A respected engineer once said, “There is no way out of a bad pit design”. It is a statement that resonated with me. The only solution is to get the design right before you implement it. Given the increasing costs of extraction, high operational efficiency supported by an accurate and practical mine plan is more important than ever.
A good open pit mine plan starts with the pit optimization/design and the assumptions and decisions made throughout this process. Ideally, the design should be such that the pit is operationally efficient: within the mining rights area and away from exclusion zones, low strip ratio, minimizes haulage distances, maximizes ore recovery, supports production targets, and is compliant with geotechnical and safety restrictions. These aspects often need to be traded-off. It could be the situation where one needs to choose between more flexibility for the haulage ramps or lower strip ratio, or maybe a larger pit will reduce the space for stockpiles and waste dumps. There is really one way to go, which is to test the different options and choose the one the yield the best result.
Whilst engineers will start a design with the best intention of optimizing these aspects, it is often disregarded when someone sets the due date for the project. Now there is another variable in the equation: time. Time is something that engineers often don’t have, or at least not as much as we would like to. This often leads to suboptimal compromises being made to meet the deadlines. Sound familiar?
But what if you didn’t need to make that compromise because the tool you are using allows you to rapidly generate alternate practical pit designs, so that you can test the options you want to test and still meet that deadline?
I recently completed an assignment with a major mining company in Australia where I was asked to deliver around 6 pit designs for three different scenarios, including ramps position, water table effect and possible pit extensions and I was given a very tight deadline. Some of the challenging points of the project:
- High strip-ratio sensitivity
- High haulage flexibility needed
- Tenement/mining rights space extremely constrained
- Hilly topography with difficult access to the upper benches
- A number of heritage sites located close to the pit
The key point of this work was to define the pit accesses to achieve the highest haulage flexibility possible and understand how that would affect the remaining area for the large waste dumps (more than 250 Mt capacity), ROM pad, stockpiles, and other local infrastructure features (which was also extremely space-constrained). And of course, the cliché: minimize the waste and get all the high-grade ore.
My weapon of choice for the task was Datamine’s auto pit design solution Studio OP. I was able to create multiple design options for each of the pits within a weeks’ time. It was a very iterative process in which the space constraints for the waste dumps and ROM pad required several design iterations until all the surface features could be accommodated with a reasonably flexible haulage network.
The result was 3 different designs for 2 different 300 Mt pits with more than 10 different ramps and a good match to the optimal shell (<5% difference). And it was delivered on time.
I could not have done it without Studio OP.
What is your daily struggle when doing your designs? Let us know by leaving a comment and find out how Datamine can help to increase efficiency and optimize your open pit design workflows.
Datamine Australia is expanding the consulting portfolio with Technical Secondments.
The Datamine expertise is already widely known inside of the mining industry. After exciting acquisitions such as Snowden and Minemax, the Australian team have expanded the current consulting portfolio, growing the technical secondment department.
Technical secondments on site (or main office) are a Datamine expertise providing services related to:
- Open pit optimisation
- Underground Stope optimisation
- Open pit/Underground design and scheduling
- Open pit/Underground Drill and Blast
- Drillhole planning and Grade control modelling
- Resource modelling and estimation