RELEASED BY CITY OF LONDON PR LIMITED ON BEHALF OF TERTIARY MINERALS PLC: OCTOBER 4 2001 PHASE I TESTWORK ON ROSENDAL TANTALUM DEPOSIT SHOWS 95P.C. OF ORE HAS COMMERCIAL VALUE · High-Grade Tantalum Concentrate Can Be Produced By Relatively Simple Processing Plant · Marketable Industrial Minerals Also Recoverable As Byproducts · Planning Underway For Next Stage Of Project Evaluation AIM-listed Tertiary Minerals plc says that completion of Phase 1 metallurgical testwork on samples from its Rosendal tantalum deposit in south-west Finland has shown the pegmatite ore is mineralogically simple and that tantalum can be recovered in a relatively simple processing plant. In addition, most of the other constituents of the Rosendal ore are commercially valuable industrial minerals which can be recovered as marketable byproducts. The testwork, on samples collected on Tertiary's behalf by the Geological Survey of Finland, was undertaken by Lakefield Research, an independent Canadian laboratory. It included detailed mineralogical investigations, six gravity concentration tests and two flotation tests. The results of the first two gravity tests were reported in August this year. In their final report, Lakefield concluded that: · Respectable recovery of tantalum from the Rosendal pegmatite ore can be achieved using gravity concentration which yields a high-grade concentrate averaging over 30p.c. tantalum pentoxide. · Sodium feldspar can be recovered from the gravity tailings and a premium-grade feldspar concentrate was produced in the preliminary tests. · · Additional marketable products of mica and quartz were produced as byproducts of the above tests. The Rosendal ore contains a minimal amount of waste material; the various marketable minerals (tantalum, feldspar, quartz and mica) recovered during the testwork represent approximately 95p.c. of the raw ore. Tertiary says that the Lakefield testwork also showed that the tantalite in the Rosendal ore is present as the high-grade ferrotantalite and ferrotapiolite minerals and that commercial recoveries of tantalum can be achieved at relatively coarse grind sizes and with no sizing of the ground ore. The Rosendal pegmatite is estimated by the Geological Survey of Finland to contain 1.3m tonnes of material to a vertical depth of 100m with an average grade of 289g/t tantalum pentoxide estimated from previous surface sampling and limited drilling. The deposit is located on the coast adjacent to an existing industrial minerals processing plant and ship-loading facilities. Planning is underway for the next stage of evaluation of the Rosendal deposit which will include infill drilling and economic scoping studies. Further Information: Patrick Cheetham, Executive Chairman, Tertiary Minerals. Tel: 01625-626203 John Greenhalgh, City of London PR Ltd. Tel: 020-7628-5518