The discovery in the mid-19th century of iron-rich black band ore in this region helped revitalize the Mahoning Valley’s iron industry. The land now called Mineral Ridge had been primarily a farming community before the 1850s, and in the 1830s coal was discovered there and mining began on a small scale. For years, the coal seam was believed to rest on a layer of slate considered to be of little worth, but in the mid-1850s John Lewis, superintendent of the Mineral Ridge Coal Mines, identified that material as valuable black band ore instead. This newly discovered black band iron ore was mixed with other ores at Governor David Tod's Brier Hill furnace and Jonathan Warner's furnaces in Mineral Ridge. The resulting product, an exceptionally fine grade of iron, became widely known as "American Scotch Pig" and "Warner's Scotch Pig." The discovery of black band ore, together with the use of Mahoning block coal as fuel for blast furnaces, laid the foundation for a revival in the Mahoning Valley's iron industry.