This document discusses the determination of the Bond work index of limestone samples from Lucky Cement Limited in Pakistan. The Bond work index test involves grinding limestone samples in a ball mill and measuring the grindability over multiple cycles. Test results found that 6 of 7 limestone samples had a Bond work index over 20 kWh/t, qualifying them as "hard rock." However, one sample from Face-4A had a Bond work index under 20 kWh/t, indicating it was less energy intensive to grind and had higher grindability than the other samples. This study aims to help optimize energy efficiency in limestone grinding operations at Lucky Cement.