ac4u2nv
Geotechnical
- May 30, 2013
- 52
Dear all
Was rotary coring into good quality mudstone interbedded with siltsotne
And sandstone. Recovery dropped and then the water rose to almost ground level and started bubbling!
We thought we either hit a service but felt it was unlikely 5 m down into bedrock. Or we’d hit a void and this was releasing gas. Gas readings on monitor and PID all indicated 0 readings. After leaving it for a day the level has dropped to 1.6mbgl similar to nearby borehole level.
Any ideas what this could be?
No history of coal mining either in area
Was rotary coring into good quality mudstone interbedded with siltsotne
And sandstone. Recovery dropped and then the water rose to almost ground level and started bubbling!
We thought we either hit a service but felt it was unlikely 5 m down into bedrock. Or we’d hit a void and this was releasing gas. Gas readings on monitor and PID all indicated 0 readings. After leaving it for a day the level has dropped to 1.6mbgl similar to nearby borehole level.
Any ideas what this could be?
No history of coal mining either in area