Taconite (iron ore) pellets abrade during handling, forming large quantities of fine particulate matter that are easily carried by the air as dust. This dust must be controlled in order to meet air quality standards for particles finer than 10 mu m (PM(10)). It has been assumed that the most effective method for suppressing dust is to spray the pellets with surfactant solutions that maximize the wetting ability of the fine particulates. However, surfactants that provide the most rapid wetting of iron ore have not proven to be highly effective taconite dust suppressants. In order to determine what factors were actually important in controlling taconite dust, a novel dust tower apparatus was used. In these studies, improving the suppressants ability to engulf fine particles did not result in PM(10) reductions. Furthermore, surface area coverage did not appear to be a significant factor in iron ore dust suppression. Using a hygroscopic reagent which retained moisture (and actually made the iron ore wet more slowly) reduced PM(10) by as much as 85%. (C) 2009 Elsevier B.V. All rights reserved.