Show the zinc ZI nc mine and its Calci ning plant bv H RYAN the property of the exploration C company is located near the north end of th the e argus range nine miles by road from the town of darwin inyo county california and thirty four miles from the nearest railroad oad point which is keeler the terminus of ae he southern pacific narrow gauge railroad it is of particular partle blar interest because it is he largest known deposit of hydro nd md also because the ore is being lefore shipment heretofore the practice it t calci ning zinc carbonate ores has been son fined to old districts where the average A 7 A view in glory hole zinc mine photo by geo H ryan ade d of the ore had reached such a low nc or that in order to handle it at a profit became necessary to subject it to close ng and treatment Calci ning is f d in the e european zinc fields to a great it but i has never been employed exten ey y h in the e united states although the alts alts obtained at the and two j er r plants in the west would indicate that prop process ess possesses a great deal of merit should oula receive more attention I 1 occurrence of in 1 ven of if the magnitude and grade of 8 asit deposit a brief description of its occur alining 11 irling eng engineer ineer salt lake city rence may be of interest the ore is principally the oxides and occurring in massive formation as the oxidized product of the original replacement deposit and judging from all appearances the alteration has taken place in the original location the greatest thickness so far disclosed was over twenty five feet measured at right angles to the dip and strike the was all the massive white and pink variety averaging over 40 per cent zinc and 12 per cent moisture although some of it after getting down about fifteen the main Ore body the main is a replacement of a massive gray crystalline limestone and occurs along the intersections of two fracture zones one trending northwesterly with a northeast dip and the other almost due north with a westerly dip the lime beds strike NW SE at this point and dip to the NE the main oreb ore bearing caring lime is practically free from chert but the strata above and below are darker colored limes and contain large amounts in irregular bands and nodules As far as can be seen from pres ts X ssie SSi 5 lit xz ap iss 20 3 ar sia rw sw Si 4 fa IS 1 gia gi 41 rf i ey at if i 1 l ay 7 7 7 r arg TIT Z A 3 r i arci L hate r vt A S 2 df x pw i Z at K 41 sa 1 y 4 tat camp and Calci ning plant looking east photo by geo eo H ryan rvan showed as high as 15 feet into the deposit per cent and when struck with a hammer or pick would fly around like ice mixed through this zinc were occasional bunches and stringers of lead carbonate containing clearly the extent showing bunches of galena occasionally one of these of oxidation lead pockets would yield a ton or more but mostly they were small and very irregular of the zinc by mining the lead is kept out but most of it is separately when possible friable carbonate and goes with the a very lead the zinc to a grizzly and screen where other than k keeping all goes into the fines to out the lead the ore requires no handling prepare it for the kiln or crude shipment ent development both series of fractures extend above and below the ore bearing lime but the primary ore deposition was confined to the lini limestone estone having the least chert secondary deposition of has occurred under the and follows the fracture down into the cherty lime for as much as fifty feet occasionally the is over two feet thick one place having been nearly six feet but as a rule it is necessary to break it mixed with waste and sort it clean making a product clear of lead and containing very little moisture small amounts of calamine crystals occur in the which forms the main ore body being mined on the west end of the deposit heretofore the fra franklin aklin furn furnace ace N J ha has i s been the principal producer of but this deposit already shows evidence of permanence and such magnitude that it will become quite a factor in the production of ore for grade A spelter er the kiln design although the will run about 42 per cent in car lots it was decided to try calci ning so as to bring the grade up to about 53 per cent in order to off offset set the truck haul to keeler and avoid the payment of truck and railroad freight on from 10 to 15 per cent moisture in the crude ore the writer who was engaged as superintendent and engineer for the company in conjunction with mr M P kirk of tile the firm of kirk leavell principal owners in the property designed and built the plant J J V C 1 57 fit cam h ta 7 T I 1 5 k 27 0 17 CJ J q PLANT exploration CO darwic INYO COUNTY CALIF CEO H RYAN ENGINEER S IT I T L which has been in successful operation since may 1918 the accompanying drawings show the construction of the plant which is a modified adaptation of the belgian and Si lician designs it is built of lava rock laid in lime mortar but with very bittle little mortar surface exposed to the heat this rock withstands the heat very well and does not break off f from rom the ore rubbing against it as the charge settles in treating this character of ore it would be better to design the kiln with the bottom about one foot larger in diameter than the top so as to prevent the charge sticking as it burns and drops and it should also be built with two discharge openings placed at opposite sides these would facilitate drawing the ore and would also allow it to cool more by exposing a larg larger er surface to the air very little trouble has been experienced this kiln kila in the uneven settlement of the ore be because apse it has a sheet steel hopper hopped built into the e bottom which allows the charge to slip easily T the he style 0 of f construction shown the e illustration would answer very well wherever the excavation could be made easily but if much hard pan or rock were encountered it would be better to build entirely above the ground and make the kiln walls thicker or use a sheet steel cylinder as liner and build masonry work around it if good material is at hand which will stand the abrasion of the settling charge the steel may be put on the outside which will permit using lighter gauge sheet the open top flush with the charging floor is used here because the ore is broken by hand before charging to a maximum size of about four inch cubes the brea breaking king is done with picks and the labor is di divided between the mine and the kiln As t the he ore breaks in large chunks in the it would mean too much work at the kiln to do all the breaking there unless the plant is provided with a crusher this would be the ideal method of preparing the charge as it would make it possible to run the kiln at maxi maximum muni capacity with only two operators in order to increase the rate of combustion which was found to be slow due to the rapid disintegration of the after burning the original design was changed by putting in ill eight air vents arranged at equal distances around the kiln about eight feet from the bottom these vents were made of 6 inch iron roil pipe and after they were e 1 installed list ailed th trouble I 1 8 experienced fro from 0 ni choked fore this was done a good dealoe de alot was e experienced d in not ot gett ing a combustion of the coal which the q anely disintegrated disintegrate do ore and hot until it t came out the th botto drawing the charge the rate raa oft tion nl ft was also increased by put over the top and keepin keeping 13 the ile openings tightly closed W when N a charge the first stack was wood which answered the until a new man let the fire r enough in the kiln so the flaw flames the top and set fire to the ste stack I 1 L stack taller and of steel was Ms go judging from the results ehod wooden stack this one should material increase in the rate of eo and consequent discharge operation the kiln is started hy by charge t ore only leaving all fines until tit ot running regularly until the ore i 1 about five feet of the top when vilen fast fisi and wood are laid in around a eighteen inches for a depth of abot M J or a little more ore is used ter and then coal put ton on top wd I 1 of ore on top of that it avas feud d use two cars of ore mine earns cars W this plant held about goo coundi a charge this would occupy till about twelve inches in depth butt butr count of using about pounds boiu C each of the first three or four the success occupy more space are built u up p carefully after wood with oil and leaving som through which fire in may ay be apen tot to E kindling care mu must st be taken first few charges char coarse ore in the of stop will not be any chance ed and wood draft As soon as the first charge is barni burning ng evenly of tile the kiln it is time to begin bottom bottOn from the crude ore ao ro for and make the c harge charge removed fro two cars of or ore e 60 t next nest the will make room for aad should be put on aln mediately 1 bickly 0 in as qu qi put charge t to I 1 dojk da until the fire is drawn above the air vents the M ri has I 1 until the fire I 1 01 be let alone avbel of tile the top 01 within four feet the ID to draw and charge fegin again th e drs ea in regular operation and add ty Q be re regu 0 tv charging should be of combustion which mj may b I 1 4 partly p fa ariy any ot whether 81 0 noticing and bott bot botteman toman du at the comes out be may this i cation of the fire I 1 the ch through ugh tile the top or t thel tw tha 0 should be so placed nahe 0 DO peep holes t convenient red dull shows dead or only vents it is time to draw the fire down closer to the vents and thus give it more air if the charge is drawn below the vents the coal will be e only partly consumed due to the excess of fines shutting off the draft care must be taken when starting to drop the newly fired charge that the ore is drawn evenly and not allowed to hang on one side so that the fire will be separated to two different elevations care must be exercised cn account of the low temperature at which zinc volatilizes great care must be exercised to not let the fire rise so high that flames come out the top of the charge because if it does the zinc contained in the form of vapor will be lost in the atmosphere the reason for keeping the fire about four feet below the top of the kiln is so that any zinc which may become vol utilized will condense in the cooler part of the charge and not be lost when the fire is drawn too low and the hottest part is opposite the vents the zinc may be seen to vaporize and i te condense on the aper part of the vent in the form of a white oxide and by observing the amount which will collect lir in a short time one can see that the loss q would be considerable were it to be allowed to escape from the top of the kiln c As soon as the kiln is running regularly the fuel may be reduced until it comprises as low as 6 per cent by weight of the ore in j a charge archarge this direct application of the heat uses less fuel than the other types of furnace and gives a better result it may even be used to put through all the ore coarse and fines by special arrangement of the charge and while it will slow up the rate of discharge it makes possible the treatment of the entire product which will doubtless show a profit prof it over the crude shipments results A careful record was kept of the opera ton on of this kim from the time it was fired and abild while costs ar are very high it must be remembered that this property is situa situated cited in n a very inaccessible place wages are high gh and labor difficult to get a and id tation tion cond conditions irions are very bad in spite of a all these the difficulties the cost of calci ning rail n from to per ton of crude ore f the e plant ed lump coal at first but later got 0 car of slack which gives even better t re results bouhl as it burns more quickly y and thor it hughly and costs a little less than the 4 1 loth other 1 most alost sn I 1 of the time two operators were 1 the be entire who took care of the plant ant for 0 two t twenty four hours by working fowee hour shifts with three hours be 11 shifts 1 l and an hour for lunch during each b one put bhea en working this way the plant b through rough OU is aitho a maximum oi of eight SU tons per P day a good stack and using a mixed charge with a good stack and of 0 ore no pieces 0 lb in i the he I 1 charge nor or agn e larger than four inches nailer aller than an one inch a kiln of this size should put through at least twelve tons 0 o of crude ore per day and not use any more labor if the ore is input put through a crusher so the kiln tender will not have to break it the value of calci ning will be seen from the fact that this ore which will bring about 2250 at the mine after deducting railroad freight sampling assaying and other selling charges and paying freight on an average of 10 per cent moisture will bring with the moisture only 15 per cent this is an increase of over 60 per cent the rate of shrinkage in calci ning was shown to average about 22 per cent of the weight of the crude ore this is a phase of the zinc industry which will yield good returns and offers some fine opportunities for research and experiment peri ment in the reduction of zinc ore which all will admit has not nol made any startling advances in the past twenty five or thirty years |