این منبع از بخش «High Confidence اولیه» مرحله 11A پذیرفته شد. سطح C و امتیاز 70 بر اساس پروتکل ارتباط با مس، معدن، مواد معدنی حیاتی و مدیریت/سیاستگذاری معدن تعیین شد. دلیل پذیرش: ریسک فرونشست در معدن لوبامبه؛ پشتیبان عملیات و ریسک.
چکیده انگلیسی
Lubambe copper mine is an underground operation with a thin orebody of width ranging between approximately 5-5.5m. Between May 2020 and 2021 the mine experienced a total of six sink holes which were all sudden without giving prior indication of subsidence. The mining subsidence has led to increased mining cost and cycle times due to the closure of 182 ml decline on the eastern limb and 175 ml truck route on the southern limb and disturbance on surface infrastructure. The main purpose of this study is to investigate the causes and effects of sinkholes on mining operations and surface infrastructure. Geotechnical empirical and numerical analysis of the ground, core logging, review of rock mass characterisation and evaluation of mining practices were undertaken. The mapping data was analysed using dips, Unwedge and RS3 software. It has been established that the east limb sinkholes were developed after a catastrophic failure at R3. 82 mL decline which affected a lateral stretch of approximately 50m. The first sinkhole on the southern limb was developed after a blast at Ramp 2.325 mL tips and the second was formed after a fall of ground at Ramp 2.372 ml. Empirical analysis for rock mass classification using the Q-system and RQD showed that the ground condition on the south and east limbs were poor to fair. The sinkholes development on surface are as a result of the sill pillar failures from historical and current mining operations cascading from one level to another and creating hanging wall instability as the ground unravels to fill the voids.
