912 COPPER 



to the right. The throw of tho vein occurs, therefore, in one case to the right, and in 

 the other to the left ; but in both instances, it is to the side of the obtuse angle. This 

 disposition is very singular ; for one portion of the vein appears to have ascended, while 

 another has sunk. See FAULTS. 



The copper-mines of the isle of Anglesea, those of North Wales, of Westmoreland, 

 tho adjacent parts of Lancashire and Cumberland, of the south-west of Scotland, of 

 the Isle of Man, and of the south-east of Ireland, also occur in primitive or transition 

 rocks. The ores lie sometimes in masses, but more frequently in veins. The mine 

 of Ecton, in Staffordshire, and that of Cross-gill-burn, near Alston-moor, in Cumber- 

 land, occur in carboniferous or mountain limestone. 



The copper ores extracted both from the granitic and schistose localities, as well as 

 from the calcareous, are uniformly copper pyrites more or less mixed with mundic ; 

 the red oxide, carbonate, aresenate, phosphate, and chloride of copper, are very rare in 

 these districts. 



The working of copper-mines in the isle of Anglesea may be traced to a very 

 remote era. It appears that the Eomans were acquainted with the Amlwch mine near 

 Holyhead. Mr. Thomas F. Evans has been so fortunate as to obtain and preserve 

 three copper cakes found at Bryndu, Amlwch, which are evidently of Eoman origin. 

 The copper-mines in Parys Mountain were not worked with activity until the year 

 1779. In 1784 these mines produced 3,000 tons of copper annually. This deposit 

 lies in a greenish clay slate, passing into talc slate ; a rock associated with ser- 

 pentine and euphotide. The veins of copper are from one to two yards thick ; and 

 converge towards a point where their union forms a considerable mass of ore. On 

 this the mine was first commenced by an open excavation, which is now upwards of 

 300 feet deep, and appears from above like a vast funnel. Galleries are formed at 

 different levels upon the flanks of the excavation to follow the several smaller veins, 

 which run in all directions, and diverge from a common centre like so many radii. 

 The ore receives in these galleries a kind of sorting, and is raised by means of hand 

 windlasses to the summit of a hill, where it is cleaned by breaking and jigging. 



The water is so scanty in this mine that it is pumped up by a small steam- 

 engine. A great proportion of it is charged with sulphate of copper. It is con- 

 veyed into reservoirs containing pieces of old iron ; the sulphate is thus decomposed 

 and metallic copper obtained by cementation. The Anglesea ore is poor, yielding only 

 from 2 to 3 per cent, of copper ; a portion of its sulphur is collected in roasting the ore. 



The copper-mines of these islands, now so important, were so little worked until a 

 recent period that in 1799 we are told in a Keport on the Cornish mines, ' it was not 

 until the beginning of the last century that copper was discovered in Britain.' This 

 is not correct, for in 1250 a copper-mine was worked near Keswick, in Cumberland. 

 Edward III. granted an indenture to John Ballanter and Walter Bolbolter, for work- 

 ing all ' mines of gold, silver, and copper ; ' but that the quantity found was very 

 small is proved from the fact that Acts of Parliament were passed in the reigns of 

 Henry VIII. and Edward VI. to prevent the exportation of brass and copper, ' lest 

 there should not be metal enough left in the kingdom, fit for making guns and other 

 engines of war, and for household utensils : ' and in 1665 the calamine works were 

 encouraged by the Government, as 'the continuing these works in England will 

 occasion plenty of rough copper to be brought in.' 



At the end of the seventeenth century, some ' gentlemen from Bristol made it their 

 business to inspect the Cornish mines, and bought the copper ore for 21. 10s. per ton, 

 and scarce ever more than 41. a ton.' 



In 1700, one Mr. John Costor introduced an hydraulic engine into Cornwall, by 

 which he succeeded in draining the mines, and ' he taught the people of Cornwall also 

 a better way of assaying and dressing the ore.' 



The value and importance of copper-mines since that period regularly increased, 

 until within the last few years. There has been of late a steady decline in the pro- 

 duce of our copper-mines, and a falling off in the per-centage of metal in the ore. 



Mechanical Preparation of the Copper Ores in Cornwall. The ore receives a first 

 sorting, the object of which is to separate all the pieces larger than a walnut ; after 

 which the whole is sorted into lots, according to their relative richness. The fragments 

 of poor ore are sometimes pounded in stamps, so that the metallic portions may 

 be separated by washing. 



The rich ore is broken into small bits, either with a flat beater, or by means of a 

 crushing-mill. The ore to be broken by the bucking iron is placed upon plates of 

 cast iron ; each about 16 inches square and 1 inch thick. These plates are set 

 towards the edge of a small mound about a yard high, constructed with dry stones 

 rammed with earth. The upper surface of this mound is a little inclined from 

 behind forwards. The work is performed by women, each furnished with a bucking- 

 iron : the ore is placed in front of them beyond the plates ; they break it, and strew 



