Coal Preparation » Fine Coal
Accurately estimating the proportion of expected fine size material (typically -1 to -0.125mm) from coal borecore exploration is critical to design and operation of coal handling and preparation plants to process the coal, and in resource predictive potential and economic outcomes.
Interaction with process plant personnel indicates that, in particular, underestimation of fine material from borecore predictive outcomes occurs with some frequency. Thus ensues under-designed plants fines capacity and restrictions of plant throughput and / or economic burden of increased capital and operating expenses, and inaccuracy in prediction for yield. Additionally, troublesome fines generating stone bands that are known to cause difficulties with excessive fines in coal handling and preparation plants (CHPP) are observed to produce minimal fines from standard laboratory practices of drop shatter and wet drum tumbling.
This projects objective was to devise and test attrition methodologies on small samples such as borecores to better determine predictive size distribution.
Attrition methods using currently available laboratory apparatus were trialled on minimally broken coal from a “Bulk Strip” (strip sample) and a “ROM Bulk” (stockpile sample). These were compared against plant feed / in-plant samples (companion plant feed samples - that were taken of the same coal source as the Bulk Strip / ROM Bulk sample, at approximately the same time of mining and processing), CHPP operations data and operator expertise in relation to predictive / actual size distributions was also sought, documented and used in the planning and evaluation stages.
The outcomes of this project were the design and testing of currently available laboratory preparation apparatus, for additional breakage definition. This was attained from the described “Bulk Strip” and “ROM Bulk” samples, and comparison of outcomes with companion plant feed samples, historical plant feed samples, ALS pilot plant sample and proximal borecore washability tested outcomes. Successful apparatus and method for use were produced for application to routine unbroken coal predictive samples (borecores and strip samples).