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Blast Vibration Analysis: Proposed MMRR Quarry Page 5 ORP and pH monitors both employ a glass electrode as the sensing instrument. While intended for use in industrial applications, care must be taken to prevent electrode breakage or the loss of sensor seal integrity. ADO monitor utilizes a galvanic sensor behind a 5-mil Teflon membrane. All of these instruments are connected via cable to a microprocessor-based monitor, which in turn relays output to the plant SCADA system. Blast-induced shock and/or vibration could damage the sensor, seal integrity, or displace the cable connections; any one of which could produce erroneous signals and thus improperly treated effluent. Most of the level and flow instruments at the plant employ ultrasonic sensors. To measure liquid level, an ultrasonic pulse emitted from the sensor is reflected back by the surface of the liquid and received by the same sensor as an echo signal. The water level is then calculated from the run time of the ultrasonic signal. For flow measurement, two sensors simultaneously send and receive ultrasonic pulses. At zero flow, both sensors receive the transmitted ultrasonic wave at the same time. However, when liquid flow is present, the waves of ultrasonic sound do not reach the two sensors at the same time and the transit time difference is directly proportional to the flow velocity. While these instruments are intended for industrial applications, shock or vibration exceeding expected parameters could produce physical displacement of the sensor. Even the slightest misalignment will result in inaccurate level or flow measurement that may result in potentially improper process control. As with the water quality sensors, blast-induced shock and/or vibration could also dislodge or displace the cable connections and produce erroneous signals. The dual- sensor flow measurement system is especially sensitive to shock and vibration; even the smallest misalignment of the instrument or the open flume will result in inaccurate flow measurements. Accurate monitoring of flow is required under the plant's Colorado Discharge Permit. Other instrumentation also is susceptible toblast-induced shock and vibration. Magnehelic gauges are used to measure differential air pressures in the odor control system. Their manufacturerZ recommends "...a location free from excessive vibration..." for installation. Finally, the cumulative impacts of blast-induced shock or vibration on sensitive instruments requiring precise calibration aze difficult to predict. Using the dual ultrasonic sensor flowmeter as an example: even if 1 or 2 shocks do not result in misalignment, 8 or 10 may produce a substantial cumulative displacement that would result in erroneous readings. The predicted maximum PPVs, which aze intended to protect drywall, do not provide the degree of protection necessary to assure that cumulative blast-induced effects will not adversely impact plant instrumentation. Physical Plant Equipment The wide variety of physical plant equipment will exhibit differing responses toblast-induced shock and vibrations. Some shock and vibration are anticipated in the design of the structure and its contents via expected operating conditions and seismic requirements. Additional displacement (exceeding the UBC Zone 1 seismic conditions where the plant it located) due to blast-induced vibration could adversely affect the following equipment: ' Juras2, William, Technical Support Engineer, Endres + Hauser, personal communication, November 1, 2005 Z Amton International, 1380 Aspen Way, Vista, CA 92081 ©Leonard Rice Engineers, Inc. November I Q 1005 -Job No. 1086BCS03D