Influence of Pre-Existing Mobilized Zones on B3 Cave Propagation and Initial Subsidence at the New Afton Mine
Author: Kevin Davenport1, Corey Kamp2
Conference: 9th International Mass Mining Conference and Exhibition
Date: September 15-19, 2024
1 Knight Piésold Ltd., Canada
2 New Gold Inc., Canada Canada
ABSTRACT
New Gold’s New Afton Mine is an operating gold-copper block cave mine located 10 km west of Kamloops, British Columbia, Canada. Block 3 (B3) mining was initiated in June 2021 and comprised New Afton’s second lift, located approximately 750 metres below ground and partially beneath the previously mined Lift 1 West Cave (600 m below ground). B3 cave propagation resulted in mobilization of the overlying Lift 1 extraction level and existing muckpile, with increasing subsidence observed on surface. The timing and extent of B3 cave progression and initial subsidence expression are interpreted to have been significantly influenced by pre-existence of broken, mobilized material within the overlying West Cave muckpile and its associated subsidence zone. Initial minor subsidence deformations from B3 mining were observed throughout the existing West Cave subsidence zone as the B3 cave initially yielded an intact orebody region adjacent to West Cave, resulting in limited remobilization of the West Cave muckpile along its westernmost boundary. More significant, accelerating surface deformations were observed as the B3 caved zone fully-mobilized the Lift 1 extraction level and the overlying West Cave muckpile.
State-of-the-art block cave and subsidence monitoring programs have been implemented at New Afton to track cave propagation and subsidence progression in response to mining, including towards critical surface infrastructure. This paper summarizes observed B3 cave propagation and initial subsidence manifestation, using examples from the available instrumentation and monitoring techniques. Application of each monitoring technique to observation-based interpretation of the conceptual B3 block cave (i.e., seismogenic, yielded, and caved zones) and subsidence zone (i.e., crater, fractured, and continuous zones) subcomponents is also presented.
REFERENCE
Davenport, K., & Kamp, C., Influence of Pre-Existing Mobilized Zones on B3 Cave Propagation and Initial Subsidence at the New Afton Mine, in Johansson, D., & Schunnesson, H. (Eds.). (2024). Proceedings of the 9th International Conference and Exhibition on Mass Mining, MassMin 2024. pp. 1239-1254, https://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-110088
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