Part 10

In the vicinity of the mines described in this district are numerous other claims, some of them having considerable development, but all lying idle at the time of my visit. One claim has an 80-foot tunnel, and shows some lead and silver ore of good grade. This claim is patented.

THE ALVORD MINES.

Twenty-three miles northeast from Daggett are the Alvord Mines. The property has changed hands several times, but is now owned by a party of Pasadena capitalists, who have under consideration the reconstruction of their mill, which was burned in September, 1891.

The property consists of six full claims located on one mineral-bearing zone. The strike of the belt is a few degrees south of west. The mine is well equipped. The company also owns a millsite at Camp Cady, on the Mojave River, 9 miles distant from the mines, and valuable water rights at Paradise Springs, 11 miles northwest from the mines, and a spring about 1½ miles east of the camp, which is used for camp purposes only.

The mines lie along a broad zone or belt of crystallized carbonate of lime (calcite), which may be seen for many miles traversing the dark-colored inclosing rocks. A huge dike of porphyritic rock cuts across this belt at an angle approaching 90°. The principal mineralization of the lode occurs east of this dike.

The country rock is described by F. R. Burnham, E.M., formerly the Superintendent, in his report on the property to the company, as rock more or less schistose in character, through which, at frequent intervals, are intruded eruptive dikes. At the east end of the belt is an accumulation of tufa and basalt. The belt dips south at an angle of 75°. The mineralized portion of this lode extends from the porphyry dike east through three full claims, disappearing finally beneath the eruptive rock and desert wash. The dominant point on the lode is 550 feet above the base of the hill.

The entire lode is gold-bearing, some of the iron rock being extremely rich; gold also occurs in the calcite, though it is usually of a lower grade than where accompanied by the iron. Iron sulphide containing gold has been discovered, indicating plainly the origin of the slag-like iron ores and limonite found on the surface.

To Mr. Burnham’s report I am also indebted for information concerning the value of the rock, tonnage, and bullion output to date. He has given arbitrary figures for shipments aggregating $37,000, and an estimate on $13,000 more, making a total of $50,000. This ore was milled mostly at the Camp Cady mill and at Hawley’s mill.

An arrastra was used in the early history of the mine. The average assays made on a ten days’ mill run just prior to the burning of the mill returned $12 75 per ton. Tailings, during the same period, averaged $1 25. Bullion produced, $1,430. It was found very difficult to sort the ore, though it varied constantly in value from $2 to $20 per ton. About 90 per cent of the assay value, it is claimed, was saved in the mill. In looking through a daily record of assays made in July and August, 1891, I find them to range from a trace to as high as $1,750, most of them running from $6 to $18. Mr. Burnham figures 184,000 tons of mill rock in sight, including all grades, besides large amounts presumed to be available, but not blocked out for stoping. The value of the ore is placed at $5 to $6 throughout.

The cost of milling this ore is placed at $2 50, and mining at 50 cents in large stopes. Should the company now controlling the Alvord Mines determine to rebuild their mill it will doubtless again become a bullion producer.

ORO GRANDE DISTRICT.

The Oro Grande Mining District is located immediately east of the Southern California Railroad, at the town of Oro Grande. It is commonly supposed to embrace all the mines for some miles around, though, in fact each group of mines or hills has been given a separate name, but as these so-called districts are mostly without organization, all the claims and mines will be considered under one head.

The geology of the district about Oro Grande is complex, the formations being uplifted, greatly faulted, and broken, besides the intrusion of dikes of felsitic rock, diorite, and quartz porphyry. I had not sufficient time at my disposal when at Oro Grande to study out the somewhat intricate geological problem, and will describe the region in general terms.

Commencing at the town of Oro Grande, which stands on the bank of the Mojave River, the country rises in a gentle slope toward the hill half a mile distant; gently rolling hills are reached, which in turn give place to more rugged masses, and finally to a rough mountainous area, the hillsides being almost precipitous. The lowlying country about the base of the hills is mostly made up of schistose micaceous rocks, a quartzose mica schist predominating. The first hills of any consequence are eruptive, mostly a light-greenish felsite and a coarse-grained porphyritic rock. Beyond are prominent hills of a dense, hard quartzite resting upon a crystalline limestone, the highest hills being made up of practically the same materials (quartzite and limestone), in part schistose with some mica schist, jasper, and many intrusive dikes of all the previously mentioned eruptives, prominent among them being diorite of dark-green color.

THE EMBODY MINE.

Within half a mile of the town, and on a lower spur or ridge that makes down from the hills, is located the Embody Mine, which, during the excitement at this locality in 1890, attracted considerable attention. The gold-bearing material is quartzose, micaceous rock of somewhat friable character. The deposit, as I may term it, has the appearance of being an impregnation without definite form.

Were it not for the fact that the shoot of gold rock makes across the strike of the schists, it would resemble some bedded deposits found at the Homestake, Black Hills, South Dakota, where micaceous schists have been silicified and hornblende schists metamorphosed to chloritic schists, the whole carrying gold across a broad zone 1,600 feet in width and 6,000 feet in length. The gold occurs in shoots or vein-like zones, without defining lines of any character. At the Embody Mine, too, little development has been done to make any positive prediction as to the future of the mine. The formation strikes northeast and southwest, and dips 70° southeast.

The country is somewhat broken up, but no considerable masses of shattered rock were observed. The croppings are quite heavily stained with iron oxides of brown and red shades, and this mineralization can be traced some distance. Two shafts, one nearly 100 feet deep, the other about 30 feet, have been sunk on the deposit, exposing rocks of uniform character, all carrying some gold. The width of the gold-bearing zone is undetermined, but it is thought to be from 6 to 20 feet.

As far as I learned, a “mill-run” had never been made on the rock from this mine. Mining operations had been stopped and the property involved in some sort of dispute. The value of the rock was given to me as $8 or $10 per ton.

THE CARBONATE MINE.

The principal mine of this district, and the one which gave the camp its fame, is the Carbonate Mine. It was discovered by a man named Collins, who was working in a lime quarry near by. Collins found croppings of ore—limonite and manganese—containing silver. He developed the property somewhat, but it finally passed into other hands, and is now owned by a Los Angeles company, which has opened the mine quite extensively.

The formation which incloses the vein has a general trend northeast and southwest, the dip at the main workings being not over 20°. Here an inclined shaft has been sunk to a depth of 225 feet on the vein. At the bottom the shaft has attained a vertical depth of about 100 feet. Two veins of ore, consisting principally of silicious and earthy iron oxide and black oxide of manganese with carbonate of lime, sometimes crystallized, extend from the surface to the bottom of the incline. These veins are very irregular in size, varying from a mere seam to upwards of 2 feet in places.

The value lies in the lead carbonate and silver which accompany the gangue minerals. The two veins are curiously formed at contact with massive blue limestone and mica schist. The schist is from 1 to 4 feet in width, the ore lying both above and below it, the whole being inclosed between hanging and foot walls of crystalline limestone. At various points in the workings is a light-colored, much decomposed rock, resembling felsite, which has the appearance of having been injected between the strata in a thin sheet. It is a notable fact that where this buff-colored, granular appearing rock occurs in contact with the vein an enrichment of the ore is noticeable, and its absence is marked by the low value of the ore or no ore at all. In this incline, at a depth of 40 feet, a short drift has been run in on ore of good grade. At 180 feet from the collar of the shaft the discovery was made that caused this mine, and, in fact, the entire camp, to become at once the scene of excitement.

At this place a small wedge of crystalline, granular quartz and calcite appeared, and with it flakes of free gold. Just below the point of this discovery the wedge widened to several inches, and the rock was a mass of glittering sheets and shot-like pieces of gold. Assays of the material gave fabulous returns. The ore was broken down on canvas, and every ounce of it sacked on the spot. This was followed down some distance, but gradually thinned out below the 200-foot level, where drifts were run, one 50 feet northeast, the other 40 feet southwest. From these drifts considerable rich quartz was obtained.

In the southwest drift the formation is badly displaced and broken and the vein is lost, a fault having thrown it, but whether up or down could not be determined, as the adjacent rock was so badly fractured. Ore was found at the face and along the sides of some of the cuttings, and some free gold was found on the 200-foot level in the southwest drift. All work on this part of the mine had been suspended some time prior to my visit, the mine having been enjoined.

ORIGIN OF THE VEINS.

This question is one which finds its answer, it would seem, in the fact that the sheet of mica schist included between the heavy masses of limestone represents what at one time was possibly a bed of sandy clay or mud, which with the metamorphosis of the region has become a crystalline schist. The planes separating this schist and the limestone above and that below it were evidently planes of weakness, and when the forces which uplifted and fractured the strata exerted themselves these rocks slipped and ground upon each other, causing considerable crushing along these planes; possibly open crevices resulted in some portions. Ore was subsequently deposited in these interstitial spaces, partly by substitution of ore for limestone, no doubt, and partly by precipitation in the crushed mass of lime and schist. The injection of a sheet of felsite into the same plane of weakness can easily be conceived, as such intrusive bodies always follow the lines of least resistance. The extreme richness of the rock, together with its somewhat unusual association of quartz and calcite, attracted no little attention to the property at the time of its discovery.

A FISSURE VEIN.

Southwestward from the deposit just described is a vertical shaft 125 feet deep. This shaft has followed down what seems to be a fissure in the limestone, in which lead carbonate, some galena, limonite quartz, calcite, and manganese oxide occur. This ore was worth at Socorro, New Mexico, $50 per ton for the gold, silver, and lead it contained, and it was shipped there in quite large quantities.

A large stope commences on the northeast side of the shaft at a depth of 30 feet from the top and extends down to the 114-foot level. Considerable ore was standing in sight in the mine at the time of my visit, but nothing was being done. The company have had to stop work, as the owners of the lime quarry claim to have this property included in their patent.

OTHER CLAIMS.

There are scores of other claims in this interesting district, but little development has been done on them. Here and there are encouraging prospects, where carbonate of lead and oxide of iron have been found; but on the most promising of these only 10-foot holes have been sunk. The mineral zones are not well defined, and the prospectors have not the capital necessary to systematically prospect the hills.

THE SILVER MOUNTAIN DISTRICT

Is 5 miles south of Oro Grande. There are a number of claims, the principal one being the Amazon. The formation is similar to that about Oro Grande. In a large dike of diorite occur the ore bodies of the Amazon Mine, which produces copper ores of a fair grade. Several holes were sunk to various depths, ranging from 15 to 30 feet, by the Mormons who settled on the Mojave River years ago. Recently a shaft has been sunk to the depth of 61 feet, and a drift run north 40 feet. The ore is principally copper-iron sulphide (chalcopyrite).

The ore in this mine occurs along slips or fault planes. This peculiar class of deposits has been described under the head of the Tiptop Mine, Lava Beds District, in this county, and as the essential features of this mine are similar to those of the Tiptop, repetition here will be unnecessary. I found a greater mineralization of the limestone in this district than about the Oro Grande, though no prospecting has been done here for lead ores.

GEM MARBLE QUARRIES.

Twelve miles northeast from Victor are the Gem quarries, that produce variegated marbles of great beauty. Shades of yellow, chocolate, black, pale blue, crimson and gray, cream-colored, rose, and white. The markings are such as to produce beautiful effects. The croppings are strong, and the surface material is apparently not at all injured by the exposure of centuries to the elements in a region where nearly all rocks decay and disintegrate rapidly. The outcrop stands boldly above the adjacent country rock from 10 to 20 feet. The entire ledge or belt is made up of bands or beds ranging from 3 to 6 feet in thickness. These strata are separated by thin seams or fractures, but it is reasonable to presume that this separating line or joint will disappear as depth is attained. The rock is all susceptible of a high polish, and it withstands a tremendous crushing force. It was said by the owners that this had been determined at 28,000 pounds per square inch.

The quantity is large, the variety abundant, and the beauty approaches that of rare onyx. With these unusual conditions surrounding the deposit, its marketing should become an industry of no small importance. The difficulties of transportation are not insurmountable.

LIME AND GRANITE QUARRIES.

Near Oro Grande and Victor several lime quarries are in operation, constantly giving employment to quite a large number of men. Lime is burned in large kilns, which finds a ready market in Southern California. Granite is also extensively quarried near each of these places, and used for building material, curbing, and paving blocks in Southern California cities. This industry employs, all told, about one hundred men.

THE KENT MINE.

Three miles from Hinkley Station, on the Atlantic and Pacific Railroad, between Barstow and Mojave, is located the Kent Mine, a vein covered by two claims. A shaft 80 feet deep and some superficial development have exposed the ore, which varies from 3 to 10 feet in width. The gangue is a rather fine-grained, granular quartz, containing galena and lead carbonate. Assays in gold and silver are obtainable anywhere in the vein. The highest grade carries lead 70 per cent, gold $25, silver 24 ounces. Some of the ore assaying low in lead contains gold and silver in paying quantities.

The property is in a prospective stage only, but is promising. Water can be obtained near the mine, and fuel is but 8 miles distant. The owner bonded the property in May, 1892, and it is at this writing being developed by the prospective purchasers. The ore is of such character that by sorting a milling ore may be obtained, the high-grade lead ore making a very good smelting material.

THE BLACK HAWK DISTRICT.

Three years ago the Black Hawk District, 40 miles east of Victor, on the north side of the San Bernardino range, attracted considerable attention through the extensive operations of an English syndicate at those mines. Development was in progress at that time, and it was planned to build a sixty-stamp mill. The quantity of gold rock, however, proved to be smaller than had been anticipated, and a small experimental mill was built; but from a short time after the completion of this mill to date all operations have been suspended, and the probability of the resumption of work is not bright.

The gold occurred in a reddish oxide of iron in bunches and stringers scattered through a crushed zone of limestone, lying along the flank of the mountains. A party, who for a time was in charge of the property, informed the writer that he had worked the rock without sorting, had endeavored to sort it, and had tried screening it, but that notwithstanding every precaution was taken, he had concluded that it could not be made to pay. The gold-bearing rock was quite rich, but it occurred in too small quantity to make it profitable.

SILVER REEF DISTRICT.

Four miles northeast of the Black Hawk Mines, lying down on the desert, is a formation of limestone and quartzite, resting on a massive crystalline rock, containing quartz, feldspar, biotite-mica, and hornblende. This reef extends from the mouth of Texas Cañon out upon the plain, sloping downward at an angle of approximately 5° for a distance of 4 miles, where it terminates in a bluff 40 to 100 feet in height. Along the entire eastern edge of this deposit it drops off abruptly as though sharply eroded. At the northern end the reef is faced by a low range of hills composed of the above-mentioned hornblende rock. From this point it swings west and with irregular outline extends for 5 or 6 miles toward Rabbit Springs. The entire area, fully 25 square miles, is cut by gulches varying from 20 to 150 feet or more in depth, that have been eroded through the strata and down into the underlying crystalline rocks. These cañons seem to have resulted from natural drainage, being started by slight depressions in the rolling plateau of limestone. On the extreme northern edge at one point, hills of considerable size have been formed by the folding and tilting of the strata. The limestone has been subjected to violent compression, as the whole area is faulted and broken into millions of fragments.

I have examined not less than twenty mining claims on the reef and traveled over the greater part of its area, and am sure I never saw a single piece of limestone that would weigh 300 pounds, most of the pieces measuring under 6 or 8 inches. Considerable masses along certain zones have been granulated, and even pulverized. This fractured rock has all since been loosely cemented by the infiltration of carbonate of lime into the seams. Geologists who have examined this peculiar deposit do not agree entirely upon its mode of formation. Some believe it to be the result of chemical precipitation of carbonate of lime from calcareous springs, similar to the Formation Springs in the Yellowstone Park. There are many things about Silver Reef which would at once suggest the probability of this mode of deposit, but I am very doubtful that such a theory will stand a thorough investigation.

It was asserted that at one time a shaft sunk in the reef passed through the lime deposit and into the “wash” of the desert beneath. On investigation I found that the lime had indeed been cut through, but the underlying rock proved to be crystalline hornblende rock in place, though somewhat decomposed. At any rate it was not desert “wash.” Over considerable areas the lime is underlaid by a stratum of quartzite of variable thickness, less than a foot in some places, and again in others 10 or 12 feet. Over certain limited areas quartzite is wanting altogether. The lime is mostly crystalline, varying in color. A small portion is as white as snow, the greater part is gray or bluish, and some of it black.

THE ORE DEPOSITS.

For fully 8 miles along the irregular front of the reef silver ores are found. The ore deposits are usually discovered by the cherty masses of silicious rock, which, being harder than the limestone, stand out from its weathered surface in bunches and small, vein-like masses. Often in breaking the cherty rocks, stains of copper carbonate are found, and from such rock silver, and sometimes gold, is obtained. Numerous shafts, cuts, and tunnels have been made on these claims, twenty or more in number, and in every one ore of good grade has been found, although the quantity is usually small. A shipment from a claim called No. 1 returned 129 ounces per ton in the Oro Grande mill. On assaying, 20 ounces can be found on any of the claims, and rock of a higher grade running into the thousands of dollars is not unknown on the reef.

The ore occurs usually as bunches, sheets, or stringers, which “roll” more or less, but in a general way follow the stratification of the limestone downward. These stringers are from 4 inches to 2 feet in thickness, pinching and swelling both longitudinally and on their extension downward. The average of the ores thus far found is probably about $50 per ton. The mines have all been opened by the discoverers, who are men of limited means, and no systematic exploration for larger ore bodies has ever been made. They may exist, though there is no surface indication that such is the case. At one claim, No. 9, I took a large sample for 20 feet across the mineralized zone and found it to assay 11 ounces silver with $2 in gold. This rock was taken from a shallow cut 4 feet in width and 5 feet deep, 20 feet long.

The ore deposits occur without exception in zones of limestone that have been crushed into small fragments, together with much very fine material. In a few places I found in contact or close to the ores what appeared to be a thin intrusive sheet of rock of undoubted igneous origin. The original nature of this rock could not be determined, as it was very much decomposed and bleached. It looked like the white porphyry of Leadville more than anything else I could liken it to, and to a great extent has, doubtless, been the source from which the minerals of the ore deposits were derived. In many places the quartzite which underlies the lime rock contains galena, lead carbonate, wulfenite, zinc-blende, iron sulphide, copper, gold, and silver. Some of this rock contains sufficient lead to be classed as a smelting ore.

The ores of the limestone deposits are chiefly chloride of silver and embolite (chloro-bromide of silver), which is usually accompanied by copper carbonate, sometimes a copper-silver sulphide, wulfenite, lead, and iron in various forms, in a gangue of calcite and quartz, with occasionally manganese oxide. Hornsilver in crystals has been found in the fracture joints and in small cavities of a pure blue limestone, taken from a shaft on one of the claims at the east edge of the district. Pasadena, Riverside, Daggett, and Victor people are the principal owners of claims. Timber can be obtained in the main range 5 or 6 miles back of the mines, and abundance of water can be had from the cañons in the neighboring mountains or from Old Woman’s Springs, 2½ miles east of the principal claims on the reef.

Altogether the district is a most interesting one geologically and also financially, as the high grade of some of the ore had induced the claim owners to sink considerable money in the development of their mines.

THE GAVILAN MINES.