With much help from Ski:It is pretty much a mish-mash but the...

With much help from Ski:

It is pretty much a mish-mash but the earliest surviving sample record is Machado 1950 who took 15 samples ranging from 0.26% to 4,84% (REE+Th) with an average of 1.94%. The 1958 sampling only reports La 0.11% and Ce 0.87%. However this fits in very well with the initial samples from Coola and demonstrates that a significant upgrade is possible from a systematic drilling program as was recently performed at Longonjo.

It should be noted that back in those days La and Ce were the primary economic REE's in demand and of highest value; being essential for TV sets


Some snippets from City Views 2005 Report

5.2 History

The only historical reference to work carried out on the Longonjo Carbonatite is in a
book titled ‘Carbonatitos de Angola’ (in Portuguese). It refers to sampling carried out
by Companhia Mineira de Lobito in the 1950’s. Machado, 1958 states (referring to
the Longonjo Carbonatite), ‘rare-earth Cb-Th bearing minerals occur in the central
part of the ring structure – the radioactivity encountered is due to the Th of a yet
unidentified mineral’.

Some sampling results are also given, with apatite said to be abundant (8% P2O5 )
and one sample returning 26% barite. A table of results is shown below:
Soil (%) Rock (%)
ThO2 1.03 0.83
Nb2O5 0.24 0.25
Ce2O3 0.87 0.62
La2O3 0.11 0.09

In addition Machado (1950), quotes results of combined rare earth and thorium
oxides from 15 samples. The range in these samples is a high of 4.84% to a low of
0.26%, with an average of 1.94%. It is unclear whether these samples are from soils
or rock.


Results from 2005 Work.

Unfortunately, a large number of the samples were destroyed between the time the
samples were taken and their arrival at the lab (due to unsuitable bagging and
labelling in the field). This resulted in approximately 100 samples remaining for
analysis. Fortunately, however, these 100 samples provide a good representative
profile across the carbonantite.
For personal use only

The results from this initial soil sampling programme are very encouraging. In
particular, they show highly anomalous levels of the Rare Earth Elements (REE’s)
lanthanum and cerium. Results for lanthanum show a maximum of 10,357 ppm and
an average of 3,015ppm, whilst cerium shows a maximum of 18,484 ppm and an
average of 5,597 ppm.

All assay results were provided on a CD,