Gold has only been mined in noteworthy amounts from one location in Pennsylvania. The Cornwall Mine in Lebanon County is the only place credited with any significant gold.
This was not a gold mine. Iron was the primary mineral here, and the ore body was being mined as early as 1742. This was once the largest open-pit mine in the entire world! It operated until the 1970s, and had 236 years of active production as an iron mine.
At this time, the miners had no knowledge that copper, silver, and gold was present within the iron ore that they were mining.
The ores of this mine are primarily magnetite and actinolite. Lesser concentrations of chalcopyrite, chlorite, diopside, pyrite and serpentine are present as well. It wasn’t until 1908 when gold was refined from copper concentrates most likely occurring within the chalcopyrite concentrations at the mine.
This first attempt to refine gold from the copper ores resulted in 35 troy ounces
, an amount that was enough to warrant further investigation. For several decades that followed, the ores were processed to recover gold and copper alongside the iron.The reported production by 1959 was 37,459 troy ounces of gold.
Most of this was produced after the Great Depression in the years between 1937 and 1959.
Gold was most certainly an afterthought at this mine. Iron was responsible for sustaining the mining here. Nonetheless, it is certainly of interest to gold prospectors today because it is one of the few areas in the Northeast where any significant quantities of gold have been mined.
Finding access to prospect for gold isn’t going to be easy. This area is primarily all private land. Additionally, it is worth noting that the nature of these gold ores are not going to be easily mined by the casual prospector. Recovering gold from chalcopyrite ore is beyond the capabilities of most prospectors.
There is some pretty neat history in this area that is worth exploring. You can visit the site of the Cornwall Iron Furnace
that was used to process iron at the mine. There is a visitor’s center and the site is exceptionally well-preserved.Next: What Does Gold Look Like in Nature?