early furnaces during the colonial era utilized bog iron and small deposits or iron ore east of the mountains, until richer deposits were located west of the Blue Ridge
Source: Atlas of the Historical Geography of the United States, Distribution and Production of Iron Ore (Plate 6b, digitized by University of Richmond)
Through the 1600's, England relied upon its domestic iron industry and imports from Sweden to supply the iron needed to build ships for the British Navy. At the start of the 18th Century, Sweden's neighbors joined forces in the Great Northern War and destroyed Sweden's control over the Baltic, simultaneously ending Sweden's capacity to meet demand for iron throughout Europe. England, which had relied upon Sweden for over 80% of its import, needed a new source.1
The Chesapeake colonies became the replacement for Sweden, even though Virginia had depended upon European imports for a century (after the iron furnace on Falling Creek was destroyed in the 1622 uprising). The iron production infrastructure in North America had to be built almost from scratch. The small scale bloomeries smelted ore and could simultaneously produce low-quality iron products, but the region lacked full scale iron furnaces that could create pig iron that forges could then convert into high-quality wrought iron products:2
According to mercantile theory, the English colonists in North America were supposed to supply raw products to the mother country - not to compete with industries in England or take jobs away from workers in the British Isles.
Thomas Jefferson described Virginia's iron resources as follows:3
John Tayloe II ran the Neabsco ironworks and, after 1755, the Occoquan ironworks in partnership with Presley Thornton. In 1755, they bought 1,800 acres in Prince William County to supply fuel (charcoal) for the Occoquan furnace, and hired John Ballendine to build it. The furnace was in blast in 1756, but the partnership with John Ballendine ended in 1763.4
by 1756, the one-year old partnership at Occoquan between John Ballendine and John Tayloe II/Presley Thornton had broken down...
Source: Maryland State Archives, Maryland Gazette (November 25, 1756)
The Neabsco and Occoquan ironworks were supplied with iron from Maryland mines. They relied upon the waterpower from the Occoquan River and Neabsco Creek, charcoal from 20,000 acres of Prince William County forests owned by John Tayloe II, and oyster shells from Freestone Point used as the "flux" to lower the temperature in the furnace at which iron would separate out from the ore.5
in 1766, John Tayloe II and Presley Thornton advertised that John Ballendine had no legal right to sell any claim to the Occoquan complex to John Semple or James Douglass
Source: Colonial Williamsburg, The Virginia Gazette (Purdie and Dixon, June 13, 1766)
indentured servants, convict servants, and slaves fled from the Occoquan and Neabsco ironworks
Source: Maryland State Archives, Maryland Gazette (September 16, 1762)
Billy, a ship carpenter, ran away from Occoquan in 1765 with fellow slaves and a convict servant
Source: Maryland State Archives, Maryland Gazette (April 4, 1765)
Billie ran away again in 1768
Source: Colonial Williamsburg, The Virginia Gazette (Rind, February 09, 1769)
slaves, convict servants, and indentured servants fled from the Neabsco ironworks by crossing the Potomac River to Maryland, hoping to get a job on a ship leading away from Virginia
Source: Colonial Williamsburg, The Virginia Gazette (Purdie and Dixon, August 29, 1766)
one runaway from Neabsco Ironworks may have sought employment at Zane's Ironworks in Frederick County
Source: Colonial Williamsburg, The Virginia Gazette (Purdie and Dixon, July 8, 1773)
one runaway from Neabsco Ironworks may have fled to Gwynn's Island
Source: Colonial Williamsburg, The Virginia Gazette (Purdie, July 12, 1776)
iron mining was done by hand, even after the Civil War
Source: "The Chesapeake & Ohio Railway Directory, Containing an Illustrated History and Description of the Road," View of Iron Ore Mines, Ferrol Furnace, VA. (p.302)
in 1856, the Tredegar Foundry produced locomotives for Virginia railroads
Source: The Richmond Directory, and Business Advertiser, for 1856 (p.124)
the Big Hill deposit in Botetourt County was brown hematite
Source: Library of Congress, Topographical map showing the location of Big Hill iron lands, Botetourt Co., VA