Sunday, November 18, 2012

North Erie Shore - Bog Iron?

On 17/11/12 10:24 PM, Jonathan Martel wrote:
... I've been doing some research on bog iron in Southern Ontario and came across your blog posting from 2009.  I was wondering if you've had any luck since then in your search for bog iron sources?

Short answer - no.
If you search for 'bog iron' on the blog, there must be several dozen articles altogether. The 2012 searches in Newfoundland may be of most interest (with images of signs in a bog). You will also want to take a look at the most recent postings - describing some field work in West Central Ontario over the last couple of weeks.
The exact chemistry and geography that is required for a *workable* deposit of primary bog iron ore is very specific. There are a couple of possibilities in mechanism too. This is complicated by the fact 'bog ore' is a term that is used by almost everyone - but for radically different materials with quite different deposit methods. In short, if there is iron ore found any place near water, it gets called bog ore - regardless.
To complicate this, deposits may be from ongoing formation - or an ancient deposit, now uncovered.

I've found some historical sources indicating that bog iron was historically smelted in Essex and Norfolk counties.  Do you know if ore exists in any quantities whatsoever or have they largely been tapped out and not at all worth while?

Jonathan is referring to deposits - and furnace operations around Normandale Ontario, on the north shore of Lake Erie. See : https://sites.google.com/site/longpointsettlers/normandale-iron-works 
Link to the Ontario Historic Plaques information with a location map : http://www.ontarioplaques.com/Plaques_MNO/Plaque_Norfolk18.html

Those deposits were largely mined out in the middle 1800's . There were most certainly ongoing deposits in boggy / swampy ground around that area (Normandale - 1820 - 40 roughtly). These supplied both blast furnaces for cast iron, and also larger bloomery furnaces for making wrought iron bar.

Problem was two fold:
First, Victorian era iron furnaces are large, and require a large amount of ore to function - and a huge amount of charcoal to fire them. This demand quickly outpaced the natural production cycle of the primary bog iron ore. Net effect was the naturally 'stockpiled' material from ages before was quickly consumed.
Second was that the combination of clearing land for farming and cutting timber for charcoal production was coupled with the draining of swamps for fields. Combined, this altered the local geography, in effect destroying the swamps and bogs required for the chemistry of iron ore formation.
So in effect the limited natural resource was quickly consumed, while the landscape was altered to reduce the possibility that more natural ore could be formed. Commercial production in the Normandale area operated at best for a decade or two, before being abandoned.

No I will caution this next remark with saying that I have not personally walked the ground in that area. I have been told from those from that region (south of Brantford) that with the tensions between the First Nations groups and others - and troubles over land claims, that often local residents are not keen on unknown strangers walking their fields.
That being said, I have seen a sample of reported bog iron ore taken from the area. Of course there are all the problems with a sample gathered by someone generally interested in local history, but not with any personal experience with bloomery furnaces. Did the sample represent the kind of ore actually used in the Normandale furnaces? Or was it a piece considered too poor, even at that time, to be harvested and used?
Anyway, the sample contained a considerable volume of sand and small gravel. On a guess, I would say well over 50% of the volume was these impurities. It was hard to tell how much iron oxide was actually present in the roughly fist sized piece I was shown.
Certainly if that sample was representative of the modern day available iron ore, it would not be suitable for the kind of small size bloomery furnaces we are currently using. (Our Pre-1000, Northern European style furnaces require about 50% iron content (or better) to be truly effective.)


Note to Readers!
I certainly would love to be proven wrong on this! If your own field walking in Central Ontario discovers anything that looks like a purer primary bog iron ore, I would be most interested in knowing about it.

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February 15 - May 15, 2012 : Supported by a Crafts Projects - Creation and Development Grant

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