erms "ore in sight" and "profit in sight" have been of
late years subject to much malediction on the part of engineers
because these expressions have been so badly abused by the charlatans
of mining in attempts to cover the flights of their imaginations. A
large part of Volume X of the "Institution of Mining and Metallurgy"
has been devoted to heaping infamy on these terms, yet not only
have they preserved their places in professional nomenclature,
but nothing has been found to supersede them.

Some general term is required in daily practice to cover the whole
field of visible ore, and if the phrase "ore in sight" be defined,
it will be easier to teach the laymen its proper use than to abolish
it. In fact, the substitutes are becoming abused as much as the
originals ever were. All convincing expressions will be misused
by somebody.

The legitimate direction of reform has been to divide the general
term of "ore in sight" into classes, and give them names which will
indicate the variable amount of risk of continuity in different parts
of the mine. As the frequency of sample points, and consequently the
risk of continuity, will depend upon the detail with which the mine
is cut into blocks by the development openings, and upon the number
of sides of such blocks which are accessible, most classifications
of the degree of risk of continuity have been defined in terms of
the number of sides exposed in the blocks. Many phrases have been
coined to express such classifications; those most currently used
are the following:--

Positive Ore \ Ore exposed on four sides in blocks of a size
Ore Developed / variously prescribed.
Ore Blocked Out Ore exposed on three sides within reasonable
distance of each other.
Probable Ore \
Ore Developing / Ore exposed on two sides.

Possible Ore \ The whole or a part of the ore below the
Ore Expectant / lowest level or beyond the range of vision.

No two of these parallel expressions mean quite the same thing;
each more or less overlies into another class, and in fact none
of them is based upon a logical footing for such a classification.
For example, values can be assumed to penetrate some distance from
every sampled face, even if it be only ten feet, so that ore exposed
on one side will show some "positive" or "developed" ore which, on
the lines laid down above, might be "probable" or even "possible"
ore. Likewise, ore may be "fully developed" or