larger part of the 500 feet of the lode to the east of the shaft has been worked out to the above depth, but the 1,000 feet to the west has not been opened except by prospect holes. An old shaft and part of the workings are still open. In this shaft and workings a considerable amount of pitchblende was mined in the early days. The miners did not know at the time what the ore was and it was wasted in an attempted treatment for gold. When the pitchblende was found the gold gave out, and therefore the owner left his shaft and started a new one 185 feet to the west, which is now the main shaft. The next owners knew the value of pitchblende and about 1898 took out several tons of good ore. When further development was unsuccessful, the mine was bought by the present owner. The mine is more than 400 feet deep. The vein strikes almost due east and west and dips about 80° S. The shaft follows the vein. The main levels are at 97, 140, 200, 300, and 400 feet.

The Kirk lode is 3 to 6 feet wide, and seems to be a fissure vein in gneiss and mica schist. It carries gold, silver, and copper, in addition to pitchblende. The best pitchblende was found between the 140foot level and the 250-foot level on the east side of the shaft. Ore was also found at other places, notably just above the 400-foot level and in this level. The ore shoot seems to pitch from east to west. Except in one place, the ore was everywhere against the country rock on the hanging wall. There were practically no stringers, spurs, or other indications that the vein was near except that the country rock carried some uranium. Much of the ore was exceedingly rich, some assaying 60 to 80 per cent U2O. At places this rich ore was a foot thick; one single piece was removed that measured 2 feet 8 inches by 1 foot 4 inches by 1 foot.

Reliable data on the production of pitchblende from the Kirk mine before the present ownership could not be obtained. Since the present owner has had the mine, in round numbers about 20 tons of ore with an average content of 35 per cent U,O,, and something over 100 tons of ore with a content of 3 to 4 per cent U2O, have been mined. Most of this ore was produced in 1905-6, and practically all of the high-grade ore was sold abroad.

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Therefore at a time when the Austrian mines were apparently the only producers of uranium ore the Kirk mine was sending pitchblende abroad and supplying a large proportion of the radium that Iwas sold on the open market.

During the last few years the Kirk has not been worked regularly; therefore the production of ore has been small.

Near the Kirk are the Jeannette and Hilda claims. Some assessment work has been done on them.

GERMAN AND BELCHER MINES.

The German and the Belcher mines are a short distance north of the Kirk mine. It has been difficult to obtain satisfactory and reliable information concerning the production of uranium from these mines previous to 1911. About three years ago the Belcher mine produced 1,600 pounds of ore carrying 30 per cent U2O, and shortly afterwards about the same quantity was mined in the German. During this period both mines were run in a rather haphazard manner with inefficient equipment. Last year both mines were taken over by the German and Belcher Mines Co.

The shaft on the German mine is down 600 feet, but is blocked at the 400-foot level. The main levels are at 130, 250, and 400 feet. The vein dips south, but is nearly vertical, like that of the Kirk mine. The Belcher mine is in the same vein as the German mine, several hundred feet to the east. The shaft is down 200 feet, with levels at 120 and 180 feet.

The country rock in these mines is gneiss and mica schist, similar to that in the Kirk. Intrusive andesite and granite are common. Unlike the Kirk, thin stringers of pitchblende are sometimes found that lead to pockets of rich ore. In addition to the pitchblende, the ore contains iron and copper pyrites and lead and zinc sulphides carrying gold and silver. The proportion of pyrites is larger than in the Kirk mine, and the ores carrying small quantities of pitchblende are much richer in sulphides than similar ores from the Kirk. Rickard states that at places a "gouge" or clayey salvage mixed with soft pitchblende ore of low grade is found. This is supposed to be the result of crushing of the vein material during a second period of rock movement. As in the Kirk, pitchblende and gold do not occur together.

There is a good showing of pitchblende in the western part of the 130-foot level. The high-grade ore is from 1 to 2 inches thick, some of it containing over 80 per cent U,O,. Lower-grade material is also found in the eastern part of the 250-foot level, indicating that the ore shoot pitches east. This is exactly opposite to the apparent pitch of the ore in the Kirk mine.

The company is doing development work chiefly at present and is working more than 20 men in two shifts, is using air drills, and has contracted for a considerable amount of diamond drilling.

The total production of pitchblende ore from the two mines from the fall of 1911 to January 1, 1913, has been 240 pounds of high-grade ore containing more than 70 per cent U2O,, 220 pounds of ore containing 20 per cent U2O, 5 tons of ore carrying 2.6 per cent UO, and 1 ton of ore carrying 2 per cent U2O.

a Rickard, Forbes, Pitchblende from Quartz Hill, Colo.: Min. Sci. Press, June 7, 1913, p. 851.

THE CALHOUN MINE.

The Calhoun mine, south of the Kirk and German mines, is at present worked for gold only. There are two shafts on this claim, but the east shaft is not used at present. The mine has been a small producer of uranium. During 1912, $1,300 worth of pitchblende was sold for specimens the total output during the year. This was nearly all high-grade material and was obtained at a depth of 387 feet. That portion of the mine from which the pitchblende was obtained is closed until a successful process for the concentration of low-grade ores has been developed.

THE WOOD MINE.

The Wood mine at present is being worked under lease by three men, who have had charge about a year. As in the case of the Calhoun, the gold is sought rather than the pitchblende. During March, 1913, a small pocket of pitchblende was struck, from which 400 pounds of high-grade ore were taken. The vein is narrow, being only 9 to 18 inches wide, but at places the ore is rich in gold. In addition, the ore carries lead, copper, silver, and near the west end of the 200-foot level, also zinc. There are two shafts on the property, with levels at 135, 160, and 200 feet. Most of the ore above the 135-foot level has been stoped out. During the past 5 years about 1 ton of medium-grade pitchblende ore has been mined. This was found a little below the 160-foot level, close to where ore has recently been found.

In general these mines are similar as regards the character of the veins, the quality of the pitchblende, and the depth at which the latter is found. A porphyry dike outcrops at several points just west of the pitchblende mines, and the workings of the Calhoun mine extend from the west shaft into this intrusion. The Alps mine, which is close to the Kirk and German, but which has never produced any pitchblende, lies west of this dike, which may have had something to do with localizing the deposition of the pitchblende. The sulphides, which are found in large quantities in these deposits, are doubtless due to secondary mineralization.

From the past showing of these mines, especially of the Kirk mine, one would be justified in classifying the veins at Quartz Hill as being among the important pitchblende deposits of the world.

WASTE OF LOW-GRADE ORE.

Until recently low-grade material has been largely neglected. Nevertheless the future of these mines depends largely on the utilization of this low-grade material. It is quite probable that much of the rejected material is low-grade uranium ore. Some rejected pieces picked up in the levels of the German mine carried 12 per cent U2O.

If such material as this was discarded, it is more than probable that a large proportion of lower grade ore was thrown out. A composite sample, taken by one of the writers from eight different points in the dump of the old workings at the Kirk mine, assayed 0.8 per cent U2O. This sample, of course, was not by any means an average of the whole dump, but it shows that low-grade material has been discarded in the past.

CONCENTRATION OF LOW-GRADE PITCHBLENDE ORES.

Attempts at concentrating the low-grade pitchblende ores have been made by various parties with fair results.

The ore should be hand sorted before treatment by mechanical means, to remove as much of the waste rock as possible. After crushing to the desired mesh, the material should be carefully sized and classified. This is essential, as a high concentration with a small loss of valuable minerals can not be obtained with unsized material. The order of the important compounds in the ore, in regard to their specific gravity is uraninite, pyrite, copper pyrites, and quartz. The difference in specific gravity of pyrite and copper pyrite is small, between pyrite and uraninite considerable, and quartz, being the lightest material, can easily be separated. In one concentrating test both a jig and an oscillating table were employed, and, seemingly, a better separation was obtained with the jig than with the oscillating table. The separation of the uraninite from the pyrite and copper pyrites can be accomplished by flotation, but better results can perhaps be obtained by magnetic separation after a slight roasting of the ore.

The pyrite and copper pyrites must be saved, as they may contain gold.

There is no doubt that a high concentration can be accomplished with little loss. Results obtained by the Bureau of Mines, which is working on the problem of concentrating low-grade uranium ores, will be published in another report. It is expected that ore containing as low as 0.5 per cent UO, can be utilized. This should help to make mining for pitchblende a better commercial venture, especially as there is a good yield of gold and silver to be derived from by-products.

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Mechanical concentration of low-grade pitchblende ores has been done in a similar manner in Austria and Germany for several years, but no definite data in regard to methods and results have been obtained.

EUROPEAN PITCHBLENDE DEPOSITS.

A comparison of the Colorado pitchblende deposits with those of Europe may be of interest, although up to the present the former have not received much attention. The important European deposits

are found in Germany and Austria. The ore deposits at St. Joachimsthal, Austria," are in mica schist interbedded with lime schist and crystalline limestone. Toward the east and northeast the formation is gneiss. The gneiss was intruded by quartz porphyry subsequent to the deposition of the vein material. In the mica schist are fissures filled with volcanic material which cut the mineralized zone at various points and depths. The veins are usually 6 inches to 2 feet wide, in rare cases widening out to 3 feet. The mode of mineralization varies greatly. The ores are in both stringers and pockets, and contain the following metals: Silver (metallic and as argentite, polybasite, stephanite, tetrahedrite, proustite, pyrargyrite, sternbergite, and other minerals); nickel (nickelin, chloanthite, and millerite); cobalt (as smaltite, bismutosmaltite, and "absolan"); bismuth (as metallic bismuth, bismite, etc.); arsenic (as metallic arsenic, arsenopyrite); and uranium (as uraninite, or pitchblende and other alteration products). Galenite, zincblende, pyrite, marcasite, and copper occur in minor quantities.

The ore beds show that deposition took place in three periods. The cobalt and nickel were deposited first, then the uranium was deposited, and lastly the silver. In some cases the uranium ore is partly replaced by a dark-violet bituminous fluorspar.

Pitchblende is found at Joachimsthal, in Austria, and at Johanngeorgenstadt, Marienberg, Freiberg, and Schneeberg, in Saxony, and Přibram, in Bohemia, having a similar origin. Dolomite spar is always present, which has generally a white or yellowish-white color, but changes to a peculiar brownish-red hue where pitchblende begins to appear, and is a dirty gray where it is actually in contact with the ore. Deep-blue fluorspar is always present. Copper pyrite is found in small crystals and masses throughout the pitchblende. Pitchblende is also frequently found disseminated in small grains through a part of the mica schist forming a low-grade ore.

The mines at Joachimsthal have been worked since 1517. In 1545 the production of silver ores declined considerably, but since then the deposits have been mined for bismuth and cobalt. During the last 10 years the mines have been worked for uranium. The Edelleut Stollen has been exploited exclusively for uranium ores and the Austrian Government has erected a factory at Joachimstahl for the handling of these ores.

In the vicinity of Annaberg, on the Saxony side of the Erzgebirge, the silver-cobalt veins resemble those at Joachimsthal. A large number of these veins are in the mountains close to the town. Tin, lead, and copper pyrite are among the minerals which have been mined in the older formations. The more recent deposits contain silver and cobalt, or iron and manganese. The gangue is composed of barite,

a Beck, Richard, Lehre von den Erzlagerstaetten: vol. 1, 1909, pp. 408-410.