Compressed Air is one of the most convenient yet most expensive utilities in underground coal mining. Used for mine de-watering, stone-dusting, cleaning, ventilation and operation of mining equipment, compressed air is an essential and safe source of energy underground. Centennial Coal, one of Australia’s leading coal producers, used a comprehensive Measurement & Verification Audit to determine electricity savings achievable by replacing two single stage compressors having reached the end of their technical life with one modern two stage compressor. To determine savings the actual efficiency of the old compressors was measured over a one week period providing the baseline for an assessment of the improvement potential. Once the new compressor was commissioned, power consumption of all compressors was metered to determine overall savings.