Jesus Christ. that looks like tens of tons of iron, and it was a lot pricier before modern technology. You can pump out nails pretty fast by hand once you have the material, but smelting and purifying ferrous metal without actually melting it is very labour-intensive, and the mining itself would have been painfully slow if they had to actually take down rock faces with no power tools or explosives (I don’t know how much of their needs could have been met with bog iron and similar).
Annual production of iron in the Empire was something to the tune of 80,000 tons per year. Roman furnaces were not, to my knowledge, uniform or exceptionally effective, but Roman mining was refined to a science.
The period actually shows up as a carbon spike in ice cores IIRC.
80,000 tons per year
So that’s a bit over 1 kg/person, assuming metric tons. I wonder what percentage employment in the industry it took to achieve that.
What do you know about the mining? The whole vinegar splashing thing is documented and continues to confuse us. Do I remember something about donkey-powered pumps and mine carts?
So that’s a bit over 1 kg/person, assuming metric tons. I wonder what percentage employment in the industry it took to achieve that.
Not sure, but there are a few employment contracts preserved for common miners, and they get a pretty nice deal for just being unskilled labor, so there was probably a lot of demand compared to the labor force that was available/willing. Also why slaves were condemned to the mines. They always needed more hands.
What do you know about the mining? The whole vinegar splashing thing is documented and continues to confuse us. Do I remember something about donkey-powered pumps and mine carts?
I don’t think there were mine carts, at least not in the sense of tracked carts. That’s a 16th century invention, I think. Pumps, though, definitely - Archimedes Screw was widely used, as was diverting water to erode the ground around metal veins, and trip hammers to smash the ore.
To be clear, mining it is just the start. I’m no history major but I know a lot about metalworking. I would probably have guessed a quarter of the figure you gave because of that.
Their furnaces could only get so hot, and even if they managed to melt the iron it would dissolve large amounts of carbon from the fuel, becoming pig iron. Much later (19th century) Henry Bessemer invented a way to turn useless pig iron back into steel, but they couldn’t, and without knowledge of the the elements involved had no reason to think it was even possible.
Instead, they would expose a batch of ore to a hot, reducing atmosphere while keeping it solid. Besides being highly fuel inefficient and preventing them from easily using fluxes to purify the metal at the source, this resulted in a bloom, which is beads of iron interspersed inside useless slag. Then, you have to knead the slag slowly, gradually out of the thing by hand. A trip hammer is indeed a big help here, but it’s still a manual process, and the ingot still needs to be reheated many times. Eventually it has a small enough amount of slag to use for tool building, although wrought iron always has some, and has a sort of grain or directionality as a result.
I’d include all the associated lumberjacking and coal and peat mining in the total employment to support this, as well as ore miners, charcoalers, furnace operators and smiths. Global steel production is around 250kg/person today, but obviously that’s an apples to oranges comparison.
Jesus Christ. that looks like tens of tons of iron, and it was a lot pricier before modern technology. You can pump out nails pretty fast by hand once you have the material, but smelting and purifying ferrous metal without actually melting it is very labour-intensive, and the mining itself would have been painfully slow if they had to actually take down rock faces with no power tools or explosives (I don’t know how much of their needs could have been met with bog iron and similar).
Annual production of iron in the Empire was something to the tune of 80,000 tons per year. Roman furnaces were not, to my knowledge, uniform or exceptionally effective, but Roman mining was refined to a science.
The period actually shows up as a carbon spike in ice cores IIRC.
So that’s a bit over 1 kg/person, assuming metric tons. I wonder what percentage employment in the industry it took to achieve that.
What do you know about the mining? The whole vinegar splashing thing is documented and continues to confuse us. Do I remember something about donkey-powered pumps and mine carts?
Not sure, but there are a few employment contracts preserved for common miners, and they get a pretty nice deal for just being unskilled labor, so there was probably a lot of demand compared to the labor force that was available/willing. Also why slaves were condemned to the mines. They always needed more hands.
https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1799&context=open_access_etds
I don’t think there were mine carts, at least not in the sense of tracked carts. That’s a 16th century invention, I think. Pumps, though, definitely - Archimedes Screw was widely used, as was diverting water to erode the ground around metal veins, and trip hammers to smash the ore.
To be clear, mining it is just the start. I’m no history major but I know a lot about metalworking. I would probably have guessed a quarter of the figure you gave because of that.
Their furnaces could only get so hot, and even if they managed to melt the iron it would dissolve large amounts of carbon from the fuel, becoming pig iron. Much later (19th century) Henry Bessemer invented a way to turn useless pig iron back into steel, but they couldn’t, and without knowledge of the the elements involved had no reason to think it was even possible.
Instead, they would expose a batch of ore to a hot, reducing atmosphere while keeping it solid. Besides being highly fuel inefficient and preventing them from easily using fluxes to purify the metal at the source, this resulted in a bloom, which is beads of iron interspersed inside useless slag. Then, you have to knead the slag slowly, gradually out of the thing by hand. A trip hammer is indeed a big help here, but it’s still a manual process, and the ingot still needs to be reheated many times. Eventually it has a small enough amount of slag to use for tool building, although wrought iron always has some, and has a sort of grain or directionality as a result.
I’d include all the associated lumberjacking and coal and peat mining in the total employment to support this, as well as ore miners, charcoalers, furnace operators and smiths. Global steel production is around 250kg/person today, but obviously that’s an apples to oranges comparison.