CHEMICAL AND MINERALOGICAL CHARACTERIZATION OF AIRBORNE PARTICULATE MATTER ORIGINATING FROM MINING AND INDUSTRIAL OPERATIONS

Abstract

Activities performed at mining and other industrial operations are capable of producing significant quantities of particulate matter that, if not properly contained, can be harmful to workers, and can enter surrounding communities causing damage to local environments. Analysis of particulate matter through routine monitoring is not always sufficient for characterizing substances of concern and differentiating between sources that contribute to emissions. To better understand the types of particulate matter generated at Ni and Cu mining and processing operations in Canada and Europe, a combination of quantitative mineralogy and methods of geochemistry (bulk chemistry, sequential leaching, trace-element geochemistry, and Pb isotope systematics) were performed. Particulate matter samples with varying size ranges (PM10, PM2.5, respirable, and inhalable) were collected within the workplace and at ambient air monitoring stations adjacent to the operations. The composition of the overall dust and the types of metal compounds present in the dust were determined with the objective of assessing worker exposure and investigating the extent to which emissions reach the adjacent communities. Baseline analysis of particulate matter generated during key activities at the operations, and analysis of source materials and settled dust provided additional information that was used for calculating source apportionment and investigating strategies for mitigating emissions. The key findings of the study are that, due to the complexity of sources, workplace exposure at any operation investigation beyond government-mandated guidelines to identify relationships between documented health effects in workers and specific exposures. Routine methods of characterizing hazardous metals in dust, such as sequential leaching, should be calibrated for individual operations that deal with a unique set of substances, and should include more than one type of analysis. When activities are performed at operations, only minimal wind speeds are necessary to transport dust distances at least 2 km from an operation into the surrounding environment and community, and a complex variety of particulate matter is present in urban areas surrounding industrial operations and can have multiple sources that are not related to the operation itself. The apportionment data allowed personnel at the operations to determine the source of emissions relative to activity, and mitigation strategies were implanted to reduce emissions.