Nadolski, S, Cartes, I, Pizarro, G, Hesse, M & Moss, A 2024, 'Advancing orebody knowledge with high-resolution rock strength measurement using the Minpraxis tester', in Daniel Johansson & Håkan Schunnesson (eds), MassMin 2024: Proceedings of the International Conference & Exhibition on Mass Mining, Luleå University of Technology, Luleå, pp. 296-307.
(https://papers.acg.uwa.edu.au/p/2435_B-09/)
Abstract: The Minpraxis Tester (MPT) is a compression-breakage test device that treats half-core samples continuously length-wise, providing a high degree of rock characterization in comparison to conventional methods. Furthermore, it is able to extract this information while operating as a crusher when used in a conventional assay preparation workflow. This expands the characterized volume of a rock mass to include samples that were recovered for assay purposes, in other words resource core, and would otherwise not be measured with industry-standard methods. The additional resolution on a local-scale (order of 1cm) and the ability to test samples while preparing them for assay results in a significant increase (order of 1,000 times more) characterization data over conventional methods. 

Outputs of the device include geotechnical and geo-metallurgical parameters, such as point load Index IS50 and DropWeight-type indices, which are measured while capturing the variability of strength within core sections. 

The MPT device can also be used to test lump samples, which provides the capability to test core pieces that have broken apart during the drilling process as well as the ability to test lump pieces, such as remnants from failed unconfined compressive strength (UCS) tests, allowing a point load IS50 estimate to be determined from samples that would otherwise lack a valid strength measurement. 

This paper presents results from a range of geotechnical testing campaigns that were carried out using samples from a Goldex Diorite deposit to demonstrate the applicability of the MPT technology to predicting geotechnical parameters and its ability to capture an abundance of data that can be used for geotechnical block modelling and subsequently improving mine design activities.