Extreme weather impacts on the mining industry: An approach to estimate impacts of extreme rainfall events in Peru
Supervisors: Dr Simit Raval, Dr Wendy Timms, A Prof Michael Hitch, Prof Ros Taplin
The impact that extreme weather events may play in the sustainability of mining projects has been clearly identified in the last decade. The catastrophic consequences of the 2011 Queensland flood still remain as the primal example of severe impact due to weather events in the mining industry. This PhD study focuses on developing an approach to assess the potential vulnerability of mining regions and operations to extreme rainfall events towards designing a practical framework for its implementation at the local level.
From a mine design and planning perspective, there remains a lack of practical methodologies for the important consideration of the impacts of different climatic scenarios on mining. Given the operational consequences and economic losses that an extreme event can inflict on a mining project, a long-term life of mine scenario involving mine development up to closure and rehabilitation is needed.
Peru has been selected as a case study, due to its relevance as a mining country and vulnerability to extreme rainfall events and subsequent floods. During the first phase of this research, mining regions across Peru with differing potentials of being affected by extreme rainfall in the next few decades were identified via examination of future climate change scenarios. Then, an analysis of global climate projections for the precipitation extreme indices overall annual precipitation, average daily precipitation intensity, consecutive days of precipitation and number of heavy precipitation days was undertaken. Results of this study point out at positive variation in precipitation extremes for zinc project in Central Peru and gold project in Northern Peru. Regions in Southern Peru, which are dominated by copper mining, could face dryer conditions in the future.
This exercise provides relevant insight for mining companies exploring new developments, as well as for government bodies in charge of regulating and promoting mining activities at a country and regional level. The approach used for this research could relatively easily be expanded to other locations and extreme weather events. A case study of extreme rainfall events in Australia or droughts in Chile would be relevant in the mining context for those countries.
A second phase of this research will provide recommendations for a practical methodology to assess potential impacts of extreme rainfall events at a mine site level. The main objective of this work is to better estimate extreme rainfall risk at an operational level, providing with an extreme-rainfall-event risk assessment methodology and risk management alternatives. Expected benefits of this research will be in the form of revised equipment performance and productivity inputs for mine scheduling and planning, which take into account historical rainfall observations, mine data and climate projections. Future work is directed towards providing an assessment of productivity losses and ore reserves potentially impacted by extreme rainfall events at a mine-site level.
Fig 1. Variation of precipitation indices (a) r10mm, (b) r95p and (c) rx5day over Peru for the period 2015-2044 compared to 1971-2000. The variation in heavy precipitation days (r10mm), very wet days (r95p) and max 5-day precipitation amount (rx5day) is indicated as a percentage. Projections from the HadGEM2-ES_rcp45_r4i1p1 realisation were used to create these maps.
Fig 2. Upper figure: Variation in precipitation indices for all mining projects aggregated by commodity type. The variation is expressed in vertical boxplots. Outliers are represented beyond 1.5 times the interquartile range as filled circles. Lower figure: Number of mining projects per commodity type aggregated in mining super-regions.