Edison, His Life and Inventions [187]
needle indicated the presence and richness of the invisible deposits of magnetic ore. We kept minute records of these indications, and when the survey was finished we had exact information of the deposits in every part of each State we had passed through. We also knew the width, length, and approximate depth of every one of these deposits, which were enormous.
"The amount of ore disclosed by this survey was simply fabulous. How much so may be judged from the fact that in the three thousand acres immediately surrounding the mills that I afterward established at Edison there were over 200,000,000 tons of low- grade ore. I also secured sixteen thousand acres in which the deposit was proportionately as large. These few acres alone contained sufficient ore to supply the whole United States iron trade, including exports, for seventy years."
Given a mountain of rock containing only one-fifth to one-fourth magnetic iron, the broad problem confronting Edison resolved itself into three distinct parts--first, to tear down the mountain bodily and grind it to powder; second, to extract from this powder the particles of iron mingled in its mass; and, third, to accomplish these results at a cost sufficiently low to give the product a commercial value.
Edison realized from the start that the true solution of this problem lay in the continuous treatment of the material, with the maximum employment of natural forces and the minimum of manual labor and generated power. Hence, all his conceptions followed this general principle so faithfully and completely that we find in the plant embodying his ideas the forces of momentum and gravity steadily in harness and keeping the traces taut; while there was no touch of the human hand upon the material from the beginning of the treatment to its finish--the staff being employed mainly to keep watch on the correct working of the various processes.
It is hardly necessary to devote space to the beginnings of the enterprise, although they are full of interest. They served, however, to convince Edison that if he ever expected to carry out his scheme on the extensive scale planned, he could not depend upon the market to supply suitable machinery for important operations, but would be obliged to devise and build it himself. Thus, outside the steam- shovel and such staple items as engines, boilers, dynamos, and motors, all of the diverse and complex machinery of the entire concentrating plant, as subsequently completed, was devised by him especially for the purpose. The necessity for this was due to the many radical variations made from accepted methods.
No such departure was as radical as that of the method of crushing the ore. Existing machinery for this purpose had been designed on the basis of mining methods then in vogue, by which the rock was thoroughly shattered by means of high explosives and reduced to pieces of one hundred pounds or less. These pieces were then crushed by power directly applied. If a concentrating mill, planned to treat five or six thousand tons per day, were to be operated on this basis the investment in crushers and the supply of power would be enormous, to say nothing of the risk of frequent breakdowns by reason of multiplicity of machinery and parts. From a consideration of these facts, and with his usual tendency to upset traditional observances, Edison conceived the bold idea of constructing gigantic rolls which, by the force of momentum, would be capable of crushing individual rocks of vastly greater size than ever before attempted. He reasoned that the advantages thus obtained would be fourfold: a minimum of machinery and parts; greater compactness; a saving of power; and greater economy in mining. As this last-named operation precedes the crushing, let us first consider it as it was projected and carried on by him.
Perhaps quarrying would be a better term than mining in this case, as Edison's plan was to approach the rock and tear it down bodily. The faith that "moves mountains" had a new opportunity. In work of this nature it had been customary, as above
"The amount of ore disclosed by this survey was simply fabulous. How much so may be judged from the fact that in the three thousand acres immediately surrounding the mills that I afterward established at Edison there were over 200,000,000 tons of low- grade ore. I also secured sixteen thousand acres in which the deposit was proportionately as large. These few acres alone contained sufficient ore to supply the whole United States iron trade, including exports, for seventy years."
Given a mountain of rock containing only one-fifth to one-fourth magnetic iron, the broad problem confronting Edison resolved itself into three distinct parts--first, to tear down the mountain bodily and grind it to powder; second, to extract from this powder the particles of iron mingled in its mass; and, third, to accomplish these results at a cost sufficiently low to give the product a commercial value.
Edison realized from the start that the true solution of this problem lay in the continuous treatment of the material, with the maximum employment of natural forces and the minimum of manual labor and generated power. Hence, all his conceptions followed this general principle so faithfully and completely that we find in the plant embodying his ideas the forces of momentum and gravity steadily in harness and keeping the traces taut; while there was no touch of the human hand upon the material from the beginning of the treatment to its finish--the staff being employed mainly to keep watch on the correct working of the various processes.
It is hardly necessary to devote space to the beginnings of the enterprise, although they are full of interest. They served, however, to convince Edison that if he ever expected to carry out his scheme on the extensive scale planned, he could not depend upon the market to supply suitable machinery for important operations, but would be obliged to devise and build it himself. Thus, outside the steam- shovel and such staple items as engines, boilers, dynamos, and motors, all of the diverse and complex machinery of the entire concentrating plant, as subsequently completed, was devised by him especially for the purpose. The necessity for this was due to the many radical variations made from accepted methods.
No such departure was as radical as that of the method of crushing the ore. Existing machinery for this purpose had been designed on the basis of mining methods then in vogue, by which the rock was thoroughly shattered by means of high explosives and reduced to pieces of one hundred pounds or less. These pieces were then crushed by power directly applied. If a concentrating mill, planned to treat five or six thousand tons per day, were to be operated on this basis the investment in crushers and the supply of power would be enormous, to say nothing of the risk of frequent breakdowns by reason of multiplicity of machinery and parts. From a consideration of these facts, and with his usual tendency to upset traditional observances, Edison conceived the bold idea of constructing gigantic rolls which, by the force of momentum, would be capable of crushing individual rocks of vastly greater size than ever before attempted. He reasoned that the advantages thus obtained would be fourfold: a minimum of machinery and parts; greater compactness; a saving of power; and greater economy in mining. As this last-named operation precedes the crushing, let us first consider it as it was projected and carried on by him.
Perhaps quarrying would be a better term than mining in this case, as Edison's plan was to approach the rock and tear it down bodily. The faith that "moves mountains" had a new opportunity. In work of this nature it had been customary, as above