Abstract: A high-pressure liquid jet cutting system can include a hopper configured to contain an abrasive mixture that includes abrasive and an additive, and a cutting head configured to receive the abrasive mixture from the hopper and introduce the abrasive mixture into a high-pressure liquid jet. The system can further include a sensor configured to detect a characteristic of the abrasive mixture associated with the additive, and one or more processors operably connected to the sensor and configured to determine information about the abrasive based, at least in part, on the detected characteristic. The one or more processors can be configured to adjust or otherwise control operation of one or more components of the high-pressure liquid jet cutting system based, at least in part, on the information to, e.g., improve or optimize system performance.