An automated 3D tracking technique, Govender et al. (2000), is employed to study the motion of particles deep within the tumbling ball charge of an experimental grinding mill. A Biplanar Angioscope, coupled with a fully automated imaging technique, accurately locates the 3D coordinates of the particles anywhere in the mill. Particle trajectories for five speeds, ranging from 55 to 85 percent critical, two lifter profiles, 90 degree and curved, and a range of tracked-particle sizes and densities were used in the experimental work. The final 3D coordinates of the tracked particle trajectories are accurate to within 0.2 mm. With an average of 32 circulations per run, the data can be used for rigorous and accurate verification in the numerical modelling of the rumbling ball motion in mills.