The Wash Floor
As I left off during my Anatomy of a Mill series I was turning towards the last stage of the process: the wash floor. Here an attempt was made to separate the smallest copper particles still left in the slimes using pieces of equipment known as “slime tables”. In most lake mills two types of tables were in heavy use. The first was the “buddle”, which consisted of a sloped revolving table top on which the copper bearing slimes were worked. Slimes were poured onto the top, and the combination of centrifugal force and the slope surface would slowly work the slimes off the table. The heavier copper particles would rest upon the buddle’s surface, while the lighter waste rock would flow off the tables edge. The more modern version of this process was in use on the second type of slime table: the Wifley Table. I talk about this in some depth HERE during our Quincy Mill exploration. These machines would be housed on the lowest floor of a mill - known as the wash floor.
At the Mohawk Mill there isn’t much left of its wash floor. What greeted us was a vast landscape of broken concrete and twisted metal. This was the largest floor in the mill, measuring 178 feet in width and about 50 feet in depth. For each stamp - and the Mohawk Mill had 4 - there would be a workforce of about a half dozen slime tables at work on the slimes.
The image above is looking up at the upper floors of the mill, which consists of floors housing the refining jigs, roughing jigs, and the stamps themselves. The difference between levels is about five feet, with the stamps sitting 25 feet above the level of this wash floor. The foundation in the background is most likely for a set of refining jigs. Most of the second floor has collapsed - save the areas where large concrete footings were needed for equipment.
On this level the wast rock would be dumped into launders and taken out to the sand house behind us. Copper would of been dropped into a holding tank below the floor, where it would be shoveled into mesh mineral cars (to allow the water to drain) before being sent up by elevator to the storage bins in the mineral house (the large concrete hopper we discovered earlier). The photo above is of one of those discharge trenches - used either for the waste rock or the copper. Due to its size I would guess this is the wast launder.
Scattered about the wash floor (and you can see them in both of the photos above) are these small concrete footings. These were once used to support the steel beams that held up the buildings roof. The walls and roof of the mill were built with steel beams and trusses, clad in iron. This was to insure the maximum level of fire proofing. On this floor the ceiling would be about two stories above our heads.
Here’s one of those beams - which was incased in concrete to further fire-proof it. (as we all know too well now, intense heat can affect the structural integrity of the steel and collapse the building - the concrete here would help to keep that from happening should there be a fire.)
Along the buildings outer edge are walls made of concrete, part of which can be seen above. (The mineral house can be seen in the background left) We use this wall - or at least what’s left of it - to make our way up to the next level…