露天掘り
The earliest coal mines in the watershed can be traced to the 1860s. Early mines were underground, a practice which was in sharp decline by the 1920s and had ended completely in the watershed by 1991. Surface mining was begun post-World War II and declined in the 1970s. Coal in the watershed is primarily of the Middle Kittaning #6 variety, which is high in sulfur and has been identified by the Ohio EPA as having a high potential for pollution.