Implicit Geological Modelling Is Here To Stay

Figure 1. Implicit geology model generated with the GEOVIA Geology Modeler.

Collecting comprehensive sampling and geoscience data from the field is the first step in an exploration or mining company’s quest to define the location, shape, and grade of an orebody. After that, the operations must transform their geoscience information into reliable geological models of the subsurface. Traditional explicit modelling methods do a great job of this, by providing geologists with the tools to visualise and build their unique interpretation of the deposits' geology, down to the smallest detail. Over recent years, implicit geological modelling methods and solutions have spread through the market and proved they are here to stay, largely in part due to ease of use, speed, and intelligence. Whether implicit modelling techniques generate better results than explicit methods remains a topic of discussion. Ultimately, both modelling methods are tools, and like any tool, in the wrong hands they can be misused. The ability of a geologist to make a model that accurately reflects and represents in-ground conditions is still determined by the skill, knowledge, and due diligence of the individual geologist, combined with adequate field observations and data support, as it should be.

For several years now, implicit geological modelling has been gaining ground on the highly trusted and widely used explicit geological modelling methods, and there are good reasons for that. In Figure 1., the comparison is made between GEOVIA’s Surpac (explicit) and Geology Modeler (implicit) solutions. The benefits of an implicit modelling solution are clear:

• Speed: Generate complex geological models in a matter of minutes.
• Automation: Build models in an automated way, saving time and making the process auditable and repeatable.
• Accessibility: Geology model generation is not dependent on the skill of an individual user, anyone within a team can update a setting, or add new data, and update the model.
• Traceability: Geology model revisions capture and retain modifications over time. This provides geologists with the capability to capture settings and input data and decisions made for each model generated, which in turn allows for excellent traceability and auditability. This provides geologists with the confidence that a geology model is generated using the right data.
• Integration: Modern implicit modelling tools can integrate with other platforms used across the business, which improves data security, management, and accessibility within other business processes (such as revision and lifecycle management, task management, issue management, risk management, or project management). Figure 2. shows how GEOVIA Surpac and the Geology Modeler integrate with Dassault Systèmes 3DEXPERIENCE platform.

Explicit models are accurate and reliable, but they are often created using repetitive manual processes. As such, they can be difficult to update when new data is supplied. This makes them time-consuming and difficult to work with when responding to changing business objectives or operational demands. It can take hours, and sometimes days, for a geologist to digitise all their wireframes, create the meshes, make sure those meshes are valid, and then use them in block modelling processes. An implicit geological modeller helps geologists automate that process, which in turn makes the process much faster, as well as fully traceable and repeatable. By reducing the amount of manual work geologists are now doing, an implicit solution gives them more time to spend in the field interpreting the geology or reviewing their data, in order to better understand the genesis and evolution of a deposit.

Implicit modelling

Implicit modelling is a process where a continuous mathematical representation of an attribute is determined across a volume. This approach requires minimal interaction from the geologist and the computational calculations drastically reduce the amount of time it takes to perform the modelling. This approach means model generation can typically be completed in seconds or minutes, an improvement across orders of magnitude when compared to explicit modelling methods applied to identical data.

Although there are many flavors of implicit geological modelling solutions on the market today, GEOVIA has decided to offer it with the following additional benefits and value. Firstly, and this is the heart of the innovation for the project, Dassault Systémes has developed its very own algorithms to make the RBF algorithm better and faster. Secondly, its solution is cloud based, which is fast becoming the new normal. It offers numerous benefits, such as efficiency and scalability; when needs increase it is very easy to scale up the cloud capacity. Lastly, it is integrated into the 3DEXPERIENCE platform which brings even more advantages. For instance, geologists in disparate locations will be able to inspect results from other mines using collaboration tools, and then be able to make and share their decisions more efficiently.

Why use the radial basis function?

The radial basis function (RBF) is well-known throughout the mining industry today for its use and adoption in implicit modelling. It has quickly become the go-to algorithm for building implicit geology models. This algorithm defines how each point in 3D space is interpolated, based on the cloud of input data points. The RBF is well suited to multivariate interpolation with scattered data, fitting all input source points and generating a smooth surface. It also works well with a non-uniform set of data points and provides good extrapolation results.

Data management

An accurate and representative geology model is only as good as the data that feeds into it. This is reminiscent of the phrase ‘rubbish in, rubbish out,' and it is certainly no different with geology models. Diligent and robust data management and validation practices are essential in ensuring accurate, reliable, and representative geology models. Geologists must manage the mass of geoscience data collected by geoscientists, engineers, consultants, and contractors. This includes drillhole records, geological and geophysical field observations, geochemical, lithological, and remote sensing data, assays, etc.

Many exploration and mining companies today work with explicit modelling software, that is often centred around a file-based approach, where data and files are stored in folders locally on the user’s machine or file servers. This traditional data management tends to be slow, subject to human error, and, as a result, often causes rework or delays.

A business enterprise platform, leveraging a unified data model, either on-cloud or on-premise, provides a secure central data repository where geologists can store geoscience and mining data in any format, structured or unstructured. From there, all geoscience data, along with all other data, such as parametric mine designs, pit optimisations, infrastructure, simulations, land use, etc., will become part of a unified data model where one data source will always speak to another, and all data is interconnected and relational. Whenever a new piece of data arrives in the repository, it is updated across the platform.

Greater control

How can implicit modelling methods leverage data and benefit from pre-existing explicit geology models to give geologists a better representation of the sub-surface environment? The GEOVIA Geology Modeler provides features to give control back to geologists, these are explained below:

• Constraint lines: Associate or digitise polylines within implicit modelling processes, to support the available borehole data to realise desired outcrop patterns or cross-sectional interpretations within an implicit geology model.
• Explicit intrusions/orebodies: Associate explicit solids within an implicit modelling process, to gain explicit control over high-priority domains, while still implicitly modelling surrounding geology and structures.
• Pinch-outs: Globally control the taper of a pinch-outs.
• Structural measurements: Utilise downhole structural measurements to better model faults and/or folded deposits.
• Dynamic isotropy and trend surfaces: Quickly model the changeable geomorphology of orebodies and/or intrusions.

These features and more make for a comprehensive implicit geology modelling solution, which makes it possible for geologists to revise and refine models until they generate the exact model that they need, within an automated and repeatable process. This allows geologists to spend time getting the geological interpretation right, giving them confidence in the resulting implicit model.

Figure 2. The Geoscience Data Administration application provides geologists with the tools to manage borehole revisions, track changes over time and revert changes when needed.

Read the article online at: https://www.globalminingreview.com/mining/02042025/implicit-geological-modelling-is-here-to-stay/