So – What IS a Coal Washery?
“As coal is never found pure … the impurities contained need to be removed. The impurities such as slate, bone, iron and sulfur (in the form of iron pyrites), and the clay or dirt that is found with the coal. If the slate, bone, and pyrites are not too intimately mixed with the coal, they may be separated from it by the use of water, after the lumps have been broken into small pieces. The coal being lighter will float off, while the bone, slate, and pyrites will settle. This method of separating the impurities is called coal washing.” What that basically means is that there were many different ways of making what was essentially a giant washing machine. There was a need to crush the coal prior to washing it – but that is another subject altogether. On page 67 there is a sectional view and a side view of a ‘Stewart Jig’. The diagrams gave me enough information to start to re-create the structure in Sketchup. |
Stewart Coal Washery![]() In another book titled “Coke: A treatise on the manufacture of coke and other prepared fuels ..” Copyright 1905, I hit the jackpot as there are even better drawings and description of the Stewart type washery. The drawing to the left shows what I started with. This along with the text allowed me to pretty much figure out where all the bits fit. |
Sketchup’ered![]() Here is the washery as modeled in Sketchup. I left off all of the various machinery bits as I was concerned with the construction of the washery itself. None of the joints are butt-joints but are jointed as they would have been in ‘real life’. I’m going to sub-divide the Washery build into probably four sections. This is simply so I can make sense of what I am attempting and have no basis in anything other then that: |
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Logic and GuessesFor the next while I’m going to post up what I modeled in Sketchup. I used the drawing from the book and then to the best of my ability how I interpreted that drawing. Where I couldn’t transfer that drawing to the 3d model I tried use logic. Not being in any way an engineer that ‘logic’ may be suspect. Feel free to comment on that point if you wish. I expect at some point someone will point out that I have ‘Widget A’ incorrectly connected to ‘Widget B’. Be nice. I’m just a hobbyist doing my best and not .. as I said an Engineer. Simply explain why ‘Widget A’ should be connected to ‘Widget B’ and if I agree I will change it. See. Simple. I haven’t started the model yet .. I’m just laying out the plan for it now. This will then be a guide for when I actually start building the model. When I do that I will update each section with photos and text. If/when I make changes based on the hands on – I will then correct the ‘plan’ to reflect those changes. There are a multitude of flat belt pulleys, belts, sprockets and chain represented. The diameters of the pulleys and sprockets can be fairly well deducted from the drawings. The ratios between these various pulleys and sprockets then can be calculated. Given a speed for the engine we can then calculate the RPM for each pulley or sprocket. The only remaining variable is the HP. Given this we can then find the needed width for each belt (and therefore the flat belt pulley width) and I suspect the width of the sprockets/chains (that last bit still needs researching).
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ColorI have nothing to go on other than I would guess the timbers would undergo the same procedure as bridge timbers from the same time period. Bridge timbers that are new are dark brown from creosote. When they have weathered over the years they are gray. I could *pressume* (close to an assumption with all the baggage that can have) .. that this will fall somewhere in between. I was thinking about this a bit and with no supporting evidence at all I would bet that the parts that are in constant contact with water such as the tanks would have been tarred. If you think about it .. boat hulls were tarred .. joints between boards stuffed with oakum and then covered in pitch. I would be willing to bet that the insides of the tanks were mopped with hot tar/pitch. |
Milling Stop
I used a milliling stop similar to this to notch the timbers for my Ore Bin. |
Section I - Overflow and settling tanks Overflow and Settling Tanks Here in Section I we have the Overflow Tank – what it says .. overflow of water from the Jig tank. It is at this point that the water is pumped back to the Supply Tank to the start of the cycle. Settling tank...
Section II - Supply and Jig Tanks Supply and Jig Tanks Section II – Consists of two major parts: A Supply Tank – Filled with water continuously (recycled from the Settling Tank) and the Jig tank – an agitator. This is the working part of the Washery .. the agitation separates the coal and shale....
Section III - Unwashed Coal Bin Unwashed Coal Bin At the very top of the structure is the Unwashed Coal Bin – this receives the coal from the breaker via a conveyor belt. It will contain crushed and broken coal, shale, dirt and clay. A door and chute will allow the material to be processed...
Section IV - Mechanicals There is quite an assortment of "mechanicals". I put that in quote as some items are more like what could be called infrastructure .. but .. mechanicals is good enough for now: two Belt Elevators a Chain Elevator sprockets with chains pulleys of various sizes with belts the jig...