Chapter 2

Data collection

Using advanced data analytics to get more from drilling data: applying data science and AI methods on core image data

By Parham Adiban, Consultant (Data Science/Geology), SRK Consulting

Efficient data collection is crucial for making informed decisions about resource extraction and management. One of the emerging techniques in this field is the use of AI methods such as image segmentation and convolutional neural networks (CNNs) to automate the process of logging core images. This technology aims to optimise how geologists and mining engineers analyse drill cores, by allowing them to collect quantitative and semi-quantitative data that has not been collected or cannot be collected by logging geologists. Automated logging is faster and more cost effective relative to a logging geologist or a photo relogging campaign.

Traditionally, logging drill core is a labour-intensive process that involves visually inspecting each core and manually recording observations. However, recent core logging studies, including SRK led projects, have demonstrated the potential of using photos to extract valuable information directly from the image data. This approach leverages machine learning techniques to automate various aspects of core logging and augment the work of geologists.

Instance segmentation techniques can be employed to identify every vein along a core and quantify veining intensity within geological domains. Similarly, these techniques can detect breaks and rubble zones, providing insights into zones of deformation. This information is crucial for understanding the structural integrity of the rock and planning safe and efficient mining operations. Instance segmentation can also be used to assess the core damage index, which is important for geotechnical evaluations. By automatically identifying damaged sections of the core, engineers can make more informed decisions about the stability and safety of the mine.

Image classification models, such as ResNet, can be trained to identify different lithologies, alteration and foliation intensities from core images. This automated classification helps in creating more detailed and accurate geological models, which are essential for resource estimation domaining and mine planning.

Despite the promising advances, there are challenges associated with the variability in data collection. Factors such as core size, core box material, photography tools, lighting conditions and image distortion can all affect the quality of the data. Additionally, historic data collected using older methods and equipment may not be directly compatible with automated logging techniques.

To address these issues, there is a growing effort within the industry to standardise data collection techniques. Using specific photography equipment to minimise distortion and incorporating colour scales to correct for lighting variations are steps in the right direction. Moreover, tools are being developed to make corrections to historic data, ensuring that it can be used effectively with modern automated logging systems.

In conclusion, the integration of image segmentation and CNNs into geological core logging is positively affecting the mining industry. While challenges remain, the collective effort to standardise data collection and improve data quality is paving the way for more efficient and accurate geological analysis. As these technologies continue to evolve, they hold the promise of further reducing costs and enhancing the overall efficiency of mining operations.

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Influencing drilling decisions

By Alex Tunnadine, Principal Consultant (Geology), SRK Consulting

As we progress towards the energy transition we face a shortfall in the metals required to meet decarbonisation targets. S&P Global Market Intelligence predicts annual global copper demand will nearly double to 50 million tonnes by 2035, yet global exploration spend and discovery rates remain well below historical peaks and the average time from discovery to mine production has ballooned to 15.7 years (S&P Global Market Intelligence).

2022 global exploration spend was a mere US$11.24 billion, barely 50% of the 2012 peak (US$20.52 billion) with US$2.9 billion (26%) directed to grass roots exploration, well short of 41% in 2007. Unsurprisingly, discovery rates have faltered, as just 65 initial resources were announced in 2022, compared with 175 in 2012 (S&P Global World Exploration Trends 2022).

Given this investment scenario, explorers must adapt and find cost-effective, innovative ways to efficiently and effectively make discoveries. We must seek improvements in data collection and develop effective methods for the timely communication of findings to key stakeholders and decision makers.

One important area that has been a focus for developing more innovative and better methods of data collection and analysis is at the drill site. Various lab-at-the-rig type solutions (discussed elsewhere in this edition) can be paired to innovative workflows for field data collection,allowing a seamless flow of ‘live’ data to inform exploration decisions in near real time.

One such example is the implementation of near real time modelling to influence drilling decisions. Key downhole data can be modelled as it is logged using implicit modelling software. By implicitly modelling logged estimates of sulphide species, sulphide abundance, vein abundance, alteration mineralogy and intensity alongside existing data we can better inform decisions in real time on navigational drilling, end of hole depth, design of the next drill hole and/or broader programme strategies.

Given turnaround times for assays can be longer than the length of a drilling programme, it is possible to utilise well-calibrated core scanning, pXRF or spectrometer data as interim inputs to the near real time model. Data derived from these can overprint the visually estimated data to increase the confidence of models, in turn being overprinted as assay data is received.