The static column experiment was conducted to evaluate feasibility of lime cake by-product produced from the soda ash production (Solvay process) to neutralize the pyrophyllite mine wastes, which have discharged acid drainage to surrounding soil and stream in watershed. The pH of the mine wastes was strongly acidic at pH 3.67 containing over 16% of Al₂O₃ and 11% of Fe₂O₃. Whereas the lime cake by-product was strongly basic at pH 9.97 due to high contents of CaO, MgO and CaCl₂ as major components. The column packed with the wastes (control) was treated with the lime cake by-product, calcium carbonate, dressing soil or combination. The distilled water was eluted statically through each column and leachate was collected for the chemical analyses. Treatments of the mine wastes with the lime cake by-product (or calcium carbonate) as mixtures increased pH of the leachate from 3.5 ~ 4.0 to 7 ~ 8. Concentrations of Fe and Al in the leachate were also decreased below 1.0 mg/L. A similar result was observed in the combined treatments of the mine waste, the lime cake by-product (or calcium carbonate) and the dressing soil. Results indicated that lime cake by-product could be used as the remedial agents for the active treatment of mine wastes.