New grade control optimiser

A new approach to classifying material for mining eliminates the manual generation of polygons, taking the guesswork out of grade control while maximising economic value.

Maptek Vulcan Grade Control Optimiser generates optimised and practical mineable polygons in a repeatable, auditable process.

Grade control is vitally important at open pit mines. Decisions are made daily about where to send the newly mined material, and in this fast paced operating environment sub-optimal decisions have an immediate, irreversible impact on the mine’s bottom line.

Open pit mines must balance the correct decision based on the geological model and analytical data, with the practical solution which accounts for the mining method. Current practice involves drawing polygons by hand, with only a cursory focus on maximising value, and does not provide the ability to conduct robust sensitivity studies.

The current process is not repeatable as different engineers can classify material differently according to their experience.

A new tool in Vulcan, the Grade Control Optimiser, tackles the problem in a different way.

Instead of a single result digitised by an engineer, the Grade Control Optimiser generates thousands of solutions and evaluates them to achieve an optimised result. Depletion from ore loss and dilution is minimised, while satisfying mining parameters.

User-defined constraints

The Grade Control Optimiser uses a variety of optimisation techniques from exact to meta-heuristic, to achieve a meaningful result, faster and more accurately than could be done by hand. The process is also repeatable and auditable. Optimisation can be guided by economic value, or by cut-offs to minimise misclassification.

Mineable polygons are then automatically generated to delineate the different regions. These polygons are controlled to limit vertices and sharp angles, which creates proper operational polygons that can be staked in the field and mined when required.

Any changes to the polygons are reflected quickly in reporting of tonnage, grade and value.

Generating grade control polygons automatically leads to more in-depth analysis. An open pit mine may have a range of equipment available, some larger and less selective, and other smaller equipment that is able to more carefully extract different ore types.

The value of the more selective equipment must be quantified in order to make an informed decision. The Grade Control Optimiser may be used to generate different polygons for each choice, and the true impacts of ore loss and dilution may be measured.

This innovation provides mines with the ability to optimise their daily activities and avoid expensive mistakes.

Grade Control Optimiser was developed over the last year in partnership with Newmont and Barrick, and is being evaluated at several other sites.

Grade Control Optimiser was released alongside Vulcan 10.1.2 and is available for purchase now.