Coal Preparation » General
Correct outcomes from laboratory froth flotation testing in coal borecore exploration are critical to resource predictive potential, market evaluation and economic mining outcomes.
McMahon Coal Quality Resources (MCQR) has observed over many projects that froth flotation outcomes produced have incorrectly represented resource potential for product ash and yield - the resource then being misrepresented from misleading data. This has occurred through ineffective application of Australian Standard methods in particular relating to methodology variants (including reduction of minimum mass increments) and required reagent dosages (that may be different for each deposit and require trial and error stages that are often not easily attainable in borecore testing), and stage one / initial “no reagent flotation” that can be less effectual where lesser number of increments than required by Australian Standards are utilised. That is, modified tree flotation methods.
The objective of this project was to collate and evaluate data attained in froth flotation across several deposits to define effective methodology and reagent dosages. MCQR had attained flotation data utilising trial and error of various modified tree flotation methods and other methods. This project was aimed at defining best methods from those studies and relating those outcomes to coal quality. Coal quality parameters evaluated were mean maximum vitrinite reflectance (coal rank) and ash value of the froth flotation size tested - the latter being referred to throughout this report as the 'raw froth size ash'.
Froth flotation data sets were collated, and accumulated froth flotation data sets reviewed. Charts were created and outcomes and conditions of testing assessed for most and least successful modified froth flotation outcomes based on yield / product ash relationships, and comparison against ultimate flotation testing.
The outcomes of the project were the definition of the best outcome modified froth flotation method based generally on Australian Standards methods, definition of effective reagent dosages, an outcomes guide for different raw froth size ash outcomes, though on less increments than recommended by the Australian Standard. Australian Standard froth flotation methods were also reviewed and suggestions made for better of a modified froth flotation method based on the outcomes. This is thought to benefit the industry by providing more accurate froth flotation outcomes, save time and money in processing and reduce ambiguity in testing and outcomes.