Historic Mills of Connecticut

Use (Historic)

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Largest Documented Workforce

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Historic Narrative

For historical significance see National Register application: http://pdfhost.focus.nps.gov/docs/NRHP/Text/79002621.pdf The ironworks at Mine Hill is the best preserved and least typical of Connecticut's 19th-century iron production sites. Mine Hill is a granite ridge with a deep fissure, 8' to 10' wide, filled with siderite, or spathic ore (a carbonate of iron), and small amounts of copper, lead, zinc and silver. Efforts to extract the silver began in the early 18th century. While no significant profit was ever realized, speculation was feverish. The sale, division, and recombination of shares and leases of property and mineral rights created a legal morass that precluded clear title to the lands until 1865, when Shepaug Spathic Iron and Steel Co. bought the property from the victorious claimant. Shepaug Spathie planned to produce steel here with a puddling process, an unusual technique that was destined for failure. The firm built a blast furnace, ore roasters, engine house, and a puddling furnace. The furnace was in blast barely five years. Early on, trouble with the steam engine caused failure of the blast, thus solidifying the charge. The hearth had to be ripped down, to remove the salamander, and rebuilt. The puddling operation did not work, was rebuilt once, then dismantled and moved to Bridgeport. Under the reorganized firm of American Silver Steel Co. the furnace ran steadily for three years until 1871 when it was converted to heated blast. The change should have increased production but problems multiplied, output plummeted and operations ceased. Although details of the many failures are not known, it seems likely that there was simply not enough depth of experience to run the puddling or blast furnaces with the carbonate ore. Primary iron production was a leading industry in Litchfield County in the 19th century, employing thousands of people over several generations, but all the other furnaces smelted hematite or limonite, oxides of iron. The spathic ore was beyond the ken of local ironworkers, and the Mine Hill enterprise folded before the necessary experience could be developed. (Roth)

Number of Existing Buildings

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Architect

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Builder

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Building Type

• Blast furnace

Architectural Description

For description see National Register application: http://pdfhost.focus.nps.gov/docs/NRHP/Text/79002621.pdf The major extant structure, the blast furnace, measures 30' square at the base. Its battered granite walls are 35' high. There are four arched openings in the walls at ground level, with the south one, presumably the hearth, slightly larger than the others. Iron tie-rods, wedge-connected through iron anchor plates, bind the masonry together. The fire-brick lining is well-preserved, so little can be seen of the interior air and water passages. Outside, near the top of the east wall is a sheet-metal duct that was probably the opening for the cold blast, which was generated by a steam engine and blower. Near the top on the west wall is the tunnelhead arch, a small opening for venting flue gases that were used to fire the steam boiler. Southeast, at a level several feet lower than the furnace, stand the granite foundations of the casting house, puddling house, engine house and a deteriorated brick smokestack. West of the furnace, going up the hill, is another terraced level for the charging floor. Here lies rusting a large cone of sheet-metal screening (12' long) mounted on an axle; apparently it formed part of an ore-washing apparatus. About 100' further up the hill stand two ore-roasting ovens, each about 25' high and 25' square at the base. They are built of roughly-shaped granite, with tierods, and are about 10' apart with their rear walls joined together. Fire brick lines the cylindrical interiors. An embankment which carried narrow-gauge track runs about 3/4-mile uphill from the roasters to the lowest mine adit. The mine has three levels of horizontal tunnels, about 7' wide and 9' high, with larger rooms at intervals. Vertical shafts connect the unshored tunnels. Ore from the upper levels was dumped down the shafts to the lowest tunnel for removal to the roasters. Narrow gauge track runs throughout the tunnels. Estimates of total tunnel length vary but it is no less than 2,000'. (Roth)

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Power Source

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Specific Location

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Adjacent To

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Exterior Visible from Public Road?

Yes

Parcel ID / Assessor Record Link

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Acreage

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Use (Present)

• Other: Park

Form Completed By

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Date

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Bibliography

1. Roth, Matthew, et al, Connecticut: An Inventory of Historic Engineering and Industrial Sites (Washington DC: SIA, 1981).