Research on the heavy sands of the floodplain of the River Zambezi (Republic of Mozambique). Mining potential and economic evaluation.

In the last decades, the demand for raw materials, such as Heavy Metals (HM) and Rare Earth Elements (REE) is constantly grown due to the increasing demand from the new technologies. In particular, the REEs are mainly concentrated in apatite and zircon, largely present in pre-Paleozoic and Paleozoic cratonic rocks. Although many countries, such as Brazil, China and Iran have important deposits of HM and REE, they may only partially satisfy the increasing technology market demand. At present, extraction possibility is decreasing, and it is important to find new exploitable zones. For these reasons, mineral industries prefer to invest in exploration licenses before the mining activity.

Mozambique has a large and diverse mineral resource potential and is one of the most important exporting nations of raw materials.  Between 2009-2017 ENEA (National Agency for New Technology, Energy and Sustainable Economic Development) in collaboration with the University of Ferrara carried out explorative research to verify the presence of raw strategic materials in the Republic of Mozambique.

This research aims to investigate the sediments from the placer deposits of the Zambezi River in order to elaborate on the basis of analytical data an environmental friend extractive plan for mining activities that take into account also the environment and its preservation. The placer deposits are due to the mechanical agent, like marine, aeolian or lacustrine where minerals with high density and hardness, such as HM, are in high concentration, together with more than one economic mineral. The alluvial plain of the Zambesi River is characterized by the presence of sands, which contain heavy minerals in a percentage comprised of between 10-30%. A wide number of geochemical and mineralogical analyses (Diffractometry, XRF and ICP-MS) has been performed on samples, taken along 200 km of the river course. These data show a good presence of precious elements (Au, Ag, Pt, Pd, Os and Rh), a strong presence of minerals containing Fe and Ti, Zr, Hf and subordinately Ta, Ni and others. Moreover, Rare Earth Elements are present, in particular, is evident a good presence of Sc and Y from an economical point of view.