The fine fractions, typically defined as the material with particle sizes <60 mm to <10 mm depending on the case study, can account for 40-80 wt.% of the total excavated waste in (enhanced) landfill mining ((E)LFM). These fractions are frequently characterized by their high contents of water and problematic elements and compounds (i.e. organic and inorganic pollutants), which make them particularly challenging for conventional waste processing techniques. Hence, the fine fractions have been largely left out of the scope of waste-to-material (WtM) and waste-to-energy (WtE) valorization strategies in previous (E)LFM projects and, thus, they have been mostly disposed of back in the landfill: hindering the economic and environmental feasibility of those projects in a significant manner. Therefore, to address the challenge that the fine fractions pose to (E)LFM and unlock their potential for material and energy recovery is of critical importance. The present doctoral thesis was carried out at a landfill site in Mont-Saint-Guibert (MSG), Belgium. The fine fractions <90 mm of the MSG landfill accounted for 77 wt.% (in raw state) of the total processed landfill-mined waste and presented a median water content of 27 wt.%, and a median bulk density of 810 kg/m3. The results of this thesis demonstrate that the fine fractions <90 mm can be separated into combustible (9.0 wt.% DM), inert (37.2 wt.% DM) and soil-like (42.7 wt.% DM) fractions by means of dry mechanical processing in an effective and efficient manner, as well as that the these fractions can be a source of relevant amounts of ferrous (1.4 wt.% DM) and non-ferrous (0.3 wt.% DM) metals. The dry mechanical processing approach of the fine fractions 90-10 mm was performed in both the optimal water content (water content of 15 wt.%) and dry states, while the approach of the fine fractions <4.5 mm required to be carried out in dry state. The optimal water content state proved to be a successful way to significantly reduce material losses in the form of dust and fine-sized particles, without having a significant negative impact on the performance of the dry mechanical processing approach. The results of the laboratory analyses of the obtained combustible fractions show that these fractions complied with the specifications of the EN 15359:2011 and, thus, are suitable for WtE valorization in the EU. However, some samples of the combustible fractions exceeded the limit values for As, Cd, Co, Hg and Pb of the Austrian Waste Incineration Ordinance (AVV) and, hence, these fractions can only be incinerated in Austria. As for the recovered inert fractions, results unveil that in Austria these fractions would need further treatment in order to be valorized as a substitute for construction aggregates according to the Austrian Recycling Building Materials Ordinance (RBV), since they exceed the limit values for hydrocarbons, Cd, Pb, Zn, NH4+ and anionic surfactants in certain cases. In turn, the employed approach to the fine fractions <4.5 mm revealed that problematic pollutants (mainly TOC, Cd, Cu, Hg, Ni, Pb and Zn) cannot be sufficiently removed from the coarse particle size ranges (i.e. 4.5-1.6 mm and 1.6-0.5 mm) and concentrated in the finer ones (i.e. 0.5-0.18 mm and <0.18 mm) solely by means of particle size classification and surface cleaning processing steps. In general, the valorization/utilization of recovered materials through (E)LFM is not specifically included in existing regulations and, to this day, there are almost no overarching regulations applicable at EU level. Therefore, WtM and WtE valorization routes from the recovered fractions of the fine fractions of landfill-mined waste are strongly dependent on national and local regulations in the EU.