Background
High-speed railways in the western mountains often cut their formation into steep hillsides, bringing large amounts of high-slope anchoring work. Anchor holes are deep and numerous, rigs work from the slope face, and the compressor has to stay at the toe, sending air up tens of metres through a long hose.
Challenge
The cut slopes needed many bolt and cable-anchor holes, often 20–40 m deep. Rigs worked from scaffolding on the slope while the compressor stayed at the toe, so hoses were long, the height difference large and pressure loss significant; broken ground collapsed easily and needed casing, using a lot of air.
Solution
A dual-duty diesel unit: 31 m³/min at 25 bar for long hoses and big height differences to keep effective pressure at the bit, and 33 m³/min at 18 bar for hole cleaning and other auxiliary work, with air margin for hose length and casing.
Results
Steady supply with several rigs on the slope and smooth casing sections, keeping slope anchoring on schedule.
