Mining for Closure: Policies, practises and guidelines for sustainable mining and closure of mines

in a concentrating process. Crushing and grind- ing methods are used to reduce the mined ore to sand and silt sizes, and then the concentrat- ing process for the valuable minerals can begin. Tailings contain residual target minerals and also often contain process chemical residues. Tailings dams – Engineered holding and stor- age areas for process wastes (tailings), also re- ferred to as Tailings Storage Facilities, Process Waste Storage Facilities, Tailings Management Areas (TMAs), Tailings Retention Systems and more. Tailings dams are similar to convention- al water dams in that they are designed to be a retaining structure. However, a tailings dam is designed to retain water and solids, whereas a conventional dam retains only water. Surplus Rock or Waste Rock – Rock that must be extracted to reach economic ore but does not contain significant commercial miner- alization. While not as highly mineralized as target ore, such rock can also contain metals and sulphide minerals that contribute to the environmental problems listed above. Among the many potential or actual environmental impacts related to mining and minerals process- ing mentioned or discussed in this document, the topic of acidic drainage is of particular importance – particularly because of the considerable liabilities associated with this phenomena. In the SEE/TRB context, acidic drainage is a priority due to its dem- onstrated potential for trans-boundary pollution in the region (Peck, 2004), the potential ultra-longevi- ty of its impacts, and its widespread prevalence. The general manner in which it is perceived that these terms should be interpreted, how such matters should be approached, and some important sup- porting information resources are also very briefly 14. They include a series of booklets, a series of checklists designed to provide guidance to regulators and industrial actors and the joint Environment Australia/UNEP Best Practice Environmental Management in Mining Training Kit. The Training Kit is designed to help trainers plan and deliver effective training aimed at improv- ing the environmental performance of minerals operations. The different volumes in the Kit give extensive references to further information, including that which is available from the Sustain- able Minerals series e-booklets. Environment Australia developed this training kit in conjunction with the United Nations Environ- ment Programme (UNEP), to move the Sustainable Minerals pro- gramme into a new phase. It assists trainers in developing training sessions based on the Sustainable Minerals booklets and provides presentation slides, notes, a selection of case studies and work- sheets. UNEP has sought to ensure the kit’s international focus, particularly in promoting awareness of Sustainable Minerals tech- niques in developing countries. See http://www.deh.gov.au/in- dustry/industry-performance/minerals/training-kits/index.html. • •

leading environmental managers in mining. These booklets have been available electronically and in hard copy and from 1995 to 2000 have been dis- tributed to over sixty countries around the world. An important component of best practice is the ability to be flexible in devising solutions which match site-specific needs in terms of the types of mining operation, climate, topography, the sensi- tivity of the surrounding environment, and social requirements, which deliver outcomes consistent with sustainable development principles and objec- tives (Environmental Protection Agency, 1995b). Best practice environmental management in min- ing focuses on the principles of environment im- pact assessment and environmental management. The booklets use case studies to demonstrate how these principles can be integrated through all phas- es of resource development from pre-exploration planning, through construction, operation, closure and post-mining monitoring and maintenance. The resources developed by the Best Practice Envi- ronmental Management in Mining programme are available free of charge on the Internet. 14 Finally in this introduction of important terms, a very limited set of terms describing important physical parameters of mining and environment are provided. These parameters are referred to ex- plicitly and implicitly throughout this entire docu- ment. Key reference sources utilised in the genera- tion of this document and/or considered important resources for actors wishing to pursue the topic further are also included here. Acid Drainage – Also commonly referred to as Acidic Drainage, Acid Mine Drainage (AMD) or Acid Rock Drainage (ARD). Acid drainage arises from the oxidation of sulphide miner- als and often occurs when such minerals are exposed to the atmosphere by excavation. Inci- dent rainfall or surface water is acidified when acid-forming compounds dissolve. Effects in- clude acid drainage from waste rock stockpiles and tailings, development of acid conditions in exposed surface materials, increased solubility and or release of metals, and increased salinity or solute loads in waters. Tailings – Residue from metallurgical process- ing (process wastes), mainly comprising finely ground rock. When ore bodies are extracted the valuable mineral is surrounded by gangue (un- economic material) that needs to be separated • •

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MINING FOR CLOSURE