SmartSimulation Mining Operations

1. Overview

Mines are complex systems. They are composed of multiple dependent processes interconnected through a wide array of complex relationships. Each of these processes is subject to statistical fluctuations (e.g. even in the same extraction point, the time to load truck 'A' is not equal to the time to load truck 'B') and therefore, the system as a whole also presents statistical fluctuations or 'aggregate variability'. 

Unfortunately, the aggregate variability of the system is not equal to the sum of the variability in each of the dependent and interconnected processes. In the presence of statistical fluctuations there is an accumulation of 'slowness' in the system. Therefore, the widespread use of averages is incorrect since it totally ignores the presence of variability throughout the system.

On the other hand, analytical models to calculate the aggregated variability of complex systems do not exist. So, Is there a way to estimate the system's variability? Is there a way to test the effect of changes in the variability of individual processes? 

The answer is yes. Computer simulation can help us in modelling the aggregate variability of the system, and evaluate different 'what if?' scenarios.

MineSimulator 3.0 is a computer simulation model that replicates open pit mine operations. The model is probabilistic, therefore it does not work with averages but using probability distributions. In this way the model produces robust and reliable results. 

2. Objective

• Total number of trips and distance,
• Total tonnage moved between each pair origin-destination,
• Queue statistics (e.g. maximum number of vehicles, waiting time, average number of vehicles),
• Route statistics (e.g. speeds, number of trips), and
• Statistics related with maintenance, accidents, and fleet utilization rate.

The main objective of MineSimulator 3.0, is to assist the decision making process in determining the number of productive resources (i.e. trucks, extraction equipment, and crushers) necessary to optimize the mining operation and maximize the production. Varying the different simulation parameters (e.g. fleet size, loading and unloading rates, truck speeds, failure rates, distances) different operational schemes can be tested. The comparison of the results allows the user to determine the effect of the individual changes and most importantly, the optimal number of operational resources.

3. Model Description

a) Software

MineSimulator 3.0 has been programmed using ExtendSim. Consequently, in order to run the simulations it is necessary to have a license for this software.

b) Road network

c) Extraction

d) Truck fleet

Since MineSimulator 3.0 is a probabilistic model, stochastic speeds are assigned to each truck before entering the routes.

The model also simulates mechanical glitches, accidents, scheduled maintenance, and other events specific to the mining operation that may leave temporarily out of service the vehicles or the extraction equipment (e.g. shift changes).

e) Dumps, stocks and crusher

MineSimulator 3.0 is able to simulate different discharge rates to each destination depending on its characteristics. The model is also able to monitor the queues of vehicles at each destination point.

MineSimulator 3.0 replicates in detail the crushing operation, including unexpected stops caused by the need of reducing the particle size.

f) Production program

MineSimulator 3.0 can simulate mine operations in two different ways: i) generating its own program assigning missions to trucks based on availability and distance to the origin, or ii) based on a pre-prepared program elaborated externally to the simulation model.

4. Statistics

MineSimulator 3.0 generates a set of statistics and operational indicators after each run. Results can be easily exported to EXCEL. Among these outcomes are:

• Total number of trips and distance,
• Total tonnage moved between each pair origin-destination,
• Queue statistics (e.g. maximum number of vehicles, waiting time, average number of vehicles),
• Route statistics (e.g. speeds, number of trips),
• Statistics related with maintenance, accidents, and fleet utilization rate.