Analysis of High Frequency Microseismicity Recorded at an Underground Hardrock Mine

Abstract

This research involved monitoring for high frequency (HF) microseismic activity, in the effective frequency range of 100 to 400 kHz, at an underground hardrock mine. An HF monitor was installed to record activity in and near a pillar at a depth of 2100 m near active mining stopes. Analysis of the recorded events was done in light of production blasting records, the mine-wide microseismic data set for events below a depth of 1800 m and laboratory studies conducted to assist with a general HF data analysis. Data analysis indicated that there were two types of periods of increased activity: the first associated with the passage of the direct seismic waves from the blast through the local area, and the second associated with the arrival of the transient stress change induced by the blast in the local area. Indications of locally increased stress levels towards the end of the monitoring period agreed with the occurrence of two nearby strong seismic events.

Characteristics and Disaster-Causing Mechanism Analysis of Large Variable Section Tunnel

“…According to the Saint Venan principle, the left and right sides of the finite element model are 5 times the tunnel width, and the elastoplastic model and the Mohr-Coulomb criterion are used [10][11][12] . Constrained horizontal displacement around the model, constrained vertical displacement at the bottom and a free boundary at the top.…”

Monitoring and Analysis of Historic Building Vibration Influenced by Blasting in Complex Urban Environment

“…Because the mutual influence of natural vibration frequency of buildings and blast vibration frequency, cause some unexpected damage ［1］ . Considering the mutual influence of vibration velocity and frequency, some countries laid down blasting vibration safety standard, such as blasting vibration safety standard DIN4150 of German [2,3] (shown in table 1), the safety standard promulgated by United States Bureau of Mines (USBM) and OSMRE [4] (shown in table 2), the blasting vibration safety criteria considered both particle vibration velocity and vibration frequency , which was clearly defined in Blasting Safety Regulation GB6722-2003 [5] (shown in table 3).…”

Emerging Technologies in Subsurface Monitoring of Petroleum Reservoirs

“…These laboratory measurements usually involve mounting the prepared core specimens in a pressure chamber to enable permeability and acoustic measurements at simulated in situ pressure conditions. However, current industry practice normally involves tests done under simulated overburden or hydrostatic pressures only, and recent works indicate that permeability under constant overburden pressure can vary significantly as lateral stress is varied [22][23][24][25]. Such lateral stress variations would be expected as a function of orientation in an anisotropic stress field and in response to production or stimulation procedures.…”