In strategic mine planning, you often deal with modelling variable throughputs and recoveries that depend on the blend of rock type coming into the processing plant. Yet, many of you have found it difficult to accurately model this relationship in mine planning software.
For example, you might get a solution that includes a processing plant with multiple blends, operating in the same time period. This may be impossible for your operation or difficult to achieve for your processing plant, leaving you with a strategic plan that is impractical. So what can you do about this?
The latest version of Minemax Scheduler gives you an advanced level of control to model mineral processing in your strategic mine plan more accurately. This means you can now ensure that only one blend is active at a time to develop more reliable plans.
Read on to see how easy it is to set this up.
Model Overview
Let’s consider an open pit mine with a mill, leach and a waste dump. The mill has 5 different throughput possibilities depending on the percentage of the blend of rock type A. This is shown in the diagram as processes: Mill_Blend_80%, Mill_Blend_70%, Mill_Blend_60%, Mill_Blend_50% and Mill_Blend_40%. In addition, each blend has a different recovery.
The material type ‘Rock type A’ is defined as an attribute for all the above processes and is used to constrain the schedule in the next step.
Constraints Setup
To ensure that each blend is receiving the correct blend ratio, we define blending constraints listed below:
- 85% < Mill Blend 80% ≤ 75%
- 75% < Mill Blend 70% ≤ 65%
- 65% < Mill Blend 60% ≤ 55%
- 55% < Mill Blend 50% ≤ 45%
- 45% < Mill Blend 40% ≤ 30%
They are defined in the Constraints menu as minimum and maximum attribute constraints:
Modelling Mineral Processes
The new Mineral Processing functionality is utilising the capital expenditure menu where blends Mill Blend 80%, Mill Blend 70%, Mill Blend 60%, Mill Blend 50% and Mill Blend 40% are selected into a mutual exclusive set.
This means only one of these blends can be selected at once. In addition, when the per period tick box is ticked, one blend might be selected in one time period while another one might be selected in the next time period. Minemax Scheduler‘s optimization engine selects the optimal blend for each time period that maximizes the Net Present Value.
Results
The Reports screen shows throughputs for the selected combination of blends. Here, you can see that only one blend is active in a single time period. Mill Blend 80% has been used in 7 time periods, Mill Blends 70% and 60% have been utilised in 2 time periods, Mill Blend 50% in 1 time period while Mill Blend 40% has not been utilised at all.
In the Total Metal movement chart, you can see that mill metal produced over time varies depending on the blend that’s going in.
Summary
In this article, you have seen how easy it is to model mineral processing in Minemax Scheduler, ensuring that your processing plant is configured with the optimal blends for each time period. This level of control gives you the tool you need to create accurate and reliable strategic mine plans for your operation.
For more details on modelling mineral processing in Minemax Scheduler, contact our mining consultants who are always here to discuss your particular requirements.