166 Copper Mines of Chili. [April, 
adit, driven on the southern extension of the lode, at a point 
nearly a mile distant from the workings, but the lode proving 
barren the work was dropped; by another adit, the San 
Gregorio, likewise to the south of the mine, but much closer, 
as it commences at the foot of the steep hill on which it 
exists ; it is being pushed forward as the ground through 
which it cuts is improving; by open workings along the 
outcrop whence carbonates are still extracted; and by two 
E. and W. adits, through which the ore is now brought to 
surface by a steam engine in one case, and a horse whim in 
the other. 
The two excavations, known as the North and South 
Mines, are separated from one another by a cross course, 
which does not displace the lode. In depth the lode seems 
to cut through it. The largest stope is in the North Mine, 
400 feet long, 200 feet high, and in places 100 feet wide. 
The principal stope in the South Mine is almost as enormous. 
The workings more resemble a narrow rocky defile with 
steep sides, connected here and there by natural bridges, 
than the stopes of a mine. Paths are cut into the per- 
pendicular cliffs, along which you climb by the aid of chains 
or a hand-rail, every now and then crossing by the arches 
left to support the walls. Into one of these immense caverns 
the light streams through an opening to surface in the roof, 
producing a most picturesque effect, which is heightened by 
the echoes of the miners’ blows, and the plaintive chant with 
which they accompany their work. 
The western wall of the lode is well-defined. On it lies 
a clay selvage; then a layer of galena of varying thick- 
ness, and carrying a little silver; then the main mass of the 
lode, which consists of a solid mixture of common iron 
pyrites, magnetic pyrites, and garnet, with copper pyrites 
and a small quantity of black-jack. Not more than 10 per 
cent of what is broken is thrown away in picking, and there 
is nothing left behind in the stopes. The yield of copper is 
now about 4°6 per cent, 1 per cent less than it was three 
years ago. 
The cost of breaking, picking, and delivering the ore at 
the works is low, otherwise so poor an ore could not be 
worked. Spalling and picking is done for 1} cents a quintal 
metrico = 123 cents per ton. At this rate good hands make 
18 dols.a month. Driving is done by contra@t at 4o dols. 
afathom. In stoping the principal cost is in fracturing the 
huge masses which are dislocated from the lode by each 
blast. It is intended to try dynamite for that purpose. In 
stoping the miner is paid 1 cent per inch for boring. English- 
