GENERAL32818 - Laserfiche WebLink

Home Browse Search

DIVISION OF MINERALS AND GEOLOGY Department of Namml Resources 131 3 Sherman 51., Room 215 Denver, Coloraco 817203 Phone: 13031 86n-3567 FAX:13U3) A32 7f106 n-r A ^rr III IIIIIIIIIIIII III~F 999 COLORADO ~I~~~ DEPARTMENT OF NATURAL RESOURCES DATE: December 7, 1995 Roy Romer Governor TO: Flle NO. M-88-081 Iames s. LOChheaA Executive Director e//) Michael B. Long FROM: Allen Sorenson / Drvrsrun Direcor RE: Evaluation of the Potential for Impacts to be Caused by Blasting Related Ground Motions, East-West Mining Corp., Phil Sheridan Lode The simplest method by which to evaluate blasting related ground motions is the Scaled Distance Equation. Because the Scaled Distance Equation does not consider site-specific geologic variables, it is designed to be very conservative, i.e., the Scaled Distance Equation is very restrictive in terms of the amount of explosive that may be detonated, and is very protective of nearby structures. The Office of Surface Mining has established limitation on the peak particle velocity (a measure of ground motion) that may be caused by blasting at various distances from the blasting location. The maximum allowably: peak particle velocity for structures within 300 feet of a blasting location is 1.25 inches per second. If blasting is conducted in accordanr~e with the Scaled Distance Equation, the peak particle velocity is deemed to be within this limitation. The Scaled Distance Equation relates t:he parameters of charge weight and distance. Reducing the charge weight, or increasing the distance, results in a smaller ground vibration. The maximum weight of explosives to be detonated within any 8-millisecond period may be determined by the Scaled Distance Equation: W c ~D~Ds)2 Where: W = the maximum weight of explosives, in pounds, that can be detonated in any 8-millisecond period; D = the distance, in feet, from the blast to the nearest dwelling, school, church, or community or institutional building; DS = the Scaled Distance Factor.