Illawarra riverbed

The impact of subsidence from underground coal mining operations on surface environmental features such as rivers, cliffs and valleys is a subject of significant community concern.  Subsidence can cause damage to these features including rock cracking and rock falls, however these impacts can be minimised with various preventative and remediation techniques.

The application of impact prevention and minimisation techniques on an Illawarra riverbed by BHP Billiton’s Illawarra Coal is a successful case in point, involving the construction of an innovative stress-relieving vertical slot into a sandstone rock bar at Marhnyes Hole. Pattern grouting in the vicinity of Marnhyes Hole has also been successful in restoring surface flows and reducing pool drainage following fracturing of the riverbed.

 

 

 

 

 

 

Stress-relieving slot constructed prior to longwall mining

 

 

 

 

 

 

Marhnyes Hole