Following the mitigation hierarchy is a fundamental part when working with biodiversity. The mitigation hierarchy is a step-by-step process of avoiding, minimising, restoring, and offsetting our impact on biodiversity.
Illustration of the work with the mitigation hierarchy, which involves avoiding, minimising, restoring, and offsetting for the impact on biodiversity.
Avoiding impact on biodiversity
Ores and minerals are found in specific geological conditions, which inevitably dictates the location of mines and quarries. When developing and building new facilities we should, as far as possible, manage the design to avoid impact on biodiversity.
We minimise our emissions to air and water and reduce waste. Minimizing impact on biodiversity often means applying the best technical solutions. Much research and innovation is ongoing to produce fossil-free steel, further reducing emissions, and to make mining processes more energy efficient.
When a mine or quarry is closed, remediation and restoration are carried out. Through restoration, we create suitable conditions for desirable plants and animals to establish in the area. In this way, the area will in time contribute to biodiversity, harmonize with its surroundings, and become an integrated part of the landscape again.
Offsetting for remaining impact
Once we have applied the first three steps in the mitigation hierarchy, the final step is to offset for the remaining impact. For example, by restoring and protecting nearby natural habitats, biodiversity can be increased elsewhere. In this way, mining and minerals can contribute to increased biodiversity values at a regional level, even if some negative local impact is unavoidable.
Mitigation hierarchy – Examples from companies
Avoid
Company: Heidelberg Materials Step in the mitigation hierarchy: Avoid Contact person: Karin Comstedt Webb
– For example, in Slite, we avoid claiming land before a good conservation status of species in the area can be ensured, says Karin Comstedt Webb, Sustainability Manager at Heidelberg Materials.
When planning future quarrying, Heidelberg Materials adapts their quarrying plans, which among other things include biodiversity surveys. Heidelberg Materials cooperates with experts on a long-term basis to ensure that all actions are carried out on a scientific basis. Knowledge is key to ensuring that operations can be conducted in harmony with good nature conservation. Where the right conditions exist, Heidelberg Materials also aims to enhance biodiversity.
Company: Boliden Step in the mitigation hierarchy: Avoid Contact person: Anders Forsgren
– We carried out advanced modelling, taking into account both short- and long-term effects, says Anders Forsgren, Project Leader for the development of new mines.
In planning to mine the Liikavaara deposit next to Aitik, Sweden; Boliden explored many different designs for the industrial area and the gangue deposits. The results of the modelling showed that the best option at Liikavaara was to drive the acid-generating gangue to the gangue landfill in Aitik and to dispose of the waste rock on site in Liikavaara.
By planning in this way, the industrial area becomes much smaller while the areas with the highest conservation values are avoided. It also allows for better remediation with a reduced risk of metal leakage in the long term.
Company: Nordkalk Step in the mitigation hierarchy: Avoid Contact person: Tua Welin
– On Gotland, an island of Sweden in the Baltic Sea, there are many areas we have abstained from and divested over the years, says Tua Welin, Chief Environmental Officer at Nordkalk, Sweden.
Nordkalk avoids prospecting in areas worthy of protection. Even before Nordkalk started working more concretely on the basis of the mitigation hierarchy, it applied avoidance measures as knowledge of high conservation values became known. On Gotland, Nordkalk discontinued prospecting near the Mölnermyr wetland. They also, among other things, divested the land at Hoburgsmyr, which even today is protected as a Natura 2000 area, and set aside a protection zone around the wetland.
Company: LKAB Step in the mitigation hierarchy: Avoid Contact person: Annika Zachrisson
– The mitigation hierarcy is always with us when we claim land. The first step is to avoid negative impact, says Annika Zachrisson, Environmental Section Manager at LKAB.
In order to identify the natural values in an area, inventories such as nature value inventories and bird inventories are carried out. The impact on biodiversity is then weighed against other values such as national interests, impact on reindeer husbandry, and impact on nearby residents, to find a solution that minimizes overall impact. The choice of location is of fundamental importance, and the ambition is to prioritize areas with relatively low values, for example, because they have been negatively affected by previous operational activities in the area.
– In Kiruna, three locations were considered for the placement of waste-rock. The former open pit could theoretically exclude further land claims for a long period, but it is currently dismissed as an option for ongoing waste-rock depositing, partly due to safety and accessibility reasons. However, some backfilling occurs, when it is deemed possible and appropriate. The southern option is within the existing industrial area and is partially affected already, but there are also areas with high natural values in the area (class 2). The northwestern option, mainly outside the industrial area, has higher natural values (class 2 and class 1) and furthermore, has a greater impact on reindeer husbandry than the southern option, which is why it has been deemed the best location, Annika explains.
Map of LKAB:s location options for waste-rock depositing. The blue-striped area is the northwestern option, the black-striped area is the old open-pit mine, and the green-striped area is the southern option. Image: LKAB.
Minimise
Company: Heidelberg Materials Step in the mitigation hierarchy: Minimise
Heidelberg Materials’s plant in Slite, Sweden has applied for an extended mining permit at File Hajdar – an area in close proximity to the limestone quarry currently in use.
Heidelberg Materials’s application for a mining permit has been designed to minimise the impact on nature and key species such as the marsh fritillary butterfly.
Company: Boliden Step in the mitigation hierarchy: Minimise Contact person: Linnea Hisved
– We limit off-road driving in sensitive natural environments as much as possible when carrying out prospecting work, says Linnea Hisved, Permit Administrator at Boliden.
For prospecting work that requires off-road driving, Boliden always uses existing roads and already affected land as much as possible, so that the impact on the natural environment is minimised.
Company: Nordkalk Step in the mitigation hierarchy: Minimise Contact person: Håkan Pihl
– By gathering facts about nature worth protecting early in the process, we can minimise negative impact in sensitive areas such as Ignaberga, where we know there are high conservation values, says Håkan Pihl, Director of Sustainability at Nordkalk.
At Ignaberga, protection zones have been allocated to minimise the impact on species worthy of protection. Nordkalk uses information about sensitive areas in its long-term and systematic work for conservation values around its deposits.
Company: LKAB Step in the mitigation hierarchy: Minimise Contact person: Torbjörn Karlsson
The water that is continuously pumped out of our mines is used as process water in the benefication plants. Then it goes out to the tailings ponds and back to the beneficiation as process water, in a cycle. However, this process generates some surplus water that must be discharged – overflowed – into nearby watercourses: in Svappavaara to Liukattijoki, in Malmberget to Lina River, and in Kiruna to Mettä-Rakkurijärvi. However, this water contains elevated levels of, for example, nitrate, sulfate, and uranium, which is why it is of utmost importance for us to minimize the impact of these emissions.
The flow of water in the recipients varies, among other things by season: lower flows during winter and higher flows during the spring flood. By adjusting the emissions according to these natural fluctuations, with less overflow during low flow and vice versa, we can reduce our impact.
In Svappavaara, the water flows in our discharges and in the recipient are continuously monitored using flow meters connected to LKAB:s control system. This enables precise adjustments of emission flows in real-time. This has led to several positive results, such as improved water quality and more consistent, lower levels of nitrate, sulfate, and uranium in the recipient Liukattijoki.
Photo: Torbjörn Karlsson.
Company: Boliden Step in the mitigation hierarchy: Minimise Contact person: Johanna Holm
– By building this knowledge, we can conduct and develop our operations in a species-sensitive way, says Johanna Holm, Head of the Environmental Permits Unit.
In Kevitsa, Sweden; Boliden contributes with scientific knowledge about the rare species of smew, moor frog, and Dichelyma capillaceum and their habitats. With monitoring programs and surveys in the area, Boliden has followed the development of the species over time and can show clear results. In the birdhouses for smew, which have been set up by the lake next to the mine, around 10 pairs nest each year. 10 new premises with Dichelyma capillaceum have been identified, with a distribution much further North than previously known. And the moor frog has been shown to successfully coexist with the mining operations without being disturbed by the noise of the machinery.
Company: Zinkgruvan mining Step in the mitigation hierarchy: Minimise
When Zinkgruvan Mining needed to expand the Enemossen tailing pond with Enemossen East, part of the catchment area of Björnbäcken was claimed. Parts of the surrounding area of Björnbäcken have high conservation values, with many rare species of moss and lichen that depend on the flow of water in the brook. With a smaller catchment area, the flow of water in Björnbäcken is periodically too low for these species. Therefore, Zinkgruvan pumps water into Björnbäcken from a nearby lake during the growing season to ensure that the water flow is sufficient for the species.
Restore
Company: Heidelberg Materials Step in the mitigation hierarchy: Restore Contact person: Karin Comstedt Webb
– Hålldammsbäcken is a good example of how it is possible to move a brook and avoid damage to the Natura 2000 site downstream of our operations, says Karin Comstedt Webb, Sustainability Manager at Heidelberg Materials.
Hållsdammsbäcken flows next to Heidelberg Materials’s operations in Skövde, Sweden. When Heidelberg Materials was expanding its quarrying area, the brook needed to be diverted to a new flow. Heidelberg Materials carried out thorough investigations with a focus on creating as natural a brook channel as possible and minimising the impact on the Natura 2000 area into which the brook flows.
The work was carried out together with ecologists, hydrogeologists, contractors and a local school. Through regular inventories, Heidelberg Materials ensures that the measures have achieved the desired results. At the Skövde site, Heidelberg Materials has also restored a meadow area by planting selected plants. In one area, sheep walk in the summer to promote grazing species.
Company: Boliden Step in the mitigation hierarchy: Restore Contact person: Isabell Lundberg
The mine Långdalsgruvan was operated between 1967–1999 through underground mining followed by open-pit mining directly adjacent to the Skellefte River. During 2021–2023, remediation measures were carried out to restore nature with meadows and deciduous forest, as well as to create a recreational area for the public.
In 2021, the dam wall that previously enclosed the excavated open-pit in Långdal was demolished, and the following year, the old storage areas and roads of the area were remediated to begin the ecological restoration of the closed mine. Before the restoration, a plan for the area was developed, taking into account the preferences of nearby residents for barbecue areas and boat launching facilities, while also identifying suitable areas for plant establishment and biodiversity.
The ecological restoration began immediately after the completion of the remediation on the most erosion-prone areas near the Skellefte River. Sludge and bark mulch were mixed and spread in a thin layer with a tractor and manure spreader from a prepared road. The areas were then hand-seeded as the slope was deemed too steep for mechanical seeding. The seed mixture chosen for the slopes was a grass seed mixture without invasive species deemed suitable for the site.
In 2023, vegetation establishment continued on the old storage areas using a similar procedure, with a sludge/bark mulch mixture spread by a tractor with manure spreader. When seeding the areas, a quad bike with a seed spreader was used instead, making the seeding process significantly more effective. After seeding, the areas were harrowed with an ATV-specific harrow mat. Meadow seeds of the “Norrlandsblandning” mixture and grass seeds were used on different parts of the storage areas.
Work on the ecological restoration is ongoing, with many plans for the area. Future activities include thinning groves of trees to promote deciduous trees, laying out dead wood in selected areas, and eventually replanting the area with trees and shrubs.
In two areas along the Skellefte River, adjacent to the former open-pit mine, new habitats for pike and flowing water fish (e.g., grayling) will be created. In one area, a shallow bay will be developed, and aquatic plants will be established to promote pike spawning in spring. In the other area, large rocks and gravel will be placed out to create a spawning ground for river fish.
The vision for the entire area is a pleasant recreational area where people can gather, reminisce about the mining that has characterized the area for many years, and enjoy beautiful nature rich in biodiversity.
Photos: Boliden.
Company: Nordkalk Step in the mitigation hierarchy: Restaurera Contact Person: Tua Welin
– We have added large stones and built stone beds. This improves the flow and facilitates the trout’s ascent up the brook, says Tua Welin, Chief Environmental Officer Nordkalk Sweden.
Trout spawn in the Klinthagen brook on Gotland, and through various measures in the brook, Nordkalk has worked to improve their spawning conditions.
Company: LKAB Step in the mitigation hierarchy: Restore Contact person: Magdalena Åström
When an area is no longer used for operations, LKAB carries out ecological restoration. This is often a long-term process and may involve maintenance over an extended period. An example is the old tailing pond at Vitåfors, where LKAB conducts restoration with the aim of creating a variety of natural environments and favorable conditions for biodiversity.
By choosing the right soil materials, conditions are created for desired vegetation. Microhabitats such as stone piles, dead wood, shrubbery, and glades create variation that benefits multiple species. In Vitåfors, the measures are followed up with various indicators to ensure that the areas develop towards the different objectives. In addition to ecological values, LKAB also has a strong focus on ensuring that restored areas provide good conditions for reindeer grazing and contribute to social values.
Photo: Magdalena Åström.
Company: Zinkgruvan mining Step in the mitigation hierarchy: Restore Contact person: Charlotte Odenberger
– The meadows contribute to biodiversity while reducing dusting in the area and make Zinkgruvan a more beautiful place, says Charlotte Odenberger, Environmental Manager, Zinkgruvan mining.
It is possible to promote biodiversity even in industrial sites in operation. Zinkgruvan has carried out a project to establish meadows within the industrial area.
The meadows will be multifunctional and will contribute to biodiversity, reduce dusting in the area, and make Zinkgruvan a more beautiful place for its employees and visitors.
Information boards have been erected to explain why the meadows have been created and how they contribute to biodiversity.
Offset
Company: Heidelberg Materials Step in the mitigation hierarchy: Offset Contact person: Kerstin Nyberg
In Heidelberg Materials’s application for a mining permit for Filehajdar on Gotland, Heidelberg Materials has proposed extensive ecological offsetting measures to offset the remaining impact on nature. The proposed offsetting measures concern certain important butterfly species and the eastern pasqueflower.
An important basis for the proposed offsetting measures is Heidelberg Materials’s solid and long-standing work with various key species such as the marsh fritillary butterfly and the eastern pasqueflower. In Slite, Heidelberg Materials has carried out Europe’s largest inventory of the marsh fritillary butterfly and carries out annual surveys to monitor population trends. Together with experts, Heidelberg Materials has carried out studies on the eastern pasqueflower for many years to understand the ecology of the species and to find methods for reproduction, movement and measures to improve the species’ habitat.
Company: Boliden Step in the mitigation hierarchy: Offset Contact person: Anders Forsgren
– For us, this is very useful for when we carry out offsetting in the future, to know that the measures actually work. Above all, it will be a win for biodiversity when we learn an even better way to contribute with metals for the climate transition while still preserving or even raising conservation values, says Anders Forsgren, Project Leader.
The offsetting for the expansion of the Aitik tailing pond is one of the largest offsetting projects carried out in Sweden to date. An extensive offsetting study showed that the best option was to create two offsetting areas located directly adjacent to the Leipipir Ecopark.
The offsetting focused on adding conservation values in areas that did not already have high conservation values, e.g. by laying out dead wood transported from the affected areas. These areas now fulfill an important function both for the public and for nature conservation in a wider perspective, as they are bridges between the Ecopark and other valuable areas of nature.
Outdoor recreation is facilitated by footpaths and lookout points. In cooperation with the Swedish University of Agricultural Sciences (SLU), Boliden is carrying out a long-term research project to study how species respond to the offsetting measures implemented.
Company: Nordkalk Step in the mitigation hierarchy: Offset Contact person: Tua Welin
In Storugns outfields, Nordkalk is working to improve butterfly habitats through management and restoration measures to offset the resulting impact of its operations. E.g. careful clearing reduces overgrowth in the area. As quarrying areas have been put into service in the vicinity, Nordkalk is also working to improve connectivity between areas in the long term. To monitor the work, butterfly inventories were carried out in 2016 and 2020.
– It was pleasing to see that the Apollo butterflies had recovered strongly in 2020 and were also present within the industrial area, at the old landfill area and the spare parts depot. However, within this work we see that long-term monitoring is important, as the butterfly population sizes are dependent on weather and therefore varies greatly between years, says Tua Welin, Chief Environmental Officer, Nordkalk, Sweden.
Company: LKAB Step in the mitigation hierarchy: Offset Contact person: Katarina Oja
LKAB has since 2015 an ambition that its operations should not result in any net loss of natural values, and since 2021, a target to contribute net positively to biodiversity. Therefore, LKAB works on assessing the direct and indirect effects arising from its operations and compensating for the remaining impact on biodiversity. Offsetting is usually carried out when new land needs to be claimed, but it may also be necessary when natural environments are negatively affected, for example, by changes in groundwater flows due to ongoing operations.
Kuosajänkkä, outside Svappavaara, is one of Sweden’s largest offset areas and was part of the legal terms when Mertainen’s open pit mine was started. The offsetting involves protecting areas and strengthening natural values for 50 years. LKAB works based on a management and monitoring plan to track how natural values develop over time in the area. The nature conservation measures carried out in the area include placing dead wood transplanted from the area being used, restoring marshes, and conducting marsh mowing and nature conservation burning.
Photo: Per Juntti.
Company: Kaunis Iron Step in the mitigation hierarchy: Offset Contact person: Lars Wallgren
Kaunis Iron has conducted ecological offsetting for intrusions into rich fen environments by restoring other rich fens in the nearby area.
The measures have focused on benefiting rich fen species such as yellow marsh saxifrage Saxifraga hirculus, fragrant orchid Gymnadenia conopsea, Lapland marsh-orchid Dactylorhiza lapponica, slender sedge Carex heleonastes, and marsh hair moss Hamatocaulis vernicosus. Moreover, these measures also have a generally positive impact on the biodiversity of the rich fen environments. In total, the efforts encompass 139 hectares of restoration of drained rich fens through logging and clearing, filling in ditches, and placing dams.
