Old Stone Mill, Delta, Ontario

Under the Old Stone Mill

CAUTION - SPOILER ALERT - these photos contain operating secrets of the Old Stone Mill NHS.

A quick tour under the mill - showing the original millrace (water channel) that brought water to the waterwheel, plus the present day waterwheel and present day mechanism that operates our 200-year-old millstones.

Click on any photo to see a larger version and when viewing a photo click on it to advance to the next (or use the navigation links at the top of each page). All the photos are captioned, the descriptive text appears below each photo.

In the millrace (the channel leading to the waterwheel), looking north towards the entrance. The entrance (headrace) has a small cement dam, installed during restoration in the early 2000s. It contains a pipe and built in sluice control. The stones of the millrace have been repointed and concrete "curbs" added for stabilization. The water flows over the original bedrock which was black powder blasted in 1810 to form this artificial channel. A "buffer wall" used to be located outside of the mill along the north side, a wooden sluice built into it to allow water into the millrace. The millrace likely originally contained a wooden sluiceway to convey the water to the breastshot waterwheel.\n\nYou can see the remains of the original wooden covering of the raceway, protecting the first floor timbers (the millrace could fill with water and not flood into the first floor).
The headrace today - a sluice valve controls the flow through a pipe in the cemented bottom of the headrace. Most of the water from the creek flows through the bywash to the west. In times of flood water will rise higher than the cement plug, the bars keeping out debris (these have to be cleaned a couple of times a year)
In the millrace, looking south, downstream towards the waterwheel. One of the mysteries of the mill is why the raceway isn't parallel to the waterwheel. In part because our replica waterwheel may be closer to the west wall than the original wheel, which may have been positioned a couple of feet to the east. It also supports the idea that a wooden sluide was used, correcting the angle of the raceway.
In this photo, looking north to the entrance (headrace), we can see the bedrock that makes up the floor of the millrace. It consists of pre-cambrian crystalline limestone (marble) and skarn. The mill is built on this bedrock exposure located to the north of the original stream. The millrace and the stream channel leading to it blasted out using black powder.\n\nThe gentleman in the photo is Moel Benoit, a long time volunteer and director of The Delta Mill Society. Moel help keeps the mill in good shape doing maintenance jobs as required.


Our spinning waterwheel. We cheat today, the waterwheel spins due to water delivered to it by a sump pump. The water flow to the mill is controlled by the Ontario Ministry of Natural Resources and Forestry, so we only have what can be let through our pipe for use in the mill.\n\nThe original waterwheel was a breastshot wheel, about 12 feet in diametre (our current wheel is 10 feet in diametre), the water arriving near the centre of the wheel. There was about 7 feet of head that provided the hydraulic power to the wheel. The wheel was originally connected with gearing to supply power to the entire mill. \n\nWaterwheel power was replaced by turbine power (in the adjacent purpose built turbine shed) in the early 1860s.
It is believed that the original waterwheel, just slightly larger than this one, may be been in a "waterhouse" a separately enclosed structure within the mill. The door above the wheel speaks to this - it matched an Oliver Evan's design for a waterhouse. One advantage of a waterhouse is the ability to heat the enclosed area to prevent the freezing of the wheel.
The view out of the waterwheel tailrace. Originally this would have looked out to just water, to where the artificial channel from the mill met the original creek channel. That area is filled in today (likely originally filled when the turbine shed was built and the waterwheel abandoned).
Old and new - the waterwheel got supplanted in the early 1860s by newer technology, turbines. The turbines were located in purpose built addition to the mill, the turbine shed. The slits in the stone wall that used to be the west wall of the mill and is now an inner wall between the mill and the turbine shed, are for belts from the two turbines to supply power into the mill.


We now move to the "husk", the robust timber foundation that supports the millstones. In this photo, starting on the left we see the bottom of the flour elevator that takes the newly ground flour from the millstones and moves it up to the third floor for processing. Then we see part of the husk surrounding the electric motor we now use to power the millwheel. Then the waterwheel. Originally the hust would have been higher and there would have been physical gearing (of iron and wood) connecting the millwheel to a centre spindle that provided rotation power to the entire mill.
The hust is now centre left, the outer timber posts resting on a steel I-beam, the electric motor on the right. This new husk was installed in 2010 for the mill's 200th anniversary.
The centre shaft goes through the bedstone up to the runner (top) stone. It is only the top stone that rotates, today at about 92 rpm. Originally the stones turned faster, likely at about 98 rpm to speed up production. It also heated the flour, the first stop for the flour was a "hopper boy" on the third floor that stirred the flour to help cool it and ensure that it didn't stick together.\n\nIn the background (metal wheel on wooden structure) is the "elevator boot" where the flour from the millstones is picked up by the elevator (a continuous belt with small metal buckets) and taken to the third floor.
Another look at the base of the bedstone.


This is a portion of a c.1810 drill hole made for black powder blasting by a "jumper drill." Usually with a chisel face and about 3 feet long, this drill was held in place while one or two other men hit it with a sledgehammer. The drill would jump with each hit, allowing the driller to rotate it slightly before the next hit. It tends to form this type of irregular (not a perfect circle) hole. A blacksmith kept the cutting edge sharp.
This is the local bedrock, marble and skarn that dips at about 80 degrees. Other than larger chunks of unfractured marble, it unsuitable as a building stone. But it does work well as a solid foundation for the heavy stone mill. Most of the stones that make up the walls of the mill are Potsdam sandstone.\n\nThe rocks in the photo are pre-cambrian (very old), part of the the Frontenac Axis. These old rocks are generally hard and fractured, not suitable, except for a few pieces of unfractured marble, as a building material. \n\nThe sandstone used to build most of the mill is from a younger overlying unit, found to the north, east and south of Delta. The exact location of the quarry (or quarries) is unknown, but would likely have been located within 3 km of the mill.
A bit messy perhaps (in fairness to us, this space is not open to visitors :-) - but it shows some of the stone foundations and the bottom of an older flour elevator (the "elevator boot"). Much of the first floor was replaced during two periods of restoration (1972-1974 & 1999-2004) and these foundation stone columns were rebuilt at that time. Much of the large timber supporting structure of the first floor also dates those restorations.\n\nThe dark colour is not from fire but from hot animal fat used to grease the bearings that soaked into the wood.
Looking north at the east wall. You can see that it follows the original topographic slope of the bedrock that the stone foundation sits on. \n\nThe wiring is all modern, dating to the 1999-2004 restoration. There are also several built in smoke detectors monitoriing this area.
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