er which gathers in mines at Virginia City, although the deepest there ow return to the Comstock vein, the 'veta madre' of Washoe, and examine bodies of ore made their appearance below the level of three hundred feet. ive. ng these facts exhibited by the Comstock vein itself, and comparing with them wn about similar argentiferous veins, we believe ourselves to be justified in ollowing conclusions: the continuity of the ore-bearing character of the Comstock lode in depth must, ng local interruptions, be assumed as a fact of equal certainty with the continuity elf. it may positively be assumed that the ores in the Comstock lode will retain r of true silver ores to indefinite depth. it is highly probable that extensive bodies of ores equal in richness to the sur3 will never occur in depth. t an increase in size of the bodies of ore in depth is more probable than a deat they are more likely to increase than to remain of the same size as heretofore. t a considerable portion of the ore will, as to its yield, not materially differ at any hat it is at the present lower levels, while, besides, there will be an increasing grade ores. We are led to this supposition by the similarity in character of an utside of the rich surface-bonanzas and the homogeneous nature which almost hem exhibits throughout its entire extent. Congress, and met with the encouragement of the great companies mi the lode, all of which signed contracts with the company binding thems pay a certain sum for every ton taken from their mines after the compl the tunnel. Although the work has not been commenced, the project prospects, and it occupies an important place in the history of mining in The miners at Virginia City will never be content to abandon that drainage. 40.-COLUMBIA BASIN AND CARIBOO MINES. The first mines in what is now Idaho Territory were found in the Clearwater river in the spring of 1860, and those of the Salmon riv opened in a few months later. The placers of Boisé were struck in 180 of Owyhee in 1863, and the quartz veins of Owyhee and Alturas beg tract attention in 1864. In castern Oregon the placers of Powder an rivers were discovered in 1861, and those of John Day's river in the year. None of the Idaho or Oregon placers have proved so rich, so extens durable as those of California, although they have yielded considerable of gold. The deep diggings of Cariboo, 500 miles from Victoria, in part of Fraser valley, were discovered in 1859, and the placers in th bars and creeks at the Big Bend of the Columbia, in the territory Columbia, in 1865. California had to send miners to all these places. The number who went to Idaho was, probably, 20,000; and in 180 5,000 migrated to Montana. It was also in this year that a rumor became current that rich p been discovered at Barbacoas, in New Granada, and the result was tion and bitter disappointment of about a thousand men, who found reward their trouble. "6th. That the ore will shift at different levels, from certain portions of the loc as it has done up to the present time. More equality in its distribution may, how pected below the junction of the branches radiating toward the surface, when th probably fill a more uniform and more regular channel. Some mines which hav tofore almost unproductive, as the Central, California, Bullion, and others, ha good chances of becoming metalliferous in depth. But throughout the extent of is most likely that the portion which lies next to the foot-wall will continue unp it did from the surface down to the lowest works, while the entire portion betwe hanging wall must be considered as the probable future source of ore. As rem foregoing pages, it is also probable that repeatedly, in following the lode downwa will be found rising from its main body vertically into the hanging wall and clay of quartz. Many of them will probably be ore-bearing. Such bodies of o sought for, at all the mines, in what is generally supposed to be the eastern cour rience in upper levels would lead to the supposition that such eastern bodies migh ores than the average of the main portion of the vein. "7th. That the intervention of a barren zone, as is reported by good author at the Veta Madre of Guanajuato at the depth of twelve hundred feet, is not at al met with in the case of the Comstock lode. The argument which we have to a conclusion has some weight from a geological point of view. It is a well kno the enclosing rocks have usually great influence on the quantity and quality o certain metals in mineral veins, and that a rich lode passing into a different quently becomes barren or poor. At the Veta Madre of Guanajuato a sudden d yield of the ore at the depth of twelve hundred feet attends the passage of the l ferent formation, which from thence continues to the lowest depth attained. Να ean be anticipated for the Comstock lode, since the structure of the country see the continuity of the enclosing rocks to an indefinite depth. "In winding up these considerations, we come to the positive conclusion tha of nearly fifty million dollars, which have been extracted from the Comstock small proportion of the amount of silver waiting future extraction in the virgin p vein, from the lowest level explored down to indefinite depth; but that, from other argentiferous veins, as well as from facts observed on the Comstock lode of the silver through extensive deposits of middle and low grade ores is far 1 than its accumulation in bodies of rich ore." SECTION 2. GEOLOGICAL FORMATION, ETC., OF PACIFIC SLOPE. ↓ MR. WILLIAM ASHBURNER, MINING ENGINEER, MEMBER OF THE STATE ing interest of California.-2. Characteristics of the gold-belt-3. Northern dance with the request you made me some time since, I beg leave to following report upon the present condition of the gold mining interfornia, so far as it can be ascertained. The absence of all published of a reliable nature, with the exception of those recently issued by cal survey of the State, make it a matter of considerable difficulty to sults which shall have the merit of being perfectly trustworthy, and eans of obtaining them is by personal examination by competent inof the various gold fields throughout the State. Everybody will acthat accurate statistics of the results obtained throughout the extenal regions of the United States, particularly those where the precious found, and published under the official sanction of the government, of the greatest value. If properly compiled they in themselves alone far to remove the great ignorance which prevails in the public mind d to many important facts bearing upon the question of mining, and ple to judge for themselves how far the great majority of those wild which are so frequently made by amateur visitors and newspaper Lents are likely to be true. It is from this class of writers-who, education, are not qualified to weigh and appreciate the value of made to them, generally by interested and enthusiastic personsy all the information which the public now possesses of the gold and es of this country is derived. versally conceded that the great objection to mining is its uncertainty, neral resources of many of the States have been under scientific inves- those comparatively limited districts where there is any chance of thei being successful. Money and time uselessly expended in running, pros tunnels, or in sinking shafts that can never be turned to any accou much loss of capital and labor taken from the productive industry of the at large. It was estimated that in 1862-'63 there were some 30,000 in this State and on its immediate borders engaged in prospecting for ver, and copper; and it is a notorious fact that not even one per cen claims discovered by those persons have ever proved remunerative to th invested money in their development. In 1861-'62 the excitement ran copper, induced by the discovery of the Union mine in Calaveras county a few months the Sierra Nevada, from the foot-hills to their summits, w ered with miners fruitlessly occupied in attempting to discover new which could be worked with a profit. A few months of scientific labo in this direction would have shown how utterly futile the efforts of most would prove, and how exceedingly limited in width is the copper-bear of California. The existence of gold in California was known long before the da monly ascribed for its discovery. In several places along the Coast mountains between Santa Cruz and Los Angeles there were small, ind able "diggings" which were worked by the Mexicans, and some of said to have yielded as much as $6,000 per annum, which, at that per a considerable sum. The interest which is attached to these now is chi torical, and they were generally abandoned as soon as the more exter posits which lie in the Sierra Nevada were made known. It was on the 19th of January, 1848,* that the first gold east of t Range was discovered on the South Fork of the American river, at a p called Coloma. It was the result of accident, and although attempts w to preserve the fact a secret, the news soon spread far and wide, and by that year it is stated that the number of persons employed on the Ameri and its branches were as many as four thousand, who were obtaini $30,000 to $40,000 a day, and by November it is thought that from for millions of dollars had been already extracted. It was not until a yea quent to this discovery, or in the spring of 1849, that commenced the tensive immigration that the world has ever seen. Adventurers po California from all quarters of the globe: first from Mexico, Chili, a then from the Sandwich Islands, China, and New Holland; lastly United States and Europe. During the six months between the first 1849, and the first of January, 1850, it is estimated that 90,000 persor in California from the east by sea or across the plains, and that one-fiftl perished by disease during the six months following their arrival, such hardships they had endured and the privations to which they were sub The western slope of the Sierra Nevada was soon covered with who, with their "pans" upon their shoulders, penetrated every ravine "prospecting" the sands and washing the gravel wherever there was finding the precious metal. Mining towns sprang up with almost rapidity, and for several years they presented a scene of busy life. shallow "diggings" soon became exhausted, and in 1851 the yield of higher than it has ever been since, amounting to at least $65,000,000. the last four years California has produced an average of about $3 per annum of gold from the mines situated within her borders. At le per cent. of the total production reaches San Francisco by public co and by some it is considered that even a larger proportion is transpor manner. In order to arrive at the present production, and compare it has been produced in former years, we must take the amount of unc * History of California by Franklin Tuthill, p. 226. is known to have arrived here from the various mining districts, and en per cent. for that brought by private hands. At the same time that 3 is far from affording all the accuracy desired, it will give a closer tion to the truth than any other. g to the San Francisco Mercantile Gazette, which obtains and publarly the amount of coin and bullion received in San Francisco from , we find that the receipts of uncoined treasure from the interior, inthat from Nevada, have been as follows during the last four years: Production of gold from California during the last four years. production for 1866, based upon the receipts of the first nine months of the present year. mines, exclusive, of Nevada bullion $19,719,900 ompare this production with that of the Australian gold fields during ree years, we find that these latter have produced as follows: 1,627,066 ounces. 1,545,450 ounces. 1,556,088 ounces. ustralian gold is of remarkable fineness, averaging about, and nsequently, $19 04 an ounce. This would be, in our currency, as $30,984,336 29,425,368 29,627,916 ineral statistics which are published annually by the colony of Victoria ch valuable information concerning the present situation of the gold nterest in Australia, and from them the above information has been The average earnings of the miners in this colony have been as uring the last three years: Quartz miners. Alluvial miners. |