Show I I S 0 SF I E I I i fV I r im I U ar t F 4 9 0 J Experiments t Find Out r f iL iLat a at What Depths Men Can Safely Work Wark I in in Mines Where the Rocks Still i 1 Stills E StillI 1 ro s I detain the Volcanic I 1 r S y Heat f Past yF q 1 I II I I Ages pJ P-pJ 9 e a N i n nd d w sf yai f 1 I y k kl l i ki i l k x Y l H y L i f a t t I I f j S t E Es s a 1 y oa t ji of t t r A I vY t i o i Below Below an expert of the Bureau of Mines Mine I 4 a S S g 1 f d tr trw tra w e t r o t y tv r y ys s with an r yr C r 1 I Ir s r CS S tp Ifs Ie the temperature r a 1 Di his n wh sub sub- t t yv j jt fps ty 9 k a aa a 7 acted to intense i bo c y y i t Y v 1 e b a 5 Testing the effects of high tempera tempera- temp temperatures temperatures ere ere- tures on the pulse the blood pressure and the breathing in the experimental tal mine which duplicate duplicates condi condition tion in in mines where it grows hotter and hotter the deeper you goTHE go recent explosion of Mount THE BHE Etna has again agam made manifest the fact that there is la still plenty of hot stuff beneath the crust of the earth That very fact makes a whole lot of trouble in the United States because though we no have no burning mountains W i the deep metal mines in m n this country go godown godown godown down into volcanic rocks which are still so hot that conditions to which workers are exposed are almost unendurable 5 J The Tha problem involved isone is one ona of so 80 much importance that recently the Bureau of Mmes Mines has undertaken asci a scientific entitle investigation the object of which is to find out how working corking conditions in such deep de p burrows can be made more bearable and also alao whether it is safe to bore still deeper into the earths earth's hot bot core With this idea in view it has installed at its near Pittsburgh a remark remark- remarkable remarkable able experimental plant The main mam fea feature ture of it is a test chamber in which temperature humidity and other con con- conditions conditions conditions can be artificially regula regulated ted while men working or at rest inside of It are subjected to expert observation even their blood and sweat being an- an analyzed an 4 an Consider the Comstock mine at Vir Virginia y ginia CIt City Nev Nov where here many years ago 1 I andI the famous Big Bonanza of gold and sliver silver ore was found In that locality volcanic rocks come relatively near to the surface and formerly ice was fetched in quantities from the high Sierras and carried down into the depths to enable men to work vork in three three- minute shifts shUts To Today day ay at a depth of feet feet water vater comes out of the rocks so hot that you could not hold bold your hand in It ff But labor is rendered tendered practicable by using machine fans to force great volumes of cool air into the mine and cold water Is b continually sprayed upon the workers Originally in tho the volcanic rocks v were ere many cracks and crannies In which metals were deposited from hot solutions solutions solutions that poured up up p from down below Thus veins of gold silver sliver etc eta were formed But water Is h still flowing through the rocks rock a and Is b still sUII hot Hence in the depths of most metal mines there is h high gh humidity which rather than the heat makes working difficult I In many deep mines tho atmosphere r rune ns up to saturation meaning per cent humidity If the accompanying temperature be 86 to 90 degrees work work- workers workers workers ers lose from one third one to one one-hlf one of their normal efficiency At 98 88 degrees they can hardly do any worL work at aU all though if It the tha air be dry they can ean get along very well when the thermometer stands at In ono one mine at Butte Mont there Is ie Isn iea isa n a new working force every month The suffering is beyond endurance In an- an an another other tho the men are unable to work ork moro more than fifteen minutes at a time With V five minute intervals for rest Cool Wa- Wa Water wa water ter of vh which ch they drink copiously Is piped down to them and after they come out of the tho mine mme they take tako tepid shower baths followed by coldwater cold water I J L u I 1 11 1 5 f s sr p a f 1 r S 4 r tt v p 1 a r Mn fM y Tourists examining the liquid rock which began to seep out of the lava crust around the crater of Vesuvius in greatly increased am amounts about the time Mount Etna blew up Men who labor in metal mines are constantly working at new rocks which have havo had no chance to cool coo At Butte feet below the tho surface water pours out of tho drill holes at a tem tem- temperature of of degrees The tempera tempera- temperature temperature temperature ture of the air is 5 degrees higher At some time in the tho past there was In InthIs inthis inthis thIs locality a volcanic outburst whit Uplifted to the tha surface a s great quantity of molten material that eventually hard hard- hardened hardened hardened ened Into granite As the material con con- contracted contracted con contracted with cooling countless cracks crack and fissures formed in it which were later filled In with metal-bearing metal minerals miner miner- minerals minerals als in m solutions that poured up from the bowels of the tha earth Hence to today day ay there is found at Butte within the v very ry much localized area de- de desCribed de do described scribed an extraordinary maze of metal metal- veins and apparently the deeper the diggings go CO the richer the they get h In some of the tha deep workings the temperatures are so terrific that it was was thought hardly possible to carry carry them further But Dut the tho prospect in this re- re regard re- re regard re regard gard has hal been radically altered through the tho Installation of elaborate and scientific ventilating systems I i In a number of the mines tempera tempera- temperatures temperatures temperatures tures have been reduced 10 to 15 16 de- de deo deI de o I 0 grees green and the humidity has been less less- lessened lessened ened to such an extent as to render renderS S them fairly comfortable It js je s believed that when depths of 01 feet are reached it will still be practicable to keep on digging One of the chief troubles wherever there thero are deep workings in hot rocks is rock dust which taken talen into the lungs is the too common cause ofa of a II disease known as miners consumption For Formerly merly there thero was much of this mischief nt at Butte Dutto but It has been largely eliminated by forcing powerful currents of air through drifts and tunnels by the use of wet drills and by employing lines of 01 hose hoso to sprinkle the working faces of the rocks With water In its test chamber at the experimental mental station near Pittsburgh the Bureau of Mmes Mines has sought to duce duco reproduce all the conditions that are aro found in n deep diggings The chamber isan is an insulated room walled with cork and cement and inside of It the tho climate can be made whatever Is desired There Thero ar arc heaters to warm It a refrigerating equIpment to cool it a humidifier with spray nozzles to contribute moisture to the air and fans to create creato a breeze The Tho air of the room can be bo maintained at any temperature from 20 to de o i t 4 4 A remarkable ble pho pho- photograph e oft o f t h he hA e r dense cloud of A f 4 smoke end and R Ro Ry y h pouring from the o fiery era crater t e r of SF t Mount Etna in Italy when the recent i v r t alarming eruption was at its height t a Many of the worlds world's tt r r most valuable val u a b I Ie e v vi r i mines mine are sunk t through rocks rock which have not yet had ij 4 4 J time to cool off 3 t from the heat of 1 prehistoric volcanic I fires like liko tho t h ho o s e which still rage in Aetna and this thin is isI why such danger danger- dangerously dangerously i i high tempera tempera- temperatures temperatures tures ere arc found with fat men than with thin men But But there even when the earth outside is oddly enough It was as proved that the coveted covered with lee and snow lighter men could not endure great eat heat so long ns as fatter men and that they suf moro more from exhaustion afterward r d y o The deepest mme mine m in the limited ates r Z p w is a copper mine Tamarack No 6 in 51 r Michigan It has a depth of feet r tt cx q or r a little offer OHr II a amile t tr mIle The Calu Calu- Calumet t n rr si siA A t w C Cn e eor met ct and Hecla 1 s x t k t d to coppe- coppe mmes n the same samo state are arey y d de e x n M 1 1600 feet deep a and go down fur 1 J HW tl grees and at nt any humidity from 10 to saturation Experiments may be carried on in still air or in air moving with any velocity up to 1000 foot a minute Under all sorts of conditions of temperature and humidity the experts made observations of f men at rest in instill instill still air and at work in m still air also at rest in air moving at different vel velocities velocities ties and at work ork in air moving at dif dlf different dif ferent velocities Various novel notel and ingenious Instruments instruments instruments ments were vere used to determine with ex- ex exactness ex exactness the effects of different conditions upon tho men under experimental ob- ob observation ob observation One of 01 them strapped on the tho wrist made a record of ef the pulse bents beats bentson beatson beatson on a strip of smoked paper that wa was caused to travel by a n clockwork vork mech mech- mechanism mechanism mechanism each beat contributing a little zigzag to the automatic writing Another indicated the blood pressure another the tho body temperature Yet an- an another an-another another by means of a n thermocouple showed the tho temperature of tho the Ekin To obtain a record of the breathing a respiratory tracing was automatically cally made upon a sheet of smoked paper wrapped around a cylinder that reo re- re revolved slowly b by clockwork the tho mech mech- mechanism mechanism being connected with an inflated rubber tube strapped the chest of the tho man under observation Samples of the ho breath were vete were taken three at ono one hour intervals and analyzed Analysis of the sweat was Important i F ot for more reasons than one Miners quite commonly suffer from sort sord eyes and hitherto the cause causo has been a mystery But Dut the experts suspected that sweat might be bo the cause and they proved It Itin itin itin in a II very simple way vay I Collecting a small quantity of sweat they dropped a few drops olf ot it it into eyes e that v were ero perfectly normal and healthy and almost immediately soreness and in- in inflammation inflammation in inflammation developed As a result of this useful discovery the Bureau Bureau of Dines 1 recommends mine mme workers to sear ear ears s spent scat cat bands on their foreheads to pI pie pie- vent pic-vent e- e event vent sweat from getting into their eyes One fact incidentally ascertained was wag that sweat from the chest sliest was much mOl more e irritating ig to the the eyes than face faco sweat Evidently human perspiration chemIcally speaking is not quite quito the tho same product tor for all parts of the tho body But Dut that is an Inquiry Into which the experts have not yet had time or op- op ope opportunity opportunity e to go It was ns found that Increased pulse rate due to high temperature and humidity hu- hu humidity hu humidity than in- in Sn-ci Sn caused more discomfort eased body temperature At 95 de- de degrees de degrees grees there was a mat marked ked rise riso In ln tOdy body temperature and a marked increase of pulse At 99 degrees the symptoms were more matke marked with dizziness and perspiration so 80 pi of use tha that sweat sweat was actually y pour poured d out of the shoes of the themen coon under observation Loss of weight under high tempera tempers turo conditions was found to be greater I c ther than other diggings below seli sea l level vel The Tho deep mines mmes of the tl-e Michigan Peninsula ore are relatively cool because the volcanic rocks in that region are very cold and have bavo had time timo to chill The deepest mine mme in the tho world is Ie the St John del Roy Rey gold old rime mine at Ouro Brazil It goes do down don n feet feet and Is gaining additional depth at II a irate of feet every yew The latitude IS in hi the tropics and the tha heat in the lira 10 erinest workings is frightful the rock ben being degrees deCrees Never Neier Nevertheless thele q by loy pumping gnat volumes ot of odry dry air sir distantly constantly into the tha mine condi condi down below ate rendered fairly com conditions are presented by tn Oruro sih silver tt and tin mine in Bolivia l which v is situated on a plateau of 01 tb Andes more moro than two miles above the tLe level of the sea It Is frozen region and cov covered red by an Ice lee cap Thus the miners on entering the main mein shaft first I pass through feet of ice At th the bottom the the- the tempel is 90 degrees degree and they work v naked Another curious ease case nse is that of the La Color Colorado lido mine in Sonora Mexico Mexico from whIch nil illi of the first class lead lead pencil graphIte is obtained v The mine is only feet d deep ep but the rocks have havo not had time to cool oft off and so 50 tho the tem temperature inside inside is 96 90 C de de decrees grees crees though tho the outside airis air ah- is is 15 60 00 de- de degrees dc de green grees Chilly workers ate are klad glad to Il go godown godown down into it t to get warmer I l i ii i |