For decades, the west side of the Colorado School of Mines (CSM) main campus had subsidence issues related to historical mining activities. At one point, in the 1990s, one of the married student housing units in that area was so badly damaged that it was condemned. In the early 2000s, after the school converted the subsidence-prone area into intramural-athletic (IM) fields, ongoing subsidence-related issues were still being reported.
Clay mining in Colorado dates back to the mid-1800s and Golden was a particularly good location for clay found in the Laramie Formation. This clay has been used for a variety of industrial purposes over the years including construction (bricks, structural tiles, sewer pipes), terracotta, refractory clays, and earthenware. The mining of kaolinitic claystones in what was later to become the western area of the Mines campus left backfilled/collapsed mine workings and the possible presence of underground void spaces. To complicate matters, that same area was also the site of coal mining in the 1880s and 1890s. In particular, the Pittsburg Coal Mine entry shaft may have been located in the vicinity of one of the observed subsidence features. This mine reportedly operated between 1876 and 1880, but is un-recorded by the State. The mining operations were thought to be on three levels at depths of 100, 150, and 225 feet running parallel to the mountains.
