This study investigates how thermal treatment up to 600 °C alters the physical, mechanical, and grindability properties of granite quarry waste materials, with a view to promoting their sustainable reuse. Seven representative wastes (R1–R7) from operating quarries in Türkiye were characterised through laboratory testing, and a conventional numerical integration approach was applied to quantify the thermal sensitivity of each property. Results show that no single waste material performed best across all rock properties, indicating that thermal pre-treatment must be application-specific and governed by the sensitivity of the property of interest. Grindability behaviour was assessed through Bond Work Index (BWI) tests and modelled using regression and soft-computing analyses. The study thus provides an experimental and computational decision framework, showing that thermal treatment can reduce the grinding energy demand of granite waste, while indicating that further investigation is needed to establish whether such treatment is economically advantageous prior to crushing and grinding.