Recycling Solutions - Thanatia: The Destiny of the Earth's Mineral Resources - page 447

As explained before, urban (or technospheric) mining is gaining importance
as ore grades of natural deposits decline to such an extent that extraction from
waste becomes more cost effective than taking them from mines directly. Hence,
metal and material dispersion acquires a new dimension. Dispersion should not be
solely assessed as the exergy replacement cost from Thanatia to Nature's mines, as
shown in Chap. 12, but rather from Thanatia to both, Nature's and Man's urban
mines. Indeed, if one analyses where a metal in a landfill lies in the “Exergy cost
vs concentration curves”, one realises that it is less energy intensive and thus easier
to extract directly from Nature than to salvage most dopants and non-recoverable
precious metals from the urban mine (here referred to the specific case of landfills
— see Fig. 14.6).

Conventional mining

Exergy cost, kWh

Urban mining

x Thanatia x landfill x mine

Fig. 14.6 Landfill concentration and energy required for the extraction of most scarce doping
metals in both urban and conventional mining

That said, the advantage of the urban mining is that society may change its
concentration with regulation, technology, education and lifestyle alteration which
could go on to facilitate more e cient recycling. In contrast, as Man doesn't create
natural mines he has no influence on their original concentration but rather can
only learn to better exploit them. Urban mining is thus not a “nice” metaphor but
a real need, with urban mine beneficiation and urban metallurgy urgently requiring
further development. In this respect, not only technology but also regulation, social
aspects and markets will have a decisive role (van Passel et al., 2013). Particularly,
the elaboration of new techniques and databases containing information on flows
and stocks of materials able to identify available resources and their suitability for
recovery will become critical (Paap et al., 2010; Brunner, 2011). Legislation could
also constitute an important obstacle. As pointed out by Johansson et al. (2013),