Large deposits of iron ore and limestone, together with dense forests that supplied charcoal, gave Pennsylvania all the elements needed to become the leading iron producer in the American colonies. Durham Furnace, built in 1727 near the Delaware River in Bucks County, was one of the colony's earliest and most productive furnaces. After losing money exporting pig iron to England, its original owners shifted to casting pots, kettles, firebacks, and plates for the iron stoves used by Pennsylvania German settlers. The furnace first operated in 1727 about one and a half miles west of the river at the site in Durham Village where a gristmill was later built in 1820 on its ruins. Water power from the nearby creek operated forges and a huge bellows that produced the blast, and the charcoal-fired stone furnace was lined with sandstone to withstand intense heat. In 1728, Durham Furnace exported three tons of pig iron to England as a sample, but low-cost Russian iron, expensive labor, and the high cost of shipping down the Delaware River to Philadelphia prevented Americans from matching that price. Slaves were used at the furnace from 1727 through the close of the century, though not extensively, and some escaped to the British in New York. Its location in relation to higher-quality ore and good transportation contributed to its decline, and Durham Furnace closed in 1791. The furnace was created by Philadelphia merchants William Allen, Joseph Galloway, and James Logan. George Taylor, born in 1716 and later a signer of the Declaration of Independence, arrived in Pennsylvania in 1736, rose from clerk to ironmaster at Warwick Furnace, leased Durham Furnace from 1755 to 1763, then leased it again in 1774 and produced cannons and munitions for Washington's army there until 1779; he died in Easton on February 23, 1781.