In the Copiapó Valley, Chile, copper mining companies generate fine tailings classified as massive environmental liabilities. Without proper mitigation measures, this waste can be carried by wind or water runoff. A useful mitigation technique is phytoremediation, using plants with high bioabsorbent performance of heavy metals. In the environment of a copper tailings deposit, the bioabsorbent potential of copper, arsenic and mercury of the wild plants Arundo donax and Equisetum gigantea inhabiting the banks of the Copiapó River in Elisa de Bordos was determined. Plant foliage was sampled for 10 months and the concentration of copper, arsenic and mercury was determined. Wild plants showed a significant bioaccumulation capacity of these heavy metals, present in fine mining tailings, making them suitable phytoremediation and environmental indicators of heavy metals. In the field of engineering project, this information is crucial for the design and implementation of environmental remediation strategies. The identification of wild plant species with phytoremediation potential can be part of an engineering approach to restore areas contaminated by heavy metals. Keywords: Phytoremediation; bioabsorption; heavy metals; mining environmental liabilities.