On the bulk compressibility of natural iron ore fines and its impact on stockpile density

The bulk density of a large stockpile containing natural iron ore fines is a critical parameter for accurate production accounting purposes. A uniform bulk density and the hydrostatic stress distribution represent inaccurate conditions within the stockpile. This study presented a theoretical and experimental suite of work to investigate effects of the moisture content and the major consolidation stress on stockpile stress and density distributions. Water-particle bonding states and associated macro pore structures in natural iron ore fines with the context of stockpile stress modelling was reviewed and expanded to study the stress propagation from the base to surface. A suite of natural iron ore samples were selected and bulk compressibility tests were conducted to investigate correlations between the compressibility, the moisture content and the major consolidation stress, with which a global stress and bulk density modelling methodology was developed. A simplified modelling procedure was proposed to for easier stockpile density distribution modelling in engineering applications. The findings enable improved density and total mass reconciliation for a large iron ore stockpile for more accurate production accounting.