Benchmarking and management of fugitive dust emissions from surface-mine haul roads

Dust generation from haul roads is a problem for most surface coal-mining operations and especially those in semi-arid and and areas. For these mines, which rarely have optimally designed and maintained roads, classifying different levels of dustiness, quantifying the impact on safety and assigning priorities within the constraints of limited capital and manpower are problematic. Techniques have now been developed for the description of fugitive dust emissions associated with ultra-heavy mine haul trucks running on unpaved mine haul roads. Benchmarks are established as five degrees of 'dust defect' for trucks travelling at 40 km/h, and computer models are used to assess the likely dustiness of haul roads as a function of surface loading of fines, traffic types and volume, together with various material parameters. For a typical South African Highveld colliery haul road reapplication intervals for water spraying were found to vary from 33 to 63 minutes for rear-dump trucks and from 21 to 41 minutes for bottom-dump trucks between summer and winter operation. The models can be applied, in conjunction with the results of quantitative exposure profiling, in management and mitigation strategies for water-based spraying.