Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/170

From Wikisource
Jump to navigation Jump to search
This page has been validated.
Mr. William Phillips on the Veins of Cornwall.

south veins traversing metalliferous veins is here exhibited, for the load of the contre, which, as has been said, is rich in copper, not only passes through the north and south vein, but also heaves it out of its regular direction four fathoms. This is the only instance of the kind that has come to my knowledge. On consulting the ground plan of Herland and Drannack mines, it will be seen that the effect of the cross vein on the contre in that mine was exactly that of the contre on the cross vein in Huel Alfred.

The run of the cross vein is direct north and south; it underlies west about one foot in a fathom; is nine feet wide, and close to the contre (where only it has been seen) is chiefly filled with quartz, accompanied by blende and carbonate of lead in very small quantities, but in it there is no flucan; at and below forty fathoms from the surface, the quartz assumed the form of a fine sand, and the water from the cross vein was so powerful as to wash the sand 90 fathoms into the contre, so as occasionally to choak the pumps. It should be remarked that no ore was seen in the latter while passing through the cross vein for more than 100 fathoms from the surface.

About 45,000 tons of copper ore, the produce of Huel Alfred, have been sold since the beginning of 1801, for the sum of about £350,000. The number of men women and children, employed underground and on the surface, amounts nearly to 1500. There are three large steam engines for drawing the water, and two steam whims for drawing the ore, now on the mine. The monthly expenses for labour, coals, ropes, timber, &c. amounts now to about £5300. The profit hitherto divided amongst the adventurers amounts to about £120,000.