  The lunar surface is extremely harsh and current mineral processing and metal
extraction technologies are not adequately equipped to address this
environment. In this paper we review the metals available for extraction and
conditions at the lunar surface, and analyse the challenges associated with
comminution, beneficiation, and metal extraction operations. The potential
beneficial effects of the natural lunar conditions are also evaluated. This
investigation concludes that process plant design on the lunar surface will
favour lightweight, schematically simple flow sheets that enable automation,
and that utilise the local environment wherever possible. The elimination of
traditional comminution and beneficiation stages and their replacement with
basic classification could be economically favourable. The most promising metal
reduction pathways are identified as molten regolith electrolysis, and vacuum
thermal dissociation, other processes with merit are hydrogen reduction,
carbothermal reduction, and solid electrolysis. Finally, it is identified that
a significant research effort in all areas of astrometallurgy will be required
before industrial-sized extra-terrestrial mineral processing and metal
extraction operations will be viable.
