This study investigates the effects of incorporating iron ore tailings in their raw (as-received) state as a partial substitute for natural sand and stone powder in the production of interlocking concrete blocks. The research aims to evaluate the technical viability and environmental benefits of utilizing this mining residue as an alternative fine aggregate. Granulometric analyses were conducted to determine the compatibility of the tailings with standard grading curves recommended by Brazilian technical norms. Experimental concrete mixes were formulated with varying replacement percentages (6%, 13%, and 20%) of the tailings, and corresponding curves were compared to reference limits for block production. The results demonstrated that the inclusion of iron ore tailings from 6% up to 20% maintained the granulometric conformity necessary for non-structural concrete block fabrication and testing the bloc's compression resistence for 30 days as brazilian normatives indicate . This approach offers a sustainable and cost-effective solution by valorizing mining waste and reducing the demand for virgin raw materials.