Background
Northeast China is a major iron-ore base, and bench drilling in its open pits runs almost all year. In winter, temperatures of -20 to -30 °C are the toughest test: oil thickens, batteries weaken, diesel waxes, and many compressors won't start in the morning while drill rigs stand idle.
Challenge
Winter lows approach -30 °C. The old units started poorly in the cold and needed long warm-ups, delaying the morning shift. Iron ore is dense and its cuttings heavy, needing more up-hole velocity than ordinary rock.
Solution
Two diesel units were matched to rigs of different hole sizes — the 400 HP unit for large bench holes and the 260 HP unit for small and medium holes. Both have the cold-start system and pre-heater, coolant rated for the local minimum, and flushing air sized up for dense cuttings.
Results
Warm-up waits on winter mornings were shortened so drilling starts on time, large holes flush cleanly, and jamming and re-crushing are reduced.
