SimSched Pit Optimizer

Frequently asked questions

What is SimSched PO?

It is the only tool in the market for pit optimization that seeks the best undiscounted economic value for a mining project, whilst respecting practical minimum bottom width during the optimization process, and without the need for manual post-processing. This tool surpasses those using algorithms that disregard economic aspects. Furthermore, the generated pit surfaces do not have geotechnical glitches. .

OK, but what is the cost of this innovative technology?

SimSched PO is a free software, with free tutorials in multiple languages and with free support. To have complete access, simply register via the The first license granted will be valid for 6 months, which can be extended when the customer responds to satisfaction surveys, or recommends the tool for other professionals in the area, and there is a possibility for obtaining lifetime licenses.

It makes no sense. How does the company support itself?

SimSched PO is only a simplification of SimSched Direct Block Scheduler (DBS), which is the commercial software developed by MiningMath. In the context of direct block scheduling, or optimized scheduling, the pit optimization is nothing more than a schedule that has a single period, without process/waste dump limitations and no use of stockpiles.

Why should I use SimSched PO?

The great advantage of SimSched PO is its ability to define minimum pit bottom width within the optimization, respecting the operational requirements of the mine, by implanting proper adjustments to the pit walls rather than simply trimming of pointed pit bottom. The whole idea of optimization is to develop plans that are implementable in practice, rather than just glimmering numbers in a spreadsheet that cannot be achieved in real life. What mine planning professionals seek is a practical solution resulting in maximum undiscounted cash flow without geotechnical problems. Unlike conventional methods that use block precedence to define the optimum pit, SimSched is based on surfaces that ensure there are no slope errors in all sectors of the generated pit. For further information and technical details, please refer to the article CBMina 2014 - The impacts of slope angle approximations on pit optimization.

SimSched PO also allows surfaces to be imported for restricting certain regions from being mined if necessary, e.g. for environmental reasons, or to force mining in certain regions, for other strategic reasons of the company. Multiple economic conditions can be imported and you can generate a family of nested pits which comply with the required minimum bottom width.

There are many reasons for selecting SimSched PO such as, it is as a tool that will generate results that are closer to your project’s operational reality, it can provide educational materials, technical support, and above all because it is free. In addition, the importation process for SimSched DBS is identical to SimSched PO, so that the entire project can be configured and validated with SimSched PO, then a SimSched DBS license can be rented only for the required period, allowing you to analyze multiple scenarios of scheduling optimization without impacting the company's budget, and avoiding the cost of acquiring licenses and staff training.

Is SimSched PO suitable for my Project? What are the limitations of the current version?

The current version of SimSched PO suits any open pit mining project that is modeled with blocks of regular dimensions. If your project has sub-blocks, the model can be converted to the sub-blocks level to be optimized. If your project has multiple sorts of rock per block, there are ways to manipulate the inputs in order to handle these cases. SimSched is 100% based on 64-bit technology and has a highly efficient algorithm, capable of handling hundreds of millions of blocks without the need of supercomputers or cloud computing.

In terms of usability, the current version requires the user to calculate the economic values for ore and waste for each block, and if there is a need for producing nested pits, multiple columns of economic values can be created in the file to be imported. Until now, MiningMath has focused on developing intuitive and efficient algorithms that deliver value to the world’s mining projects, but future versions will certainly bring greater ease to users, including the development of components (plug-ins) to mining software packages in the market.

OK, it makes sense, but how could I buy a lifetime license of SimSched PO?

SimSched PO will not be sold as MiningMath believes that it is only by providing real value that people’s trust can be acquired. This is not a trick or a temporary offer; it is the company’s policy. If SimSched PO is enough for your business, research or studies, we want you to make a good use and bring us your feedback, so that we can continue improving the package. If you need a more advanced tool, regarding what is the most recent advances in open pit optimization, and based on proven technology, then we suggest you to carefully evaluate our zero risk policy and to make your own tests with SimSched DBS. .

Everything sounds very innovative and I still do not feel safe.
How can I be certain that SimSched PO works for my project?

We suggest you to test and compare it to the software of your preference. Alternatively, if you do not currently have an optimization package, format your data appropriately and ask the software suppliers that are being evaluated to provide you with a demonstration.

We suggest you to complete economic values calculations yourself and have them imported in each software, in order to avoid human errors or communication failure that might cause inconsistent results. Do not forget to make adjustments so that the minimum bottom width is respected, and to analyze the geotechnical errors report. Compare the surfaces graphically to verify the geotechnical consistency. Remember that the greater the geotechnical error the greater the pit economic value will be; to achieve a fair economic comparison, take the average error reported by the other software and add it to the slope angle(s) provided to SimSched, allowing you to quantify the observed slope error.

We suggest that for auditing purposes, in the first instance compare and report a single base case, in order to show the SimSched PO’s advantages described above. For the subsequent scenarios, every surface generated by SimSched PO can be used for reporting in the software of your preference, to show that the economic results and resources for the blocks contained in the pits are correctly reported.

SimSched PO’s algorithm is still being extensively tested on many real cases, including tests run by independent experts, and developments are presented in technical articles. However, if any inconsistencies are found, we will gladly analyze them and make the necessary adjustments.

If you can see ways to improve the product for your application please share your thoughts with us at, particularly if you think something is missing, so that we can include this technology in your working routine. We welcome the opportunity to consider and analyze your suggestions and look forward to meeting your requests.

Does SimSched PO have the Lerchs-Grossman algorithm (LG) implemented?

The short answer is no. LG was an innovative algorithm for its time, but there have been significant advances in the area of pit optimization over the last 40 years that are incorporated into the new generation of software packages, such as SimSched, that seek to overcome some of the barriers that LG have faced for decades and continue to face. There are also new software packages that implement the same mathematical model as LG, but are based on the Maximum Flow (Max Flow) algorithm. This algorithm can be run tens or hundreds of times faster than LG. However, both LG and Max Flow have no flexibility to include other important restrictions, such as a minimum pit bottom width or blending.

SimSched follows the most recommended framework, both by professionals and by research centers, which is the most advanced proven software available when it comes to optimization. It was implemented using modern techniques based on Mixed Integer Programming (MIP) and heuristics. SimSched’s mathematical model is highly efficient where you are considering a minimum bottom width, and using surfaces to return solutions without slope errors. In practice what is mined are surfaces, not blocks. This type of technology is flexible, and can allow the addition of other important constraints, such as blending.

Can you conceive a pit optimization that takes into consideration blending restrictions? It is not possible by using LG or Max Flow, but it is possible using the technologies based on MIP and heuristics.

In practice, how does SimSched PO perform pit optimization?

Straight from a block model, the pit is generated by defining the best destination for each block. It is possible to define, from the economic values, whether a block will be mined and processed, mined and sent to a waste dump, or not mined.

The resulting surface must comply with the parameters defined by the user, such as slope angles and a pre-defined minimum bottom width, allowing it to generate the final pit and the associated report.


Figure 1: Pit optimization steps performed by SimSched PO. A- Imported block model. / B- Blocks contained in the generated final pit. In red – Blocks assigned for the waste dump. In blue –Blocks assigned for processing. / C- Report generated by the optimization.

What is the difference between SimSched PO and SimSched DBS?

The main difference is that the DBS considers the impact of time on money: the discounted cash flow. The Net Present Value (NPV) of the project is maximized by taking into consideration a discount rate over the mining periods.

The PO version aims to maximize the undiscounted cash flow of the project. This is the maximum profit that the project can generate if the material is mined and processed without regard to time (infeasible in practice), which will not necessarily be the best solution, given the simplistic approach of this mathematical model.

SimSched PO is a simplification of SimSched DBS and will continue to receive most of the developments related to SimSched DBS, such as blending restrictions.

How can I get a license?

It is possible to get your free license through the link:

The license is valid for six months, and it may be extended by answering a brief survey: SimSched Pit Optimizer Beta Evaluation .

How can I learn to use SimSched PO? Is there any tutorial available?

It is possible to download the Marvin block model and a step-by-step SimSched PO tutorial without any cost through the following link: Tutorial Simsched Pit Optimizer - Beta - English.