sixty or
seventy feet below the surface, and from this point the miner or
"drifter" works upward, and as he loosens the rock it falls to the
bottom of the shaft, where it is put in the bucket to be hoisted to the
surface. Our quartz mines are generally in dry hills, so that they are
not troubled much by water; but there are a few shafts where
steam-pumps are constantly at work to carry off the water.

Occasionally the miners find small quantities of auriferous quartz
which are so easily broken up, and the pieces of gold in which are so
coarse, that after the rock has been pounded a little in a mortar, the
metal can easily be picked out with the fingers.

_Arastra._--Quartz is pulverized either in an arastra, or Chilean mill,
or by stamps.

The arastra is the simplest instrument for grinding auriferous quartz.
It is a circular bed of stone, from eight to twenty feet in diameter,
on which the quartz is ground by a large stone dragged round and round
by horse or mule-power. There are two kinds of arastras, the rude or
improved. The rude arastra is made with a pavement of unhewn flat
stones, which are usually laid down in clay. The pavement of the
improved arastra is made of hewn stone, cut very accurately and laid
down in cement. In the centre of the bed of the arastra is an upright
post which turns on a pivot, and running through the post is a
horizontal bar, projecting on each side to the outer edge of the
pavement. On each arm of this bar is attached by a chain a large flat
stone or muller, weighing from three hundred to five hundred pounds. It
is so hung that the forward end is about an inch above the bed, and the
hind end drags on the bed. A mule hitched to one arm will drag two such
mullers. In some arastras there are four mullers and two mules. Outside
of the pavement is a wall of stone a foot high to keep the quartz
within reach of the mullers. About four hundred pounds of quartz,
previously broken into pieces about the size of a pigeon's egg, are
called a "charge" for an arastra ten feet in diameter, and are put in
at a time. The mule is started, and in four or five hours the quartz is
pulverized. Water is now poured in until the powder is thoroughly mixed
with it, and the mass has the consistence of thick cream. Care is taken
that the mixture be not too thin, for the thickness of it is important
to the amalgamation. The paste being all right, some quicksilver (an
ounce and a quarter of it for every ounce of go