Laserfiche WebLink
dwellings and within 500 feet of facilities such as gaslines or water and sewage lines. <br /> A review of the Operation Plan (Exhibit 12-3) will identify approximately 7 dwellings <br /> within 1,000 feet of the blasting area. Only 1 is within 500 feet. Approximately 2,300 <br /> feet of sewage line is within 500 feet of the blasting area. <br /> Due to the proximity of these dwellings and facilities, blasting operations at Nucla East <br /> will utilize stationary and portable seismographic instruments to monitor all blasts. <br /> These instruments will measure peak particle velocity in three mutually perpendicular <br /> directions. They will provide an "instant readout" of peak particle velocity immediately <br /> after each blast event. The peak velocity value and other instrumentation data will be <br /> entered onto the blasting record form as shown in Attachment 14-3. The recorded digital <br /> seismographic data will be submitted to a qualified firm for further analysis and <br /> interpretation. The firm will provide a report for each recorded blast event and be kept <br /> at the mine site available for inspection. <br /> If indicated by the monitoring system installed at Nucla East, the drilling and blasting <br /> procedures will be modified to include an increase in the number of drilling and blasting <br /> lifts, reduction of drilling pattern size, or use of more sophisticated delay systems to <br /> meet the one inch per second peak particle velocity limitation. Further, Peabody may <br /> investigate the employment of a modified scale distance equation. The request to CMLRD <br /> will provide supportive documentation obtained from seismograph monitoring performed and <br /> other appropriate investigations at both the Nucla and Nucla East areas. <br /> A specific blasting plan will be designed for the Nucla East mining area. This plan <br /> consists of three phases. In the first phase, data is collected at the existing Area No. <br /> 1 pit (5W pit) with seismographic recorders. Presently, three seismographs are being <br /> utilized. A permanent installation is located at the Smith residence to the north, and <br /> two portable instruments are utilized in the vicinity of each production blast. The <br /> portables are located at varying distances from the shot site in order to obtain a range <br /> of vibration-distance data. The data is then sent to Vibra-Tech Engineers Incorporated <br /> for data reduction. At the conclusion of data reduction, a regression analysis will be <br /> performed to determine a regression equation that depicts particle velocity versus <br /> scaled-distance factor. This equation will then be used as a basis for comparing the test <br /> shot data and to design the blasting plan at Nucla East to minimize ground vibration <br /> effects. <br /> In order for the above analysis to apply to the Nucla East area, the conditions in which <br /> 14-6 Revised 12/20/88 <br />