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“The screeching of the wild monkeys was keeping me awake, so I departed at 4:00 a.m. by torchlight. I made my way to a land lush with giant, thousand-year old trees and, despite the poor footing, made my way up stream. . .”
Thus wrote the Sumitomo leader of his search for the point where a metal vein reveals itself on the surface. What he found on that journey, undertaken a century after Sumitomo’s founding, was a vein of immense proportions—what would become the Besshi Mine. Under the surface was a mammoth area of ore that stretched out toward the northeast at 45o on the top and 90o on the bottom. It was 50 cm to 8m (average 2.5m) deep, 1.5km wide and 2.3km long. This flat layer of copper and ferrous sulfide, known as a kieslager formation, extended from 1,300m above sea level where it broke surface down to over 1,000m below sea level at its deepest point. The following year, 1691, the Besshi Mine started producing copper.
Within a few years of its launch, the output of the Besshi Mine had raised the total volume of copper production in Japan. Sumitomo, which had already made a name for itself in the copper trade, became an even more important supplier of the metal. High officials of the Shogunate, heads of Dutch mercantile firms, and feudal daimyo returning from obligatory rotating residence periods in Edo would visit Sumitomo’s facilities in Osaka to see the advanced refining technology for themselves. Sumitomo was pleased to entertain such guests, and even prepared an illustrated souvenir volume called the Kodozuroku, which explained the company’s technologies and processes in some detail, from mining to refining.
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Global mining network
To ensure stable access to resources and allow it to provide quality materials, Sumitomo Metal Mining applies its centuries of experience and technical prowess to developing mines overseas as well as in Japan. |
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