base, some
protection to the roadway must be provided. There are three systems
in use,--by wood stulls or sets (Figs. 19, 30, 43), by dry-walling
with timber caps (Fig. 35), and in some localities by steel sets.
Stulls are put up in various ways, and, as their use entails the
least difficulty in taking the ore out from beneath the level,
they are much favored, but are applicable only in comparatively
narrow deposits.

WINZES AND RISES.

These two kinds of openings for connecting two horizons in a mine
differ only in their manner of construction. A winze is sunk underhand,
while a rise is put up overhand. When the connection between levels
is completed, a miner standing at the bottom usually refers to
the opening as a rise, and when he goes to the top he calls it
a winze. This confusion in terms makes it advisable to refer to
all such completed openings as winzes, regardless of how they are
constructed.

In actual work, even disregarding water, it costs on the average
about 30% less to raise than to sink such openings, for obviously
the spoil runs out or is assisted by gravity in one case, and in
the other has to be shoveled and hauled up. Moreover, it is easier
to follow the ore in a rise than in a winze. It usually happens,
however, that in order to gain time both things are done, and for
prospecting purposes sinking is necessary.

The number of winzes required depends upon the method of stoping
adopted, and is mentioned under "Stoping." After stoping, the number
necessary to be maintained open depends upon the necessities of
ventilation, of escape, and of passageways for material to be used
below. Where stopes are to be filled with waste, more winzes must
be kept open than when other methods are used, and these winzes
must be in sufficient alignment to permit the continuous flow of
material down past the various levels. In order that the winzes
should deliver timber and filling to the most advantageous points,
they should, in dipping ore-bodies, be as far as possible on the
hanging wall side.

DEVELOPMENT IN THE EARLY PROSPECTING STAGE.

The prime objects in the prospecting stage are to expose the ore
and to learn regarding the ore-bodies something of their size, their
value, metallurgical character, location, dip, strike, etc.,--so much
at least as may be necessary to determine the works most suitable
for their extraction or values warranting purchase. In outcrop mines
there is one rule, and that is "follow