June 1, 2004

TERTIARY’S WINTER DRILLING CONFIRMS PRESENCE OF SIGNIFICANT IOCG SYSTEM AT AHMAVUOMA

• Encouraging Copper, Gold And Cobalt Values Intersected In Discovery Zone
• Down-Hole Survey Suggests Deeper Location For Northwest Zone Conductor

AIM-listed Tertiary Minerals plc says its winter drilling programme has confirmed the presence of a significant iron oxide-copper-gold (IOCG) mineralised system at its Ahmavuoma project in the Norbotten district of northern Sweden. IOCG style mineralisation encompasses some of the largest copper deposits in the world.

Ahmavuoma Hole Locations - 1.6.04 Click the image to the left for detail view

Because of the need to ensure good core recovery, however, drilling proceeded at a slower rate than expected and the company was able to complete only 5 of the planned 7-10 drill holes at Ahmavuoma before the onset of the spring thaw which made ground access and drill rig movement impossible.

The drilling programme, targeting three previously identified conductor horizons, returned best results from the Discovery Zone, where three holes were completed at 50m intervals along strike. Intersections included 5m grading 1.05p.c. copper and 0.3g/t gold (hole 04AH003) and 18m grading 0.4p.c. cobalt and 0.15p.c. copper (04AH001), both of which occur in a broader zone (33m-68m) of lower grade (0.25p.c-0.40p.c.) copper mineralisation.

Iron pyrite is the dominant mineral in this broad zone of sulphide mineralisation, also intersected in the third hole. The pyrite content diminishes from the north with the most southerly hole (04AH003) having the lowest content, this being consistent with the hole being located at the end of the electrical anomaly, states Tertiary. This hole also contains the highest copper grades.

The company comments that the highest copper values in IOCG deposits are not always directly associated with the highest sulphide content. The copper mineralisation in the Discovery Zone remains open in all directions, it adds.

The Central Zone at Ahmavuoma consists of a 1km long coincident magnetic/electromagnetic anomaly. Only one drill hole was completed in the recent programme, at the southern end of the anomaly. This intersected altered and fractured volcanic rocks containing abundant magnetite (iron oxide) breccias but only limited sulphide mineralisation. Magnetite can be electrically conductive in certain circumstances and Tertiary considers that the electrical target in the Central Zone can be explained by two intervals of massive magnetite intersected in the drill hole.

The company was unable to drill a second hole designed to test a possible de-magnetised zone further to the north along the axis of the electrical conductor where magnetite may have been replaced by more prospective sulphide mineralisation.

One hole was drilled into the third (Northwest) zone at Ahmavuoma which comprises a 2km long electrical conductor with a weak magnetic signature. The objective was to test the southern end of the conductor at a point of change in its strike direction suggestive of a possible dilation zone prospective for enhanced sulphide mineralisation. Although a broad zone of IOCG-style rock alteration was encountered this did not explain the electrical conductor, Tertiary states.

A subsequent down-hole electromagnetic survey suggested that the target conductor had not been reached by the drilling but lies some tens of metres below the bottom of the hole. This could be drill tested by wedging off the existing hole. A second hole, planned to test the Northwest Zone at its point of maximum conductance, was not drilled but will be included in the 2004-05 winter programme.

Further Information: Patrick Cheetham, Tertiary Minerals:
Tel: 01625-626203

Ron Marshman/John Greenhalgh, City of London PR Ltd.
Tel : 020-7628-5518