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Optimization of coal recovery and production rate as a function of panel dimensions 65

5.2 Panel width and production rate

In this section, a discrete-event simulation approach to determine the relationship
between panel width and production rate is described. A case study is used to illustrate
the proposed approach, which is based on previous research [1].

5.2.1 DES of production rate vs. panel width

Discrete-event simulation is useful for evaluating what-if scenarios without expensive
field experiments. It is also useful because it can estimate the performance of
nonlinear and implicit systems and account for the stochastic nature of mining activ-
ities (such as hauling, loading, and dumping). In this section, DES is used to estimate
the production rate of an R&P coal mining operation given the currently used panel
width, equipment fleet, and cut sequence. The approach taken to study the coal cutting
and hauling system is to
1. Build a valid DES model of coal loading, hauling, and dumping operations;
2. Determine the feasible range of input variables (panel widths, fleet size, and cut sequences);
3. Estimate production rates for all feasible values of input variables using the model.

5.2.1.1 Build a valid DES model
The general discrete-event modeling framework, which has been successfully used by
many authors [1, 9, 10], includes the following:
1. Formulating the problem to be solved
2. Defining system and simulation specifications
3. Formulating and constructing the model
4. Verifying and validating the model
To study the relationship between production rate and panel width, this framework
must be adapted for R&P mining. The analyst must understand system constraints,
stakeholders’ expectations, and the performance matrix needed to validate the model
in order to clearly formulate model objectives. In this case, the simulation problem is
to build a valid model capable of predicting the production rate for different panel
widths using user-specified cut sequences and fleet sizes.
In order to construct such a model, it is essential to understand how the system
operates and define its specifications. Thus, the loading, hauling, and dumping logic
for the R&P mine must be defined to construct a model that predicts a production rate
for given input variables. DES modeling requires the modeler to specify entities,
resources, and processes of the system. To initiate the model, entities go through
defined processes in a logical manner waiting for needed resources to become avail-
able at each process (i.e., resources are “busy” if they are being used by other entities)
before they go through the process. Resources are static entities that provide services
to other entities and processes. Typical resources include loading and dumping equip-
ment; for example, the continuous miner (CM) and the feeder breaker (FB) in an R&P
coal operation. Hauling equipment is usually defined as entities or transporters.