Envirotis Holding deals with the remediation and recultivation of abandoned mining sites. Typically, these are complex remediation projects that run for 5 to 10 years, since the pollution affects not only the mining site, but its surroundings as well.
Environmental impacts of the mining sites
Mines were opened in areas with rich subsurface and surface mineral reserves. Specifically because of their value these sites were already classified as natural reserves. Mines that operated in the past are still causing environmental pollution because of their former operation, improper disposal and management of dead-material, and their unprofessional technical closure. The environmental pollution appears in the soil, ground water, karst water, as well as in the waters and bed sediments of surface water flows.
Remediation tasks
Wastewater treatment
Natural water-flows have appeared in mine passages that were abandoned several decades ago, and this water dissolves different minerals and metals from the disturbed rock. These elements then appear in a concentrated form as pollutants in the surrounding water flows, ground water and process lagoons.
After the successful localisation of the wastewater sources, all this water is routed to a central wastewater treatment and purification system, which has to be built during the remediation process. Then the treated water can be discharged into natural water flows, this way increasing the natural runoff of the latter. Water purification can be carried out by mechanical (e.g. sedimentation, filtering), biological (by microorganisms) and, if required, by chemical agents, depending on the pollution type. After the purification process we forward the remaining sludge to adequate waste disposal sites (for recycling or final disposal).
Wastewater purification and disposal of the waste produced by this process is a continuous task for mine owners.
Mine closure
We carry out the technical mine closure in cooperation with mining specialists in accordance with their plans for the future. After the structural survey, exhausted mines are closed by backfilling. Dead-material or other geological layers that do not contain hazardous materials provide good backfilling material. In the case of mines with future excavation prospects, the technical closure is done – after the polluting sources of wastewater have been eliminated – in such a way that a future mine reopening remains possible, but structural safety is ensured.
Treatment of waste dump
The dead-material, which is excavation waste, is usually stored in the close vicinity of mines. When determining the disposal site, the main criteria were undisturbed excavation, quick processing, and cost effectiveness. During remediation we classify and treat rocks based on their hazardous properties and then we carry out remediation or recycling. The hazardous waste is usually stabilised by pre-treatment, then transported to an adequate disposal site which can be a local dumping-ground with proper protection measures. Because of environmental and economic efficiency reasons, part of the hazardous waste unsuitable for recycling is secured for long-term storage by on-site protection and the implementation of a monitoring system. An important part of the liquidated waste dump and newly installed dumping-ground is an adequate monitoring system which enables the supervision of ground water pollution and provides long-term remediation results.
Demolition of mine buildings
The remediation also includes the liquidation of the industrial facilities used for the processing of excavated rocks. The preservation of structurally stable buildings that have not been contaminated with hazardous materials is essential for the launch of a brown field project. We demolish contaminated buildings and other industrial facilities (e.g. transport network) and hand them over according to their hazard classification (danger class) to an authorized waste management company. We have a preference for recycling technologies.
Remediation of polluted geological layers
Polluting components have appeared in the soil and also in the beds of natural and artificial waters in the area affected by the mining activity. We perform different tests during the removal of polluted geological layers. After on-site treatment, the material removed can be filled back into its original place or handed over in accordance with its hazard classification to an authorized waste management company, with priority given to recycling technologies.
Purification of freshwater and water-storage reservoirs
In the past, water-storage reservoirs or even artificial lakes were built in order to supply the large industrial water volumes required for mining-related activities (e.g. augmentation of liquid in ores), and all these are now polluted. The wastewater produced during mining was discharged into natural water flows near the mining site after passing through purification lagoons built for the natural binding of pollution agents.
A full-scale mining site remediation must also cover the purification of all these natural and artificial water facilities. This work will be done downstream by partial diversion of the water flow, followed by the excavation of the riverbed. Waste produced during excavation will be classified and treated in the way presented earlier. Because of insoluble polluting agents, no water purification is required on this section, or the purification of wastewater flowing out of the mine has already solved this problem. Nonetheless, ground water purification may be required on the sites of liquidated industrial facilities and waste dumps. This operation would be done by pumping the wastewater into the purification facility through a drainage system, then sending it back by desiccation.
Results of the recultivation activity
After cleaning and eliminating waste and pollution, recultivation, namely the reintegration of the area into the landscape, is the final remediation phase. In this phase, the protected dumping-grounds are given a cover layer, then indigenous flora and fauna is settled back. The remediation of water flows and lakes ends with the restoration of watersides and beds, and the installation of all the required water-engineering facilities. This will allow the quick resettlement of natural biotopes.
Tourist resorts or local recreational sites can be set up on the cleaned areas, or the abandoned industrial facilities may be used for brown field projects.
Application areas
- Remediation and recultivation of abandoned mining and metallurgical sites and facilities
- Remediation and recultivation of waste disposal sites left after mining and metallurgical activities.
Envirotis Holding deals with the remediation and recultivation of abandoned mining sites. Typically, these are complex remediation projects that run for 5 to 10 years, since the pollution affects not only the mining site, but its surroundings as well.
Environmental impacts of the mining sites
Mines were opened in areas with rich subsurface and surface mineral reserves. Specifically because of their value these sites were already classified as natural reserves. Mines that operated in the past are still causing environmental pollution because of their former operation, improper disposal and management of dead-material, and their unprofessional technical closure. The environmental pollution appears in the soil, ground water, karst water, as well as in the waters and bed sediments of surface water flows.
Remediation tasks
Wastewater treatment
Natural water-flows have appeared in mine passages that were abandoned several decades ago, and this water dissolves different minerals and metals from the disturbed rock. These elements then appear in a concentrated form as pollutants in the surrounding water flows, ground water and process lagoons.
After the successful localisation of the wastewater sources, all this water is routed to a central wastewater treatment and purification system, which has to be built during the remediation process. Then the treated water can be discharged into natural water flows, this way increasing the natural runoff of the latter. Water purification can be carried out by mechanical (e.g. sedimentation, filtering), biological (by microorganisms) and, if required, by chemical agents, depending on the pollution type. After the purification process we forward the remaining sludge to adequate waste disposal sites (for recycling or final disposal).
Wastewater purification and disposal of the waste produced by this process is a continuous task for mine owners.
Mine closure
We carry out the technical mine closure in cooperation with mining specialists in accordance with their plans for the future. After the structural survey, exhausted mines are closed by backfilling. Dead-material or other geological layers that do not contain hazardous materials provide good backfilling material. In the case of mines with future excavation prospects, the technical closure is done – after the polluting sources of wastewater have been eliminated – in such a way that a future mine reopening remains possible, but structural safety is ensured.
Treatment of waste dump
The dead-material, which is excavation waste, is usually stored in the close vicinity of mines. When determining the disposal site, the main criteria were undisturbed excavation, quick processing, and cost effectiveness. During remediation we classify and treat rocks based on their hazardous properties and then we carry out remediation or recycling. The hazardous waste is usually stabilised by pre-treatment, then transported to an adequate disposal site which can be a local dumping-ground with proper protection measures. Because of environmental and economic efficiency reasons, part of the hazardous waste unsuitable for recycling is secured for long-term storage by on-site protection and the implementation of a monitoring system. An important part of the liquidated waste dump and newly installed dumping-ground is an adequate monitoring system which enables the supervision of ground water pollution and provides long-term remediation results.
Demolition of mine buildings
The remediation also includes the liquidation of the industrial facilities used for the processing of excavated rocks. The preservation of structurally stable buildings that have not been contaminated with hazardous materials is essential for the launch of a brown field project. We demolish contaminated buildings and other industrial facilities (e.g. transport network) and hand them over according to their hazard classification (danger class) to an authorized waste management company. We have a preference for recycling technologies.
Remediation of polluted geological layers
Polluting components have appeared in the soil and also in the beds of natural and artificial waters in the area affected by the mining activity. We perform different tests during the removal of polluted geological layers. After on-site treatment, the material removed can be filled back into its original place or handed over in accordance with its hazard classification to an authorized waste management company, with priority given to recycling technologies.
Purification of freshwater and water-storage reservoirs
In the past, water-storage reservoirs or even artificial lakes were built in order to supply the large industrial water volumes required for mining-related activities (e.g. augmentation of liquid in ores), and all these are now polluted. The wastewater produced during mining was discharged into natural water flows near the mining site after passing through purification lagoons built for the natural binding of pollution agents.
A full-scale mining site remediation must also cover the purification of all these natural and artificial water facilities. This work will be done downstream by partial diversion of the water flow, followed by the excavation of the riverbed. Waste produced during excavation will be classified and treated in the way presented earlier. Because of insoluble polluting agents, no water purification is required on this section, or the purification of wastewater flowing out of the mine has already solved this problem. Nonetheless, ground water purification may be required on the sites of liquidated industrial facilities and waste dumps. This operation would be done by pumping the wastewater into the purification facility through a drainage system, then sending it back by desiccation.
Results of the recultivation activity
After cleaning and eliminating waste and pollution, recultivation, namely the reintegration of the area into the landscape, is the final remediation phase. In this phase, the protected dumping-grounds are given a cover layer, then indigenous flora and fauna is settled back. The remediation of water flows and lakes ends with the restoration of watersides and beds, and the installation of all the required water-engineering facilities. This will allow the quick resettlement of natural biotopes.
Tourist resorts or local recreational sites can be set up on the cleaned areas, or the abandoned industrial facilities may be used for brown field projects.
Application areas
- Remediation and recultivation of abandoned mining and metallurgical sites and facilities
- Remediation and recultivation of waste disposal sites left after mining and metallurgical activities.