Since this date, it has, on the whole, diminished, although large outputs occurred in isolated years, for instance, a production of 40,000 tons in 1893 was followed by 60,000 tons in 1896 and 40,000 in 1897.
Spain ranked second in 1850 with about 47,000 tons; this was increased in 1863, 1876 and in 1888 to 84,000, 127,000 and 187,000 tons respectively; but the maximum outputs mentioned were preceded and succeeded by periods of depression.
Australian deposits were worked in 1872, and in the following year the production was 3000 tons; the maximum outputs were in 1881-1883, averaging 10,000 tons annually; but the supply declined to 2420 tons in 1898 and has since increased to about 5028 tons in 1905.
Level, greatly increasing many mine values and outputs; in 1906 the work of drainage was again taken up, and work on a long bore was begun in May 1907.
The table gives the outputs in metric tons of the most important producers in 1900 and 1905 (from Rothwell, Mineral Industry, 1908).