Microseismic Monitoring Setup & Calibration Guide (PDF)

Microseismic monitoring detects and locates low-magnitude seismic events (typically −2 to 3 ML) generated by rock fracture and stress redistribution in mine walls, pillars, and stopes. Accurate setup and calibration are critical because errors in sensor geometry, clock drift, or velocity assumptions propagate directly into location uncertainties—often exceeding hundreds of meters if uncorrected. The guide emphasizes a systems-based approach: starting with site-specific geological and geomechanical characterization, followed by optimal array design (e.g., minimum 4–6 well-distributed sensors per monitoring volume), precise surveying of sensor positions (±5 cm spatial accuracy), and rigorous time-synchronization using GPS-disciplined oscillators or PTP (Precision Time Protocol). Calibration involves iterative refinement of the 1D or 3D P-wave (and optionally S-wave) velocity model using controlled-source tests (e.g., shot firings, hammer blows) and statistical residual analysis (e.g., RMS traveltime residuals < 10 ms). It also addresses environmental and operational noise mitigation—such as filtering out blast harmonics, conveyor vibrations, and pump cycles—through spectral analysis and adaptive thresholding. Finally, the guide outlines performance validation metrics, including detection threshold estimation, location repeatability testing, and blind calibration event analysis, ensuring long-term data integrity for hazard assessment and pillar stability management.