No. 161.] 
141 
Economical considerations. 
Few beds of ore have been extensively worked in this part of 
the country; the Arnold bed has already been referred to as the 
one most extensively wrought. This bed has been leased to the 
Peru Iron company for the last 10 years, and there have been 
4,000 tons of ore annually raised from the mine, for which they 
have paid ^1.80 per ton, thus yielding to the proprietors of the 
mine an annual income of more than $7,000. This income might 
be secured froai the avails of the mine for an indefinite period, if 
care was taken in the working to provide security for the w^alls or 
roof, which otherwise collapse, and render a new opening neces- 
sary. From the inclined position of this bed, it was necessary to 
support the roof when the ore was removed; this was done so im- 
perfectly, that about two years since the supports gave way, and 
the roof fell in, which now prevents the working of the bed at 
this place. Should this bed ever be reopened, the expense of 
clearing it of the fallen and broken rocks would be more than the 
first expense of raising the ore; and after this was done, the wall 
upon that side would require far more to support it than before; 
with this inconvenience, that all the surface water would percolate 
through the fissures into the mine, thus causing continual annoy- 
ance, and increase of expense in working it. 
A want of knowledge, both of the science and art of mining, is 
manifested in the working of most of the mines. They are prin- 
cipally in the hands of men who use them for present profit; and 
even many of the proprietors,,who should be attentive to the man- 
ner in which their mines are worked, yet leave them to the con- 
trol of individuals who attend only to raising the ore with the least 
possible present expense; the mine being left, so that after a few 
years, at farthest, it is unsafe to enter, and finally, the roof falls, 
and then a new place is opened. In no case does the ore deterio- 
rate on descending, but, on the contrary, improves in quality, in 
most beds. This should be an inducement to keep open the shafts 
until the expense of raising ore was so great that it would compel 
the opening of new ones. No accidents have occurred in work- 
ing these mines, except from blasting; but this is not owing to the 
care of securing the walls, the rocJ^s being of such a quality that 
they will remain if but slightly supported; but after the bed is 
penetrated to a great depth, the support being taken away gradu- 
ally, as the ore is removed, the weight becomes too great for the 
