| October 23,
2002
TERTIARY TAKES MAJOR INITIATIVE IN
FINLAND TO SEARCH FOR OLYMPIC DAM STYLE IRON OXIDE-COPPER-GOLD DEPOSITS
- Eight
Large Targets Secured Under Claim And Claim Reservation
- Focus
On Known Iron Oxide Systems
- Joint
Venture Partner To Be Sought After Data Evaluation
AIM-listed
Tertiary Minerals plc has launched a major initiative to explore
in for Olympic Dam style iron oxide-copper-gold (IOCG) deposits
in Finland. The company says its move is partly based on the fact
that most Finnish iron ore deposits were discovered before Olympic
Dam. As a result, IOCG orebody models were not available, and the
broader potential of the Finnish iron oxide systems was perhaps
not fully recognised.
Award-winning
geologist Patrick Cheetham, who heads Tertiary, also says that past
exploration in Finland for iron oxide systems was based largely
on the use of airborne magnetics. This focused almost exclusively
on the magnetite-rich sections of the iron oxide systems, an approach
that would have missed the less magnetic haematite-rich systems
which are also prospective for copper and gold.
OLD DRILL CORE TO BE RE-LOGGED AND
SAMPLED
After several months of review work focused on known large iron
oxide mineralised systems in Finland, Tertiary has secured eight
targets, including former producing iron ore mines. It says it will
shortly begin detailed evaluation of the projects using information
from the well-developed geological, geophysical and geochemical
data bases of the Geological Survey of Finland. This will be followed
by re-logging and sampling of the extensive drill core that still
exists for many of the deposits, work that will extend through the
winter months. On completion of the data review assessment the company
will seek a joint venture partner to fund the further evaluation
of its IOCG projects.
Tertiary says that IOCG orebodies are typically large and represent
one of the most widely sought style of deposits in the world today.
A number of major mining companies, including Rio Tinto, Anglo American,
BHP Billiton and Phelps Dodge are actively exploring for such orebodies
in Sweden, a country in which two major IOCG deposits are in production.
These are Kiruna with over 1bn tonnes of iron ore, and Aitik with
more 300m tonnes of material averaging 0.4p.c. copper and 0.2g/t
gold.
Both are located in the Norbotten district of northern Sweden and,
although the prospective geology of this region extends across the
border into large areas of northern Finland, the latter has not
received the same exploration effort as its neighbour.
Historically, exploration and mining for iron ore in Finland was
dominated by single-purpose, State-owned companies who focused on
the most magnetic anomalies and overlooked the wider potential of
such features. Since the IOCG systems are commonly zoned, the most
intensive magnetic anomalies previously tested may not represent
the most prospective zones for copper and gold mineralisation. These
could easily remain hidden beneath the extensive glacial till cover
that blankets much of Finland, says Tertiary.
Five of the company’s eight targets are located in the Kolari
iron district, 200km north-west of Rovaniemi which is adjacent to
the Swedish border. These are:
Rautavaara where over
13 million tonnes of iron ore was produced between 1975 and 1988
and several million tonnes of open ended low grade copper mineralisation
was discovered along strike from the magnetite deposits.
Hannukainen where
several near surface contiguous stratabound ore bodies have resources
of several tens of millions of tonnes of iron ore and where open-pit
mining operations produced 4.6 million tonnes of ore grading 43%
iron, 0.9% copper and almost 1g/t gold from the adjoining Keuervaara
and Laurinoja ore bodies.
Taparova, a zone of
hematite mineralisation with IOCG characteristics estimated to contain
20 million tonnes of near surface iron mineralisation (43% iron).
Sivakkalehto, the
largest mineralised zone in the Kolari area with an estimated 200
million tonnes of magnetite mineralisation with under-evaluated
copper and gold potential.
Lauttaselkä a poorly explored zone of copper-gold-iron mineralisation
with multiple down hole drill intersections of typical IOCG grade
copper-gold mineralisation.
Other targets in Northern Finland include the Vähäjoki,
Palokiimanselkä
and Raajärvi
deposits.
Vähäjoki
comprises multiple deposits (total 10 million tonnes to 100m) of
magnetite breccia with associated but under-evaluated copper-gold
and cobalt mineralisation.
At Palokiimanselkä
trenches dug and sampled in the 1950’ returned gold values
to 10g/t in north-south trending magnetite-bearing metavolcanics.
A later airborne magnetic survey shows these trenches to be located
within a 2km long north-south striking magnetic anomaly, now a priority
for follow up exploration.
Raajärvi is a
poorly documented iron ore deposit that produced 5mt of magnetite
iron ore between 1962 and 1975.
Further
Information: Patrick Cheetham, Tertiary Minerals:
Tel: 01625-626203
Ron Marshman/John Greenhalgh, City of London PR Ltd.
Tel : 020-7628-5518 |
