Mine haul road fugitive dust emission and exposure characterisation

Abstract

Excessive dust generation from unpaved mine haul roads is a problem common to most surface mining operations and especially so in semi-arid and arid areas. Optimal wearing course material selection parameters reduce, but do not totally eliminate the potential to produce dust. Mines rarely have optimally designed and maintained roads, and the problem of identifying the haul road dust defect, quantifying its impact on health-risk and assigning remediation priorities within the constraints of limited capital and manpower is problematic. This paper describes fugitive dust emission and operator-exposure characteristics associated with mine haul trucks running on unpaved mine haul roads in Sub-Saharan Africa. Following a description of fugitive dust emission rate models developed, the methodology of operator-exposure profiling by quantitative dust sampling for airborne particulate matter is described. Typical Air Quality Indices that a haul truck driver would be exposed to during a typical cycle are reported following the South African Mines and Works Act (78/1973) Guidelines. The majority of truck driver exposure was attributable to loading and dumping activities with the haul roads and ramps themselves accounting for between 10%-15% each of the total exposure (open cab) and 5-10% each (closed cab). A 30%-55% reduction in dust concentrations measured in a closed cab as compared to an open cab were realised. Through the combination of these models with the results of quantitative exposure profiling, it is shown how a mine can effectively reduce worker exposure and health-risk by adopting appropriate haul road dust palliation strategies.