Arizona weekly journal-miner., 1901-04-24
HOW TO VALUEAMINE
Experts Method of Estimating the
 Worth of "Ore in Sight"
Always. an Element of Uncertainty Even Under the Most AdvaA- tageouA Investigations of
 Deposits.

With the news that John Hays
 Hammond's proposal to take charge
 of the Independence gold mine had
 been accepted by the London owners
 came the report that the mine had
 been worked out" This statement
 had been made many times before, and
 much doubt existed in the minds of
 interested parties when MT. Ham,
 mond's latest report was received,
 says the New York Tribune. This
 document showed that the property
 which for long time yielded 40 per
 cent. dividend on large investment,
 was still rich in ore, and capable of producing large profits. MT. Ham,
 mond said that the lore in sight" war
 ranted him in guaranteeing a divi- dend of ten per cent, or S4ss,0O0 and that would leave about $500, ,OOO out of the years deposits to be used toward the further development of the prop erty and locating new ore beds.
 The phrase lore in sight" is one that is well understood by people who are interested in the mining business, but is misunderstood by the average layman. The ore is not "'in sight" on the surface, but its existence is es- tablished by series of operations which are in many instances exceed ingly difficult, expensive and labori- ous.
 Speaking on this subject, Dr. A. R. Ledoux said: There is no way to de termine the existence of gold ore, its quantity, quality, or anything about itunless one gets on three sides of the deposit, and even then there is an ele- ment of uncertainty about it. Ore in sight is what has been found after blocking out a certain section of ground. The blocking is accom- plished in various ways in keeping with the nature of the ground. Thus, by sinking a shaft of 20 feet in width 100 feet into the earth and then run ming level from this, say 200 feet, to another shaft the same depth and width as the first, and then taking samples of the ore or rock from all parts of this block one would have a good idea of the yielding qualities of that particular block. This block would be 100000 cubic feet, or about 10000 tons, and the assays from the four sides, the two shafts, the tunnel and the surface would be the gold in sight The center of the block, which cannot be reached until actual opera Uons are begun, might yield much more than the assays indicated. and. on the other hand, it might be found worthless or barren rock. In cases where the block of 1OOx2OOx2O feet would he deemed insufficient for de- termining the value of the mine. an- other block of similar size may be laid out below or beyond the first. and by this series of blocking the value of the mine as a gold producer is esti- mated. It is a well-known fact that gold is often deposited in shoots that run in Oblique and tOrtuous direc- tions from the surface, and one must be posted on the geology of the coun- try to arrive at correct estimate of the value of the land that has been blocked out. A shaft, for instance, may run for 100 feet through rich ore and another parallel shaft 200 feet away may not strike any ore until a depth of 100 feet or more has been reached. The next shaft 200 feet fur ther away may have to be sunk still further before the valuable rock is reached, and this would indicate that the shoot runs diagonally from the surface. This is only one of the many in the matter of gold veins that present themselves to the miner, and no set rule can be followed in or der to locate the valuable ore or to determine its extent But the term gold in sight or ore in sight is usu- ally applied to the block or to the series of blocks which have been ex. amined and assayed on three sides"