260 likes | 367 Views
Mitigating Approaches for Environmental Hazards Resulting from the Operation of Copper Mining Company in Lefka. Prof. Dr. Nur Sözen. Definition of the problem. Abandoned mines cause serious environmental problems: F atal effects on habitats and their inhabitants .
E N D
Mitigating Approaches for Environmental Hazards Resultingfrom the Operation of Copper Mining Company in Lefka Prof. Dr. Nur Sözen
Definition of the problem Abandoned mines cause serious environmental problems: • Fatal effects on habitats and their inhabitants. • High metal concentrations, sediments, acidity etc. threaten surface/underground water quality and aquatic habitats. • The waste material deposited on the surface is transported with the rain and the tailings containingcopper, lead, zinc, and cadmium etc. carry them to Lefka River and Morphou Bay. • Surface drainage can remove soils and may make large areas unstable.
Definition of the problem • Acid allows toxic metals to dissolve and wash into streams and ponds. • Discarded containers and tanks buried in waste rock piles or just scattered around the site. • Piles of trash and debris, open pits, waste rock piles, and access roads destroy landscape values and scenic vistas. • Where the wastes of old mines are seen as secondary resources, and old wastes and tailing dams are reworked for metals and minerals the impacts are likely to reoccur.
Definition of the problem • The accident at the Aural gold and silver producing plant at Baia Mare in Romania showed the environmental consequences of reprocessing wastes releasing large amount of cyanide into the Danube river system on January 30, 2000. The cyanide plume travelled to the Black Sea some 2000 km. from the source of the spill (UNEP/OCHA, 2000). • CMC operated in Gemikonaği near Morphou Bay between 1913 and 1974 primarily to produce copper and to some extent silver and gold. • Hazardous wastes such as acids for copper extraction and sodium cyanide for gold and silver have been threatening the environment and human health seriously ever since it started operating.
Definition of the problem • The leachates migrated and severely contaminated Lefka River which runs into Morphou Bay and thereafter diffuses into the Mediterranean Sea (Gökcekuş, H., et al. 2002). • Winds carried the particles of toxic substances and spread over the agricultual land. • The landscape features of the area are also severely damaged, the soil eroded and the land has become infertile for vegetation and dependent life forms. • CMC operation stripped away not only the vegetation but also the topsoil.
Definition of the problem • The barren lunar faced hills incapable of supporting life, continue to erode and harmful sediments interfere with natural flow patterns. • Soil and water contaminated with heavy metals and chemicals are also harmful to terrestrial wildlife, pastures and valuable agricultural areas of the Cyprus Island which all together cause serious health problems for the communities of the island. • We must keep in mind that such disasters don’t recognize any national, social and economic boundaries.
Objectives • Restoration, protection and improvement of the damaged ecosystem and providing long-term benefits to the society are the main objectives. • The efforts should be focused on innovative, cost effective and environmentally acceptable techniques and technologies that can be used to stop acidic water and heavy metal generation from waste dumps and aerial flow of contaminated waste particles. • A holistic environmental management programme including risk assessment analysis and life cycle assessment data would be helpful for managing hazardous mining wastes.
Objectives • The following actions will be required: i) Decontamination of hazardous wastes by chemical leaching, bacterial leaching and chemical stabilisation. ii)Removal of heavy metals from acidic mine waters and leachates (chemical treatments, reactive barriers, artificial wetlands). iii) Prevent oxidization of the sulphidic phases in the waste dumps. (iv) stop aerial transfer of contaminated fine particles by the application of a composite cover. (v) Landscape remediation. (vi) Relevant EC environmental legislation and directives for hazardous waste management as well as identification of the risks shoul be considered as guides.
Strategical Approach • Understand and identify the environmental problems of the area that are primarily related to the activities of CMC, and create a basis for a bi-communal consensus. • Joint activities must be encouraged; such an approach would promote stakeholder attitude and help maximizing the expected efficacy. • Define priority areas; some of the hazards both terrestrial and aquatic having high priority in this abandoned mine area are to be dealt first. Thus a list of priorities needs to be drafted for further discussions.
Strategical Approach • Existing and proposed instruments and resources (financial, legal, technical, knowledge, data etc.) must be used in a most feasible and acceptable way. • Improve, exchange and maintain the gained technical expertiseand capacityby working more closely with both communities and other stakeholders to remedy the environmental degradation of mutual interest. • Estblish a contact officewhich can coordinate and monitor the remedial process.
Strategical Approach • Apply acceptablescientific, technological and cost effective innovationsto estimate and mitigate the hazards caused by CMC activities. • Prepare a program that can evaluate and monitor the achievements and progresses to fulfill the established environmental criteria. Establish a multi-disciplinary team to deal with the environmental problems at the scale of individual sites with a holistic management approach.
Mitigating Hazards • Construction tasks necessary to reclaim an old mining area usually include: (i) moving large amounts of material such as waste rock and mill tailings, (ii) removal of dangerous structures and debris, (iii) filling or blocking hazardous openings, (iv) diverting streamwater away from contaminated areas, (v) placement of topsoil, (vi) revegetation.
Mitigating Hazards • Local community involvement in the site investigation and reclamation plans can help identifying and addressing the concerns of people affected. • The local public might be concerned about a variety of things such as warning signs, fencing, previous unsuccessful efforts at reclamation, historic structures, financial responsibility, the level of cleanup etc. (www.deq.mt.gov). • Priorities for mitigation are defined by considering the level of danger and potential for resource damage.
Mitigating Hazards • The chosen method for mitigating a hazardous site depends on available materials at the site, the types of landscape elements, proximity and access to the site, and availability of the financial resources. • Carefully planned reclamation can restore natural processes and greatly speed site recovery. • Reclamation focuses on reestablishing landscapes and environments that are similar to the surrounding undisturbed lands.
Mitigating Hazards • Otherwise, the pre-mine condition is restoredwherever possible. • Reshaping the surface stabilizes slopes and drainages as well as waste rock piles, tailings ponds, and access roads etc. • Cleanup or treatment of toxic materials prevent further impairment of the environment. • Naturally occurring materials, such as unweathered waste rock that produces acids, may be treated on-site. • In more severe cases, limestone drains or artificial wetlands filter heavy metals and reduce acidity.
Mitigating Hazards • Revegetation of mine sites implies restoration of native plant populations and patterns. • Reclamation covers all relevant activities to return the mined land to a level of productivity and ecological stability that meets the approved Post Mining Land Use and It covers the actions taken to restore mined land and, aims creating a site that will support and sustain biodiversity. • Applications of lime may provide a buffer to prevent the generation of acids.
Mitigating Hazards • The main purpose of rehabilitation act is returning a disturbed site into a stable form and productivity level. The damaged area will be returned to a form and productivity in conformity with a prior land-use plan including a stable ecological state and is consistent with surrounding aesthetic values. • Restoration means returning a damaged area to the same state it was prior to the damage. This may require rebuilding the soil, precise placement of trees and rocks, and use of only native plants and fauna to repopulate the site. The Society for Ecological Restoration (SER) defines ecological restoration as ‘the process of assisting the recovery of an ecosystem that has been degraded.
Mitigating Hazards • Recoveryis the processwhere presence of populations of plant species in a particular site will depend on the ability of propagules to be transported to the site and to germinate, reproduce and survive. • Remediation is defined as the process of rendering metalliferous contaminants less toxic, or ideally removing them from the contaminated environment in terms of using metallophytes for remediation. This process called phytoremediation and uses metal-accumulating plants to remove the pollutants from contaminated soils (Whiting et al. 2002).
Mitigating Hazards • Recoveryis the processwhere presence of populations of plant species in a particular site will depend on the ability of propagules to be transported to the site and to germinate, reproduce and survive. • Remediation is defined as the process of rendering metalliferous contaminants less toxic, or ideally removing them from the contaminated environment in terms of using metallophytes for remediation. This process called phytoremediation and uses metal-accumulating plants to remove the pollutants from contaminated soils (Whiting et al. 2002).
Mitigating Hazards • Metallophytes offer huge potential for the development of environmental phytotechnologies; There are many thousands of species of metal-tolerant, nonaccumulating plants that might be considered for phytostabilization. These species are unified by the act that they restrict the transfer of metals to their shoots. Metal-tolerant plants that do not accumulate metals in their shoots are selected for phytostabilization to minimize metals entering the food chain.
Mitigating Hazards • For phytoextraction, so far approximately 500 species have been found with the ability of hyperaccumulating metals at concentrations which are between 102 and 105 times greater than in ‘‘normal’’ plants (Whiting et al, 2004). • The efforts to understand the chemical dynamics of metals in soils has yielded a highly promising phytostabilization technology. This technology has been used with success on Pb-, Zn- and Cd-contaminated sites in the U.S.A. and Poland, and on Ni-contaminated sites in Canada (Whiting et al, 2004).
Conclusion • Mining is a temporary land use, the mineral deposit is finite and eventually exhausted. The reclaimed land surface is to remain indefinitely and requires to meet the major goals of sustainability. In this context, ecological restoration of mined land represents the best approach to promote both sustainability and the maintenance of biodiversity. • Cleaning up metal-contaminated soils by phytoremediation is most feasible on low to moderately contaminated soils.
Conclusion • The following comments may be helpful for defining research priorities for the use of plants to remedy the hazards of mining: (i) Scientific understanding of the physiological, molecular, and genetic mechanisms of metal hyperaccumulating metallophytes; (ii) Screening and breeding hyperaccumulating plants for higher biomass and/or higher metal accumulation; (iii) Development of agronomic practices for these plants; (iv) Methods for processing the biomass, including incineration, metal extraction from the biomass and/or ash, and disposal in landfills; (v) Environmental risk assessment of phytoextraction crops, for example, their impact on the food chain.
Conclusion • In the light of the above given information a plan can be prepared for the CMC mine area that covers the following steps: (i) Local metallophytes native to the CMC mining area can be defined. (ii)Propagation of functional native plant species and production of seeds can be encouraged. (iii) Fertilizer use can be replaced by nitrogenfixing metallophytes for low-maintenance plant cover; (iv) Develop metallophytes with multiple metal-tolerance systems for use on heterogeneous wastes and other chemically complex mining substrates;
Conclusion (v) Develop metal-excluding plants to minimize transfer of metals into the food chain on the restored sites (both livestock and native fauna); (vi) Evaluate opportunities for case studies of ecological monitoring of restored sites to provide longer-term ecosystem development (Whiting et al, 2004). • With a careful and functional landscape planning approach this damaged land can become one of the tourist attractions of the island; it may exhibit old mining technologies and instruments in addition to how minig damaged the area and how it is rehabilitated.
Conclusion • Finally, 2013 is only six years ahead. That means this CMC originating disaster has been going on for a century. Time has come to change it. Every effort should be spent not to live with the same problem for another hundred years and clean it for the generations of the next century.