Table 11:
Classification of rockburst.
Rockburst level
A
B
C
D
Description
Slight
Moderate
Strong
Very strong
Duration
Sporadic explosion
Long duration
Fast
Sudden
Block depth (m)
<0.5
0.5-1.0
1.0-2.0
>2.0
Impact in excavation
Small
Certain impact
Reasonable impact
Large Impact