Stability In Surface Mining
Transsitional condition data are available to suport contension that many, if not most,ecomicallly ,significant failures began life as regressive and because of varied elements became progresive. This situation,which is describleb y displacement curve. Led to the formula for failure prediction relies upon character zavodni and broadbent (1980) . The Prediction radies upon characteristic and relation ship of regresisive phase and the "onset of failure"point in the time histori of the failure.
The transitional condition failures are significant because type 1 structural contion are ofthen controled or the highly unstable type 2 condition fails immediately during construction but,trasiotional condition require extensive engineering, control, protection, and reconstuction.
Type 3 regressive/progressive condition-topling or wedge induced "(calder and blackwell,1980) failures would be characteristic of type 3 structural condition . These types are unique and have highly varied characteristic . they can be regressive , particularly in the caseof wedge induced instability, or progressive as typified by domino-type falls referred to as toppling. we might say type 3 condition ere uncharacteristic and demand intensive study and analysis if sensible inprovment is to beachieved.
Examples of Structural types
The exsampe chose to illustrate a type 1 structure is the mineral creek failure which occured in 1971. The kinematics of this failure were reported by broadbent and ko (1971) at whichtime it was show that displacement occured in cycles roughly related to peaks of pit blasting activity . Figure 3 is across section of this failure. The mean structure di is less than the slope angle and less than the effective strength of the stucture. because a<beta .
The transitional condition failures are significant because type 1 structural contion are ofthen controled or the highly unstable type 2 condition fails immediately during construction but,trasiotional condition require extensive engineering, control, protection, and reconstuction.
Type 3 regressive/progressive condition-topling or wedge induced "(calder and blackwell,1980) failures would be characteristic of type 3 structural condition . These types are unique and have highly varied characteristic . they can be regressive , particularly in the caseof wedge induced instability, or progressive as typified by domino-type falls referred to as toppling. we might say type 3 condition ere uncharacteristic and demand intensive study and analysis if sensible inprovment is to beachieved.
Examples of Structural types
The exsampe chose to illustrate a type 1 structure is the mineral creek failure which occured in 1971. The kinematics of this failure were reported by broadbent and ko (1971) at whichtime it was show that displacement occured in cycles roughly related to peaks of pit blasting activity . Figure 3 is across section of this failure. The mean structure di is less than the slope angle and less than the effective strength of the stucture. because a<beta .
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