There is no honest single fuel number for a drilling rig
Fuel use changes with drilling method, engine and emission version, rock or soil, hole diameter, depth, bit condition, compressor load, hydraulic demand, operator behavior, idle time, altitude and ambient temperature. A seller can report a real number from one job and still give you a misleading forecast for another.
The useful question is not only liters per hour. It is fuel per accepted unit of production under recorded conditions: liters per drilled meter, per completed hole or per pile. Hourly fuel remains useful for budgeting, but it must be paired with output and idle time.
Choose a denominator that matches the work
For surface blast-hole rigs, record liters per drilled meter and per accepted hole, including collaring and rod changes. For rotary piling rigs, record liters per completed bore or per working hour along with diameter, depth, geology, casing and spoil-handling delays. For compressors, separate loaded and unloaded time.
Also record non-drilling fuel. Warm-up, tramming, setup, idling while waiting for support equipment and cleaning contribute to the daily bill. A machine that is efficient while drilling can still waste fuel through long idle periods or poor cycle coordination.
Run a controlled pre-purchase fuel test
Use a measured refill-to-refill method or a calibrated temporary supply where safe and permitted. Record starting fuel level, test duration, engine hours, work performed and ending refill quantity. Keep the video continuous around the measurements and show the instrument or container clearly. Do not rely only on a dashboard average that cannot be reconciled.
