This experimental study investigates the influence of silanized micro-size silicate-based minerals on mechanical, thermal, and rheological properties of wood (maple) polymer (high-density polyethylene) composites. The silicate-based minerals used in the experiments are prepared from mine tailings through the inertization process (acid leaching). Two different types of organo-functional silanes including vinyl-trimethoxy and amino-ethyl amino-propyl trimethoxy silanes (3%) are used to modify the mineral fillers. The different amounts of mineral fillers (1-5%) are added to the composites as wood filler replacement and while the composite properties are evaluated. The obtained results implicated that the addition of 1% silane modified minerals decreases the rigidity and increases the ductility (up to 25%) of wood polymer composite. Mineral fillers modified with vinyl-silane were more effective to improve both tensile and flexural strengths and less advantageous on rheological behaviour. Amine-modified minerals had no negative influence on rheological performance even if they significantly decreased the rigidity of composites. Both surface modified minerals improved the thermal stability of wood plastic composites. (C) 2016 Elsevier Ltd. All rights reserved.