Planning for the weather

Materials World magazine
,
1 Mar 2015

Philip Beauvais, from the Met Office’s International Mining and Agriculture Department, explains the need to understand the impact of the weather and climate when developing future mine sites.

It is increasingly important that weather and climate are taken into account when planning any major engineering site or operation, particularly mining sites, which could run for more than 30 years. Environmental and social impact assessments (ESIA) can help to ensure this happens. ESIA is a process designed to identify, analyse and evaluate the environmental effects of proposed projects and ensure any findings are factored into project decision-making. An effective ESIA should contain good environmental information, including on the climatology or past weather of the area and future climate change projections.

An ESIA focuses on the impacts of establishing a large site at a specific location. A major part of the report involves the potential impacts on local weather patterns and climate that may develop. It focuses on three areas:

  1. Understanding baseline meteorological conditions for the site area.
  2. Predicting and evaluating the potential changes in these baseline conditions resulting from site activities.
  3. Identifying the measures that the project will take to avoid or compensate for resulting impacts.
  4. Understanding baseline meteorological conditions

Mines are major working sites, often with access roads and rail, and a port out of which the ore is shipped. In the planning stages of such a site, it is important to have accurate baseline weather data. This can be provided using existing observations that are recorded by national weather services in all countries. However, if there are not consistent, uninterrupted observations for a site, synthetic weather observations can be used. Forecast models allow this type of weather information to be provided for any global site. This can be used to complement existing observations in order to generate the recommended 30-year climatology, or weather history, for a particular site.

If you do have some weather observations for your site, whether from your own installed equipment or from previous records, synthetic observations can be used to extend the records and provide an understanding of localised weather variability over a longer timescale. This is important to capture longer-term influences to climate variability, including flooding and drought. 

When the basics change

Understanding the local climate gives an idea of the average temperature, precipitation and wind, and this can help a company plan for the future. Climate change predictions forecast how those boundaries are likely to change over the coming century. Understanding how weather impacts business activities is the best way to predict what the associated environmental and social consequences are likely to be.

The conceptual stage of site development may also benefit from an overview of how climate change could affect the proposed location. The aim of this would be to highlight some of the key areas that should be considered in the later stages of the ESIA. How can the threats and opportunities of weather and climate change be factored into decision-making or operational practices, to ensure that resources are effectively allocated to reduce risk and increase potential returns?

There is a real need to consider weather and climate change as an integral part of a mine’s strategic planning and operation. As the lifetime of a mine can be 50 years or more, it is vital to understand the changing environmental risks throughout this time period and consider how to adapt to those changes. A detailed understanding of the local impacts of climate, taking into account accurate past weather at the planning stage, can reduce the risk that operations could be compromised by a lack of water resources or flooding later on. 

For instance, snow storms and deep snow fall is common in Central Asia, losing many working days. When investors looked to reopen a mine there, they needed to know how the local climate might change and how the number of working days lost as a result of weather would be impacted.

Access roads and railways are also affected by flooding. A port built just to serve the mining area will be subject to changing currents, waves and surge pattern as sealevels change. 

Powerful techniques for high-resolution site analysis have been developed by the Met Office to investigate in detail the impact of mining activities anywhere in the world on local weather patterns. This is particularly useful, for example, when looking at mountain-top mining in regions where rainfall is influenced by local topography. Weather forecast models are run at very high resolution for historical case studies where the local topography is likely to have had some impact on rainfall patterns. The topography of the model is then adjusted to simulate the mining activity and the model is re-run. The results from the two models are then compared. By repeating this for several scenarios (dry or heavy rainfall periods, for example) it is possible to understand the overall impact of mining operations on the climatology of the site. This can then be used by hydrological and vegetation modellers to understand the resulting impact on the local environment.

A 250km pipeline to carry minerals was planned for South America from a mine with a projected lifespan of 40 years. The company needed reassurance that sufficient water would be available throughout the duration of the project. An ESIA study provided data that enabled engineers to substantially modify sea defences and port structures to prevent unforeseen erosion, as well as provided information that could be used to change the priority given to water catchment licensing.

Dodging the bullets

As part of initial feasibility studies, a detailed study of how climate change is likely to influence the environmental and social impacts of a proposed site can be developed and the relative impacts of activity and climate change can be assessed together. Ultimately, strategies can be developed from the outset that will minimise the impact of both climate change and production activities on the surrounding environment. 

Operations can be optimised and environmental impact minimised by taking account of weather and climate in both day-to-day planning and strategy. For example, through the completion of a detailed climatological study, as part of an ESIA, a number of weather sensitivities may be identified. A climate change study will then identify how these sensitivities are likely to change throughout the lifetime of a site. These can then be used to inform both the design of the site and its operation.

Knowledge of the weather conditions that impact a site’s operations on a day-to-day basis can also be used to tailor site-specific forecasts, which can provide warnings of severe weather. This allows management to consider moving expensive equipment and personnel away from danger and checking the drainage systems are working properly. This all improves the safety, efficiency and environmental performance of the site. Knowledge of the forecasts can help reduce down-time so that production tonnage is disrupted as little as possible.

It is important that we understand the environment and the weather and climate that we are operating in. By properly integrating these factors at the heart of an ESIA, we can minimise disruptions and costs in both the short and long-term and can maximise the profitability and lifespan of operations.