8milli-seconds. [Ds=D-JW] At a straight line distance of 820 feet from the blast site to the neazest structure (the Plateau Creek Bridge @ Forest Road 514) a 57 pound load per hole, fired at a greater than 8milli-second delay, produces a scaled distance of Ds = 109 feet (...neazly two times better than the minimum required monitoring threshold). Ds = 820 Ft - X57 = 820 _ 7.5 = 109.33 Ft It would take 211 pounds/hole/delay of explosive under the same specifications to produce aColorado- measurable scaled distance of Ds = 55 feet. Ds = 820 Ft - ,/21 l = 820 - 14.5 = 56.55 Ft At an explosives load of fifty-two percent (52%) of that delay hole-load limit, we consider the safety factor for this blasting plan to be more than adequate. Adeauacy Item #21 2. The application indicates thaf the final slope of the benched highwall shall approximate 0.58H:1V. Pursuant to Rule 3.1.10(3), final slopes must support rangeland post-mining land use and shall not be too steep to be traversed by livestock. DMG recommends 3H:1 V slopes for rangeland post-mining land use. Please clarify how the proposed 0.58H:1 V slopes address the requirements of Rule 3.1.10(3). McStone Response #2: Per Rule 3.1.10(3) the proposed slopes of the vast majority of the disturbed extraction area are to be essentially flat and nearly level. The steep perimeter headwalls and their protective crest-fencing are an intentional significant livestock and wildlife barrier at the west, north, and east property boundaries. Access is to be provided via the remaining entrance road ramp at the north edge of the extraction area. A solitary near-vertical barrier wall will be left separating the extracted azeas from the Plateau Creek gorge. Of note is that steep highwalls allow not only efficient extraction of the majority of the available resource, but also allow for a greater portion of the remaining extracted disturbed area for a more rangeland-compatible, nearly level plain. Slopes of even 3:1 and 4:1 aze marginally useful for livestock due to their steepness, and are much more difficult to re-vegetate. (A box is a much more efficient and useful container than a cone.) A naturally occurring near-vertical slope makes up the canyon walls of the Plateau Creek gorge immediately west of the extraction areas, demonstrating compatibility with existing terrain. Adequacy Item #3) 1. Pursuant to Rule 3.1.5(3), the application must demonstrate how the final configuration Z CFR 3Q Sections 715.19(e)(2)(ii)(c)(1), 816.67(d(3)(i), and 817.67(d)(3)(i)