The influence of rock properties on mining technology of deep levels of Chibuluma East

Field and laboratory measurements of rock properties were conducted to investigate the behavior of rock masses at Chibuluma East deep levels. Intact rock strength was obtained by point load testing, Joint spacing, Joint condition, separation of Joints and the infilling materials were determined by scan line surveys. Groundwater conditions and rock quality designation were also investigated.
These properties are input parameters for an empirical derivation of the insitu rock mass strength from the geomechanics rock mass classification. Necessary adjustments are allowed to the insitu rock mass strenghth to arrive at the design rock mass strengthThe latter provides quantitative data for pillar design, rock support and for the selection of mining methods. The footwall Quartzite at Chibuluma East is a good competent rock. The Orebody Quartzite is generally of lower competency, and the intensity of jointing in this rock varies and may thus affect its competency. The Hangingwall Quartzite is also of lower competency and its strength is affected by leaching. The Hangingwall Conglomerate is extremely unstable and any break through it must be prevented. , it is recommended that Hangingwall Benching and in-stope Scraping method be adopted for the extraction of the Chibuluma East flat area deposit.