TWO HISTORIC IRON MINES IN THE HIGHLANDS REGION OF NEW JERSEY AND THEIR EFFECT ON WATER QUALITY

This study examines water quality in and around two historic magnetite mines in the Highlands province of New Jersey. Blue Mine and Roomy Mine, developed in Middle Proterozoic pyroxenites, are located in Norvin Green State Forest near Ringwood, New Jersey (Wanaque quadrangle). Blue Mine was worked sporadically beginning in 1765; both were operated extensively between 1840 - 1890. Operations ceased in Blue Mine because of its tendency to flood; Roomy Mine closed because it ceased to be profitable.

In Roomy Mine, groundwater seeps in from the overlying strata, in places collecting in stagnant pools, but elsewhere infiltrating downward. Blue Mine is flooded, with a permanent pool developed in the entranceway; a small seep flows ~30 meters into Blue Mine Brook approximately 500 meters upstream from Wanaque Reservoir, the principal water supply for Essex, Passaic, and Hudson counties.

Water samples from both mines and Blue Mine Creek, both upstream and downstream from the Blue Mine drainage, have been analyzed for Fe and Mg using atomic absorption (AA) and ultra-violet-visible (UV-vis) spectrometers; ion chromatograph data is forthcoming. Preliminary results of the AA and UV-vis indicate Fe and Mg are present an order of magnitude greater in the mines and the Blue Mine seep compared with Blue Mine Brook. Concentrations of Fe in Blue Mine Brook (< 1 ppm) are within “aesthetic” limits, although elevated in the immediate vicinity of Blue Mine.