UBC Theses and Dissertations

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UBC Theses and Dissertations

Atmospheric fuzzy risk assessment of confined spaces at mine reclamation sites Mohammadi, Ladan


In 2006, a tragic accident took place at the Sullivan mine in Kimberley, British Columbia. Four people died as the result of their entry into an oxygen-depleted sampling station located at the toe of a waste dump. The dump had been in active use for over 50 years and the sampling shed for about 5 years without any problem. The accident was reported as being unprecedented in the history of mining. The accident shows that reclamation sites can be an atmospheric danger only recognizable if a risk assessment is carried out on a regular basis for many years after closure. It is important to conduct regular assessments since there are physical, chemical and environmental factors that affect oxygen-depletion in waste dumps that change over time. In this thesis, an Atmospheric Fuzzy Risk Assessment (AFRA) tool was devised to recognize confined space dangers at sulfide waste dumps undergoing reclamation. The tool is a fuzzy expert system to transfer knowledge on atmospheric hazards. Modeling the complex environment of a waste dump where internal and external factors change temporally and spatially using conventional mathematical tools is a difficult task. Therefore, a technique based on fuzzy logic and weighted inferencing was applied since this method relies on a heuristic approach that allow for case–based reasoning. AFRA can help mining engineers and other safety professionals to recognize this type of danger while developing a confined space inventory at any site. The second goal of this research has been to create an application for hand-held pocket PCs and/or Smart phones that can be used by first-responders to provide answers about a possible confined space situation to help them decide to enter or not into that space.

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