Previous reports of the composition of water discharged from bituminous coal mines generally discuss only pH, acidity, iron, and sulfate. We have analyzed five samples of mine discharge for ferrous iron, total iron, aluminum, manganese, sodium, potassium, calcium, magnesium, chloride, sulfate, silica, and pH. Selected trace elements were sought in two of the five samples chosen because of their extreme values in pH (3.2 and 7.4).Four of the samples may be considered "acid mine drainage" so characterized by pH of from 3.2 to 5.5, total iron in excess of 500 ppm, and aluminum greater than 100 ppm in the more acid samples. The fifth sample resembles uncontaminated ground water from the Monongahela Group and has a pH of 7.4, total iron less than 4 ppm, and aluminum less than 20 ppm. Similar distinctions in composition are reflected in trace elements of the two extreme samples.The marked differences in the neutral sample and the acid samples are evidence for the efficacy of minimizing contact of water with the underground workings. The high quality water is discharged from a mine that was designed to minimize residence time of water in the workings, whereas the acid samples come from more extensive drainage systems, each utilizing one discharge pump.