Slurry commissioning of the Carrapateena copper concentrator began in Q4 2019, with first concentrate produced in December of that year (Reinhold et al, 2023) and nameplate throughput capacity of 500 t/h achieved in Q1, 2020. Having achieved the nameplate capacity, site personnel worked through a comprehensive sequence of operational improvements to debottleneck the plant towards 700 t/h. Carrapateena engaged Hatch to support the grinding circuit improvement activities, including planning and analysis of a full grinding survey, the subsequent development of a site-specific model of the SABC circuit, and the investigation and validation of opportunities for increasing throughput rates. Hatch were also requested to review the semi-autogenous grinding (SAG) and ball mill lifter and liner designs in consultation with the manufacturer, with a view to optimising the designs for the conditions in the Carrapateena circuit. The project identified various opportunities to increase throughput, including via increasing power utilisation, optimising SAG parameters such as mill filling, ball load and mill speed, and increasing pebble production rates via optimisation of the grate and pulp lifter designs. Optimisation of the shell lifter and liner designs for both the SAG and ball mill was also identified as an opportunity to provide improved process and maintenance performance. These initiatives were implemented by the site team, and in combination with the other debottlenecking activities outside of the grinding circuit, the new target peak throughput of 775 t/h (55 per cent increase) has been achieved. The work highlights the synergy of process simulation and detailed lifter-liner studies to provide not only an optimal solution but also allow streamlined implementation. Following the successful implementation of the recommendations, Hatch was then requested to support the site via analysis and evaluation of existing concepts for possible plant upgrade options to allow throughputs above 1000 t/h. This paper provides an overview of the journey of the Carrapateena grinding circuit to date – from commissioning, through ramp-up and optimisation – as well as the pathway for future expansion.