successful mining districts of the west; and there seems to have been a very large proportion of disastrous failures among the many gold mining enterprises that have been undertaken here. But, as I have already remarked, there is some reason to assume that many of these failures have been due to ignorance and bad methods of working. The depth to which the rocks have been rotted and decomposed has, moreover, been a serious obstacle in the way of arriving at a proper understanding of the geological relations of the deposits, and while it has tended to make the surface-showing unduly rich, has undoubtedly been an important factor in preventing systematic and successful mining in depth. Some go so far as to say that gold in this belt ceases in depth beyond the water-level, or zone of surfacedecomposition of country-rock. For such a statement I can see no valid geological reason. That the chemical composition of ores changes below this line is recognized everywhere and is readily explained; it is, moreover, an observed fact, that is not always susceptible of scientific explanation, that the metallic bases contained in an ore in some cases undergo a remarkable change in depth.

It would naturally be expected in a region where decomposition has gone on uninterruptedly for so long a period as it has in this belt, that by the gradual removal of the more readily attackable and less valuable constituents, the proportion of gold (a metal that is practically uninfluenced by the agents of decomposition), remaining in the decomposed and superficial portion of the region, should be greater than it was in the original deposits before decomposition had set in. Hence the deposits will contain on the average somewhat less gold to the ton from the surface downwards until the unaltered rock is reached, and in this rock they will vary in richness from point to point as do all ore-deposits, but any assumption of a disappearance of the gold in this unaltered rock is geologically untenable.

After the water-level is passed the sulphurets will be found in an unoxidized condition, and such gold as is actually contained in them cannot be separated by the ordinary process of amalgamation. It can, however, be obtained by suitably conducted chlorination or by smelting. To how great a depth it will be profitable to work a given deposit is then a question not for the geologist but for the technical mining engineer. It may be that, while the deposit still carries gold in a proportionate amount to what it did above, it will be no longer profitable to work it, on account of the increased cost of mining and reduction. The plant that successfully reduced the free gold-ore at the surface may require considerable and expensive modifications to

adapt it for the treatment of unoxidized ores. Although this treatment presents many practical difficulties, and has in a great number of cases proved commercially unsuccessful, it is based on wellknown chemical and metallurgical principles and involves no hitherto undiscovered chemical processes. The question is simply, whether the expense of treatment will be greater than the average yield of ore, and is one that a competent mining engineer should be able to answer by practical experiments before establishing an expensive plant. Of those patent processes by which it is claimed gold is extracted from the sulphurets by a secret and hitherto unknown chemical reaction it may be safely said, that either they will not do what they claim when applied on a large scale, or that they contain nothing not already known to the science of ore-reduction, and hence nothing worth paying a royalty on.

The most important question from a geological standpoint, with regard to these deposits, is, whether the quartz-bodies have been formed along fracture- or fault-planes, or are simply lenticular masses following the bedding of the schists. The latter view has been held by many in regard to the auriferous belt in general; but what I have seen of the Montgomery County deposits leads me to regard them as of the former class, and hence belonging to the category of true veins.

Judging from the developments thus far made, and from the great number of parallel veins in a comparatively small area, it would appear that these deposits have been made along a series of co-ordinated fractures or "compression joints," in which the predominating direction is nearly north and south, with comparatively few cross-joints, or fractures at a considerable angle to this direction, such as are common in a region where a torsional strain has been associated with that resulting from compression. It is probable, therefore, not that any very great single veins, of extent and width comparable to those found on the more prominent "faultfissures" of the west, exist here, but that the vein materials are distributed along a series of small co-ordinated fissures, often so nearly on a line as to appear to be part of the same vein, when traced by isolated outcrops alone.

It is likely, also, that in a given vein the quartz will be found to be very irregularly distributed, widening rapidly at one point, thinning out again in comparatively short distances, often almost en

* Trans., xvi, 824.

tirely disappearing, even though the fracture-plane can still be distinguished and gold-bearing material be found along it. But even after it has disappeared it is likely to come in again, if not on absolutely the same plane, on one nearly adjoining and parallel with it. The underground workings are still too limited in extent to afford any data for estimating the average extent of these quartz-bodies, but it is probable that, when sufficient mining has been done, it will be found that there is some sort of system in their distribution, as there generally is found to be in the distribution of bonanzas or rich ore-bodies in the greater veins. A few fundamental principles may be laid down which should govern the development of new districts of this nature.

It should be borne in mind that the quartz is not the only veinmaterial; it was probably deposited more or less contemporaneously with the gold, pyrite and what other metallic minerals may be found. The quartz filled whatever openings were formed by the fracturing and faulting of the country-rock, but the solutions that accompanied it penetrated the fractured and sheeted country-rock on either side, depositing there pyrite and gold with some silica, so that a portion of the country-rock constitutes ore as well as the quartz. How much this may be in the case of a given vein can only be determined by actual test, and it behooves those working the mines to have frequent tests made of the material along the sides of their vein, either by assay, or if this is not practicable, by panning, to determine the width of vein-material which it will pay to reduce. It will be found to vary very much from place to place; and it is evident that profitable results cannot reasonably be expected, if good ore is thrown away, or material which costs more to reduce than it carries in gold is, to any considerable extent, passed through the mill.

In such a district as this, it is of especial importance that underground exploration should be carried on far in advance of actual reduction of ore. No extensive reduction-plant should be erected until an amount of pay-ore sufficient to supply it for several years has been actually opened and fully tested. Underground developments should not be confined to a single vein, but frequent crosscuts should be made in the softer and easily-worked ground immediately above the hard rock, to determine the existence of parallel veins to be opened; for it is only by working great quantities of ore that costs of reduction can be reduced to a minimum, and large profits be obtained; and such large quantities can hardly be expected

from a single vein. The number of the veins gives reasonable promise for such production, however, if mining is conducted systematically; and the mine-owner here has a great advantage over his Western brother, in that he is not exposed to annoyances resulting from the mining law of the United States, but has a clear title to all the ground within the vertical side-lines of his property, and, when he has developed a valuable body of ore underground, runs no danger of having it taken away from him by his neighbor, who, after such discovery, may have constructed an apex for the body within his own side-lines.

A separate and distinct problem is presented by the evidently large amount of gold contained in the soil and loose material near the surface along the croppings of the veins. Such material can evidently be treated very cheaply, if its working is conducted systematically, and on a sufficiently large scale. It must first, however, be carefully prospected and tested, so that the amount available and its average yield can be determined with reasonable accuracy. The most successful treatment of low-grade gold-ore is that of the Homestake mine in the Black Hills, which yields an average of only $3.71 per ton in gold and silver, but which is mined and reduced at a cost of $2.52,* leaving a profit of $1.19 per ton. It is to be noted, however, that this low cost of treatment, and the obtaining of a profit from such ore, is only possible, because nearly one-quarter of a million tons per annum are treated, and that similar deposits in that region, worked in a small way, have not proved profitable.

To work this material at a profit, operations must also be conducted on a large scale, for the average yield will probably be low, though the gold is in a most favorable condition for treatment. In Georgia, similar material has been treated by turning a head of water on the ground and washing it down in boxes to stamp-mills. No large streams are available here which would give such a head, and hence some method of handling, other than by water, and consequently more expensive, must be used. It is probable, however, that this material can be pulverized for amalgamation by other machinery than by the power-wasting stamp-mill, and more cheaply, provided a machine be selected of sufficiently simple construction and effectiveness of power. Most of the machines which are advertised to do such work, are too complicated in construction for successful use by the ordinary mill-hand, and do not present a thoroughly effective use of power from a mechanical point of view.

* Carpenter, Trans., xvii, 570.

ELECTRICITY AND HAULAGE.

BY FRANCIS A. POCOCK, M. E., SCRANTON, PA.

(Washington Meeting, February, 1890.)

THE writer is continually asked, if this electricity is all you claim for it, why do not the mines put it in and use it? The best answer was given by Mr. John Fox Tallis, in his paper read before the South Wales Institute of Engineers in 1888, namely, that the reasons are similar to those which have prevented the more general employment of other systems of haulage. Managers, as a rule, are "not experienced mechanical engineers; neither are they all versed in electrical engineering." It may be said that there are a number of "able and practical electrical engineers who could do the work; but those electrical engineers are not conversant with the practical routine of colliery work and are, therefore, placed at a disadvantage by not knowing the actual requirements of mining engineers, and the many little difficulties to be met and contended with in underground workings; and, until mining engineers have acquired the necessary knowledge and a confidence in electricity, it is only natural that they will continue to follow the beaten path."

In the above remarks, Mr. Tallis has hit the nail on the head. In the face of the partial failure, financially, of the haulage-plant which the Union Electric Company of Philadelphia had set to work at Lykens Valley, Pa., an electric haulage-plant was installed near Scranton, Pa. The question was not whether electricity could do the work, but whether any electrical company knew enough about the practical difficulties to attack and overcome them. That point being settled, the remainder was easy.

The contract for the Erie Colliery haulage-plant was signed in January, 1889.

This colliery is owned by the Hillside Coal and Iron Company, Mr. Samuel Hines, President, and Captain W. A. May, Superintendent. The company has been using arc-lamps in its breakers for three years. It is the only company in the Lackawanna Valley which has had enterprise enough to do so. Consequently, it was acquainted