The use as secondary raw materials (RMs) from marginal resources as industrial wastes, such as the WEEE (Waste Electronic Electrical Equipment) and the mining wastes, is of strategic importance for European industrial production, for economic and environmental reasons, due to their high concentration on valuable metals [1]. The availability of RMs is fundamental for the economy of the European countries and essential for maintaining and improving the standard of living of citizens. European Union (EU) is almost completely dependent by RMs. Several external countries have dominant supplies of RMs, mainly USA, Brazil and China. Ensuring access to certain RMs, is becoming a growing concern in the EU and around the world. RMs (i.e. gold, silver, copper, zinc, manganese and nickel) and critical raw materials (CRMs) (i.e. platinum, indium, cobalt, vanadium, magnesium, antimony, niobium and rare hearts such as scandium, yttrium and lantanoids), are essential for many industrial activities, for the application of emerging modern technologies and for the environment [2]. It is therefore important the development of environmentally friendly processes, to achieve RMs and CRMs of economic interest, by exploitation of the secondary RMs. The advancement of innovative bio-hydrometallurgical integrated circuit experimentally developed, compared with the conventional processes, is given by the lowest environmental impact and energy consumption and by the greater degree of purity of the valuable metals obtained: these sustainable technologies have been applied to the treatment and exploitation of mining tailings. Gold extraction by thiosulphate leaching represents an example of the application of these new processes: Au extraction of 80% was experimentally obtained after leaching, under ambient conditions of temperature; moreover, the overall process achieved about 70% Au recovery, this being in line with the conventional cyanidation process. These results are very encouraging, considering that this is a commercially innovative process, applied to a low gold content ore (from 1 to 3 g/t). The optimization of process parameters and operating conditions should permit the best results in terms of process yields to be achieved.