Roxbury Iron Mine, Mine Hill, Roxbury, Litchfield County, Connecticut, USAi

Regional Level Types
Roxbury Iron Mine	Mine
Mine Hill	Hill
Roxbury	Town
Litchfield County	County
Connecticut	State
USA	Country

A mine on a primarily siderite and quartz hydrothermal vein formed along a fault trending about 120 degrees E of N and dipping SW at 75 to 90 degrees. The large vein is 2 to 3 meters thick, at least 600 meters long and extends at least 60 meters down, probably much more. It is reportedly one of the largest deposits of siderite in North America. Three adits (2 still open) and numerous shafts (4 still open) were put in on the vein. The openings have been gated off to prevent human entrance but allow access by the bats that now make it their home. Short adits far to the north and south of the vein were also started but did not progress very far. Maps and plans of the veins and mines are shown by Bell and Mayerfeld (1982) (note, the north adit is mislocated). Januzzi (1976) includes sketches and photographs from inside the mine. Besides siderite the locality is best known for its excellent pyrite and arsenopyrite crystals.

The first confirmed mining at this site was in 1750, about that time, Moses Hurlbut and Abel Hawley are said to have worked Mine Hill for silver and lead. About 1760 a company headed by two brothers named Brownson worked the mine energetically under the supervision of a German goldsmith named Feuchter; two shafts were sunk (still open), one going down 175 feet from the top of the hill, into the vein of ore. This search for silver in the relatively sparse galena continued for several years until the available funds were exhausted.

A new company was organized; the vein traced down the surface of the hill toward the river and horizontal drifts were made. Several other companies followed, working the mine for silver and lead, but there was not enough galena and these late 18th century operations were short lived. The last operation recognized the iron potential of the ore, but did not pursue it.

By about 1816 Prof. Benjamin Silliman of Yale identified iron in the form of siderite as a valuable ore, this was followed by inspections in 1830 by Prof. Charles Shepard. At last the vein’s value as an iron-ore was appreciated, and by 1830 David Stiles began operating to extract it. His operations became tied up by lawsuits from previous operators or leaseholders.

Finally, in 1865, the Shepaug Spathic Iron and Steel Company was formed after exploring the prospect, running some of the ore through other furnaces, and seeking the best advice available from an economic geologist, mining engineers and metallurgists, plus four Yale professors: Brush, Porter, Dana and Silliman (senior, now 85 years old). Professor George Brush wrote on May 30, 1864: “The ore...is spathic, or sparry iron ore....something over 40% metallic iron, most highly prized of iron ores, comparatively rare...It produces a white pig iron…well adapted for conversion to steel.” Quality steel was being made in Prussia and Styria from siderite, so the thinking was that the presence of carbon in the iron ore would simplify the 3-step steel making process and allow a more direct, larger scale, and thus cheaper process. (One has to wonder why they thought that the abundant carbon being added to the furnaces in the form of charcoal fuel would not do the same thing as the carbon in this ore was supposed to and render that supposed advantage of siderite over goethite ore moot?)

In 1867, the company name changed to The American Silver Steel Company. It greatly expanded the mining and built the railbed, furnaces and facilities whose ruins are now preserved at the site. The steel works were not successful apparently because "Silliman had incorrectly assessed the ore's steelmaking potential, and that none of the experts it had hired could run the steelworks" (Gordon and Raber, 2000). They could not replicate the "feel" the Europeans had for their process (which lacked any method of directly measuring the carbon content) and the presence of carbon in the ore was of no consequence to the steel making process as it worked the same way with the roasted iron oxide ore (Bell and Mayerfeld, 1982).

After some problems with the blast furnace in 1868, the mining and smelting ran well, producing pig iron until 1872, when a change over to a hot blast ruined the furnace and all activity ended. Because the original plan was to produce quality, high-priced steel from the pig iron, this furnace was not competitive as solely a pig iron producer. The costly underground hard rock mining and the cost of roasting the ore to remove the sulfides and carbonate content were not incurred by the open pit, "soft ore" goethite mining operations elsewhere in the Connecticut/Massachusetts/New York iron mining district.

Sometime in the early 1900s the Columbia School of Mines arranged to use the mine for field study by students of mining engineering. They reinforced the lower adit with concrete. In the summer, the cool, moist air exiting this adit sends a breath of refreshing fog across the trail.

The mine is now part of the Roxbury Land Trust’s Mine Hill Preserve. The complex is listed on the National Register of Historic Places. Coordinates are for the Brownson's shaft area near the middle of the stretch of workings.

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References