APPENDIX “B.”

HINTS FOR THE USE OF PROSPECTORS AND PERSONS ENGAGED IN THE EARLY DEVELOPMENT OF MINING PROPERTY.

Having thus pointed out some of the causes which have retarded our progress to a successful result in many portions of Nevada, it remains to show in what way we may avoid them in the future; and for this purpose I would suggest the following remarks on the development of mines and the reduction of ores:

When indications of a mineral deposit have been observed, the first thing to be ascertained is its extent, as accurately as may be; and secondly, the character of the ores, and the facilities which exist for their successful treatment-as on this latter circumstance the value of the property will be in a great measure dependent. If the requisite means of reduction are near at hand, and equally accessible, a lower grade of ore will be remunerative, than would be the case if costly fluxes and machinery or transportation of ore and materials to a considerable distance are unavoidable. At the same time some attention ought to be given to the rocks which are associated with or contain the mineral lodes. If a mine in any district has been proved by development to be valuable, the country rock in which it is found should be carefully noted, as it is not unlikely that wherever they occur in the same district, other mines equally good may occur in that connection. Nor is this the only advantage to be derived. If the mine is offered for sale, almost the first inquiries will relate to these matters, experience having shown that certain minerals are usually associated with rocks of a certain age and character, and that mineral-bearing lodes are more apt to be permanent in some formations than in others. The direction of the vein, with regard to the general structure of the country, should be ascertained, noting particularly whether it runs parallel to or crosswise of the various formations; nor should traces of recent volcanic action be overlooked, as in localities where the country is much broken, it is not unlikely that the veins may have been extensively "faulted" or dislocated—an accident of great importance in the successful working of mining property.

When a mineral deposit has been discovered, the first thing to be done, as before stated, is to trace it as far as possible on the surface, to ascertain if it possesses the visible characters of a true vein; or if only an isolated or "segregated" mass, whether its extent is sufficient to warrant the cost of development and the erection of works for its reduction. When the vein-stone is hard and crops out prominently, but little difficulty will be experienced: the chief point to be noted in that case being the character of the ore in different portions of the lode, so that the most promising place may be selected on which to begin the work of development. But when the gangue is soft, and the lode has been reduced by the action of the weather to the level of the ground, or has been covered up by the formation of a bed of earth, a different course must be

adopted. After ascertaining as nearly as may be the course of the vein, or "strike," as it is technically termed, narrow pits or trenches should be sunk, at intervals of, say one hundred feet, across the ground where it is supposed the lode ought to be found. These pits should be sunk until the rock is found unbroken, and continued until the walls of the vein have been developed. While tracing a vein in this manner, the "dip" of the vein, or its inclination to the horizon, should be taken into account; as, provided the dip be considerable, and the country through which the lode passes be rough and broken up by deep ravines, it will apparently have a very zigzag course on the surface, though really following a straight line through the district. Or yet another plan may be adopted. Starting at the point where the original discovery was made, the vein may be stripped or laid bare on the surface in the direction of its length, and in this way the character of the lode and its comparative richness at different points may be very thoroughly ascertained; and though the process may seem a slow one, nothing will be lost in the end, as the knowledge obtained by this method will be of incalculable value in all subsequent operations.

In a country where the fever for making locations rages as violently as it does in Nevada, this method of exploration has the additional advantage, and no small one, either, of defining the boundaries of the claim and obviating the risks of adverse locations and subsequent expensive litigation. This item is worthy of serious consideration, when we bear in mind how large a proportion of the profits of our mines has been squandered in this way. Even should the developments show that different claims come into conflict, it should be remembered that it is easier to come to a settlement, in most cases, while the value of the property is yet prospective, than when one or both of the locations have been proved to be valuable.

Having, by these means, ascertained the probable character of the property, and the nature of the ores, and more especially whether any changes have taken place in its composition, as is frequently the case in passing from one series of rocks to another, the prospector is then in a position to inquire whether the requisites for reduction are within an available distance. If the ores are such as may be reduced by a simple amalgamation process, as those, for instance, carrying free gold, or some of the simpler compounds of silver, all that will be necessary is water sufficient for amalgamation and motive power for machinery. If the employment of steam be indispensable, the supply of fuel, either wood or coal, must be greater than if hydraulic power be feasible. Should the ores require roasting, as is often the case in Nevada, the supply of fuel must be greater, and within a reasonable distance, or the cost of transportation will consume the profits of the mine, unless the ores are extraordinarily rich; and in this case the items of fire clay for the lining of the furnaces, and salt for use in the roasting process, must not be forgotten. In cases where smelting must be resorted to, the item of fire clay will be still more important, as will also the quantity of fuel; and the presence of suitable fluxes, such as lime, carbonate of soda, etc., should be ascertained. These considerations are of vital importance, and ought never to be overlooked. Mines will, of course, sometimes be found where one or more of the requisites for reduction are absent, as, for instance, wood or water; and then it will be necessary to ascertain whether the ore can be cheaply sorted or "dressed" up to a grade sufficiently high to pay for its transportation to a more favored locality. This branch of mining, which forms a large item in many European mines, has apparently been but little thought of in Nevada, probably on account of the high

* In the Cornish mines, veins which produce copper in granite frequently change to tin lodes on passing into the "killas" or slates, and vice versa; and lodes in limestone producing lead, as in many Derbyshire mines, are not unfrequently barren in the associated green stones.

price of both labor and transportation. The time is rapidly coming, however, when there will be a material improvement in both these items, and the plan, if judiciously carried out, might be adopted with advantage. The preliminary explorations, when accomplished, will have supplied the data on which to found a rational method of development. The best will depend greatly on circumstances, but in all early works, one imperative rule may be given, "never lose sight of the quartz or other vein stone." If the vein crosses a rough country, and is accessible from a ravine, it will, in most instances, be the wisest plan to start from the lowest available point and run a drift on the lode, as the ground can not only be more cheaply excavated and removed by this method* than any other, but it possesses the additional advantage of exploring a large amount of ground which can all be removed by stoping upwards, and of draining all the vein which lies above the level of the tunnel. When this plan is impracticable, because the country is comparatively level, or the vein runs along a mountain side but little cut up by ravines, the choice lies between an incline and a perpendicular shaft. The instances in which the latter can be sunk within the vein are comparatively few. The dip of most veins renders an incline preferable. Inclines, as a rule, cost less to sink than shafts, besides exploring more ground, and care should be taken to commence them in the most favorable position. The question of drainage will naturally be a leading consideration. Under the latter supposition, there will not be much choice in the matter, but in a country deeply cut up by gulches, if an incline be preferred to a drift on the lode, care should be taken to avoid the ravines; for, though they offer the advantage of attaining depth more rapidly, it should be borne in mind that they are the natural water-courses of the country, and more difficulty will be experienced, as a rule, in keeping the water under control, than if the incline be started on the sides or summits of the dividing ridges. It not unfrequently happens that the convulsions which led to the formation of the ravines have broken up the country-rocks in their beds, allowing the surface waters to penetrate more readily to a great depth, and increasing the difficulties of drainage, and the cost of timbering the works, and at the same time have dislocated the veins, which present a less promising aspect to the miner. In the location of mining works, the facilities for dump and roads should also have their weight; but these considerations are of less importance in works for exploration merely, than in such as are intended for the permanent working of the mines.

If a shaft or incline be adopted, it may be carried down to a depth of about two hundred feet by manual or horse labor, if no great body of water be encountered; and at regular intervals, say every sixty or one hundred feet, cross cuts should be run to the walls of the vein, if the whole width of it be not taken out in sinking the shaft or incline. Should appearances warrant, drifts can then be started on the same levels, from which other cross cuts can be run at intervals; and in this way the character of the mine may be fully and satisfactorily ascertained.

The whole of these works may be run as small in size as a man can conveniently work in, and as cheaply as is consistent with the safety of the mine; but however well the lode may look on the surface, no special provision for the reduction of the ore on a large scale should be made until the mine has been so thoroughly prospected in this manner as to leave no doubt that ore sufficient in quantity and quality is there to warrant the erection of suitable machinery or reduction works.

If the result of these explorations is satisfactory, the property is in a good shape for future work; and if the reverse, the value of a mill or furnace, which

* See cost of running drifts and sinking shafts.

in Nevada are no small items, will have been saved. No necessity for these latter exists during preliminary operations where mills are already running in the neighborhood, as tests can be had from time to time if any doubt should arise as to the value of the ore. But even where no such works are in operation, and the isolation of the district makes transportation an important consideration, it would still be the wiser policy to freight small quantities of ore to some distance for experimental reduction, even though the cost should be greater than the result obtained; or several companies might unite in the erection of small prospecting works, an arrangement which would render the cost to each but a nominal item. Beyond this nothing should be done during the early explorations. This position is abundantly proved by the value of the capital locked up in reduction works throughout Nevada; these works being erected before the development of the mines had shown the character of the machinery necessary, or demonstrated satisfactorily that there was material sufficient to keep them steadily employed.

When development has proceeded thus far, permanent machinery for hoisting and freeing the mine of water may be erected, and means for the reduction of the ore thought of. Of the former it is not my intention to speak, much judgment and skill having been expended on such works in Nevada, of which we may reasonably be proud; but the importance of the latter calls for a passing notice.

The character of the reduction works will of course depend on the nature of the ores to be treated, and too much attention cannot be given to them before deciding on the machinery to be employed. The importance of analytical examination as a guide is far from being appreciated as it ought to be in Nevada. In the case of true silver ores, the majority of them can be successfully treated in Nevada, either by simple amalgamation of the raw ores, as in Virginia and Gold Hill, or by dry crushing and roasting, as in the Reese River District. But we have some few silver ores, as those found in the American Basin and Sheba Companies' claims, at Humboldt, which contain so large a per centage of antimony and zinc, that some other plan must be adopted. In this class, too, come all our argentiferous galena and copper ore, the whole of which should be smelted to obtain even an approach to a satisfactory result. And then the question arises whether we can do this as well at home as abroad-whether the results obtained here, when compared with the cost of reduction, are superior to those obtained in old smelting localities, where every appliance can be brought to bear, as compared with the cost of shipment and smelting.

The process of smelting is thought by many to be an exceedingly simple operation, and when thoroughly understood it may be so; but good judgment, which can only be acquired by long practice, is essential to success. No definite rules can be laid down which will work in every instance. A general theory may be adopted, but as the composition of ores varies to an unlimited extent, so must the theoretical practice be indefinitely modified to suit the varying circumstances. Nor should it be forgotten that the very basis of the Swansea smelting operations is the mixture of different ores, so that the ingredients in one may assist the liberation of the valuable portions of the other. Ores which by themselves are difficult to beneficiate, yielding poor results at a large expenditure of labor, become remarkably docile in the presence of other materials. This fact may often render the shipment of ores preferable to reduction on the spot, their nature entailing too great a loss or too heavy an expense if worked by themselves. In all cases, however, whether smelted on the spot or shipped for treatment elsewhere, the ores will require a previous dressing to fit them for the furnace; and this must be done at the mine or nearest locality, where water for concentration is abundant. This branch of mining has received but little attention in Nevada, but the time is not far distant when the dressing of ores for ship