Mohave County miner., 1910-06-11

many, that an average sample was a fair and accurate test of the true value of an ore body; but this theory is in- correct unless the values are evenly distributed from wall to wall. The term average sample" sounds well, but, in reality, the average sample is more often misleading than it is cor rect.
 In the matter of average samples a mine-owner is apt to be misled as to the true value of his property, and a great many operators, taking such tests at their face value, are liable to meet with some hard and disappoint- ing propositions if they are governed by them. For instance, large body of ore is uncovered in which occur streaks and zones of pay mineral, as sociated with shoots of vein matter carrying but little values. An average sample is made clear across the vein with results that are most encourag- ing. The pay streak possibly, is two feet in width, assaying 50S to the ton: while the whole vein, ten feet in width, averages 75S. This looks good to the owner of the mine, and he goes ahead with its development and equipment laboring under the impression that he has a ten foot vein of 75S ore; when, as a matter of fact, he has only two feet of ore which it will pay him to handle: the other eight feet being lit tie better than slightly mineralized rock Rock that cannot be handled at a profit under any circumstances, and rock winch, if mixed with the pay product of the mine, reduces it's grade without in the least increasing its value. The fact that the full ten feet of ore averages 75S to the ton really amounts to nothing and is a detriment, a hardship, without a question of doubt. to the really good ore in the mine, and does not give fair and ac- curate idea of the value of the orebody.
 No man would mix barren country rock with the ore he is shipping to the market or to the shelter. and yet he might as well do so as to mine or mill with high grade ore, mineral so low in grade that it cannot be handled at profit on it's own merits: on its own intrinsic value. As a matter of fact, the eight feet of vein material would go only a little in excess of 3S a ton, and this would not pay shipping and smelling or milling charges; and. therefore, is valueless excepting in the matter of tonnage.
 Along the same line of reasoning. it is not fair to the mine or to the owner to state that the average of an ore body is 75S or lOOS, as the case may be. when, as a matter of fact, four fifths of the vein is so low in grade as to be practically worthless. The av- craze sample has a tendency to make the proposition look big, but the idea conveyed is deceiving and often works a hardship to uniformed and inex- perienced parties who are in any way interested in property from which the average sample has been taken.
 The question of What is an average sample?' has often been called to the attention of the writer when reports have been submitted in which it is shown that an entire ore body assayed way up into pay values, but where it was shown that only part of the vein was high in grade, and that the maln portion of the ledge was almost value less for the mineral it contained.
 In such instances the querry arises: ''Is this an average sample, or is the mine owner unknOwingly fooling him. self?''-Salt Lake Mining Review.