THE DIRT:The History of the Cataldo Dredge

One of the most scenic views along Interstate 90 in the Silver Valley is arguably found when driving west across the Mission Flats area of Cataldo. As the trees break away, you encounter the beautiful site of Latour Baldy and Silver Mountain in the background, with the historic Cataldo Mission in the foreground surrounded by serene swamps and wetlands. This area may look beautiful today, but it was not always so. In fact, historically this area was used for the consolidation of massive amounts of mine wastes traveling downstream from the many mines and mills of the Upper Basin.  

Historically, hard rock mining in the Silver Valley region used disposal methods that were common across the nation. Flowing creeks and streams provided an easy disposal mechanism for industrial waste. In the Silver Valley, those wastes were primarily mine and mill tailings, and slimes. While not the original intention of mine operators, these practices harmed the environment, the ecosystem, and human health. 

By the early 1900s agricultural areas, especially along the lower sections of the Coeur d’Alene River, became inundated with these waste products. Farmers watched helplessly as their crops died and their livestock became poisoned, leading to dozens of farmers filing lawsuits against the mining companies. The mines were given preferential treatment in these court rulings, but due to court costs and settlement fines, the Mine Owners Association (MOA), an organization comprised of thirteen local mining companies, began efforts to curtail the amount of mine waste migrating downstream. Early efforts included the construction of a series of plank dams that the MOA hoped would slow the migration of the waste. Dams were constructed on Canyon Creek at Woodland Park and on the South Fork of the Coeur d’Alene River (SFCDA) at Osburn and Pinehurst. While the dams reduced the volume of suspended solids carried downstream, they could not contain the finer tailings generated by the new flotation method being implemented across the Coeur d’Alene mining district. The dams were also easily damaged and breached during high water and flood events. Without proper maintenance and constant re-building, they stopped functioning.