A MAGNETIC SURVEY OF THE YORK IRON COMPANY MINE AT P. JOSEPH RAAB COUNTY PARK, YORK COUNTY, PENNSYLVANIA

In the fall of 2007, the authors conducted a magnetic survey at the former site of the York Iron Company mine in P. Joseph Raab County Park, York County, Pennsylvania. From 1854 to about 1890, miners targeted specular hematite concentrated along quartz veins in the Cambrian Harpers Phyllite. The mining operation was one of the largest in the county, with open pits, adits, and shafts, and ore being transported by rail to furnaces in Ashland, Maryland and Harrisburg, Pennsylvania. Since 2003, the park has organized archaeological excavations to teach techniques of archaeological exploration and interpretation. Students and volunteers collected and catalogued more than 400 artifacts including chisels, picks, star bit ends, railroad spikes, shoes, clay pipes, and an 1876 shield nickel. Stone foundations and the hoist house floor and have also been excavated.

The 2007 magnetic survey used a cesium vapor magnetometer, as commercial metal detectors are of no use at this site due to the magnetite and specular hematite in the rocks. In the southwest corner of the park, west of Strickhouser Run, a north-south linear magnetic high was identified. The following summer, excavations focused on this anomaly. Students unearthed a thirty-six-foot-long standard-gauge rail nine inches below the surface. Voids where railroad ties had rotted away, an in-place joint, and six inch spikes were also exposed. The unveiling of this standard-gauge rail is significant in that, until this time, only narrow-gauge rails had been found. This standard-gauge rail, installed in the later years of the mine’s operation, connected to a siding along the main line of the Hanover Branch Railroad.