Paine, R, James, G & Ruiz-Tagle, JP 2022, 'Managing seismic events through demarcation zones at a large block cave mine', in Y Potvin (ed.), Caving 2022: Proceedings of the Fifth International Conference on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, pp. 1423-1430, https://doi.org/10.36487/ACG_repo/2205_99 (https://papers.acg.uwa.edu.au/p/2205_99_Paine/) Abstract: In 2017, a very large seismic event generated a significant amount of damage and dust throughout a largescale block cave operation in Indonesia. It was then thought that a visual alert and evacuation system may improve the safety of underground personnel, with the initial idea being inspired by airplane emergency exit strip lighting. With the demand for safer mining operations, the mine owners began to search for an existing off-the-shelf system that the mining sector could possibly utilise. The initial scope for this emergency/evacuation system was that it needed to be able to provide real-time demarcation of where it was safe or unsafe to be inside the cave footprint, at any point in time. And then to be able to trigger real-time emergencies and evacuation events. This required multiple-light colours (red/blue/amber/green/white) combined with synchronised flashing and chasing modes. This system requires a centralised software control platform; and ultimately, to be able to be automatically triggered by the mine’s microseismic monitoring system or people on site in case of major events. The system will also be combined with the existing radio communication infrastructure in the mine, to have a redundant verification system between the control room and underground shift. Various LED strip lighting technologies were trialled and ultimately found not to be suitable. Total cost per meter versus features was big concern as the supporting devices required to reach the defined requirements. IoT Automation was then approached to design and develop such a system that would be suitable for an underground block cave mining environment and with features to have a cost effective and operational based solution, with the FireFly smart lighting system being the result. In 2018, the system was initially deployed into just one of the panels in a key production block of the mines extraction level, with encouraging results. Subsequent modifications to both the hardware and software of the system throughout 2019, including the use of the system as a network link for geotechnical instrumentation, RFID tag detection (pedestrians and mobile equipment) and software integration with microseismic and ventilation monitoring systems – resulted in approval to expand the system into all production block areas of the mine. This paper details the planning, design, initial rollout, feature development, and expansion of the FireFly smart lighting system at this large-scale underground caving mine. Keywords: instrumentation, seismicity, safety, automation, iot