During the late eighteenth and early nineteenth centuries, the Lehigh Valley's abundant trees for charcoal fuel and substantial ore deposits attracted many iron facilities, but as wood supplies dwindled, the search for new fuel sources intensified. In 1822, Josiah White and Erskine Hazard formed the Lehigh Coal and Navigation Company to build a canal capable of carrying anthracite coal, which burned hotter and more efficiently than charcoal, and they hired David Thomas to design a new kind of furnace that could burn the hard "stone coal." The adoption of anthracite fuel ushered in a new age in iron making and helped spur new iron works across the Lehigh Valley. In 1868, just after the Civil War, the Thomas Iron Company expanded to Alburtis, where railroad connections, plentiful water, and access to ore favored iron production, and the new Lock Ridge Furnace's two large furnaces could produce 15,000 tons of iron each year for tools, steam engines, guns, and other finished goods. The company prospered for 40 years despite coal strikes and growing competition, but the founding of US Steel in 1901 and nearby Bethlehem Steel in 1904 signaled the end of profitable small-scale iron production. Increased demand during World War I kept the company profitable briefly, but the last cast of iron came out of Lock Ridge in 1921, and when it closed that year it was reportedly the last operating anthracite iron furnace in the United States.
