Mineral exploration projects in regions with arid and semi-arid climate are challenging in many ways. Water is a principal resource and its low availability in these regions requires that the estimate of water availability be carefully carried out, because in a low amount it can make the project unfeasible. In addition to the low water availability, most dry regions present high annual precipitation variability. In other words, annual precipitation has large oscillations around its average value. From a water resource management perspective, the challenges cited may pose risks to mining projects in dry climate areas.
As a result, it is important to provide integrated and dynamic water balance modelling services of the various structures of the mine and their interactions with the climate for mining projects inserted in this context.
Flexible and robust models are developed to allow the evaluation of various scenarios (e.g., alternative sources of water, different arrangements of the elements of the project for optimization of water resources, adverse scenarios). Such models allow a direct and intuitive analysis of the sensitivity of its parameters, a step that helps in understanding the main sources of uncertainty of the model and guides on the need to acquire more data to increase the accuracy of estimates.
Due to the sensitive aspect of water resources in arid and semi-arid regions, SRK Consulting (Brazil) develops probabilistic models (GoldSim software) to quantify the uncertainty of the model, including the variability of climatic variables. It is believed that the accuracy of the model are important, but especially when water availability is not much greater than demand, a refinement of the model to identify the probability of failure is desirable for the management of water resources. The probabilistic and continuous approach of the models naturally allows quantifying the risk under a broad spectrum of severity vs duration of dry periods, besides allowing uncertainties between the layers of the model to interact with each other, which provides a more realistic estimate of the probability of failure in meeting the water demand of the enterprise on the project horizon. This is key information that seeks to contribute to the studies, assist in the evaluation of the feasibility of the project and the need for alternative sources of water.
With the investment in appropriate tools and models, the planning and management of water resources of mining projects in challenging regions in terms of water availability can be developed to identify and minimize risks and assist in the planning and operation of mining project.
