Analysis was conducted of initial particle size in the slurry lift tank on a weekly basis (see Fig. 4). A Kruskal–Wallis test concludes significant variance between weekly samplings of acid and base slurry lift tanks, indicating that the incident material varies significantly on a weekly basis, and no internal mechanism results in mass-transfer to generate uniform size distribution. Thus, each week's samples require individual analysis in order to determine if significant trends in particle
size or other filtering effects exist.