Talu, S, van As, A, Henry, R, Hilton, J & Whiteman, DS 2010, 'Installing Smart Markers to monitor Lift 2 North extension ore flow behaviour', in Y Potvin (ed.), Caving 2010: Proceedings of the Second International Symposium on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, pp. 623-631, https://doi.org/10.36487/ACG_rep/1002_43_Talu2 (https://papers.acg.uwa.edu.au/p/1002_43_Talu2/) Abstract: Numerous attempts have been made to study the mass flow of rock within block cave mines using markers installed in the uncaved cave rock mass. The markers are subsequently retrieved as they are recovered from drawpoints on the extraction level. The success of the markers has been questionable, largely due to their poor recovery, and hence most block or panel caving operations have been reluctant to seriously invest in flow monitoring on a large scale. As a result the flow monitoring employed (if any) comprises typically of ‘dumb’ markers in the form of old concrete filled tyres, concrete blocks and steel tubes, opportunistically scattered throughout the block. Recent advances in technology have led to the development and successful implementation of electronic ‘Smart Markers’, which, once loaded from a drawpoint, transmit their identity number and that of the loader to receivers on the extraction level. The marked improvement on the recovery of these markers over the old dumb markers allows for greater application of flow marker monitoring in cave mines, the results of which will undoubtedly improve our understanding of mass flow and assist in the calibration and validation of predictive flow models. This paper describes the successful trial of prototype Smart Markers at Northparkes Mines, the objectives of the trial being to test the recoveries and the ruggedness of the markers to withstand the internal forces within the moving ore column as they make their way from their initial position to the drawpoints below. It is Northparkes Mines’ vision to implement a full, mine-wide scale flow monitoring programme for their future caves, of which Smart Markers will form a major component.