Environmental and safety risk assessment in mines

Abstract

Mining is a hazardous operation and consists of considerable environmental, health and safety risk to miners. Unsafe conditions in mines lead to a number of accidents and cause loss and injury to human lives, damage to property, interruption in production etc. But the hazards cannot be completely obliterated and thus there is a need to define and reckon with an accident risk level possible to be presented in either quantitative or qualitative way. Safety is paramount in the mining environment. The mining industry has for many years focused on injury prevention at the workplace through procedures and training, and has achieved considerable success. However, the statistics on major accident events such as fatalities and reportable incidents has not shown the corresponding levels of improvement. In the area of major hazards control, the mining industry approach has emphasized mainly on past experiences and lessons learnt, while other high hazard industries such as the chemical process industry and oil and gas industry have taken system safety techniques to new highs. There are various methodologies and techniques related to the study of Risk Assessment, as profiled in the literature review in the last section. The next step lies in the application of these tools to create a Risk assessment or Disaster Management plan for the utilization in the mining scenario. It has been seen that Indian mines have not been applying Risk Assessment to the desired degree. For the appropriate method to be designed, it is important to address a few basic questions and design a step wise formulation of questions to be answered. The objective of hazards and risk analysis is to identify and analyze hazards, the event sequences leading to hazards, and the risk of hazardous events. Many techniques, ranging from simple qualitative methods to advanced quantitative methods, are available to help identify and analyze hazards. The use of multiple hazard analysis techniques is recommended because each has its own purpose, strengths, and weaknesses. Some of the more commonly used techniques include preliminary hazard analysis (PHA), failure modes and effects analysis (FMEA), hazard and operability studies (HAZOP), fault-tree analysis (FTA), and event-tree analysis (ETA). Environmental risk assessment (ERA) involves the examination of risks resulting from natural events (flooding, extreme weather events, etc.), technology, practices, processes, products, agents (chemical, biological, radiological, etc.) and industrial activities that may pose threats to ecosystems, animals and people. Environmental health risk assessment addresses human health concerns and ecological risk assessment addresses environmental media and organisms. ERA is predominantly a scientific activity and involves a critical review of available data for the purpose of identifying and possibly quantifying the risks associated with a potential threat. Identification of an emerging issue or priority for further action can result in a demand for ERA to determine whether an initial indication of a problem is valid or not. ERA provides the basis for most legislative and regulatory programs as well as for international agreements to address identified threats. If a threat to human health or the environment is identified through ERA, risk management is performed to consider the need to impose measures to control or manage the risk. A Safety Management System (SMS) consists of comprehensive sets of policies, procedures and practices designed to ensure that barriers to unwanted incidents are in place, in use and are effective. An integrated SMS focuses on both the traditional OHS area and on management of engineering safety. The SMS tends to integrate all aspects of safety into the ongoing activities of everyone involved in the operations—from the operator to the chief executive officer. The responsibility for safety is both individual and collective. FaultTree+ analysis program for Microsoft Windows enables us to analyse the availability and reliability of both complex and simple systems and is easy and intuitive to use. FaultTree+ provides an integrated environment for performing fault tree analysis, event tree analysis and Markov analysis. The program is rich in features and can model a wide range of scenarios. LOGAN for Windows™ allows the construction and analysis of Fault and Event Trees in the Windows™ Graphical User Interface environment. The option to edit Fault and Event Tree data files directly is not available in LOGAN for Windows ™ but as an alternative the files can be created or edited using a text editor such as Notepad. The Fault Tree module of LOGAN can also be used to solve problems expressed in success logic such as Reliability Block Diagrams and Success Logic Diagrams. We created two working programs for calculating the event possibility of a mine fire using Fault Tree and Event Tree analysis. The first program was created using C++ and FaultTree+ 11.0, latter being used to create the fault tree for the respective problem, and C++ to create the programming code. The program works on the simple input to a set of questions which are treated as basic events, and logic gates to compute the eventuality of a Mine Fire.