資源開発技術／開発機械／岩盤工学

[3K0101-10-08] Analysis of seismicity at Mufulira Mine, Copperbelt Province, Zambia

○Pardon SINKALA¹, Masahiro NISHIHARA¹, Yoshiaki FUJII¹, Jun-ichi KODAMA¹, Daisuke FUKUDA¹, Ellan CHANDA² (1. Hokkaido University, 2. Mopani Copper Mines Plc, Mufulira)

司会：才ノ木 敦士（熊本大学）、羽柴 公博（東京大学）

Keywords:Rock mass, Microseismicity, Induced stress, Rockburst, Seismic monitoring system

Microseismicity and its associated rockburst damage constitute a great risk to underground mining operations at Mufulira mine. This mine is located in the Copperbelt province of Zambia, hosting sulphide orebodies, which are rich copper and cobalt mineralization. The rock units are metamorphic sedimentary rocks of the Neoproterozoic Katanga Supergroup. Mufulira mine has been in operation since 1933, mainly in copper production. Serious events of microseismicity and the associated rockburst damage began to be recorded at the mine since the inception of 1970s. In January, 2018, the mine recorded a seismic event of magnitude 2.8, which caused severe rockburst damage in the mining drive at a depth of 1440 meters below surface. The capacity to measure microseismic movements at Mufulira mine was first built in 1991, but the system had low efficiency in providing adequate quantitative parameters of seismic events. Therefore, in December 1994, an integrated seismic system (ISS) was purchased from South Africa and installed to record mining induced seismicity at Mufulira mine. The system deteriorated with time, but in 2006 the mine made efforts to update the system through the addition of new sensors. This paper analyzes microseismicity at Mufulira mine based on trends of seismic events from 2016 to 2018, and proposes possible remediation measures to seismic damages. The overall aim of this study is to provide knowledge for management's decisions to improve safety in seismic prone underground mines, so as to sustain production, and enhance consistent generation of revenue.