Open Cut » General
The planning and operation of a coal mining operation requires a clear and up to date understanding of the nature of the coal that would be mined, the manner in which the coal would be upgraded in the preparation plant and the target specifications of the product that will be produced. The process of product prediction and beneficiation strategies begins in the exploration phase with the drill core and its characterisation through visual logging, geophysical wireline logging and bore core treatment programs. Such, characterization enables determination of the mining sections within a seam or seams across a mining lease, and blending and scheduling strategies to meet product specifications. The more data that can be gathered, the better, but there is always a cost. In addition, any changes to sampling approach (i.e. redefinition of plies) during the life of the project can create difficulties in integrating historical coal quality data to model for natural trends or surprises change product character. To address these issues, the application of core scanners to collect coal quality data is becoming more popular, but the task is to determine which methods or combination of methods are applicable and how best to analyse the data.
This project examines the application of hyperspectral and X- CT scanning to derive information on coal quality, in particular coal lithotypes and mineral matter composition that will influence breakage and washability predictions. Hyperspectral scanners analyse different wavelengths allowing the identification of the minerals occurring in a rock. This project furthers studies that illustrate its applications to minerals in coal, and to identifying the coal itself. It builds upon previous projects, that demonstrated methods for determining the relationship between impact energy, coal hardness, and density to predict the distribution of product size and density after a breakage event, and the use of X Ray to derive density and washability. Breakage was characterised by the JK Rapid Breakage Testing device and simple drop shatter of core samples with different lithotype compositions.
No single technique gave all the characterisation data, but the project demonstrated that most attributes could be related back to the lithotype. If so, then the attributes might be propagated across a deposit via the core scanners (eg Corescan® HCI-3 system, X-CT Scans), or eventually downhole scanners and wireline log data, resulting in higher granularity integrated 3D property models of the deposit. This finding has significant impact on the application of the protocol in the industrial application because it means that the workflow for the industrial application might only require the characterisation of the breakage and washability of the end members. A recommendation is to trial the image analysis approach on X-CT core scans or high resolution downhole images to derive the lithotypes and density simultaneously.