Background
Hydropower development in southwest China is a key part of the national west-to-east power transmission programme. These projects lie in high mountain gorges, with dam foundations, slope support and underground caverns under way at once — scattered faces and heavy air demand call for a flexible supply plan.
Challenge
A large project with dam foundation, slopes and underground caverns worked simultaneously; total air demand was high and units had to move frequently as faces advanced.
Solution
Nine electric portable units form the core in two sizes: two 250 kW units for concentrated high-flow demand and seven 185 kW units spread across the faces to supply locally and cut long-hose losses. Early faces and temporary points without grid power are supplemented by CM260-21/18-24/14 dual-duty diesel units. All underground faces use electric units, so there is no exhaust.
Results
Supplying each face locally shortened hoses and reduced pressure loss; the main electric units run on the site grid, with diesel used only by a few supplementary units and no exhaust in the caverns; electric and diesel units are all KayDrill M Series, so operation and maintenance are the same. The units ran steadily through the main dam and cavern works.
