Water Balances of Tailings Impoundments, A New Approach

Abstract

Traditionally, tailings impoundment water balances have been developed based on theoretical models supported by the experience of the consultant developing them.

The traditional models consider as inputs the water contained in the tailings as well as rainfall water, and as outputs the water retained in the tailings considering a 100% saturation, evaporation and infiltration into the foundation soil.

A key aspect to understand is that water release is a dynamic process, i.e. it is a function of time. This phenomena occurs simultaneously with evaporation and with downward migration of water under the influence of gravity and soil suction, with the greatest amount of water which is possible to be recovered from a tailings impoundment being determined by the difference between the released water and the evaporated water.

Generally, the evaporation data which is incorporated in a water balance is based on the records. However, the rate of water release needs to be computed from models. This study presents a new approach for developing tailings impoundment water balances by incorporating dynamics in the water release phenomenon. A comparative analysis between a water balance developed based on the traditional method and a water balance developed based on the results from laboratory analysis (using the data from a campaign conducted for a copper Peruvian mining company located in an arid region), is included in this work.