Seismic Service Audits

Key questions to be posed periodically to ensure optimal use of mine seismology services © 2007 by SiM Mining Consultants

On Data Collection... Have monitoring objectives been formulated? Are system configuration and performance aligned with monitoring objectives? Are quality assurance procedures in place? Is the seismic system operated efficiently? Are operators competent?

On Data Analysis... Do analysis methods represent 'best practice'? Are methods successful? Is the format in which results are presented suitable? Are reporting intervals appropriate? Is there sufficient capacity to provide services ?

On Customer Needs... Are customer needs satisfied? Does presented information add value to the operation? Are procedures in place to ensure adequate response to critical information? Are recipients proficient in the use of seismic information? Are legal requirements being met?

On Quality:
Quality is the totality of features and characteristics of a service or product that bear on its ability to satisfy stated or implied needs. (ISO 8402, 1986)

This definition implies that quality should be judged in relation to a defined requirement, i.e. relative to expectations and needs, but not in absolute terms.

Seismic Service Audits

The quality of raw seismograms is determined mainly by low noise levels and clear P- and S-arrivals, each with a steep rise and a complete waveform. The sampling frequency must be sufficiently high to accurately represent the recorded ground motion.

In the example seismogram, both wave arrivals are clearly visible and are well separated. The seismogram is complete, but the noise lelel in the red component is too high.

Score card:
Research initiated by the Mine Health and Safety Council (project SIM050302) produced a score card for mines to assess the compliance with accepted guidelines for seismic system design and operation.

more...

Seismic Monitoring Score Card

System design according to monitoring objectives
30%
  1. Mine subdivided into zones of varying seismic hazard.
  2. Monitoring objectives defined per hazard district.
  3. Monitoring objectives translated into required network performance.
  4. Network design according to desired performance (within constraints of access).
  5. Network installed according to design.
  6. Calibration blasts carried out for velocity model and location accuracy.
  7. Motivation and design process documented.
 
Seismic system operation and data collection
40%
  1. Station days lost below 20% for past year, no deterioration over time.
  2. 80% of sensors fully functional (stable over time).
  3. Adequate resources for system maintenance and upgrade.
  4. Seismic raw data are quality controlled.
  5. Minimum of 5 stations per event, 8 picks, 8 spectra.
  6. Data back-up procedures in place.
  7. Magnitude relation adjusted to CGS catalogue; time base calibrated.
  8. System operation & maintenance procedures documented.
  9. Annual review performed (internal or external)
 
Seismic data analysis procedures
30%
  1. Emergency event location.
  2. Back-analysis of large events.
  3. Short-term seismic hazard procedure(s).
  4. Medium-term seismic hazard procedure(s).
  5. Long-term seismic hazard procedure(s).
  6. Exchange of information with other disciplines (production, geology, rock engineering, safety)
  7. Needs of recipients of seismic information assessed.
  8. Written procedures for communication, roles and responsibilities adopted.
  9. Performance of methods assessed; improvements planned and implemented.
  10. 2-3 yearly review of procedures (external); results documented.
 

[After: SIM050302 Progress report, Phase 2, Output 3, SIMRAC 2006]