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The appointment of George Chalmers as Superintendent of Morro Velho proved to be an astute one, as the mining operations reached their heyday under his watch in the 1890s. One of the main reasons for the increase in production during that decade was the decision of Chalmers to greatly increase the amount of electric power provided to the mines. He achieved the power increase by constructing no fewer than three new power plants in the vicinity of Morro Velho.

The power plants constructed and operated by the Saint John d'El Rey company produced the electricity that powered much of the mining equipment. Everything from the power drills to the automated mining carts relied on electricity generated by the company plants. The electricity traveled from the plants to its various mechanical destinations along lines protected by pipes. The end result of fully powered mining operations was greatly increased mining efficiency.

Prior to the 1890s neither electricity nor electric-powered machines were commonplace at mines, even in more economically developed areas such as western Europe. Although some steam equipment would have been available, many mining operations would have needed to be conducted by hand. The ability to power multiple machines from one source afforded by the construction of power plants offered numerous advantages, not only in terms of increased efficiency but also in terms of lower fuel consumption.