Longwall operations implement PDRRs to realise safety and productivity benefits. PDRRs involve:
- Development of an additional roadway (single or double pass) at the LW take off
- Installation of secondary support and pressure rated shutters along the roadway and affected intersections
- Fully backfilling the PDRR with a specifically designed low strength cementitious grout delivered via borehole/s.
- LW shearing into the grout filled PDRR at close to full production rates and is recovered from within the supported roadway.
The advantages of a PDRR are;
- Reduce personnel exposure to bolting unsupported ground
- Faster LW critical approach
- Quicker recovery time
- Achieve PIC at an accelerated rate
- Increases production up to 10-20 days
- Advantages & mitigation strategies for weak roof & floor recoveries
For more information, see the 2016 paper “The Evolution of Pre-driven Recovery Roadways at Crinum Mine”.Over 100 full or partial pre-driven recovery roads have been used in the US, Australian and South African underground coal mines (Thomas, 2008). In every case of recorded failure, standing supports were utilised. There are no recordings of a failed grout filled PDRR.
OUR past Pre-Driven Recovery Roadways JOBs
Grosvenor, Anglo American
Contract award for pre-driven recovery roadway PDRR LW104 and 106....
Appin, BHP
Pre-driven Recovery roadways PDRR LW705 and LW706 were made by...
Crinum, BHP
Pre-driven Recovery roadways PDRR LW21, 22, 23 and 24 from...
Broadmeadow, BHP
Southern Mains were previously mined roadways but then mine plans...
