Side A: Mineral Ridge Black Band Ore. The discovery in the mid-19th century of iron-rich black band ore in this region helped revitalize Mahoning Valley’s iron industry. The land now called Mineral Ridge was primarily a farming community before the 1850s. In the 1830s, coal was discovered and mining began on a small scale. For years, it was believed that the coal seam sat on top of a layer of slate, which was considered to be of little worth. In the mid-1850s, however, John Lewis, superintendent of the Mineral Ridge Coal Mines, identified what was previously thought to be slate as valuable black band ore instead. (Continued on other side) Side B: Mineral Ridge Black Band Ore. (Continued from other side) 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 and the use of Mahoning block coal as a fuel for blast furnaces, laid the foundation for a revival in the Mahoning Valley's iron industry.