Abstract

Dust generation during mining, especially open-pit mining is a nearly inevitable issue that requires mitigation on many mine sites. Dust inhalation poses risks to worker health and, depending on location, community health or enjoyment and thus mines are typically required to employ various dust abatement methods such as sprinklers on tailings storage areas or water trucks on road. However, these require frequent re-application and water use and they don’t work well on steep slopes, such as pit walls, reject piles, etc.

Some recently developed foam-based dust palliative compounds were evaluated for their effectiveness. However, product safety evaluation requires that a product is both effective and (environmentally) safe. The composition of new products is commonly proprietary and may contain substances for which analytical methods are not available, presenting a challenge for evaluating product safety.

In the absence of analytical chemistry methods, biological testing provides a direct measure of the potential for environmental harm and was therefore the approach adopted. The palliatives would be applied, first in a field trial, using a foam applicator to steep slopes. The dust palliatives tested prevent dust by adhering to soil particles. We thus postulated that this adhesion might reduce exposure by ecological receptors and that the product adhesion to site materials could be tested by comparing the acute toxicity of the dust palliative with and without mixing with site soils. This hypothesis was tested using standardized methods of elutriate generation and testing the toxicity of the elutriate.

An experimental design aimed at simulating the foam-product application conditions on site using site materials and the application of a variety of concentrations. The elutriate generated from these tests were tested for toxicity. Although the parent dust palliative was toxic, toxicity was removed after mixing with site soil which has important and positive implications for the runoff from such a dust control program. A biologically based environmental monitoring program was designed to address residual uncertainties.

The approach followed here provides a practical and effective means for testing new products that function by adhering to soil/sediment particles and the results produced from this study show that the new product has the potential to safeguard worker safety by preventing dust inhalation risk at its source while still being an environmentally safe option