During the boom years of 1830-1855, twelve new furnaces were built and dozens of mines opened in the Baltimore-Washington area to handle the "Arundel" ores. Among these was Muirkirk Furnace (established in 1847 by Elias Ellicott and his partners) and its surrounding ore pits. By the late 1880's, the industry had seriously declined because of a number of factors. Maryland iron was expensive because it was produced mainly with charcoal (Fig. 6f and g), itself an increasingly expensive and dwindling resource. In addition, as mentioned earlier in the discussion of the origin and character of Arundel ores, the "pockety" nature of the deposits made mining expensive. Finally, the reduction of transportation costs made imports competitive.

Figures 6.— The Muirkirk Iron Works, near Laurel, Prince George's County, Maryland.