Saint John d'El Rey Mining Company

Morro Velho in 1907

The Morro Velho mine is in a low valley near Nova Lima, about 12 miles (19 km) from Belo Horizonte.[11] The company invested significant amounts into improving infrastructure, and quickly increased production. The first dividends were paid in 1842. The company encouraged British miners to come to work in Brazil, and employed slaves until they were emancipated in the late 19th century.[4] After the Gongo Soco mine closed in 1856 some of the Cornish miners found work in Brazilian mines operated by the Saint John d'El Rey Mining Company.[12] The Cornish formed the majority of British miners at Morro Velho, numbering about 350 in the 1860s.[11]

A fire caused the mine to collapse in 1867, and it took seven years to bring it back into operation. In the 1870s the superintendent was found to be engaged in fraud and had to be fired. A rock fall in 1886 caused the mine to collapse again, and the company went into temporary liquidation. The mine was reopened and again became profitable in the 1890s.[4] At one time the Morro Velho mine was the deepest in the world, as 2,545 metres (8,350 ft) below the entrance adit.[3] After the revolution of 1930 a miner's union was formed. Strikes reduced production and the infrastructure fell into disrepair.[4]

Systematic exploration of the area around the Raposos mines to the east of Morro Velho seems to have started shortly before 1910. By 1930 the main lodes that had been discovered were the Mina Grande and Espirito Santo lodes, both west of the das Velhas River, and the Morro das Bicas lode about 1 kilometre (0.62 mi) south of Raposas on the east of the Rio das Velhas. 23,404 tons of ore were extracted from the Raposos mines between 1910 and 1928, from which 8,388 ounces (237,800 g) of gold were extracted. Mining at the Morro das Bicas was suspended in the early 1930s but continued at the other mines, which were important producers.[13] As of 1955 the main lodes were the Espiritu Santo, Mina Grande and Espiritu West, which were connected by underground workings and had reached a depth of about 640 metres (2,100 ft).[14] At the end of 1955 the Raposos mines had total reserves of 1,694,080 metric tons of ore with an average of 9.5 grams of gold per ton.[15]

The company drove an exploration adit in the Bicalho mine in 1925, and seems to have opened a lode before halting operations. In 1936 the mine was pumped out and exploration continued to a depth of 610 metres (2,000 ft). 36,800 tons of ore gave 8,238 ounces of gold in 1940–41, and 40,700 tons of ore was processed in 1942–43. There was no activity in 1944-45, 200 tons extracted in 1946, after which operations stopped. The company bought the Fernan Paes estate to the west of Honorio Bicalho around 1863 and began working the Gaia and Gabirobas mines. 5,777 ounces of gold were produced between 1867 and 1873, after which mining halted. Some exploration was resuming in 1887 after the Morro Velho mine collapsed, but results were discouraging.[15]

The Faria mine, about 1 kilometre (0.62 mi) south of the Gabirobas mine, was developed and worked by a French company for a short period around 1900. The Saint John Company began to pump out and explore this mine in 1931. The company started to drive an adit known locally as the Gaia tunnel from the west side of the Rio das Velhas at Honorio Bicalho in 1934, running in a west-southwest direction. It was meant to unwater the old Gaia mine and provide access to deeper levels of that mine. In 1935 the adit was extended further to the west-southwest, and reached the foot of the Faria mine in 1936. The Gabirobas mine was pumped out in 1936 and explored for 30 metres (98 ft) below the original workings, and the Gaia mines was explored to 30 metres (98 ft) below the Gaia tunnel. There explorations were stopped in 1937 due to the low price of gold.[15] The company continued to develop the Faria mine, and began regular production in 1940. Between 1940 and 1947, when production was suspended, 176,286 tons of ore were milled.[16]