Water management is becoming a growing challenge for the mining industry. Thus, it is important to assess mine site water balance issues. Discover an approach based on metallurgical accounting to provide consistent water balance, and thus consistent water reporting.  An article presented during the congress oof the French Mineral Industry Society, SIM 2022.

Why perform water balances in mining

Water is a key factor in the implementation of a mining complex. It is involved in many issues that need to be understood to ensure its proper functioning: social acceptability, environmental and safety constraints, etc.

From a more operational point of view, the general decrease in grades in the newly exploited deposits leads to an increase in the quantities of ore to be processed and, consequently, to a greater consumption of water for the mineralurgical and hydrometallurgical treatment plants. A global trend towards the reuse of process water is emerging, but this recycling can have a significant impact on the operation of the plant: in addition to the quantitative need for water to ensure the continuity of operations, there is also a qualitative need, and therefore potentially the need to set up treatments, to guarantee the maintenance of performance.

Thus, linked to both technical and strategic issues, water management is becoming increasingly important. It requires, among other things, precise knowledge, i.e. of the quantities but also of the composition, stocks and flows of water on the site. In this context, the concept of water balance is increasingly encountered in a wide variety of sources, ranging from scientific and technical literature to environmental reporting standards such as those developed by the Global Reporting Initiative or the Carbon Disclosure Project.

Water management: the metallurgical accounting approach

But what are we really talking about when we talk about water balance? It is not always clear what the concept encompasses, and the scope it covers as well as the means to be used for its realization depend in particular on the objective of the approach.

The aim of this presentation is to detail the different frameworks in which a water balance can be carried out as well as the related purpose of this balance. The principles of the metallurgical balance, for which good practices have been established in the form of the AMIRA code P754, is then be presented, as well as their possible adaptation to the water balance via the parallel between the two methods. Finally, the implementation of water balances applied to the scale of a process plant is illustrated through different case studies corresponding to existing installations.

Authors 

• Etienne Braak, PhD. – CASPEO
• Philippe Wavrer, PhD. – CASPEO