| JULY 19,
2002
ENCOURAGING
RESULTS FROM PRELIMINARY ORE FLOTATION TESTS AT TERTIARY'S GHURAYYAH
TANTALUM PROJECT
··Optimisation Expected To Improve Both Recovery And
Grade
· Results Indicate Coarser Grind Of Ore May Also Be Possible
· Assays Awaited From Sampling Of Additional Pegmatites At Rosendal
AIM-listed Tertiary Minerals plc says that encouraging results have
been returned from preliminary mineralogical and metallurgical tests
on ore samples from its Ghurayyah project in Saudi Arabia, reported
to be the world's largest single deposit of tantalum. Tertiary holds
a five-year exclusive exploration licence over Ghurayyah.
In its end-June quarterly the company reports that a 50-fold upgrade
of tantalum and niobium levels at acceptable recovery levels was
achieved by conventional flotation and magnetic separation. Optimisation
of process parameters is expected significantly to improve on both
grades and recoveries, it adds.
The programme of characterisation and mineral processing testwork
on samples from archived Ghurayyah drill core is being undertaken
by Lakefield Research laboratories in Canada with input from Tertiary's
consulting metallurgist, St Barbara Consulting of the UK.
Tertiary says that the major part of the planned testwork remains
to be completed but the programme is on target and initial results
are encouraging. Work to date has concentrated on the processing
characteristics of the Ghurayyah mineralisation and has included
gravity, magnetic and flotation separation.
It also included mineralogical examination of the ore to identify
the tantalum and niobium bearing minerals. Significantly, testwork
has suggested these minerals might be liberated from the rock at
a more favourable, coarser grind size than was initially expected.
The results of preliminary tests using the industry-standard flotation
technique suggest that commercially acceptable recoveries if tantalum
and niobium may be achieved using this technique, says Tertiary.
Magnetic separation was used to remove most of the contained zircon
from the flotation concentrate to give a preliminary concentrate
grading approximately 13p.c. combined niobium and tantalum.
The Ghurayyah deposit contains an estimated Inferred Mineral Resource
of 385m tonnes grading 245g/t tantalum pentoxide, 2,840g/t niobium
pentoxide and 8,915g/t zirconium oxide. It is amenable to low-cost
open pit mining and is characterised by a remarkable consistency
of grade and distribution of mineralisation.
Meanwhile, the results of the Phase 1 drilling carried out as part
of the pre-feasibility study on the company's other tantalum project,
the more modest-scale Rosendal property in Finland, were released
during the quarter. The objective of this programme was to infill
and extend the tantalum mineralised pegmatite previously explored
by the Geological Survey of Finland (GTK).
The outcome was to raise the weighted average grade of drill intersections
to 346g/t tantalum pentoxide, 77p.c. higher than the equivalent
grade from previous GTK drilling. Tertiary believes this increase,
at least in part, reflects the collection and assaying of larger
drill samples compared with those of the earlier GTK programme.
The Tertiary programme also extended the drill-tested strike length
of the main Rosendal pegmatite to 500m from 200m. It remains open
along strike in both directions and at depth. The results of the
Phase 1 drilling and prospecting will now be included in a revised
resource estimate as part of the development pre-feasibility study.
During the quarter, Tertiary also mapped a number of additional
pegmatite dykes at Rosendal. These range from 1m to 13m in width
and some contain visible tantalum mineralisation. A sampling programme
to assess the additional resource potential has been completed and
assay results are awaited.
Elsewhere, Tertiary is planning a four hole diamond drilling programme
as an initial test of the Gallujavri prospect in the Finnmark district
of northern Finland and is currently awaiting various access permissions
and clearances. This is a platinum group metals prospect associated
with a zone of outcropping low-grade nickel-copper mineralisation
where previous sampling returned values of 2.5g/t platinum, palladium
and gold.
Further Information: Patrick Cheetham, Tertiary Minerals Plc. Tel:
01625-626203.
Ron Marshman/John Greenhalgh, City of London PR Ltd. Tel: 020-7628-5518
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