Jig Floor

Stamps were large, heavy, and cumbersome pieces of equipment. Most mills only had a few, and only the real profitable mines (such as C&H) could install more. The Mohawk Mill had 4 stamps. Only question was: where were they? Not that we expected to find them (most stamps were removed for scrap) but we at least expected to find a pedestal on which they once sat. These were large pieces of equipment that required a good amount of structure to support i

Exiting the pump house, we found ourselves facing a long line of concrete pillars stretching out ahead of us. There were three sets laid out in parallel rows. The first consisted of a single square base – not a pillar really – sitting about two feet high. The next line consisted of conical pillars about four feet high that looked like grey traffic cones. Next to them was a line of larger pillars that were longer in length but roughly the same width. And last – stepped down a level – were a series of much larger and taller structures more randomly placed with some sporting slanted tops. It was a sea of pillars.

As originally built the new mill at Mason was built much like all other mills along the copper range; a wooden structure, built down a hillside in a step stair fashion. Building along a hillside allowed gravity to do most of the work, and its high back made room for rock storage bins and an overhead trestle used to fill those bins. This original layout, as seen above, lasted almost twenty years before the brick and concrete addition were added to the east end of the building. It was that addition that we were leaving on our exploration, and we now turned to that original wood building. Or at least its foundation.

With the winter months killing off most of the vegetation around the ruins we were able to get much better shots of a few highlights from our last trip. First is this panoramic look at the pump house ruins, which were hiding behind a veil of brush last time. This building housed the steam pump used to bring water up from the lake to the top of the stamp mill. The angled concrete platform on the right (barely visible below the snow) houses the feeder pipe from the lake.

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.

After leaving the final stages of the sizing process, the copper ore that entered the mill as pieces of rock have been reduced to a coarse gravel and mixed with water to become a muddy concoction known as slime. Within that slime is a mixture of copper and rock of various sizes and shapes. Now it’s the mill’s job to remove as much of that copper from the mix as possible – in a complex multi-stop process known as separation. The first step in that process is carried out by a series of machines known as jigs.

Old Sanborn maps indicate the Mohawk Mill consisted of four levels, which would have adhered to the somewhat standard order of stamp level, roughing level, refining level, and wash floor. Those maps also indicated a height difference of 5 feet between the first two floors and a 15 foot difference between the 3rd and 4th. While this was rather clear, the remains of those floors on site were a little less so.