Presentations

Understanding the influence and impact of fragmentation on cave performance.

The following presentations from SRK Consulting, UBC, and Geovia, and industry updates from New Afton and Ekati mines were first presented at Cave Mining Forum’s second workshop.
Click on the orange titles to see the full presentations.

 

Introduction | Jarek Jakubec

This presentation will discuss the design criteria directly impacted by fragmentation in the cave mining setting. It will also highlight some of the current tools available for prediction and analysis of fragmentation, as well as the reliability and potential short comings of fragmentation prediction.

 

Why Fragmentation is Important in Cave Mining | Jarek Jakubec

This presentation will discuss the design criteria directly impacted by fragmentation in the cave mining setting. It will also highlight some of the current tools available for prediction and analysis of fragmentation, as well as the reliability and potential short comings of fragmentation prediction.

 

Downstream Effects of Cave Fragmentation | Adrian Dance

This presentation will highlight one of the cave mining phenomenon related to surface and ground water. Water combined with clays and fine particles generated by having processes could result in mudrushes and mudflows. This presentation will also include the discussion about mitigation strategies and mudrush risk assessments.

 

Preconditioning via Hydraulic Fracturing – Updates from Recent Conferences | Michael Diering

This presentation will address a selection of papers delivered at recent conferences on the subject of hydraulic fracturing in cave mining. The focus will be on preconditioning with hydraulic fracturing and other applications of hydraulic fracturing in cave mining.

 

Results of a Cave Fragmentation Study Being Conducted at the New Afton Mine | Stefan Nadolski

As part of a cave-to-mill research program being conducted by the Norman B. Keevil Institute of Mining Engineering and New Gold, the fragmentation sizes for over sixty drawpoint muckpiles at the New Afton mine were measured using image-based methods to develop a model to predict hangup frequency and mill feed size. Relationships between fragmentation size, production data, and analyses of collected muckpile samples will be presented.

 

Evolution of Block Size Distribution Within a Draw Column During Block Cave Mining | Leonardo Dorador

This presentation will cover the evolution of block size distribution (BSD) within a draw column during block cave mining. BSD plays an important role in controlling gravitational flow, secondary fragmentation, and fines migration in broken ore—all of which are fundamental in preparing a reliable feasibility assessment for a potential caving operation. However, there is a marked lack of procedures for assessing secondary fragmentation and its influence on BSD, especially at the pre-feasibility level. Recent efforts have focused on the use of advanced numerical modelling, for which the level of detail required is suitable for advanced feasibility and mine design stages. A simple-to-use, empirical method for estimating BSD has been developed based on laboratory and field data reported in the literature. The method accounts for a combination of secondary fragmentation processes and fines migration under both isolated and interactive flow. The model is tested against field data from the El Teniente mine in Chile to calibrate it and determine its limitations. The resulting procedure provides an improved means of assessing secondary fragmentation and hang-up potential for pre-feasibility and feasibility level studies of large block caving projects.

 

Data Uncertainty and Data Variability: How These Important Parameters Influence the Characterisation of Block Caving Fragmentation | Davide Elmo

Particularly at the earlier stages of a rock engineering project, the lack of appropriate data manifests itself in the form of increased uncertainty and difficulties in characterizing rock mass variability in an objective manner. When mine-scale problems are considered, it is not possible to sample all of
the rock mass, therefore a relative large number of unknown parameters remains and model uncertainty increases. This presentation address several key questions about the characterization of fragmentation processes, for example: what are the critical parameters that we need to measure and what do we need to change in current practices? Engineers need to be aware of the implications that such limited knowledge (and increased uncertainty) could have on fragmentation analysis
and mine design in general.

 

Modeling Fines Migration in PCBC | Tony Diering

GEOVIA’s PCBC software has been used to model fines migration in various ways for over twenty years. There are three different flow mechanisms in PCBC which allow some form of fines migration to be simulated. The first is Pre-Vertical Mixing in which fines material is assumed to move downwards faster than coarser components. The second and third are Template Mixing and Cellular Automaton in 3D (CA3D). These methods utilize probabilities applied to coarse and fines
components. The presentation will outline how these methods work and provide examples showing how the fines migration can affect productions schedules, particularly with respect to early dilution entry. Examples of these methods will also be presented. The effectiveness of these tools as applied to projects with significant fines migration issues will be discussed.

 

The Evolution of Koala Cave | Rick Woodward

The evolution of the Koala mine, from open pit to inclined cave has taken place over a number of years at Ekati. This presentation will show some of the challenges of the open pit transition to underground mining, first as an SLC cave, and eventually to its current inclined cave configuration. It also touches on some elements of fragmentation, as well as challenges with wet mud events, and reconciliation.

 

Industry Updates on Fragmentation | Tyler Roberts and Grant Komelson

In this series of short presentations, subject matter experts from New Afton’s Geology, Geotechnical, and Mine Planning groups will discuss fragmentation from a practical, on-site perspective. The speakers will share their own data and findings from recent projects.

 

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