Manufacture of lightweight prefabricated panels employing mine tailings

The present study describes the incorporation of mine tailings from the silver mine La Guitarra in the manufacture of lightweight prefabricated panels (LPPs). Tailings have concentrations of heavy metals below the maximum permissible levels according to Mexican regulations. Their acidity potential (AP) of 2.22 kg of CaCO₃ per tailings ton, along with their lack of neutralization potential (NP), indicates a possibility for the generation of acid mine drainage (AMD). It was reported that concrete could be employed to prevent AMD, thus we proposed to stabilize mine tailings with differ-ent concrete ratios and employ these mixtures to fabricate concrete panels. To obtain lightweight panels, a foaming agent was added to the tailings/concrete mixture. Then, a fiberglass mesh was employed to reinforce the final structure. The resulting LPPs (dimensions: 254 × 139.7 × 12.7 mm) showed a flexural strength of 5.80 ± 0.06 MPa, bulk density of 712 ± 104 kg/m³, thermal conductivity of 0.159 ± 0.004 W/m K, mass water absorption of 59 ± 10 %, and net neutralization potential (NNP = NP/AP) > 1.2. According to Mexican regulations, these LPPs are not potential generators of AMD.