Successful exploration work at Tara continued in 2018, with no other major contributions to report. Exploration drifts are under development at Tara and Kristineberg in order to establish improved locations for drill towards the new mineralisations. Garpenberg, Aitik and Kevitsa have Mineral Resources and Mineral Reserves sufficient to secure production for many years to come.
“We are continuing to focus our exploration activities on existing mine-site areas. Developments around Tara continue to look promising, and we are looking forward to establishing new drilling positions in the Boliden Area later this year,” says Stefan Romedahl, President, Business Area Mines.
Exploration costs in 2018 totalled SEK 520 m (470).
No extensive exploration work is currently being carried out at the Aitik mine. Work is, however, continuing on preparing the Liikavaara deposit, approximately 3 km north-west of Aitik, for mining. Exploration and evaluation work is also being carried out on the Nautanen deposit, approximately 15 km north of Aitik. Changes in Aitik’s resources and reserves since last year were minor: 38 Mtonnes was extracted, but more than half of that amount was added to the Mineral Reserve by a change in the design of the open pit.
The Boliden Area
The Maurliden open pit will be mined out in early 2019, and there are consequently no longer any reasonable grounds for extracting the remaining Mineral Resources at Maurliden. Almost 1 Mtonne was added to Renström’s Mineral Reserves by the scheduling of two new areas for extraction. At Kristineberg, drifts have been cut towards a new lens 2.5 km to the west of the mine, in the old Rävliden area. Drilling from the drift towards the new lens is scheduled to begin in 2019. The Mineral Reserve for the area as a whole is almost the same as for last year, while Mineral Resources have decreased.
Garpenberg’s long-term planning in terms of Mineral Resources and Mineral Reserves is good. No major changes occurred during the year, but minor updates and design changes have meant that the Mineral Reserve only declined by 1 Mtonne in spite of the extraction of 2.6 Mtonnes of ore. The mine’s mineral resource increased marginally.
Minor changes were made to the economic parameters that control mining operations at the Kevitsa mine, which was acquired by Boliden in 2016, along with some fine-tuning of the open pit’s design. As a result of these changes, the Mineral Reserve only decreased by 5 Mtonnes, in spite of the extraction of 8 Mtonnes of ore in 2018. A comprehensive review of the Mineral Resource was carried out during the year, including adjustments to calculation methods designed to bringing them in line with Boliden’s normal method of defining Mineral Resources in open pit mines. The Mineral Resource comprises a mineralisation in the vicinity of the existing open pit but, mining of this mineralisation – despite its grade – is currently not justifiable, due to economic conditions. This year’s report takes into account the distance from the existing open pit, and more distant mineralisations have been excluded. This resulted in a decrease in the mineral resource of 20 Mtonnes, or 11 %.
The Mineral Reserve is small, and the mine is consequently coming to the end of its life. A little over 400 ktonnes were, however, added to the reserve this year due, in part, to improvements in room design but due primarily to improvements in the concentration of nickel and cobalt and to better pricing terms and conditions from the smelter. 790 ktonnes of ore were mined in 2018, and the Mineral Reserve has, therefore, decreased by just under 400 ktonnes. Mineral Resources have increased due to exploration and infill drilling in the mine and to the improved economic conditions.
Investigations of the Tara Deep mineralisation at Tara continue, with simultaneous drilling from the surface and the exploration drift towards Tara Deep. The size of the inferred mineral resource at Tara Deep is now estimated at 18 Mtonnes (13 Mtonnes in 2017). Work has also continued on improving the geological models of the ore lenses and the design of mining rooms at the Tara mine. The Mineral Reserve has still decreased slightly, but the Mineral Resource has increased due to the contribution of Tara Deep.
Mineral Resource and Mineral Reserve calculations, 2018
Boliden is switching from reporting in accordance with the recommendations of the Fennoscandian Review Board (FRB) to those of the Pan-European Reserves and Resources Reporting Committee (PERC). The PERC standard includes more stringent demands with regard to documentation and the “Competent Persons” who evaluate the information reported by the companies. The transition to the PERC standard will be an ongoing process during a transition period that allows companies time to adjust to using the PERC standard. The reports here have, as far as possible, been compiled in accordance with the PERC standard, but do not claim to be completely in accordance with the specified regulations.
For each mine and project Boliden makes a summary report over Mineral Resources and Mineral Reserves that is published on Boliden’s website. All these reports have been reviewed and approved by the Competent Persons presented in the respective reports. This summary of Mineral Resources and Mineral Reserves has been reviewed and approved by Gunnar Agmalm, Boliden’s Mineral Reserves and Project Evaluation Manager, who is a member of the Australasian Institute of Mining and Metallurgy (AusIMM) and the Fennoscandian Association for Metals and Minerals Professionals (FAMMP), both of which are approved organisations for designation as Competent Persons in accordance with PERC.
Mineral Resources and Mineral Reserves are the basis for the company’s long-term planning and will be mined for many years to come. Planning prices, which are an expression of the anticipated future average prices for metals and currencies, are, therefore, primarily utilised in the estimations.