Show some notes on pitchblende WRITTEN FOR THE MINING REVIEW BY EDWARD R E M considerable interest is being taken in the mineral urani nitle or pitchblende on account of the stimulus recently given to the search for it by mr thomas F walsh of denver mr walsh has issued a circular letter to the mine operators and prospectors of colorado calling attention to the fact that radium nas never been produced in this country and that it is obtained with the uranium in pitchblende re he urges in the letter that a search be made for this mineral and has established a fund at the colorado school of mines to assist in carrying out the work the vinson walsh research department is prepared to make free determinations mi nations for uranium and rare metals of samples sent to it until october 1 1910 the letter also states that the research de aj 4 fig i apartment part ment has undertaken to produce radium in colorado and is now in the market for tie purchase ot dign grade pitchblende ore A sample of pitchblende is hr to be sent to the postmaster ot every mining town in n colorado and possibly other states for the public TO see and examine pitchblende is in demand for the uranium it contains which is used in considerable quantities in chemistry and in the pa painting inting of porcelain and also as a material for the preparation of radium bromide and chloride geology and occurrence pitchblende is found as asa a primary mineral in graniti rocks crocks and as a vein mineral with silver gold and copper ores in n the first case it is usually crystallized and occurs curg as cubes or of the regular system under this form of occurrence itis it is found at the middleton conn feldspar quarry at hales quarry near glastonbury Glaston bury conn at branchville conn in veins in small octahedral crystals in mitchell county N C at various mica mines where it is rather abundant but altered in part to or also in south carolina at marietta in llano county tex and at the villeneuve mica mines ottawa county quebec can in norway it occurs in veins at several points near moss also near arendal at the barta feldspar quarry As a vein mineral it occurs mostly in the massive form with sulphides sulp hides of silver lead cobalt nickel iron zinc copper arsenical pyrite etc in this form it is found at johan georgenstadt georgen stadt annaberg anneberg Ann aberg marienberg and schneeberg in saxony also at joachimsthal and in bohemia Rez banya in hungary and lat at the tin mines at redruth in cornwall in the united states it occurs in the black hills S D and in jefferson and gilpin counties colo the principal supply of pitchblende is obtained at the mines at joachimsthal bohemia and is limited colorado GD lorado furnishes most of the mineral in this county at central city in 1872 the wood shaft cut through a lens shaped mass of pitchblende and abd part of it was thrown over the dump belore before its nature was discovered the remainder ma inder about three tons was mined on a lease and sold in england at a pound it was said to average 70 of uranium oxide mineral resources 1882 pp ap pitchblende also occurs at the kirk and german mine in gilpin county and at the joe reynolds mine near georgetown while it is reported to have been found on on the dolores river montezuma county aud and in paradox valley montrose county regarding the geology of the veins in which pitchblende is found the country rock varies somewhat though all of the occurrences curren ces agree in this that they are in the neighborhood of large intrusive masses with which they are genetically connected at joachimsthal which as above stated has produced more pitchblende than any other locality the veins occur in mica and schist with some limestone gneiss and granite are found in the immediate neighborhood the region is cut by numerous strong dikes of quartz por phyra and by later dikes of of basalt with accompanying tuffs the ore is found in fissures which were first worked as silver veins there are two systems of veins at nearly right angles one striking north nort h and south accompanying the porphyry dikes and the other striking east and west following the basalt dikes the veins are younger than the quartz porphyry but are cut by the basalt and tuffs in a general way they are parallel to the dikes beside the silver minerals cobalt nickel and bismuth sulphides sulp hides occur as do pitchblende and its alternation products the gangue minerals are quartz calcite and dolomite the silver minerals include argentite steph enite and others arsenical pyrite pitchblende etc occur in some quantity the mica schist in some cases contains small grains of pitchblende impregnating the ot or the ven which cc caslo ally uini u ini up to 03 or more of uranium oxide the silver production at joachimsthal has gradually fallen off and for the last ten years especial attention nas been given to deve pitchblende ores in 1898 over 50 metric ton tone s of pitchblende were produced pitchblende also occurs with the silver oress ores of annaberg anneberg Ann aberg in saxony the country rock is a gray gneiss which atas ci chatas stocks and irregular masses of granite also subordinate mica syenite and basalt dikes the veins are fissures and carry silver cobalt nickel and bismuth sulphides sulp hides in a barate fluorite and dolomite gangue various other sulpha sulphides sulp ldes hides and pitchblende occur the pitchblende is younger than the cobalt nickel and bismuth minerals but older than the silver and arsenical sulphides sulp hides the mines have not been worked for some time at also in saxony the geological conditions are similar tourmaline granite is intruded into the mica and tji tho vein minerals are practically identical with those of anneberg annaberg Anna Ann borg aberg some of the veins are rich in pitchblende pich blende another mineral from which some uranium is produced is a potassium uranium A few words in regard to this mineral will not be out of place here is canary yellow in color and contains from 47 to 54 per cent of uranium oxide ua Os 09 and from 15 to 18 per cent of vanadium oxide V Vs Os 05 while pitchblende is almost entirely uranium oxide and carries over 84 per cent of uranium ores are found in montrose county colorado and at several points in utah the utah deposits are described by J M boutwell bulletin no U S G S 1905 pp ap they occur in the ex eastern and southern part of utah in the basin of the grand green and colorado rivers the principal deposit is near richardson grand county the occurs in thin patches and coatings in a fractured zone in sandstone from colorado is reported to have been tested and found to be radioactive radio active Et En gr and min journal yol vol 77 pp ap 1904 mine mineralogical or or pitchblende when crystal iced occurs as of the regular system with occasional rhombic dodecahedral faces ar or cubes it u usually s balfy occurs massive with an irregular irr Irre egmar guiar or curved wavy structure also in grains the color of pitchblende Is black to grey dark green or brownish but usually black and the lustre is bright and greasy resembling pitch it also occurs or dull pitchblende has a high specific gravity from 8 to 97 and a hardness of 5 to 6 it is very brittle and breaks with a or uneven fracture the streak on porcelain is brownish black shining and opaque pitchblende weathers readily into a number of decomposition products of lesser hardness and specific gravity among which may be mentioned and in addition to the uranium it contains a large number of other metals including iron bismuth and magnesia while a small part of the uranium is replaced by lead thorium is sometimes present as are also the metals of the lanthanum and yttrium groups pitchblende contains nitrogen in varying amounts from up to per cent this is true especially in those varieties which carry the rare earths it is fig 2 interesting as being the only ease case where nitrogen has been identified in an original mineral it also carries radium and the gas helium tile the crystallized variety known as contains about 6 per cent of thorium oxide the varieties cle and contain up to about 10 per cent of the yttrium atrium earths the chemical structure is s complex uranium forms two classes of oxides with a valence of IV and VI pitchblende consists principally of a of i 1 e it is the of the uranium with a valence of IV U U which is equivalent lent to Us Os 08 while this neglects certain of the other metals which may be present in small quantities quantifies it approximates the efie chemical mical composition sufficiently closely for all practical purposes the following simple tests are useful for identifying pitchblende it is easily so auble in warm nitric add acid and a bright ye yellow 1 l precipitate is obtained from the solution by the addition of ammonia it is insoluble in hydrochloric acid defore before the blowpipe with borax and salt of phosphorus it gives yellow beads in the oxidizing flame and green in the reducing flame the green borax bead be becomes omes enamel black on flaming with soda on charcoal it generally gives reactions for lead pitchblende somewhat resembles magnetic iron but is not marne magnetic tic radioactive radio active properties substances which continually give oft radiations similar to the cathode and to the X ra rays s without any visible supply of energy are said to be radioactive radio active H Becque rel a frenchman in 1896 discovered that pitchblende sends out peculiar rays which move in a straight line and act on a photographic plate but which cannot be reflected or polarized they are similar to the X rays in that they penetrate substances like metal and if the rays pass through a gas or even air they make it an electrical conductor Becque rel first observed this property in metallic uranium and its salts but it later proved to be more a property of substances mix mixed ed with the pitchblende than of the element uranium itself the radiation is known as Becque rei rays M and mme ame curie of paris showed that the emission of these particular rays the radioactivity radio activity was caused by the presence of very small quantities of three elements that were unknown before and which they named radium polonium and actinium they found that the pitchblende in the crude mineral state possessed an activity 3 to 4 times that of pure metallic uranium and cal colite a phosphate of copper and uranium an activity twice that of pure uranium the only guide for the separation of these new elements from the other compounds of the pitchblende after separating the uranium was the radioactivity radio activity which was measured after each operation this was done by measuring the electrical conductivity of a layer of air which was exposed to the rays without this method the discovery of these elements would hardly have been possible as they are present only in extremely small quantities to produce a few centigrams centi grams of radium chloride about 2000 kg two and one fifth tons of the residues from the pitchblende must be treated radium remains closely associated with the barium salts in the pitchblende residue its chloride is less soluble than that of barium in 1902 mme ame curie by a fractional crystallization of a large quantity of radioactive radio active barium chloride obtained a small amount of pure radium chloride and from this determined the atomic weight of radium to be this is a high atomic weight and apar approaches baches that of uranium 2395 which is the highest combining weight of any known element all the radioactive radio active elements have a high atomic weight polonium a accompanies the bismuth of the pitchblende while actinium is intimately connected with the thorium compounds radioactive radio active lead is obtained from the uranium residues but loses its after about six months this is a short time compared to radium itself which according to recent determinations bulletin U S G S radioactivity radio activity of yellowstone park waters loses one half of its activity in about 2600 years radium causes certain phosphorescing materials namely barium cyanide to glow but it is necessary to have a strong radioactivity radio activity glass is colored brown or violet by its rays sodium and potassium chlorides change to a blue color substances which are brought near a radioactive radio active material for a time themselves acquire the property of sending out bec duerel rays this property is called induced radioactivity radio activity it is short lived however and is usually lost after a few hours radium possesses the remarkable property of con tenuously giving out heat curie and le bardi found that the temperature is always 5 or 6 degrees above that of surrounding objects radium preparations are made of which barium chloride is the base which have an activity many thousand times that of metallic uranium such a preparation in a glass tube when held in the hand a few minutes shows an appreciable warmth and if exposed to the skin long enough is said to cause art an effect somewhat similar to sunburn radium bromide and chloride are used in medical work in the treatment of cancer or tubercular growths lupus and other skin diseases the rays given out by pitchblende as before stated penetrate opaque substances and act on photographic plates several photographs were made with pieces of crude pitchblende collected by the writer atthe at the joachimsthal mines in 1903 an ordinary photographic photograph i le plate was wrapped in black paper to exclude daylight on this were laid a small brass hook and several copper silver and nickel coins an empty cardboard plate box was placed over the plate and the pitchblende laid on top or of this box the object of the box was to hold the pitchblende away from the plate the coins being between the plate and the pitchblende after standing seventy two hours or exactly three days the plate was developed and showed a distinct image or shadow of the hook and coins see pig fig 1 the rays passed through the box and black paper but did not penetrate the coins at least boast they did so only to a small extent copper silver and nickel were used to see which was most easily penetrated but with the crude pitchblende and comparatively short exposure no difference is shown fig 2 was waa made under similar conditions only wit with a larger and more irregular lump of pitchblende which cast half shadows beside the coins a bent wire nail was laid on the plate it is infer interesting esting to note in these two photographs that shadows were cast by the rubber bands used to hold the paper in place light vertical lines in photos in connection with the above it may be noted that rutherford of mcgill university montreal discovered that the radiation from radioactive radio active elements consists of three rays 1 the alpha rays 2 the beta rays 3 the gamma rays the gamma rays are the most penetrating the beta rays cause a large part of the photographic action while the alpha rays have a very low penetrating power the photographs figs 1 and 2 were shown to dr francis francis williams of boston an authority on X rays in medicine and he called attention to the fact that the shadows cast by the rubber bands were due to the alpha rays as the beta and gamma rays both penetrate the rubber bubber production and uses pitchblende is in demand not only as a material for the preparation of radium bromide and chloride but also for contents which is used in considerable quantities in chemistry and in the arts uranium is not to be classed as a rare element but it is not at all common and consequently brings a good price uranium oxide at t the present time selling for 3 to 4 a pound the following are some of the uses to which uranium and its salts are put it is used in the manufacture of porcelain and glass the oxides producing a pure black glaze on porcelain or yellow colors according to the process of baking A hydrous sodium urani nate and a hydrous ammonium urani nate are |