Latin American Mine Uses Microseismic to Mitigate Risks Related to Sublevel Caving
A Latin American mine was changing its mining method to sublevel caving. One of the main geotechnical risks inherent with this type of mining method is large uncontrolled caving events that can result in air blasts, posing risk to equipment and workers.
Sublevel caving requires careful monitoring of the developing cave front, which can be accomplished with a microseismic system. ESG’s microseismic monitoring system and advanced data analysis allow mine engineers to gain a deeper understanding of rock mass behaviour.
ESG’s continuous microseismic monitoring acts as an early-warning system for potential hazards caused by changing rock conditions. The insights gained from the system have in turn allowed the mine to develop an alert protocol, helping to protect staff and equipment, and reduce downtime.
Seismicity is common in mining operations as the rock reacts to blasting and extraction operations through redistributing stress, which results in micro fracturing. Consistent evaluation of seismic data on a routine basis serves as a crucial instrument to quantify and understand stress-induced rock mass behaviour.
A Latin American mine was changing their mining methods from sublevel stoping to sublevel caving. This mining method is meant to boost productivity but can also introduce new challenges. A microseismic monitoring solution was specified to help identify potential hazard areas, observe microseismicity patterns and obtain a full three-dimensional image of the caving front development in real time.
ESG installed a microseismic system comprised of uniaxial and triaxial geophone sensors, Paladin® digital recorders and Hyperion software suite. Once commissioned the ESG system immediately began to provide vital insights on rock mass response to mining operations, allowing users in the mine to gain a better understanding of the seismic response to mining operations. This understanding then served as a crucial component for mine personnel to develop an air blast safety protocol.
Microseismic monitoring has allowed the mine to mitigate risk in their daily operations. In May of 2017, the microseismic system showed abnormal seismicity and notified the onsite monitoring team to initiate the established alert protocol, prompting staff to take precautionary measures. Re-entry to the mine was allowed only after seismic activity returned to normal conditions. At post-event inspection, it was determined that a detachment of rock mass from the roof of the mine generated an air blast event. This caused minor damage to the mine’s ventilation system, rock slides and displacement of objects located in the sector that could have caused fatalities or injured the crew had they been onsite.