Name of the Mine
Boliden Tara Mines.

Location  
Two kilometres north-west of Navan in County Meath, in Ireland.

Mine Owner/s  
Boliden.

Brief Description  
Tara mine is the biggest zinc mine in Europe and also one of the largest in the world.

Brief History
Mining began at Tara in 1977. The mine had extracted more than 85-million tonnes of ore until it was put on care and maintenance in June 2023.

Boliden acquired the mine in 2004.

Primary Metals/Minerals  
Zinc and lead.

Secondary Metals/Minerals  
None stated.

Geology/Mineralisation  
The Navan orebody is located on the footwall (northern) side of a major south-dipping normal fault that constitutes a basin margin controlling feature. The orebody is controlled by a complex array of lower carboniferous normal faulting, and slides on the uplifted footwall of this major fault.

The orebody generally dips at about 10° to 15° to the west-south-west and consists of several locally stacked, tabular stratiform to stratabound lenses, orientated in general concordance with the host limestones. The mineralisation ranges from a few metres to more than 70 m in vertical thickness. A major slide and overlying debris flow cuts the orebody obliquely and is also mineralised. The orebodies are masked from the surface by a thick succession of deep-water calc-turbidites that comprise the Dublin basin.

Although there are several sizeable lenses and fault blocks at Navan, more than 95% of the mineralisation occurs as sphalerite and galena in partly dolomitised limestones as intricately textured replacements, veining and open-space infill where zinc:lead ratios are typically about 4 or 5 to 1.

Gangue mineralisation comprises subsidiary calcite, pyrite, marcasite, dolomite and barite. The remainder of the mineralisation occurs as massive pyritic lenses, containing sphalerite and galena hosted by debris-flow conglomerates that overlie the deposit.

Reserves  
Total proven reserves as December 3, 2022, were estimated at 1.1-million tonnes grading 5.8% zinc and 1.3% lead. Probable reserves were estimated at 13.9-million grading 5.5% zinc and 1.5% lead.

Resources  
Total measured resources as December 31, 2022, were estimated at 30 000 t grading 5.7% zinc and 1.3% lead. Indicated resources were estimated at 2.1-million tonnes grading 4.9% zinc and 1.8% lead. Inferred resources were estimated at 38.2-million grading 7.5% zinc and 1.5% copper.

Type of Mine
Underground.

Mining Method  
Room-and-pillar, and longhole stoping.

Major Infrastructure/Equipment  
Access to underground operations is through two major declines. Subsidiary access-drifts then enter mining blocks that contain the stopes and are then used for truck haulage of ore to several underground crushers feeding conveyors that take the ore to the base of the main production shaft and then to surface. The coarse fraction of the mill waste product is used for backfill while the remnant tailings are pumped 2 km to a tailings management facility.

Prospects  
A decision was made in June 2023 to place the Tara mine under care and maintenance, and production ceased on July 5.

The recovery value for Tara is based on prices. Boliden has said that operations at Tara will restart in the “relatively near” future.

Contact Details
Boliden
Tel + 46 8 610 15 00
Email info@boliden.com

Sources
Boliden. Website: https://www.boliden.com/
Boliden. Summary Report, Resources and Reserves 2022, Tara Mines.
Boliden. Interim Report for the second quarter of 2023 (August 20, 2023).