Sahupala, HA, Szwedzicki, T & Prasetyo, R 2010, 'Diameter of a draw zone — a case study from a block caving mine, Deep Ore Zone, PT Freeport Indonesia', in Y Potvin (ed.), Caving 2010: Proceedings of the Second International Symposium on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, pp. 633-644, https://doi.org/10.36487/ACG_rep/1002_44_Szwedzicki
(https://papers.acg.uwa.edu.au/p/1002_44_Szwedzicki/)
Abstract: On the extraction level of the Deep Ore Zone (DOZ) Mine, PT Freeport, Indonesia, a tyre marker, and tramp material such as support elements, drilling accessories and a steel feeder reported to the drawpoints. The marker and the tramp material migrated from the Intermediate Ore Zone (IOZ) block caving mine, which was located 320 m above. The material started to report after a draw of 20,000–150,000 tonnes.

On assumptions of a cylindrical draw zone and on mass movement within the zone, the draw zone diameter was calculated. For 28 case studies of marker and tramp material movement the diameter of the draw zone was from 6.3–14.6 m, with an average diameter being about 12 m. In one case, the calculated diameter of the zone was only 6.3 m indicating that void diffusion mechanism could take place. It was concluded that the diameter of draw zones increased with tonnage drawn but the diameter was not related to the rate of draw.