Examination of Mines. 25 
THE EXAMINATION OF MINES. 
VALUATION. 
The object of making mining examinations is to 
determine as nearly as possible the real and prospective 
value of mining properties. The real value is arrived 
at by making accurate surveys, samplings, assays, 
tests and estimates of the ore exposed or in sight. The 
prospective valuation of the property, of course, will de- 
pend upon surrounding conditions, viz: the locality, 
nature and probable extent of the ore deposit, richness 
of the ore exposed, cost of operation, etc. 
In any case the party making the examination 
should be governed by the facts in the matter as they are 
encountered in the course of his examination of the 
property, and his report on the mine or prospect should 
fully explain how these facts were arrived at. If a min- 
ing property cannot be (without further exploration of 
its ore bodies) profitably operated, it should not be re- 
ported on as a mine but as a prospect. i 
METHOD OF ESTIMATING THE NUMBER OF TONS OFORE IN 
SIGHT. 
According to a custom in vogue among mining en- 
gineers the ore in the mine must be blocked out so that 
at least two or three sides of the ore bodies shall be ex- 
posed before any estimate of the ore in sight can be 
made. Where three sides are exposed, their dimensions 
are accurately taken according to the surfaces sampled, 
and the cubical contents of the ore masses thus sampled 
are accurately computed. Where two sides only are ac- 
cessible to the termini of the consecutive working levels 
(which are generally 100 feet apart on the dip of the 
vein) above and below are jointed together by imagin- 
ary lines, thus dividing the ore masses up into triangu- 
lar solids. The parts exposed are accurately measured 
jl. . 
