Each had about 500 men and produced 100 000 tonnes per year.
The company has a capacity to produce 150 tonnes of products per day.
It should produce 5000 tonnes of the metal per year.
Until 1924, up to 650,000 tonnes of coal was produced.
In 2005, an estimated 700,000 to 800,000 tonnes were produced.
Despite this, some 240, 000 tonnes are still produced worldwide every year.
The well produces 50 tonnes of oil on daily basis.
By 2020 it is estimated that the field will produce 6-9 million tonnes of oil per year.
In the 1950s it produced 14,000 tonnes of coal a week.
In 2009 the mine produced 4.3 million tonnes of iron.