The Tenacity of Thomas Edison

The scarcity of platinum made it expensive. Edison knew that if he was to sell his incandescent lamps at a reasonable price, he would need access to large quantities of the metal. After investigating literature on geology, mining, and mineral processing, Edison concluded that platinum could be recovered from gold mine tailings. His team at Menlo Park began a new round of experiments.

When carbon became the solution to Edison's incandescent filament problem, he turned his attention away from platinum. Experiments continued, but now focused on ways to extract gold ore from tailings.

One experiment, the electromagnetic ore-separator, proved to be the most feasible. In Edison's design, crushed rock was fed through a hopper that allowed it to fall in a thin, even line. As the powder moved past electromagnets, magnetic grains like iron were attracted to one bin, while non-magnetic grains like gold fell in another.

Over the next decade, Edison continued to experiment with ore separating technology while building America's early electrical infrastructure -- an enterprise that relied heavily on iron, and the steel that it produced. Edison realized that his ore-separator technology might have more lucrative applications in the iron industry. He wrote research papers, filed ore-separator patents, launched new companies, and scaled-up experiments in iron ore processing plants.

After years of experimentation, Edison acquired an old mine in northern New Jersey that still contained large quantities of low-grade iron ore. There, he designed and built a mill near the mine that used his electromagnetic ore-separator to turn that low-grade ore into a profitable product.

In 1892, when his electrical company merged with a rival's, Edison left the electrical industry, retaining only stock in the new company. Edison turned his full attention to the new mill. The mill's cutting edge, automated process moved mined boulders along steel conveyor belts to the top of a tall building. Inside, multiple sets of massive rollers crushed the rock into a fine powder.

Carried by conveyor belt to another tower, the powder fell past hundreds of electromagnets that pulled granules of iron to one side, allowing waste sand to fall on the other. The concentrated iron ore powder produced at Edison's mill, pictured here, could then be sold and shipped to Eastern steel mills.

From 1894 to 1897, Edison spent nearly all of his time tinkering at the plant, only coming home on Sundays. Despite modest demand for the ore he was producing, Edison frequently shut down the plant to redesign machinery and rebuild inefficient structures. As Edison sank more money into his now-failing project, investors left, workers lost faith, and foremen resigned.

To keep his mill running, Edison sold the stock from his electric company merger and went into debt. The final blow came with the opening of the Mesabi iron range in Minnesota. High-grade iron ore became plentiful again, leaving Edison's iron ore powder unneeded.

By the end of the 1890s, Thomas Edison had spent nearly ten years and more than two million dollars attempting to build an industry around the mining of low-grade iron ore. Deeply in debt, Edison shuttered his operations, but in true Edison fashion, found a new direction in the dust of his failed mining venture.

Led by Edison's inventive spirit, the Edison Portland Cement Company became America’s largest cement producer. His innovative redesign of the rotatory kilns used in cement-making increased efficiency so much that he led the industry to overproduction.

Edison eventually profited from the general expansion of cement use in infrastructure and was able to repay the debt incurred from his ore mining venture. When Edison's friend Henry Ford began construction on Ford Motor Company's massive manufacturing complex, the Rouge plant, the Edison Portland Cement Company supplied the cement.

Like Edison, Henry Ford also found opportunity in failure. As an adversary of waste, Ford ensured his Rogue plant could manufacture Portland cement from the left over slag produced by its blast furnace. In 1928, Henry Ford used this cement to cast a cornerstone for the new museum he was building and dedicating to Thomas Edison.

Signed by Edison, the Portland cement cornerstone helps tell the story of his legacy -- a legacy built on the tenacious ability to find new opportunity in what others considered failure.