Conglomerate MillIndustry

The Old Mill In the Woods


While beautiful to admire with a serene and relaxing setting, the tumble of water at Haven Falls is in most way just another picturesque Keweenaw waterfall. Its uniqueness lies in what sits shrouded nearby. A century ago these falls probably never ran, as the water would have been diverted by a dam and launder up the bluff. Back then the water tumbling down that rocky bluff would have made its way next door to feed the thirst of an industrial dinosaur – the old Conglomerate Stamp Mill.


The Conglomerate Mine erected this meandering structure around 1881. It served the company’s Allouez conglomerate workings, a series of newly sunk shafts at the old Delaware Mine property found up the hill near present day US41.  The mine and mill were connected by seven mile long narrow gauge railroad, which also made its way down to the nearby Smelter and dock on Lac La Belle. Unlike the rest of its Lac La Belle compatriots, this industrial complex actually got to mill some copper  – three years worth in fact. The evidence of this can be found along the lake shore, where the unmistakable red-tainted mill tailings can still be found fanning out into the water.


While the sands may be quite apparent today, the rest of the old mill has not stuck around so stubbornly. Here’s the old complex a few decades after its closure, with only foundations and some wood floor trusses still remaining. This view is from atop the rock bins, which sit to the rear of the building. Off to the left is the remains of the mill’s boiler house, while off to the background the mill’s tailings along the lake can be seen. From this angle we can also clearly make out the mill’s various levels which step-stair their way down the hillside – each dedicated to a particular step in the milling process.


As with all stamp mills, the building is subdivided up into five main levels. At the top is the rock bins, which housed the copper rock brought down from the mine. The bins were filled from above via a rail trestle which ran its way through the building. That rock would then be fed into the mill’s compliment of stamps, where it was smashed down into much smaller pieces for milling. Then it would move on to two levels of jigs, machines which would work to separate out the larger pieces of copper. Smaller pieces of copper were separated within the final level of the building – the wash floor situated at the structure’s far end.


Fast forward a century and those rock ruins seen earlier have disappeared from view, thanks largely to a thick tangle of trees and brush which have overtaken the old site. The only clue to their existence is this sign – itself partially hidden by the encroaching forest.


It isn’t until you stop by the old Haven Falls park and take a look around that the old mill finally reveals itself. At first its hardly anything spectacular, only some  red-tainted stamps sands piled up behind the park’s main pavilion. Yet a closer looks reveals a bit more then just piles of sand – signs of man’s guiding hand can also be found.


Most noticeable is this very unnatural looking ridge line found half way up the pile of sand, a ridge line marked by a line of scattered rocks and partially buried timbers.


Too straight and uniform in size to be just fallen trees, these timbers are also laid out in an unmistakable criss-cross pattern. These were floor joists, large enough to support the heavy pieces of machinery which once sat atop of them.


Scattered nearby are the remains of several more timbers,  these ones being aligned vertically instead of horizontally. These were posts used to support the mill’s gabled roof above.


With these man-made attributes now identified, the shape and layout of the old mill becomes increasingly clear. Looking up that pile of stamp sands reveals two distinct floors – each outlined by their partially buried timber floor joists. The upper floor would have been housed the mill’s rouging jigs, while the lower floor was occupied by the finishing jigs. A total of 84 Collum jigs once occupied this space – 36 on the lower floor and 48 on the second.


Up on that second floor we find this squat little stone wall, its structure partially scattered about nearby. This could have been a portion of an old wall, or perhaps the foundation to a heavier piece of equipment housed inside the building.


Peering further into the woods we could make out another wall – though this one was far larger and more robust then the pile of rubble at our feet.


This wall marked the back side of the jig level, and was in fact the foundation to the next level of the mill – the stamp level.

wallpan1We followed that wall around to the mill’s south side, finding ourselves looking up at a six foot high wall of stone which looked to be growing organically out of the hillside. This was the mill’s south foundation, and due to the slope of the land alongside we were able to work our way up over the barrier in our path to take a look at what we could find of the mill’s largest pieces of equipment – the stamps.


While there was unsurprisingly no stamps to be found, their previous presence was readily apparent by just a casual look out across the old stamp level’s floor. In addition to the many trees now taking up residence here were an almost equal collection of old iron posts rising up from the ground and spreading for out into the woods ahead of us.


These were massive pieces of iron, each post about two inches thick and topped by several inches of threads.


Some were capped by equally large bolts on their heads, while others were left bare.


While some even had these  large iron flanges attached to their bases.


All these hearty bolts would have once anchored to the building’s foundation the mill’s trio of steam stamps. These stamps were of the Ball variety, and each featured a 10-inch shaft and stood over a dozen feet high. Capacity for each stamp was some 200 tons a day, making the mill’s total daily capacity some 600 tons of copper rock.


Looking up from our sea of iron bolts we discovered that we were in the shadow of a towering rocky precipice rising some 40 feet above our heads. This is the same precipice over which the neighboring Haven Falls tumbles over. Here the towering walls made for a great jumping off point for the mill’s rail trestle, which would have extended over our heads to reach the rock bins sitting just alongside the stamps.


As we made our way along the rugged wall rising high above our heads we could make out the remains of that trestle scattered about our feet in the form of several wood timbers and pilings half buried in the forest floor.

While those trestle remnants were interesting, it was the item peeking through the trees ahead which had our full attention.


Looking like a rock giant leaning up against the ridge for support was this impressive remnant – a structure whose half-circle shape suggested it to be the mill’s boiler stack. That would mean that in a very unique and ingenious move the mill’s builders utilized the high cliff itself as one side of the stack’s base, the rest of its mass looking to have simply been laid up against the natural wall. Unfortunately that wasn’t quite the case.


Turns out this it not the stack at all as that structure sits instead at bluff’s top well out of view from our current vantage point. This stack looking structure was instead a vertical flue which connected the stack to the nearby boiler house.


Here’s a look at the mill’s original stack, along with its flue and boiler house. While a stack could have been placed next door to the boiler house at the bluff’s base, the existence of that bluff would mean the stack would have to rise rather high to clear the bluff and the homes sitting atop it. To limit costs the stack was instead built on top of the bluff, as to provide an additional 40 feet of height from the get-go. The only drawback was the need to build an elongated flue to bring the hot gases from the boiler house up the bluff and out to the stack waiting up top – thus the stone lined vertical clue clinging to the bluff still today.


At the flue/stack’s base can be found this brick lined opening. This was the bottom of that vertical flue, connected here to a more traditional horizontal flue trench heading out to the neighboring boiler house.


Here’s a view from inside that trench looking up at the vertical flue.


Here’s the opposite view, now looking down the trench to the adjacent boiler house. That boiler house would have sat just within that small clearing at the trench’s end, but today almost nothing of it remains. About the only thing we could see were a few pieces of foundation walls scattered within the woods.


A century ago that limited piece of foundation wall would have been dwarfed by the ruins seen here – complete with the boilers themselves. These are a pair of Babcock & Wilcox tube boilers, still incased in their red-brick shells. By this point portions of them had obviously already been scrapped, and in the short years that followed this picture they would completely disappear from the landscape leaving behind the rather scant ruins found today.


Moving back towards where we started we come across another low foundation wall. This marks the location of the last level of the mill’s multi-tiered structure – the wash floor. Within these walls would have at 8 Evan’s slime tables, machines which worked the smallest particles of copper out of the gravel-sized rock the mill would ultimately dump into the neighboring lake as waste.


Here’s a final look at the old mill as it originally looked in its prime. Haven Falls sits just to the bottom left of the picture, with the Pavilion sitting just atop where the launders once ran. The current road runs along the old railroad right of way, and skirts just along the edge of the old mill ruins. Unfortunately those ruins are too well hidden from the road to get a good look. To really appreciate them you first have to take a stroll through the Haven Falls park.



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