World's most productive copper mine

Led by Josiah Hugh Hitchens, a group of six^[3] investors who were comfortable with the risks in establishing a new copper mine, agreed to fund the project with £1,024.^[4] The group met with the Duke of Bedford's land agent and signed a lease for the property on 26 July 1844.^[5][6] Among those investing was William Morris Sr.; his son, William Morris, served as the director of the company from 1871 to 1875.^[7][8]

The 21-year lease for the mine called for royalties to be increased at the time the mine made a profit. The mine was first named Wheal Maria (Wheal is Cornish language for 'a place of work' often applied to mines in West Devon & Cornwall), for the Duke of Bedford's wife. Work began at the site in August 1844. By November 1844, a rich copper lode was discovered at the depth of 20 fathoms below ground. It was determined that the lode was at least 40 feet wide and extended eastward for more than two miles. The company rapidly opened other mines in the vicinity: Wheal Anna Maria, Wheal Fanny, Wheal Emma and Wheal Josiah among them.^[6]

By 1847, steam engines were in use at the mine, but the cost of their operation became a concern. A plan was devised to cut costs by using water power. The company received permission to utilize the River Tamar by way of constructing leats in 1849. Three large leats were built to divert water from the river to the mine; 33 wheels at the mine were powered in this way.^[9] The company became the Devonshire Great Consolidated Copper Mining Company or Devon Great Consols on 25 March 1845.^[6] In the first six years of operation, the investors extracted and sold close to 90,000 tons of copper; the Duke received £44,000 in royalties, with the investors earning £207,000. 1,024 shares were sold and shareholders received over £200 for each share of stock held; the value of shares in the mine continued to rise over time.^[10] The shares were sold in 1844 for one pound per share. By 1864, the total dividends paid to shareholders was £818,824.^[11] The mine was 200 fathoms deep and employed 1,284 people in 1864. Of these 861 were men, 203 were boys; there were 220 female workers.^[11] The mine was considered to be the most productive copper mine in the world circa 1864.^[12]

Because of the amount of ore the mine produced, transporting it by horse and wagon soon proved inefficient. The company built its own five mile railway with completion in November 1858; this linked the mine with Morwellham Quay for the export of ores.^[13][14][15] It was the only mine to have its own railway.^[9] In time, the rail line was extended to the Wheal Josiah and Bedford United mines.^[13] Devon Great Consols owned three locomotives and 60 wagons which both transported ore to Morwellham Quay and brought needed equipment and supplies such as coal, to the mine.^[15][16] An average run from the mine to Morwellham Quay consisted of 8 to 10 wagons of ore.^[13]

The railway was closed when the mine stopped production. Most of the track was removed and sold as scrap after the mine was closed in 1903. Some track was re-laid and some portions of the line were re-opened in the 1920s. Rail connections to Bedford United mine, Wheal Anna Maria and to the arsenic works were restored, however with narrow gauge track replacing the original standard gauge. The rail line between Devon Great Consols and Wheal Emma was never disturbed. A later connection between Wheal Fanny and the new arsenic works was created circa 1920s.^[13] Much of what remains of the railway and its associated structures have scheduled monument status.^[13]

Since the mine was so productive, it was necessary for the company to build its own facilities at Morwellham Quay to handle the ore.^[17] Between 1856 and 1858, the mining company built its own Great Dock and quay at Morwellham.^[18] The company had built its railway with an incline for its last half-mile to the quay at Morwellham. Cars were lowered two at a time onto the incline where the power to move them on came from a steam engine. They passed through a tunnel and onto viaducts built on the quay.^[13][18] After the mine's closure, the track was removed and the tunnel infilled; this was partially restored in 2007. The engine house and associated structures survive, as does the incline.^[13][18] The Devon Great Consols dock was restored in the latter part of the 20th century with the bollards and portions of a crane from the quay surviving. Most of the structures have scheduled monument status.^[13][18]

Copper gives way to arsenic

By 1884, the quality of the copper ore produced at Devon Great Consols was poor, yielding more arsenic than copper. After being sorted by the mine's bal maidens, the copper ore was sent to south Wales to be smelted.^[19] The company began exploring the possibility of tin deposits at the mine but found none.^{[20][lower-alpha 1]}

As cheaper copper imports and the declining quality of its copper ore began to affect the profit of Devon Great Consols, the company found a new source of income to replace its copper mining; the mine scrap was able to be used for extraction of arsenic. Prior to this, arsenic was imported from Germany. Devon Great Consols expanded into arsenic production beginning in 1867. The company's arsenic facilities extended over eight acres; it was the largest arsenic producer in the world during the 19th century.^[19][22]

The works at Devon Great Consols now made Britain the world's largest arsenic producer; the mine produced more than half of the total output in Britain.^[23][24] The mine's high quality product was in demand by industry both at home and abroad; production was only limited by the need to sustain market prices for arsenic.^[24][23] There were about 700 persons still working at the mine in 1893.^[25]

The mine fell victim to low prices for arsenic and a need for capital for both improvements and exploration.^[26][21] The proposal was brought to the shareholders in July 1902, but was met with failure. The company was last able to pay a dividend to shareholders in June 1899. Despite this, the Duke of Bedford renewed the lease on the land, giving the company an opportunity to recover from its losses,^[27] The mine was abandoned in 1903, with the equipment being sold off in May of that year.^[21][26] During its 60 years in business, Devon Great Consols produced some 700,000 tons of copper and 72,000 tons of refined arsenic.^[28]

Copper

Arsenic