Stamp Floor

Moving up a terrace from the rows of pillars discussed earlier, we find ourselves atop a series of short rock piles. These piles are of poor rock, and are scattered in numerous spots along the back wall to the mill. These rocks once were stored in bins that sat atop the concrete wall we now faced. The bins were most likely steel in construction, and were removed for scrap when the mill was demolished in the 60’s.

Early stamp mills were a very crude affair. Before the advent of leaching, floatation, Wilfley Tables or buddles, mills relied on only one tried and true technology: the Cornish Stamp. These early stamps relied primarily on gravity to do all of the work. While these stamps did the trick, they were not very efficient. A stamp of this design could only work about 2 tons of rock per day, creating huge bottlenecks in production. By the late 1850’s, the more efficient steam driven stamps were being placed into service. These newer steam powered stamps could crush up to 125 tons per day – a significant improvement. Sitting at the dawn of this new technology – and at the end of the Cornish Stamp era – is the Central Mill, built around the mid 1850’s.

It wasn’t long after the new stamp mill at Torch Lake was constructed what Quincy underwent a dramatic increase in production – due mostly to the rich ground being opened along the No. 2 shaft. At first Quincy simply added new stamp heads to its mill at Torch Lake – adding an additional 40 feet to the building in 1892 to make room for 2 additional stamps. But this only bought Quincy time, as by the end of the century it was apparent that the existing mill – even with 5 stamp heads – could not keep up. A new mill was needed.

Due to the minimal amount of copper that required stamping at Cliff, the stamp mill that was constructed was very small and crude compared to mill’s built at other mines. The building (seen in the photo above) housed two batteries of cornish stamps, along with a very minimal amount of washing equipment. The stamps were powered by a small steam engine, which was housed in a connected building along with the necessary boilers. Elevated tramways delivered production from the shaft and adit nearby, while a wooden chute transported copper rock down from atop the bluff. The mill was closed around 1870.

The processes of mill work can be separated into four distinct stages. The first stage involves breaking down the copper bearing rock from the mill into small pieces – a process known as stamping. These small particles of rock are then passed onto a series of roughing jigs followed by a series of refining jigs. In the last stage the remaining rock is sent to the wash floor, where a series of slime tables are used to remove the last traces of copper from the rocks before being discarded. We start today with the first and most important step of the entire process: the stamps.

During the Copper Empire’s peak, over 100 steam stamps were in operation across the peninsula. As mines and their mills succumbed, these massive stamps were quickly sold or scrapped for quick cash. With the arrival of the Second World War any remaining stamps were quickly drafted into the war effort – providing much needed steel and iron for military equipment. By the end of the empire in the 60’s, stamps had become and endangered species. Today only one has managed to survive.

Leaving the engine house, we take another short climb up to the Mohawk Mill’s final floor. Here is where the mill’s four stamps would of been located, along with the massive rock bins that would of sat behind him. Today this floor reveals almost no sign of either, consisting entirely of a featureless concrete floor and very little else. The lack of details required us to take a much closer look, after which we were to gain at least a little understanding of what once was here.

The Delaware Mine is the mine of a thousand faces, having a long and sordid history under the guise of several different names and owners. Over the years the mine has been under the corporate umbrella of several companies including the Pennsylvania, Conglomerate, Northwest, and Lac La Belle. With each new ownership change came a renewed investment in the mine’s surface plant, including the construction of no less then five separate stamp mills. Three of those mills were constructed along the shore of Lac La Belle, with two others having been built near the mine itself. One of those mills was believed to be the first steam-powered mills in the district, built along the banks of the Montreal River just south of the mine site. This is the mill we take a look at today.