Present status of solid waste management and its future need

Abstract

Mining-selected waste (or simply mining waste) can be defined as a part of materials that result from the exploration, mining and concentration of substances governed by legislation on mines and quarries Identification of the environmental risks associated with such waste requires the characterization and quantification of their different types but also an assessment of the vulnerability of the specific environments contingent upon the geological and hydro geological conditions and peripheral targets.
1.- Characterization and quantification of the different types of waste. This project is based on country-by-country inventory, within the European Union, of sites associated with the management of mining, quarrying and ore-processing waste. It represents the first overview of the current situation in Europe as regards mining waste and presents the current regulatory and management measures specific to each country. The survey involved two approaches:
• A questionnaire related to the quantities of existing waste, associated with the typology of the mined substance(s), waste deposit(s) and mining systems and ore processing method(s),
• An estimation, on the basis of the different processes employed throughout the production chain in mining operations and their management at each level, of the main types of waste generated over the last five or ten years. 2.- Assessment of risks linked to mining waste. The notion of environmental impact of mining activities is only fully meaningful if it includes a change in the initial environmental parameters, due to such activities. These parameters, which govern the "quality of the environment", may have several components: chemical composition of the waters, soils, etc.; biological diversity; visual aesthetic qualities, etc. The major risks linked to mining waste for the environment are twofold:
• Risks associated with not only potential pollutant source (e.g. acidity and heavy metals in non-ferrous metallic ore) but also the specific environmental context and the presence of targets in the event of liberation. The possible risks from the potential pollutant source (such as acidity and heavy metals) in waste is dependent not only on the mineral characterization of the solid but also on the quality of the potential leachates, the direct environment (soil, groundwater, surface water, air) and the potential targets (human, fauna and flora). The realization of a Geographic Information System (GIS) specific to mining waste quantities and their pollution potential in different environmental contexts would thus constitute a tool in the assessment of risks linked of such materials. At the moment, such systems are used by some regional governments for the information management on land planning. The risk management with a GIS system in mining requires a considerable collection of specific data and additional series of external analyses. This system should be well defined and studied before to be developed. Then, results can be visualised successfully in the GIS system.
• Risks associated with the stability of the tailings dam, as indicated by the recent spectacular accidents in Spain and Romania. As regards the potential risk from tailings dams, it will be necessary to evaluate on each site the stability of tailings dam. Particular parameters such as exceptional climatological conditions should be carefully taken into consideration during the evaluation. In addition, common minimum safety standards for the design, construction, operation and monitoring should be developed and applied. These minimum safety standards could be built on the know-how of the profession.
3. - Improvement of management of waste. Mines in all European Union countries are governed by a set of laws, generally combined in a Mining Code. The numerous regulatory texts, laws and standards, reveal that mines are a matter of concern to the national administrations. Mining waste are governed by general waste laws and texts. The extent, to which environmental concerns are addressed in these national laws, varies from Member States to Member States. According to the contract.s tasks, this report refers superficially to some technical processes, the amounts and types of wastes as well as a short description of the national legislation of the various Member States. According to the returned questionnaires, a distinction can be made between the following three types of mine and related generated waste:
• Abandoned/old mines,
• Operating mines based substantially on old operating methods,
• Operating mines based on new design.
For abandoned mines, it is important:
• To undertake site monitoring (including land form(s), geology, soil type(s), hydrogeology, flora and fauna, land use, heritage, overburden and waste characterisation, recycling potential, etc.) to obtain a clear picture of the situation;
• To establish treatment objectives according to required future land use (for example, pollutant level in soil after treatment to be fixed depending on the proposed land use). For operating mines based substantially on old operating methods, it is essential to evaluate the control routine as regards pollution risks and the stability of the tailings dams, and to take all necessary measures to limit risks (for example, installing leachate collection tanks, etc.). Substantial changes in the operation and monitoring phases are likely to be necessary to ensure a sufficient level of environmental protection.