Thanks for the image description!
Since Iām seeing a few people tagging or commenting with the assumption that this post is about US history: this is a Canadian blog, based on my experiences in Canada, and this mine waste phenomenon is, unfortunately, a problem in much of the world. Nova Scotia, for example, had three separate āgold rushā phases from the 1860s to the 1930s.
Also, bonus content for those who are startled/fascinated by the arsenic concentrations, hereās a sample page from the Natural Resources Canada (NRCan) report by Mike Parsons et al., showing arsenic concentrations at Mooseland, which isnāt a site Iāve worked on, but is noteworthy because one soil sample was over one-quarter arsenic. The site I worked at with a ātablespoon of soil to kill six peopleā calculation was less than half of that.
And for added context, the āacceptable and safeā concentration of arsenic in the soil on an industrial site, if I remember right, is 31mg/kg in Nova Scotia. The lowest sample shown here is over 6,000mg/kg.
[Image ID: A map showing soil sample locations and numbers along the Tangier River in Nova Scotia near a historic gold mining stamp mill. The highest concentration is 256,000mg/kg, or 25.6% arsenic. To the south, a huge number of abandoned mine shafts are also shown in red.]