This paper will describe the methodology and procedures that were followed to measure and verify the impact on the electricity use of a lighting load reduction project implemented at a gold mine. The lighting retrofit was concentrated on the 100 level and 100 incline of the gold mine. Since the lights were underground, it was operational for 24 hours each day. The proposed project activity aimed to reduce the electric demand of the lighting system by replacing the current types of lighting fixtures with more energy efficient units.The possibility existed to reduce the lighting load by 157 kW. These impacts needed to be assessed in order to verify the DSM impacts and savings for the client, the ESCO and Eskom. Pre-implementation metering was done in order to determine the operational and installed capacity of the original lighting system. Together with the number of lights affected by this project activity and the 24-hour operational profile, this data defined the baseline electricity use of the project. The same metering techniques and layout have been used after implementation to determine the new installed and operational capacity of the new lighting system. This project achieved 99.36% of its contracted target of 157kW.