Mining generates and moves the highest volume of material in the world. At mine sites throughout the world, explosives are used to fragment rock into workable size fractions. Mine-water chemistry can be influenced by residual blasting agents used during mining. Ongoing monitoring of the water chemistry from three large-scale waste rock test piles, measuring 60 by 50 m in area and 15 m high, began in 2007 and the quality of water draining from this material is being studied. Blasting residuals comprised a large proportion of dissolved constituents in the pore water and effluent for the first three monitoring seasons. Variations in concentrations and the gradual rates of dissipation of blasting residuals provide an indication of the pile heterogeneity and the relative contribution of different flow paths. As temperatures within the piles increase with ambient temperature increases, larger proportions of the pile contribute to flow, and increased concentrations of blasting residuals are observed in waste rock effluent. Mass-balance calculations based on the ratios of SO₄:Total-N can be used to estimate the relative contributions of sulfide oxidation within the piles and sulfate released when sulfur in the host rock is oxidized during blasting. These calculations can also provide an estimate of S mass released during the first flush of the piles. This research will aid in understanding the release of constituents caused by blasting and waste-rock hydrology. [All papers were considered for technical and language appropriateness by the organizing committee.]