Authors: Claudio Vasquez, Andrei Chaura, Becky Rodriguez and David Romo
Presented at: Tailings 2026
Paper Abstract
Efficient water recovery and geotechnical stability in tailings dams currently represent two of the main challenges faced by modern mining operations. In operations where cycloned sands contain high proportions of fine particles, particularly lamellar phyllosilicates such as sericite and muscovite, significant drainage limitations arise due to low permeability and high capillary water retention. These conditions directly affect tailings consolidation rates, water recovery efficiency, and the quality of the material used for the walls construction in tailings storage facilities.
This study assess the effect of different chemical reagents on the drainage performance of cycloned sands obtained from an Andean copper porphyry operation through an extensive experimental program comprising approximately 500 drainage tests. Multiple reagent combinations were assessed, including variations in dosage, fines content, temperature, and representative operational conditions.
The results demonstrate that the combined use of Magnafloc and hydrated lime produces a significant improvement in drainage performance compared to the untreated condition. While the baseline sample exhibited drainage times exceeding 7 hours, the best evaluated conditions achieved drainage times in the range of 45–51 minutes using mixtures containing 30 g/t of Magnafloc and hydrated lime dosages between 75 and 250 g/t.
The synergy between chemical coagulation and polymeric flocculation reduces capillary water entrapment, improves the drainage grooves, and enhances gravitational water recovery. The findings indicate that the optimized use of chemical reagents can become an effective operational tool for improving the drainage performance of cycloned sands with high fines content.
These results highlight the importance of developing comprehensive characterization programs, laboratory testing campaigns, and chemical assessments aimed at addressing real operational challenges associated with tailings management, drainage performance, water recovery, and largescale tailings storage optimization.
BEngSc, BEd (Chemistry and Biology)
Claudio is a Project Engineer at Paterson & Cooke in Chile with over 20 years of overall experience in Research, Engineering, Education, and Administration, currently focused on mining project development, optimization of concentrator plants, and tailings dewatering.