In this study, aided phytoextraction was tested as a soil remediation strategy in an abandoned Pb/Zn mining site in north-western Spain. The Cd/Zn hyperaccumulator Noccaea caerulescens was grown alone or intercropped with the legume Lotus corniculatus on mine tailings, with and without compost amendment. Compost improved soil chemical and biochemical properties—enhancing organic matter, nutrient content and enzyme activity—while reducing metal availability and boosting plant growth. After 1.5 years, total soil metal concentrations remained unchanged, but extractable Zn decreased in plots with N. caerulescens. Intercropping significantly increased metal uptake in the hyperaccumulator. Establishing plant cover was essential to maintain the improvements induced by compost over time, highlighting the potential of combining organic amendments and strategic planting to restore degraded mining soils.