[From Lamplugh, Geology of IoM, 1903]
After the close and systematic search which has been made in every part of the Island, we may presume that the relative importance of the various lodes has been well established, and that no considerable body of ore presenting surface indications can have been overlooked, though there is, of course, the possibility that such may remain still undiscovered beneath a superficial covering of drift. As previously mentioned, while the valuable ores have been found in small amount in many veins, the commercially successful mines are and apparently have always been confined to two lodesthat of Foxdale and that of Laxey, though considerable bodies of lead and zinc ore have been met with also in the mines of ' Snaefell', 'North Laxey' in the Cornah Valley, and 'Ballacorkish'; and of hematite in Maughold parish. From all the other workings combined the total quantity is inconsiderable. From the depth to which the principal mines have now been sunk, we must also conclude that the average output of the last fifty years is unlikely to be maintained in the future.
LEAD-ORE.The table given on pp. 495-8 shows that between 1845 and 1850 the average output of lead-ore was 2,300 tons per annum, of which at first six-sevenths, and afterwards two-thirds was contributed by the Mondale group of mines, and practically the remainder by Laxey. A steady increase during the next five years brought the-total output of this ore in 1855 up to 3,573 tons, of which three-fourths was from Foxdale, and the remainder from Laxey. A decrease then set in, so that until 1864 the annual output ranged, in round numbers, between 2,500 and 2,800 tons. In that year however the contribution from Laxey was greatly augmented; and in the following year equalled that of Foxdale, bringing the total up to 3,143 tons of lead-ore. In 1871 the grand total of 4,645 tons was reached, of which Laxey yielded a half, Foxdale rather over a third, and eight smaller mines the remaining sixth. There was a drop of 1,000 tons in 1872 owing to a decrease of that amount from Laxey; but from 1873 to 1877 inclusive the total annual output of the Island remained steadily between 4,200 and 4,400 tons, the Foxdale contribution maintaining, as for many previous years, remarkable regularity at about 1,640 to 1,700 tons. In 1878 the returns fell below 4,000 tons, Laxey sinking again, and permanently, to the second place as a lead-producer. But this deficiency was more than made up in all suceeding years by Foxdale, which swelled the output to high-water mark at 6,868 tons in 1885, two-thirds of which was from this mine and less than a quarter from Laxey. From 1884 to 1893 inclusive the total yield of lead-ore remained between 6,000 and 6,700 tons, the decline of Laxey meanwhile continuing, so that in the last-named year its proportion was less than one-seventh, while Foxdale yielded three-fourths and three other mines the remainder. Since that date, though Foxdale has maintained its high productivenessits yield of 4,800 tons of lead-ore for 1894 being the greatest in the history of the minethe deficiency from the other mines has diminished the total output of the Island to 3,843 tons for 1900.
ZINC-BLENDE.The only other metal deserving special notice is zinc; and its history is practically that of the Laxey Mine, as except during a short period of productiveness at Snaefell, the other sources of this substance in the Island have been unimportant. In 1854 the returns of blende from Laxey were 1,435 tons, rising suddenly in the following year to 3,989 tons, and from that time until 1861 ranging around 3,000 tons more or less. Then follow great fluctuations, so characteristic of this mine, the record for 1862 being 691 tons; for 1863, 2,298 tons; for the flour following years, between 4,960 and 5,488 tons; in 1869, 7,208 tons; and so on, until in 1875 the returns show 11,753 tons of blonde from this mine, and 11,898 tons from the whole Island, a quantity which has not been since attained.
During the ensuing decade, the average was about 6,000 tons, ranging from about 2,000 above to 2,000 below this figure. But since 1885 there has been a continued decline which brought down the total for 1896 to 1,180 tons of blonde from Laxey and 1,489 tons from the whole Island, with a slight recovery to the total of 2,009 tons in 1897,2,602 tons in 1899, and 9,124 tons in 1900.
The following table gives the total annual output of the Manx Mines recorded in ordeal returns.
ISLE OF MAN MINING STATISTICS.