Constructing water balance models using GoldSim™

SRK has recently incorporated the GoldSim™ tool as part of the range of services that the tailings and heap leach group offer to our clients. GoldSim™ is a general program that can be used to simulate almost any process, incorporating the probabilistic simulation of complex systems.

While applications for this software in the engineering field are extensive, SRK is currently limiting its use to the construction of water balance models. The aim is to visualise complex inputs, such as the probabilistic simulation of rainfall inputs, to cope with ever stricter Australian water regulations and waste management controls.

When dealing with water balance models for tailings facilities or heap leach systems, many of the controlling parameters, processes and events are uncertain or stochastic; ignoring this uncertainty can lead to poor decision making. Probabilistic simulation is the process of explicitly representing this uncertainty by describing model inputs as probability distributions. If the inputs, such as rainfall or evaporation are uncertain, the prediction of future performance of the tailings facility or heap leach facility is necessarily uncertain.

GoldSim™ uses the probability distribution of such recorded events as climatic inputs while uncertainty is propagated using Monte Carlo simulation. Then, the entire system is simulated multiple times and each individual simulation or possible ‘future’ contains randomly sampled parameters, selected from their probability distribution.

The water balance models that we currently prepare are focused on tailings operations. The most important parameters that we incorporate for the analysis are: tailings throughput, climatic data (probabilistic), stage capacity curve of the tailings deposit, capacity curves of the supernatant pond and return water pond, and beach angle, among others.

Using this tool in our models allows us to predict, with a given level of confidence, variables that are among the most useful for the tailings operator, such as freeboard, water reclaim allowable rate, and estimates of the volume of make-up water.

In the future we will be developing other useful applications for the mining and water resources industries, such as closure studies, evaluation of construction budgets, remediation studies, risk assessments and failure analyses.

Juanita Martin: jmartin@srk.com.au
 

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