The Future of Economic Geology - Metals and Society: An Introduction to Economic Geology - page 146

number), La through to Nd, but the ionic clay deposits contain relatively high
concentrations of the heavy rare earths. China is therefore able to satisfy the
demand for all types of REE.
Evaluation of the future of REE mining requires that the short, intermediate and
long-term prospects are considered separately, and that a distinction be made
between the various types of rare earth elements. As can be seen in Table 6.1 ,
different applications require different REE. The majority of currently active
deposits, and those likely to come on stream in the next 5 years, produce light
REE (Fig. 6.2 ) and that, with the reopening of the Mountain Pass deposit and the
development of new deposits like Mt Weld in Australia, global demand for
elements these will soon be satisfied. In contrast, the only major source of the
heavy REE (Gd through to Lu) that is currently exploited is the Chinese ionic clay
deposits. The newly discovered Kvanefjeld deposits in Greenland contain large
amounts of heavy REE, but no realistic estimates see this deposit coming on stream
within the next 5-10 years. During this period, there will be a shortfall of these
elements and the opportunity for the sole major supplier to control, if not distort, the
global market.
Box 6.1 Rocks and Minerals of the Ilimaussaq Intrusion, Host
of the Kvanefjeld REE Deposit
There is something about alkaline intrusions that brings out the worst of
petrologists and mineralogists. These intrusions contain high abundances of
incompatible elements (those elements that become highly concentrated in
late-stage silicate liquids) and these elements crystallize as a vast array of
obscure minerals. Unlike chemists, who long ago developed a logical and
systematic way of naming chemical compounds, mineralogists continue to
assign a new name to each newly discovered mineral; and in parallel
petrologists assign a new rock name to each assemblage of obscure minerals.
The following table lists, for example, a selection of the names assigned to
rocks and minerals in the Ilimaussaq Intrusion in Greenland.
Rocks
Naujaite, lujavrite, kakortokite, foyaite as well as more common syenites and
granites.
Minerals
Ilimaussaq is the type locality of about 30 minerals. Here is a partial list of 55
of the ca. 200 minerals that have been identified in the intrusion, distinguished
because they fluoresce in ultraviolet light.