Document bOB7L43ZYnkR5MLBDaz3NdbYo

fKOJXOOIN MATTER Cf K0YS V. MJDALCO NO 116JOFJ9S7 t & 8^ ' '/ NO IMS OF 1*7 M 8H- > *% REPORT on INSPECTION OF CAPE BLUE ASBESTOS LTD. UNION OF SOUTH AFRICA \ VW-03884 FROKJCED ft MATTER CF KEYS V MIDALCO NO 114! OF 1967 PRODUCED IN MATTIHOF fcAfiROWV MIDAICO Wins OF !9e? 1HDSX zmssssxm smMAg? mmvi ytfflWG AHFAS Production - Table T mmjsmm Koeeas - Stope Layout Ventilation Water Lighting Production Ore Handling Mine Statistics - Table II Fibre Length Labour Force Cost of Production - Table Stores Costs - Table V Rates of Pay Page 1 1 3 4 5 5 .6 7 5 6 e a o 9 10 copied so Richa.'1 n**c*A-tuJN mai ifchOF HEYS V. MJDALCO NO 1161 OF 198? Tn^flx ir.cintimiecO DETAILS OF urjJTKG OPERATIONS Koeeas msnx " UllU&lX A. 2 Section Wac+.A^hA^r Ha. 4 Section WAst.erberir Ho. 8 Section s&ms. ;GCXX0 [NMATTERCf NO Pane 12 12 12 13 13 IS 15 16 16 9*mA Vieet. A**b*rft - Details ' 17 Id Plant Capacity 19 Mill Building Labour - Tailings Treatment 20 20 20 Hen Kaept.* RlA"t. 20 CLEAHI'TG PLAtrr - PBIESKA sjfrafe - General - BleWing 22 22 - Feeding 22 Hammer Hill 23 Bagging 23 Re treatment 23 Dust Collecting 24 Power Buildings 24 25 Labour 25 Plant Capacity 25 Testing 25 FroCuotiU in c- /' *^jury C as** ,cv-- \o Hicha: *>: . .. Jt' 'i I reCOJCED JN MATTER CF HEYS V. MIDALCO NO ;)6iOf 1*7 tcontinued) PRODUCED frJMAT7IH OP BAftSOW V MIDALCO NO i )i& OF 1967 J* c I > Pnpfr Milw -yr^. (Bent,, - General .ort^ Plant 25 26 26 , smsm Sketch Map Showing Distribution of Asbestos Occurrences in South Africa U*J&- i Typical Seams of Northern Section of Blue Asbestos Deposits, South Africa Stopei Soegas Mine ffesterberg Hill 2 3 4 Koegas Tailings Treatment New Koegas Hill Prieska S Plant ,5 3 7 Estimated Flow Sheet, S Grade Cleaning Plant, Prieska 0 Hamer Hill, Prieska 9 Prieska X Plant 10 papspg^pas Panoramic view of Xoogas hills Page *2 Panoroaic view of testerberg Valley 2 Looking couth into Westerberg Vulley West side of 7?esterberg Volley 5 3 We st side of iVesierberc Valley showing sorting dumps 3 West side of Y/esterberg Talley showing sorting imps 4 Natives sorting or, VTesterberg Valley 4 Hand screening tailings dumps 5 Miners* houses in Westerberg Valley 5 Asbestos Fibre bearing strata, Xliphuis 6 Drive entry, Xliphuis 6 Hand cobbing station, Xliphuis 6 Produced in Asbestos Personal Injury Cases; Auamo l ? c ar d copied to Richard f\ wokx:ed in mattb? cr BEYS V. MJDAICO NO 1161 Of 1987 ad ex (continued) pROoucedw matter op &Aj^OW V MJDALCO^ NO U4$gf i98? E 6r Hand Cobbing long fibre Sative woaen hand cobbing long fibre 7 7 The town of Prieska a Cleaning plant, Prieska with dust collecting rooBss d Cleaning plant, PriesSce with short fibre recovery plant. o Cleaning plant, Prieska showing bagging of long fibre _* loading adn* timber at Prieska 9 9 1 _\ ... Produced in-Asbestou Personal Injury Cases: Abiarr.: artel cooiod lo Rfch?:J C rruC'T' 12th Septenter, 1049 SAS&..Sim. k3Bg6?CS..C0Ml>m PRODUCED IN MATTERO'* HARROW V MiDALCO NO 1148 0? 198? "S' Arrangements to visit the Cape Blue Asbestos Limited aines near Kimberley were aide by Us* c.w.R. Powell in London with Ur. Giles Kewton, Managing Director or Cape Blue Asbestos Company. in South Africa arrangements were Bade through Colonel R. filley. Director of Cape Blue Asbestos in charge of asbestos airing in South Africa, whose headquarters are in Johannesburg. ihe arrangement were to travel by train overnight from Johannesburg to Kimberley, a distance of approximately 400 miles, then fly by charter plane from Kimberley to Prieaka, a distance of approximately ISO miles. After looking through the blue asbestos cleaning plant located at Prieska which is the railhead for despatch of asbestos to Cape Town the remainder of the journey to tha main mining centre at Koegas was made by car, a distance of approximately $0 miles. < * .} swmThe oain asbestos deposits of the Cape Blue Asbestos Company are located on the Orange River at Xoogas in British Bechuanaland approximately 150 miles west of Kimberley. Asbestos ore has been extracted from outcrops scattered over an area of about twenty square miles during the past forty years. Cntii recently there has been no systematic mining -and all work including drilling was done by hand with native labour. Host of the fibre seams dip steeply and only the fibre bearing ore is extracted. No waste rock is broken and support is provided by means of timber posts. There is no mechanisation underground either for handling ore or.for tramming. In most of the stapes the ore gravitates to the loading points but elsewhere ore Is shovelled by hand into mine cars. There is no mechanical underground haulage, all tracing being by hand. Die extracted ore is hand picked by native women and child! Produced to A f'fxrlor fr^Jury C;J83: A'.rcris to * i oacJ copied lu NfchftJd =. Sc?upgg -* : - ,, w uAMni iCH UJ* HEyS V MIDALCO NO UiJOFM ..'ittenoosu ?he bagged fibre is f'r.OlX.CLD IN MATTES Of bARKOW*1 V MJDA-CO NO 1146 OF 198? thendcsp-tehcd by rail 800 mll< to Cape Sowa or 400 miles to Port Elin,.both for shipment oversea Production is about 800 tons of fibre per month from all sources and the cost of production is from 35 to 40 stg. per short ton equivalent to A53 per long con. < 3 S --* H-ioL'Uwfck B\ Mni ifc* U* HtVSV WIOW-CO f<0 116? OF 196? -- *> it each drive entry, the barren rock being left to fora a dump ana the fibre- bearins ore token to the vd.n for treatment. long fibre is hand cobbed it the mine entry and receives no further treatment at the tain. Only small amounts of asbestos are produced from each working section, there being about a dozen such places in the Koegas-Westerberg area, each with its own waste dump. Each r working point only produces two or three tons of fibre per day on "one shift. Koegas is the aiae township on the rth side of the river and there are several working areas north and south of It. Westerberg is the name of a valley on the south side of the rive in which there are about eight working areas. All of these- mining sections are under the control of the Manager ot'Soegas. Formerly Soegas ana Westerberg each operated a small nilil . < vhieh treated the hand picked asbestos bearing ore, producing a >v1 fibre containing approximately 20% of rock and dust. The Soega S' 4 aill has now been cowerted to retreat, mill tailings dumps from previous years* operations to recover short or X grade fibre. The tfesterberg mill which was rebuilt about two years ago treats v 4*; all the ore produced at Koegas, V/*terberg and the surrounding areas. A nev: mill is in course of construction at Roegas to treat all the fibre produced from both Koogas and '.Testerberg areas when the underground output' is increased in the course of the next few years. All the fibre from the various are^s is brought to Pr-lesk. 1 for cleaning, blending and grading before despatch. A, B, C an. > grude fibre are the long hand cobbed grades &ivl these are blcn< utvi picked over by hand to remove stone. The S grades, which a: the mill products from Koegas ajid v/esterberg, are blended, clean* mechanicelly and bagged ready for despatch. S grade is roughly equivalent to Wittenooa lo. Z grade but la more open and better cleaned. 7. arc.de fibre from f.oogas together t.'ith the tailings from the 2 grade cleaning plant are treated to produce the finished X grade tfcich is about equivalent to the proposed No. 4 grade at V WDfi,l0 ^ *0 II6J0F J9S7 t. ' '^LCri/frVMArrTRCf QARfcOVfV MJtJALCO NO H8 0f 1987 PERBOHEBL. Johannesburg - Director Colonel R. Riley General Agent Ur. K. Biskett Kimberley Soegas i Prieaka - General Mgr* Ur. Hodgson Assistant Baker Manager Hr. Sinclair Mine Manager Lewis Assistant Todd Surveyor Isaacs Chf. Engineer Campbell Accountant Hawkes Manager Ur. 4er i C Sg <Ji? gW Messrs. Lewis, Todd and Campbell have only bees with Cape Blue Asbestos for one to two years. Prior to their engagement Mr. Sinclair was the only technically qualified person employed and was responsible for layout and operation of both the mining and the milling activities. Messrs. Lewis and Todd were trained on the Johannesburg goldfields and Hr. Campbell is a retired Railways maintenance engineer so that none of these officers are very well versed in blue asbestos production problems. Unfortunately, Mr, Sinclair was absent on leave at the tine, the -mine as visited* She Sales and Executive Office was formerly at Kimberley under Mr. Hodgson but Colonel Riley was in process of transferring these to Johannesburg. It is uwfefstood that Colonel Riley was appointed resident Director because of the inability of the existing organisation in South Africa to cope with demands for Increased output. The lack of trained technical staff at Koegas and Prleaks was most apparent. The Manager of the Prieska cleaning plant had no training of any kind end had been promoted from the position of despatch clerk. ftOCOC0 in MATTSfl Cf HVS V MIDALCO NO D6lOF 198? >.;-'..J iNMATI l.'.i'f barrow v msdai.co NO IMgOf |9$7 Prieska Is a township of only & few hundred people which serves as a railhead for sons pastoral interests in surrounding areas in addition to handling blue asbestos. 2he surrounding country is saxtiy desert and the summer temper atures reach about 120?. The Orange River passes within half a mile of the town. Koegas is also on the Orange River, a township consisting only of people working on the blue asbestos leases. These are approximately fifty white people at Xoegas, the greater part of the labour force being nomadic natives of the Bushman tribe. The country around Soages and ftesterbe'rg, which ore the two sain mining sites and are on opposite hanks of the Orange River, is broken up by irregular steep ridges rising from v 500 ft. to 1000 ft. above the surrounding plains. Bae veget ation consists of a dry grass (not as great a nuisance as Splnlf and stunted salt bush and other shrubs* The genara1 colour of the country is not as red as at Wittenoon but is core of a brown, colour. In the mined areas at least this appears to be due to greater weathering having taken place. Bie rainfall is very lo' but irrigation from wells which abound in the district or by pumping from the river enables good garden crops to be grown. Telephone communication is available between Koeg&s and Westerberg, Prieska, Kideriey and other points. There Is no district power supply at Koegas so that all power ts generated on the site by alesel units. Supplies are carried into and out from Koegas by road mostly to Prieske. Approximately 20 miles of road at the Koegas find is owned by Cape Blue Asbestos. The leases held by Cape Blue Asbestos cover a considerable area totalling some hundreds of square miles and scattered over a wide area. pm.onti ...... i-WOOUCI-D IN MATTE* OF MPV5 V MIDALCO W Si6JOFi? 5. <A.a.L> in i^HKOWV MIOAICO NO S148 OF 1967 t -.i % C i i Owing to the disturbed nature of the country'1 In which the blue asbestos occurs, asbestos seams or areefs" (as they are called locally) lie at all angles from horiaontal to vertical. There are three well defined seams known as the Inner, Main and Outer Beefs, which occur throughout the deposit. The main production centre is Westsrberg, in which the fibre outcrops round the rla of a *U* shaped valley, the arms of the "U* running north to the Orange Elver. The fibre seams dip from all sides towards the centre of the valley and there Is every Indication that the fibre is also under the valley floor being continuous from one side to the other. -.The seams on the west aide of the valley appear to continue across the Orange River In the Koegas region. So far there~has cot r been any record of the asbestos seams in the eastern wall of the valley continuing on to north side of the river. Other areas worked are at Snruman are! Black Ridge about 100 miles north of Soegas and Ksauwpoort, Kliphuis and Engeldewilgeboossfontein which are approximately 20 miles east of Koegas. Approximately half the output of fibre comes from the Westerberg area, one-third from Koegas and toe remainder from the outlying areas, Production ltaTable._I Average 22 shifts operated per month. 30 short tons fibre per shift. 600 * n v month. Westerberg So. 2 Drive 4" 8" 7 it Koegas Keilb&eh Big Hill Mill Bill Black Ridge Kuruman, Haauwpoort ) Kliphuis, etc. ) 5 tons 48 5* 3 3* 3* 28 2* S8 "So" short tons U..ILiUWgSS Produced in A sti- r*;-.'\onnfi tojurv Case:*: csp id d lo R J A :* b:r.V. > : io.l and bcnJS-JS l< A c \ * .1. . HEYS V MIDALCO NO 1)6! OF 1987 6 .. *.i., . . v \ MJDALCO NO i;-ieOF 19*7 MJffJKG UETBOPB. KoeRas. In the Koegas->*esterberg area, mining is carried on at about twelve locutions over a distance of several miles* A portable compressor is used to serve each two or three locations. There is a white shift boss in charge of each ares controlling groups of twelve natives each group being la charge of a native ganger (certificated by the Uiaes Inspector) who inspects the stop face after firing and mekes it safe, marks holes for drilling by the machine men, charges the holes and fires them. It should be noted that the practice of permitting natives to handle explosives is only permitted In outlying areas such as Koegas, and is not allowed anywhere on the main mining centres round Johannesburg* XOQ% extraction is carried out in the siopea, the hanging wall being supported by mine timbers. Australian eucalypts of various species are most used for mine timber, bei) grown round the Kimberley area and transported to the mine* The average stope height is about 42" but as the stopes are inclined to the horizontal, head room is not a problem. The men use the timbers as a ladderway for climbing through the stopes* Prilling is done by means of jackhammers of about 40 lbs. weight. Pressure is applied to the drill by the feet, the native driller bracing his back against the sine timber. Stope Layout. In an average stope the -ore body has a dip of say 50 and would be worked at several levels commencing from the top, the stope face being about 100* la longth measured down the dip. The stope face is usually *" inclined to the dip at such an angle that ore will rill down to the loading point at the lower end of the stope face, that is to say, in a steep stope, the top of the stope face leads the bottom by perhaps 20 or SO ft. whereas in a stope with a flat dip the stope face would be either parallel to the dip or with the lower end of the stope face slightly in advance of the upper. PRODUCED IN MATllft Of MVS V MJDAtCO NO \ 161 OP t9ff? 7 ' '-u:D;.s\wr;uc,f v MsOalCQ i Ui Of wm Haulage drifts are advanced wttft the stope face instead of being developed beforehand as U the common practice elsewhere. The development end for the haulage drift is kept a few feet ahead of the stope face always. The inclined stope face is drilled io a series of .benches with holes about S* apart near the footwall and the hangingwall* The holes are drilled at an acute angle to the stope face, usually about 50 so that a S* hole has a burden of IZ to IS at the bottom of the hole. By adopting this prentice Cwhich is almost universal on the goldfields) each hole when firing acts independently and a misfire only affacta Oh# shot and not a large part of a face* The advance per round with this system la only about 1 ft. and an average atope face is about 80* long, and 42" high, so that about 280 cu.ft. of rock is broken per round (25 tons). This on an average yields one ton of asbestos. Osually one machine man and a helper drill a stope face each shift, there being from SO to SS boles in a face and the actual drilling time about si* hours* The holes * average S* deep so that approximately 100 ft. of drilling is done per machine shift. l|n bits are used, generally of the P. & U. detachable type bit which have a life of about S-5 ft. Tungsten carbide bits made by Cemented Carbides in Johannesburg were just coking into use and cases were on record of one bit having drilled several thousand feet. In addition to coating less per foot drilled, tungsten carbide drills faster and saves time taken up in frequent bit changes with P. & U- type. The cost of ?. & M. bits is 5d. each at Koegas (cost at Johannesburg ijd,). The cost of a tungsten carbide bit and 4* steel is 22.15. 0. Ventilation* As the mining to date has been mostly above the general ground level, natural ventilation has been provided by sir passing in through haulage ways inside to the reaches, passing up through stope face and out to ataosphere WuIX-U& iN MATTER Or KEYS V MIDALCO NO J16* Or 1987 8. .0 U ",,oU' 1,67 VaftTe toe asbestos originally outcropped. Water. Water Is carried to e&ch mining place and fed to the working places from a Read tank at a co vardent high point- &&&&&& Carbide lamps are used exclusive for lighting within the mine. Production. A group of four jackhammers is operated off one portable 200 c.f.a. compressor, the pressur* at the drills being about 60 p.s.i. The actual production t asbestos from four gangs {four machine shifts) is S tons of recoverable asbestos fibre. ^ --f As noted above, 25 tons of rock is broken at each group of four faces making 100 tons of rock per. shift. Shis is concentrated by hand picking and cobbing at the estrt to the mine from 100 tons to about 15 tons which is then sent the mill. The quantity of recoverable fibre in the min fee therefore ranges from 20% to 30*. Each native gang numbering twelve men consist a ganger or boss boy, one machine man and a helper, two aen timbering, two men hauling trucks, toe remainder of the gang cleaning out the atope, laying track and drawing ore at the b holes. Pre_Bandliry;. As most of the stopee are on steep slope, the ore aa fired, collects at the bottom of toe stops and is dra?m off through timbered box boles into small mine cars of about 1 ton capacity. A native gang sweeps dor the stop face in preparation for the next round of drilling. Generally each gang of twelve men works two stope faces,, drilling and blasting each face on alternate days. Shis als< is common Witwatorsrand practice although where It is necessa: for safety to advance a stope face rapidly drilling, blasting and cleaning are completed in one day by overlapping shifts. This latter method also reduces the amount of development required for a given output. --* > .!*.< u d jn I5w Jr V A'< I' *o '-bo C IS" te .y go: id Sa q a^S ffiOOUCtOWMATlWOP HY$V. MIDAICO NO IMiOfWW 3. - !.\ mahth of u^tiOVJ v MJDalCO NO 11*6 Q? J38? trucks of ore are pushed by hand to the aine entrance, usually a distance of a few hundred .feet. the ore is tipped sideways on to a dump where native tfoaen and children hand sort the ore containing fibre end reject waste rock. The contract rate for this work is one penny per 60 lb. drum of picked ore. Pieces of rock containing long fibre are put aside and hand cobbed on tha sice using a short handled maul weighing about 5 lbs. with a piece of rock as an anvil. This work is mostly done by native women. Contract rates of pay are i/9 per drum of 60 lbs. or S/6 per bag of 100 lbs. of cobbed fibre. Native pickers and cobbers work in the open usually without cover. The piles of waste rock extend outwards as mining continues, the underground rail track being formed in a loop on the top of the pile. The fibre bearing ore is loaded on to a 5 ton lorry for delivery to the mill where it is dumped in open heaps on the ground. Ore from the various mines is kept In separate dumps and mixed by the operator feeding the mill. Mine Statistics. Table IT Feet drilled per ton rock broken .... S Tons rock broken per white man employed 16 tiutiva hoys per ton rock trammed ... i,B Pounds powder per short ton of rock broken 1.26 % Fibre in rock mined ... 6,5 % Fibre in ore to the mill ... 35 T Fibre, (and rock), recovered from milled . '"jA ore S&* i .* fThis la reduced to about 30> when allowance is made for the rock and dust removed in the cleaning plant at Prieska. Cost of drill repairs per hundred ft. drilled 5/6d. TABLE III Fibre Length. The^rooortlons of fibre in the various grades are as follows5- Qrade A B, C k D 8&X w . Length. t Long fibre 6* J to i : 4% !$" to in i 80;S 4 to 4 0DU:eP8N WAITER HEYS V MiDALCO NO tttt OF iWJ X.r.'OSJMATOfiO' -\RKOWV WIDA1CO NOlMBOF 1987 Trucks of ore are pushed by hand to the sine entrance, usually a distance oC a few hundred feet. Tfcc ore js tipped sideways on to a dump where native women and children band sort the ore containing fibre and reject waste rock. The contract* rate for this work is one penny per 60 lb. drum of picked ore. Pieces of rock containing long fibre are put aside and hand cobbed on the site using a short handled maul weighing about 5 lbs. with a piece of rock as an anvil. This work is mostly done by native women. Contract rates of pay are 1/9 per drum of 60 lbs. or S/6 per bag of 100 lbs. of cobbed fibre. Native pickers and cobbers work in the open usually without ewer* The piles of waste rock extend outwards as aiaiw r continues, the underground rail track being formed in a loop on the top of the pile. The fibre bearing ore is loaded on to a S toa lorry for delivery to the Bill where it is dumped in Open heaps on the ground. Ore froia the various mines is kept la separate dumps and aimed by the operator feeding the still. Mine Statistics. Table_Il Feet drilled per ton rock broken *.. - 8 Tons rock broken per white nan employed 16 Native boys per ton rock trammed ... 1*8 Pounds ponder per shOTt ton of Took broken 1.S5 fFibibrree in rock mined ... 5.5 % Fibre in ore to the silll ... 55 Fibre (and rock), recovered from milled ore 5S#` / *JThis is reduced to about SO# when allowance is made for the rock and dust removed in the cleaning plant at Prleska. Cost of drill repairs per hundred ft. drilled 5/6' Fibre length. portions of fibre in the various grades are as follows Grade A n B, C & D e* , *r 4* +ij" to r\*4 ffiOOUCEO MATTEROf HYS V MJDALCO NO 156! OF 1987 io. ' LU ii' *'> i l <..v Ur barrow v midaico no 5J48CF 598? X Grade fibre is very short and has only been recovered recently. It is recovered at PriesJsa from the 8 grad tailings and at Koogas and Westerbsrg from re-treatment of the mill tailings dumps. Although some of the faces examined in the testerher* drives carried a total of 4" to 5* of fibre with a maximum fibre length of 1&", toe overall mine average appeared to be about S| total fibre in an average stop height of 42". Labour Force. Ifce total number of operators employed at Eoogas and Westerberg is as follows: *V 7 t'jV Europeans - 25 Natives underground - 320 Natives on surface Native women & children Contract workers - 280 4 - 150 Natives employed elsewhere - 150 Tptal_Cast. of_Productlon of.Fibre - Table I? sty. per sftort ton Salaries & Wages, Vine & Hill Labour 1? Asbestos charges (made up of working expenses for motor vehicles etc.) Transport Eoesas to Prieska $d. per ton mile contract rate 1.4 Maintenance materials $ Stores {fuel, explosives, drill steel, timber) (L 29*d Cleaning at Priesia 2 Plant depreciation 3 Administration Expenses 8 Compensation, taxes, social services B 10.0 Freight from Prieska to Cape Town 2 0_ . Total : 41.4 Stores includes a cost of 1.5 per ton for sacks. For the eleven months ending November, 1348 a total cost per ton excluding freight from Prieska to the Port was 35 stg. per short ton. rftoUA,U~> iN fv\ t'lth Dr HEYSV MIDAUCO no n6i or vm ,10 NO s:e OK iW X Grade fibre is very short and has only been recovered recently. It is recovered at Prieska from the S grade tailings and at Koes^s and Westorberg from re-treatment of the mill tailings dumps. Although some of the faces examined in the testerberg drives carried a total of 4" to 5n of fibre with & maximum fibre length of 1%*, the overall mine average appeared to be about 2}a total fibre in an average stops height of 42fl, Labour Force. The total number of operators employed at Koegas and Westerberg is as followss 3> ka J Europeans - 25 Natives underground - 320 Natives on surface - 2S0 Native women & children Contract workers - 150, Natives employed elsewhere - 150 Total Cost, of .Production of Fibre s tg^. Per, short ton Salaries & E?ages, S4J.no & Ulll Labour 17 Asbestos charges (made up of working expenses for motor vehicles etc.) 'Cg-p fsa ts-a C7) p (9 P U. H 8 s fft Stt. il Transport Koegas to PriesJca 6d. per ton stile contract rate Maintenance materials Stores (fuel, explosives, drill steel, timber) Cleaning at Priesfca Plant depreciation 1,4 3 9.4 s or m `St3'S" Administration Expenses Compensation, taxes, social services. Freight froa Prieska to Cape Town Total 10.0 41.4 Stores includes a cost of 1.5 per ton for sacks. For the eleven months ending November, 1948 a total cost per ton excluding freight from Prieska to the Port was 35 stg. per short ton. < rj T. Z5 - u. _ " 9 ** i: N IW OF S98? .11 PRODUCED MATTER OF Barrow v msdalco NOiWOF J907 The cost dissections given above are as detailed as Che records kept at Koegas and It v/Hi be observed that a much sore complete dissection is required to enable an adequate check to be kept of the cost of individual operations. Until recently the supply of cheap labour has been sucb that there has been no incentive to keep accirrste cost records. Stores Costs - Table V Explosives per 501b, case 4* x |M dia. or 4" x 1" dis. 54/6 Brill Steel per lb. ?. Drill steel per ton 65. Ralls per ton 22.- Rails per yard 16. Fuel oil per gallon i/S Fuel oil per ton 16, Timber per 14 ft. pole 6" dia. S/6 Timber per ton landed Koegas 4. Timber Cost Dissection - / Material cost per ton 1.2 Rail transport cost 1.7 Road transport cost 1.0 3,9 * * Salaries and Charges per month and per year. ,r per month "per annua sterling sterling Shift boss 25 to 50 560 Mine Foremen 40 480 Mine Surveyor 60 720 k house> water, fuel and light are supplied free to such employees. Native Rates of Pay. Mine boy 5/- per day Boss boy 6/- per day There are no organised compounds and messes at Koegaa or Sestesberg and the natives find their own food and rttvs V MJDALCO NQ auoFim u. PuCIXCti* IN MAlTtK OF 8ARKQWV M10ALCO NO 1144 OF JSS7 The cost dissections given shove are us detailed as the records kept at Koegas and it will be observed taut a much more ootaplote dissection is required to enable an adequate check to be kept of the cost of individual operations. Ontil recently the supply of cheap labour has been such that no incentive to keep accurate cost records. Stores Costs - Table- V Explosives per 501b. case 4* X i" dia. or 4" * 1" dia. 34/6 Brill Steel per lb. 7d. Drill steel per ton 63. Bails per ton Bails per yard 22. 16. Fuel oil per gallon Fuel oil per ton 1/6 16, Timber per 14 ft. pole 6" dia. 3/6 Timber per ton landed Koegas 4, * Timber Cost Dissection Material cost per ton Ball transport cost 1.3 1.7 Hoad transport cost U 3.9 * Salaries and Charges per month and ..per year. per flbnfch per annum Shift boss sterling 25 to .30 sterling 360 Mine Foreman 40 480 Mine Surveyor 60 720 A house, water, fuel and light are supplied free to such employees. Native Bates of Pay. Mine boy &/- per day Boss boy 6/~ per day There are no organised compounds and messes at Koegas or Wasterberg and the natives find their own food end `heVsv. HIDALGO no nuaevasi '-v* *V u\ MAlTtrt Of V MIDAl_rQ NO U48QP j9g7 accommodation. On the Witwatersrand mines the natives are paid at the rate of 5/- per day of which 2/6 is taken out to pay for food end accommodation in the compound. Emits QF MIKING OPfiftATIQ^. goegas* ItLning operations are carried a at three points north of the Orange River spread over a distance of several alias. All three operations are undergrouai and era on different parts of the same seam or reef. Tbe seam has been worked out in earlier operations wherever It outcrops over the greater part of a length of two to three miles. The areas htch have been chosen for underground working are in small C Isolated hills where the ore body is well above the surrounding ground level so that there is no need for hoisting ore from underground operations. Weiibaeh. Shis area is about three miles north of the Orange River. The ore body being worked dips at about 65 fluttenlrsg out somewhat about 200' below the outcrop. The ore body proved is about ?50* long Sy 500* deep on dip. Saulsge levels are established at approximately 5G vertical intervals which gives a stop face approximately S0 to 100* long on dip. < Saulageways are continued until they break through to an entrance on the side of the hill and a sorting dump is then established at the entrance. A road connects the several sorting dumps so that '* ore can be removed by lorry. 2ost of the ore has been removed from the top three levels. A European shift boss is in charge of the area and there are four gungs of twelve men each with one jackhammer. The dally production from this area is about 15 tons of picked ore equivalent to about three tons of fibre from the mill. Native women hand sort ore which Is minus 6, and native boys spall any ore greater in size than 6. All ore sent to the mill is minus 6n. Compressed air is supplied from a portable compressor of 300 c.f.m. capacity located at the bottom of the kWXOCcD B* MATTO*Of HEVS V MlDAlCO NO U*iOMW .12 accomodation. On the Witwatersrand mines the natives are paid at the rate of 5/- per day of which 2/6 is taken out to pay for food and accommodation in the compound. sm;n,s of aifrigrs opgr^Tgowjg. Koeeas. liining operations arc carried on at three points north of the Orange River spread over a distance of several alias. All three operations ere underground and are on different parts of the same seam or reef. The seam has bean worked out in earlier operations wherever it outcrops over toe greater part of a length of two to three miles. The areas which have been chosen for underground working are in small isolated hills ifeete toe ore body is well above the surrounding ground level so that there is no need for hoisting ore from underground operations. ffellbach. This area is about three miles north of the Orange River. The ore body being worked dips at about 55 flattening out somewhat about 200* below the outcrop. The ore body proved is about 750* long by 500* deep on dip. Haulage levels are established at approximately 50* vertical intervals hich gives a stope face approximately 00* to 100* long on dip. Baulageways are continued Until they break through to an entrance on the side of the hill and a sorting dump is then established at the entrance. A road connects the several sorting dumps so that ore can be removed by lorry. Wost of the ore has been removed from the top three levels. A European shift boss is in charge of th area and there are four gangs of twelve men each with on jackhammer. The daily production from this area is about 15 tons of picked ore equivalent to about three tons of fibre from the mill. Hative women band sort ore which is minus 6", and native boys spall any ore greater in size than 6". All ore sent to the mill is minus 6B. Compressed air is supplied from a portable compressor of 500 c.f.ra. capacity located at the bottom of the PRODUCED IN MATTER OF MtVSV MiDALCO *0 M6JOFW87 13 ^`WOF ,*7W hill in which the ore body is situated. Water is darted by true* to a tarte at the top of the hill. Maintenance is carried out by a "flying squad" who travel to the various mining centres from the workshop at Koegas as required. Sl&JLUX* This area, the most southerly of the Koegas workings, is located close to the Orange River immediately facing the Westerberg workings of which it appears to be a continuation. The ore body is V shaped in end elev ation, approximately 1,000 ft. long and 00 ft. deep with the outcrops at the tops of the arms of the ? about 100 ft. apart. The seam forming one arm of the V is practically vertical, while the seam forming the other arm dips at an angle of 45* to 90 to the horizontal. In some areas the seam Ms been atoped out completely leaving a V shaped section of barren rock entirely supported on min* timbers. In the vertical arm of the seam, the stops face is stepped so that It lies at an angle of approximately 450 to the horizontal, in order to provide safe working. The pro duction from Big Hill is approximately nine tons of picked ore per shift equivalent to about three tons of asbestos per day. Most of the stopes have been followed down from a& outcrop rather than worked from below as is common mining practice elsewhere. The latter method is coming into use on "nev; developments in the Westeyberg area. mi} Hill.. This ore body is somewhat similar to Big Hill measuring approximately 500* long by 150* deep. The fibre from this area is a more steely blue and is more like crude shingle fibre in the way it breaks up into short sticks of fibre* In parts of the workings where there are two seam close together on a comparatively flat dip the hanging wall Is supported by packing waste rock. Vtester-berg g Section This area is better laid out and mined on more orthodox principles than the older Koegas underground workings. There are three seams of asbestos being mined referred to as the Bain, Inner and Outer Reefs. The f} '*5 < <25 5i ri.Ol CEDkSMXm.ROF HVS V MIDALCO N0 1161 OF i97 14 * si? is approximately 80, . . i^UJ>N MATTEROF tJAROwV MfDAiCO NOlUSOFWW Tasya is approximately 6* of barren rock between the Kain and Inner Reefs and after complete extraction of the ore this membrane of rock is supported entirely by mine timbers. In places the football of the Inner Reef is punctured by the pressure from mine timbers supporting the banging wall in the Bain Reef. The puncturing only arises usually from failure to use headboards on the timber supports. The stop face is benched in steps about 41 high and stepping back 4* each time. Approximately three holes 3* long are drilled in the horizontal step of each bench at an angle of 60 to the vertical with the hotton of the hole towards the stope face. <See Figure Bo. ). A stope drive about 100 ft. below the top of the stope collects the broken ore which is then drawn through a box hole to a haulage way about 12 ft. below the stope drive. The ore is then hand trammed out to the sorting dump. The method of using a stope drive is safer than having a haulageway at the bottom of the stope. With the latter arrangement there is a danger of tramming boys being struck by ore rilling down the stope face. The stope drive acts as a buffer storage for the broken ore. It was estimated that the average for all of the faces examined in Weeterberg Bo. 2 area was a total of 4* of f. i*bre, the mining width being about 43*. The average face would contain from eight to twelve veins from 1/10* 'to 1R in fibre length. At the south end of a development drift on the Outer Reef approximately 200 ft. below the surface, there was a total of 6" of fibre in a 43* seam over a length of approximately 50 ft. along the strike. In only & few places was much fibre seen over 1 in length. Approximately five tons of asbestos per shift is produced from Westerberg Bo. 2 area from four jackhammers and there was difficulty in providing sufficient labour for picking on the sorting dumps beoause of the high production. At Westerberg Xo. 2 there were approximately QO Produced in a 4 PRODUCED fi MATTER Of HEYS V MIDAiCO NO HOF WW is. PRODUCED IN SCATTER O' SARROW V MJDAtCO HO ? \%? native women and children hand sorting to cop with the output from four Jackhammers. The ore from this area was very friable and broke to minus 4" la the mine. The ore was discoloured with yellow ochre dust from weathered ironstone, It was estimated by the 0lerground Uanager that there was probsbly a 10* loss of fibre on the sorting dumps. ifa system of screening has been evolved to prevent this loss of fibre. Some attempt was being made to recover fibre from the sorting dusp by feeding the stone over hand operated shaker screens about 4f long by 2 wide having an upper deck of i/2a mesh and a lower deck of 1/16* mesh. The material remaining on the top deck was discarded and the overs from'the lower deck were sent to the mill. testerberg KO_.4 Section This part of the mine is on the Main Seam south from Ko. 2 Section at the point where the reef begins to swing round to the east. The dip in this section is flatter than farther north, being approximately 30. In this section there are small patches of fibre approximately 2* long, this being a D grade fibre*. la development work is this section a form of burn cut is used, referred to locally as a "diamond* cut. Four holes 5* long are drilled* spaced in the fora of a square at the face, the four holes running together at the bottom so that they form the edges of a square pyramid of 10" base and 5* height. A total of eighteen holes is drilled in a round, the other fourteen holes being spread rouaj the diamond cut which is fired first. An advance of 1$ rounds or approximately 8 ft. is made per shift. l-S/8* diameter P, k U. detachable bits are used and these ftxiii for S' to 6' before being discarded. The explosive used is 7/8" or 1" diameter by 4" long plugs of gO,4 ammonia-dynamite with a count of 400 sticks per 50 lb. case. c m .$ H 3 PnO&JCZD IN MATTER OF HEYS V MiDALCO NO 1161 OF 1987 , ^Vi.^CrD IN MATTER OF bARRQy, V MlDAl CO *0 h OF WJ The minimum water pressure permissible $t the jackhammers in order to allay dust is 15 p.s.i. The air consumption per Jackhammer averages about 70 c.f.m. WeSteuben So. 8 Section. This section is on the east aide of the Westerberg Valley almost directly opposite to Section So. 4. The Sip here is also comparatively flat. All the upper levels in the slope above the valley floor have been worked out and a shaft was being put into operation to hoist ore recovered from seams below the valley floor. The shaft was sunk about fourteen years ago but work was subsequently abandoned in the area and the shaft was never used. Ho cord drilling has been carried out to determine to what depth below the valley floor the seam dips, nor is it known definitely that the seam is continuous with the seam on the west aide of the valley although It appears highly probable. The fibre from Ko. 6 area is dark steel blue in colour and the rock is also bluc/blacfc and shaley in appearance. This may be due to the fact that weathering and oxidation have not taken place to the same extent as on the west side of the valley where there are many small fissures throughout the ore body. Sliphuis. Eliphuis is a small settlement about 0 miles east of Koegas and also on the north side of the Orange River. It was inspected mainly because it was thought to resemble the ffittenoom deposit more closely, so that the mining system under such conditions could be observed. Whereas the asbestos seams or reefs in the Koegas area are mostly steeply Inclined and headroom is therefore not a problem, at Kliphuis the seams are comparatively flat. For the most part, mining in this area has been carried out by contractors who have not worked to any system and a start was being made at the time the mine was inspected to adopt a systematic layout. There is about 8,000 ft. of driving divided between several drives and crosscuts, the height generally being only about 4 ft. to 5 ft. . --. -- `ir\ l . ,,*. L.t' \wWVOwV MiDMCO WODUGED IN MATFER Of MOll Of m? MfiYSV MIDALCO NO 1161 OF 1987 17. Q The dip is about 5 into the hill from the mine entrance* The first drives made were across the dip to avoid nauling up hill and in consequence are unnecessarily long. It is now proposed to have a aain haulage on dip and develop by the stoping method used elsewhere.. Ventilation is obtained by natural circulation from an open ended crosscut up through the aain haulage drift. Prat examination of the faces at a masher of points the area appeared to average about 2" total length of fibre. In places the total length of fibre in a face was as much as 5" and the longest individual fibres seen were about i in length. ssa '* fc! 8g? ~ Sii. .%g,s ;,*;*.<JJ.t'*~' 1?s 5 \$ :f--fCi MILLIM* General. The silling is a comparatively staple process as the ore contains approximately 50 to 40& fibre and there is thus comparatively little rock to get rid of. The general circuit in both the Westerberg arsi Koegas mills consists of a primary jaw crusher followed by a trommel and picking belt, a shaker screen to rosove fines, then a stage of rdl crushing again followed by a trommel to remove fines and oversize. The middlings product from the trommel la then passed through a disintegrator and after further trommel screening to remove fines and short fibre, the Billing is complete and the fibre coming from the last trommel is bagged. However, this product is further treated at Prieska where approximately 201 of dust and stone is removed. Attention is drawn to the fact that at no stage In the milling is an aspirating process used for separating rock from stone or for cleaning fibre. This work is done exclusively by reducing the rock to dust by roll crushers and disintegrators 0:vd removing the dust by means of a trommel screen. This process results in a much more open or teasod fibre than is produced by the mill at SJittenoom. < iv -. <iz . t ~* 1 V H50D0CS0 IN MATTEROF WftVSV MtDALCO I'd. NO U6tOF19B7 We sterberg. ^WCUMNM^rnytCfr' fc^UKOW V MSDAL.CO NO H4&0F 1987 ^nUs, The ore is brough t t:-,s aill lay road from the areas in Zoegus and '.Testerborg Valle and -Iso from Kuruwan, Block Bidge and other outlying centres. Oro from each area is dumped in separate stock piles so that it may be treated separately. The maximum size of ore handled is about 6". The ore is wheeled in barrow loads froa the various dumps awl tipped on a steel plate for convenient shovelling/ above a small jaw crusher. The crusher is about 14" x 8" and is fed by hand shovelling. The ore from various working places differs considerably in its appearance and each ore is allied separately in order to keep a check on the'.tozmago produced and the yield* The ore from the Westerberg area is considerabl; v/eathered and contains a lot of yellow ochre which tends to discolour the fibre. On the other hand ore from the Black Ridge area is of a dark blue colour and has a flaky fracture like shale From the jaw crusher which has a minus 2B product, the oro passes through a tapered trommel 6ftlong, 4t*dia. of 1/2" mesh revolving at 16 r.p.ra. Oversize goes to a picking belt about 40 ft. long running at approximately 30 ft, per minute where six native women remove approximately 105$ of waste rock. The are then passes .through a second jaw crusher being reduced to minus 3/4*, and discharges together with the throughs froa the trommel on to a 1/16" mesh 10 ft. x 3 ft. shaker screen driven at approximately 600 strokes per minute to remove fines which go to waste. The overs from the shaking screen are further reduced by a pair of rolls 24" diameter, 12" face, runnins at approximately 100 r.p.m. and then pass through a 1/16" mesh tram* driven at about 12 r-o.ra. The throughs from this trommel go to waste awl the overs, approximately 1/4" in size, pass to a disintegrator running at 1800 r.p.m. The machine is made by Christy and llorris and has four quickly detachable arms with separate beater heads (set 'Irawings and sketches Fig: k ). V MJOALCO " *0 116} of mi 1&. ,7`-W.rL:.V\unt&rw m1OVV V NOiiOF|987 It is possible to change the disintegrator beaters in about three minutes plus a pproximately rive minutes lost Billing time. The boater arms are changed every four }iou?s. The crushing roll surfaces are ground by band each weetc to remove ridges and about every sir. reeks &?& turned in the lathe. The life of a set of roll shells is about 18 reeks, in 'Which time about *?0G0 tons of ore would be crushed. It was estimated from a visual examination that the tbroughs from the 1/16S mesh trommel contained approxi mately 10'S of fibre of 1/8" and less in length. The disintegrator opens out the fibre to approximately the condition in which it is used irv aa asbestos cement plant. The fibre from the disintegrator is passed through a trommel * ft. long, 4 ft. dia* 18 r.p.a., the first fcaif of which is covered with 3/i8" screen and the rest with 5/8* screen. The throughs froo the first section are sent to an adjoining tailings treatment plant for recovery of X grade fibre, the threughs from the 3/fi,r section, consisting mainly of stone aivi small bundles of unopened fibre, ace returned to the disintegrator and the overs sro ba^ed as S grade fibre to be sent to Prieska Co? cleaning. Use fibre discharging from the trommel drops c on to a grid of inclined bars which further assist in removal of jstone from the fibre, short sticks of fibre and stone dropping through the bars are shovelled up and returned to the distntegratoi The fibre is picked av on forks filled into 'Vugs of ISO It. ^eevy hand reaming is necessary to get the quantity of fibre in the bag. Sote bags of a similar quality to those at Wlttanoom are used* There was a considerable dust nuisance in the jj Plant although some attempt was made at the shaking screen and the disintegrator to house over the units causing dust. Thera ware no exhaust fans used for removing dust* Plant $apftcj.ty It was claimed that all or to produce 25 tons of fibre per day w*s treated in the Weaterberg mill. This requires a throughput of SO tons of ore per day rKOUXED IN MATTE# Of HEYS V MiOALCG NO mi OF MR? .20 .U'.'wL^;NMAnE#C uAHROwv MiDAiCO NO J|S OF mi assuming that 20,1 stone and dust regains in the fisre. The average hourly rate is thus about 3 tons per hour through the jaw crusher and about 4 tons per hour through the disintegrator* Mill Building. The plant is arranged on the side of a small hill to obtain gravity flow where possible. The building is timber framed with corrugated iron covering, about 10 ft. wide by 50 ft. long. See photograph, page . frafrouy. One European and eighteen natives per shift produce 24 tons of Asbestos Fibre per day on one i2 hour shift. The European acts as Still Foreman and Maintenance Fitter. c */ I ; j; <!< 2 a5 S* ]xT??l 'Z\'Z Tailings Treatment. Originally the Koegas Mill was similar to the Vasterberg Mill but since extensive re-treatment of tailings dumps has been undertaken, the Koegas Mill has bees used exclusively for this purpose. A new mill is in course of construction at Koegas and is described later. The tailings are reclaimed from dumps around the Mill and fed through a Christy & Norris disintegrator. The mater ial discharged from the disintegrator is passed through a trommel having l/S* screen from which the oversize material is bagged as X grade fibre. Throughs are fed to a trommel having I/lS" screen opening, the oversize from this tromel being returned to the disintegrator su* the throughs discarded as tailings. The X grade fbre from this plant still contains a considerable amount of dust and stone and the fibre is given further trommel treatment at the cleaning plant in Prieska. See sketch of mill circuit, Fig, The New Koegas Plant. The new Koegas Plant was designed primarily by ir. Sinclair and follows the general principle used in the other Cape Asbestos Mills, depending on trosnel screens for cleaning and separation of the fibre from the rock. The plant is srrurged on the side of a slope so tiiat for the most part gravity feed is obtained through the pro cess. The plant is driven by line shafting from an engine house in a dustproof building alongside the mill. Ore will be fed by hand from a steel "lashing" plate into a law crusher set to about l-jn discharge* The PRODUCED w MATTES Of HEV$ V MJOALCO no mi of mj 21 KOmftOF H*7 ~ maximum si2e of ore is about 6". The jaw crusher dXschttrges to a trommel having 1/2" openings from v.hich overside passes on to a horizontal picking belt About 20 ft. long which discharges to a second jaw crusher. Undersize also drops on to a belt conveyor. Tha fines from the belt conveyor and the throughs from the jaw crusher discharge on to a shading screen of 1/8" mesh, the throughs from which go to the tailings treatment plant* Oversize from the shaker screen is elevated in an inclined bucket elevator to a set of crushing rolls about 16* diameter by 12* face set to 1/4". & second pair of rolls ia series follows set to 1/6". The discharge from the second set of rolls passe through a trommel, the first part of which is covered with 1/iS" mesh and the second part covered with l/2" mesh. Throughs from the first section go to waste and oversite from the second soctioc is returned to the second set of rolls. Throughs from the second section are fed to a disintegrator which discharges to a 1/16" trommel. Throughs from this trommel go to waste and over size goes to another trommel, the first section of which is covered with 5/16" mash and the second section with 5/16* mesh* Throughs from the first section go to tailings treatment plant and throughs from the second section are returned to the dis integrator. Til oversize product from this trommel is the finished fibre. As this plant was not working it was not possible to determine the speeds of the various units or the mill capacity. It was anticipated,, however, that this mill would hove at least 50# more capacity than the Westerberg Mill* raOOJCED (N MAHIR OF hVS V MJDAl.CO NO ii62 0fl7 Ch'AKW* WV>A1_CQ NO >U8 0F 1987 CLSATCftPIAOT - PfilSSKA, Generals Fibre is received at Prioska from all the mining areas at fcoegas, Vfesterberg, kurusan and Kllphuis. The fibre bos already been silled and roughly graded into X, S, A, B, C op D grades and the treatment at Prieska is to blend, open and remove stone from the fibre in order to obtain a cleaner eras more uniform product. There are large storage warehouses at Prleaka sufficient for several thousand tons of fibre. Prleaka also serves as a base for the receipt and. despatch of stores to the various mining areas. The total operating labour employed at Prieska numbers 150 natives and there are 10 Europeans including clerical staff. w:' ; Power is generated as required from oil engines. Biending. S grade fibre is put through the cleaning plant in batches of 1300 bags (60 short tons). The number of bags In each batch from each of the different areas is roughly proportional to the production from the area and a constant "formula* for this blerasing is worked to. This is necessary because fibre from different areas varies in colour and texture and a fixed proportion must be maintained to give a uniform product. The fibre is emptied from the bags into a large open bin on the floor, the fibre from different areas being placed in layers right across the whole area. The bin measures approximately 60 ft. x SO ft. The fibre is fed by hand using a multi pronged fork to shovel the fibre into the boot <3t arv inclined open bucket elevator, the tell pulley of which la about 5 ft. below the floor level. There are three feed points and three parallel lines of similar cleaning plant. From the three feed points the bucket elevators, travelling at J60 ft. per minute, deliver to three trommels in parallel, the trommels being 9 ft. long, tapering from 5 ft. to 5 ft. diameter, revolving &t 16 r.p.sa. end covered *it* S/l6a screen. The ihroughs from the trommels drop on to a belt S*QDuCU> SN MATTER OF HEYS V MIOA3.CO NO i 16] Of 196? '3. s.-ol.G^V MiOAlCO NO l NR Of No7 conveyor And ere delivered to a disIntegralor Tor further treatment. The oversize from tne trommels drops into a second inclined elevator consisting of slats attached to a rubber belt conveyor. This elevator delivers to a hammer mill running at 1200 r.p.m. Banner Mill. T&e hammer mill is locally designed and built in Johannesburg and consists of a light mild steel casing with a serrated wear plate covering an arc of approximately 45 of the circumference. The plate is spring loaded and has a screw adjustment for taking up as it wears. Use life of the plate is from two to three weeks. The hammer mill rotor is approximately 16s diameter and has four beaters attached by two radial arms to the rotor, the beater blades being 10" wide and 2" x 1* cross section. (See drawings and Figure So. r The beaters are reversed after two shifts* running and have a ) total life of three days. The hammer mills discharge to a third inclined elevator which feeds the fibre Into a cleuning trommel similar to the first trommels and covered with 3/16" mesh. The throughs from the three cleaning trommels drop on to a belt conveyor and are returned for further processing. The fibre discharged fro the trommel is filled into bags as toe finished S grade'product* S&ging> At each bagging station there is a native shovelling fibre into the bag, a second native stamping down the fibre using two heavy wooden clubs awi a third man carrying 'bags away for sewing and stacking. Satives working 11 around the discharge from the trommels wear gauze pads strapped I across their souths. II Retreatment. The throughs from the three cleaning trommels are returned to a fourth trommel of 3/16" mesh in line with the first set of trommels. Oversize material, from this tronsael which should be all fibre, Is conveyed back to toe blending bin and passed through the cleaning circuit to be recovered as S grade fibre. The throughs from the trommel Join the throughs from the three other primary trommels and are elevatet to a fourth hammer mill arranged in line with the other three. * .V .'* *.*^< HiODUCED IN MATTS? OF IN MATITR or hEYS V MIDALCO 24. bA^nOvvv MlOALCO NO 116J OF }7 NO Ji*6 0F 1937 The product from the hammer Bill which is driven at 1900 r.p.m. as compared to 1200 r.p.m, for the other three, is elevated to a trommel in line with the three S grade cleaning trommels. The first half of this trommel is covered with 1/8" mesh screen and the rest with 5/16" mesh screen. The throughs froa the first section are collected on a belt conveyor and delivered into a 3/4 ton aiae car for delivery to the adjoin!: tailings treatment or X grade plant. The throughs from the second section of the trommel Join the throughs from the cleaning trommels and go through the return circuit. Overs from the trommel are bagged as S grade fibre. Dust Collecting. All trommels and the.elevatoi between the hammer Bills and cleaning trommels are enclosed and connected to a dust collecting system. There are four fans, one located alongside each hammer mill. Bach fan draws through a 9" duct from each of the two trommels and a 6" duct from the hammer mill discharge chute oa each of the four parallel lines of troatac plant. The fans are approximately 24 diameter running at 1800 r.p.m, and have 14" diameter delivery ducts. It is estimated that each fan has a capacity of approximately 4000 c.f.a The fans deliver to a dust room, a brick building 40 ft; long x SO ft. wide x 12 ft. high alongside the sill building. The air enters the dust room through the ceiling at one end, passes under a central baffle and is discharged through two stacks 3 ft. diameter, BO ft. 'high. The discharge froa the dust room appears as a fine hate. There are two cleaning doors In the wall of the building (see photograph, page ) and the dust is shovelled into bags at the erei of the treatment of each batch. Approximately 20 bags or 1 ton of dust and short fibre is recovered froa each batch of 60 short tons. This material is sent to Cape Asbestos Insulation plant at Benoni hear Johannesburg. The maximum length of fibre in the shorts is l/16n. Power. All of the above plant is driven by two 42 h.p. Rational oil engines through a series of counter shafts anc belt drives. c '& 2 x? tn a> ro n ijVo i*h PRODICED IN MATTER OF HEYS V MIDALCO 25. H.OLCCELi IN MATTERCf BARROW V MIDAtCO NO 48 0f 19S? NO U6JOF196? Bandings. The main mill building ia approxi mately ISO ft. X 75 ft. wide x 20 ft. high. The walls and roof of the building are covered with corrugated iron and the frame work is of steel sections. An area of the building 50 ft. z 75 ft. is used for the storage and blending of fibre. The cleaning plant takes up approximately 60 ft. x 75 ft. ogri the remaining 50 ft. x 75 ft. is used for sewing and stacking clean fibre There are two storage warehouses, approximately 400 ft. long x 40 ft. span with a rail track between. Labour; The operating crew for the leaning plant consists of 50 natives and 5 Europeans, the latter being responsible for maintenance and running of the plant. The plant operates for approximately ten hours per day. ........ ' The natives are paid 5/- per day with a maximum of 6/- per day for boss boys. Quarters are provided for the natives but they provide and cook their own food. Of the 5/- per day, 2/6 is intended to represent living allowance. Plant Capacity. The plant treats fibre at the rate of about 100 bags (5 short tons) per hour and a batch is put through in from 1 to l shifts. 20;, to 252 stone and dust is eliminated from the feed. The begged fibre contains an average of Z% stone and should not contain acre than 52. Of the material screened out of the fi grade fibre, approximately 16^ is recovered from the tellings treatment plant as X grade fibre so that the overall recovery from the S grade fibre fed to the cleaning plant is from 802 to 832. 2S&SXQ2. The Prieska Manager (Plant Super intendent) checks the amount of stone in the fibre by hand picking through a 40 os. sample each day. Tallin*s Trpatpent Pliant. General. The tailing# treatment plant has been built as an annexe to the main plant (see photographs page ), and is being operated on two shifts at present to cope with the output from the Xoegas tailings treatment plant in addition to the handling of the < >, y .'IsO! ,,*> SN MATTER OF Hf.YS V MiQALCO NO l)6J OP 1987 2$ PIOIXCiD IN MATTER OF &ARROU;v M1DALCO NO in* OF 1987 tailings from the Prieska S grade cleaning plant. piafit She tailings from the S grade plant are elevated on an inclined conveyor and fed into a Christy 4 Norris disintegrator running at 1600 r.p.m. The product from the disintegrator is discharged into a trommel 9 ft. long, tapering from 4 ft. to 6 ft. diameter, and driven at S r.p.m. The first half of the trommel is covered with #6" mesh and the throughs from this section go to waste. The rest of the trommel is severed with 1/&* mesh screen and the throughs from this section are returned to a i/16" aesh 6 ft. x Z ft. Hummer vibrat ing screen driven at 1200 r.p.sw by a ks L'.G. set. fro& the trommel are bagged as X grade fibre. The overs *. , The Bummer screen is mounted on twelve flat springs set at an.angle of approximately 45 to the vertical. Throughs from the Hummer screen go to waste and the oversise joins the feed to the disintegrator. There is a second trommel 9 ft. long, tape* lug 4 ft. to 6 ft. diameter, covered with 1/16" mesh through which the X grade fibre from Xoegaa is passed for a final cleaning^ The oversite product from this trommel is mixed in the proportion of two parts to one with the product from the Prieska X grade fibre and bagged as the finished X grade product. The whole of the above plant Including the U.G. set is driven by e 27 h.p. Rustan engine. Eighteen men and one European per shift are employed in the plant and it is operated for tr*o shifts. The output of X grade fibre is approximately 7 short tons per day. Lon* Fibre. Band cobbed fibre which is sold as A, B, C or D grade is sorted, blended and cleaned by hand at Prieska. Several bags of fibre are tipped out on to a concrete platform approximately 10 ft. square and picked over by hand (see photographs page ), to remove any discoloured fibre or fibre which is of a higher or lower length grade. There is a considerable proportion of what is WOU/CtD IN MATTLftOF HKJDUCEDJNMA7TERCF BARROW V MlDALCO KEYS V. MlDALCO NO U61 OF we? 27, NO n48 OF 1987 referred to locally as adiscoloured" fibre, which is somewhat similar to the material known at 'A'ittenooas as dead fibre. The fibre is of a reddish colour and somewhat more brittle than good quality blue fibre end appears to have suffered some oiidatiO) from weathering. Apparently the fibre has a market value but its presence in blue fibre is a serious defect. Differences in colour and texture of fibre from the different areas are most apparent ia the longer grades. After the sorting and cleaning, fibre is bagged again by hand. The total of A, B, C and D grades represents 10 of the 'total output* Including the variations of A, , C and D grades which include discoloured grades and different quality fibres of the same grading, there is a total of approximately 30 grades of fibre. duced in Asbestos Persona) --Produced in Asbestos Personal Qjnjuy Cases: Abrgros feed -'d "N to Richard F. Sen..;js O Produced P~sor> o Jn;ury Ca**: Ai** .= ' ? O copied to Ricf.-'c?' ' *" ' ,r' JS6I iO ill ON joyauvw *5 apnoow I mi iOfn on ooivaiw a moasvs ioaauvw^csDnooMd tuanaci Produced m Asbestos.Persona* tnjuiy Cases: Abrams tesd and copied to Rtch&fd F. 2-- ^ / y a///r oo fraduced in Asbestos Personal Injury Cases: Abror-*- ^r.i ^ copied to Richa/d F. - oo PRODUCE ANMATVEROF oo OF oO ' "'MATTERCF /W V MIDALCO <> msofim PRODUCED ft MATTER OF F otfuced so 4 > * -_____ < ,Jfy Cas*s; Abrarrs Pieo to Richard F. Scrubs < W a Produced & Asbestos Persona] : Injury Cases: Abrams lead and copied to Richard F. Scruggs oo p'^DUCEDW MATTER Of f*OOUCD IN MATTERCfHFYS V. MiDALCO w vO H tJjtyM :/ OO o I PnODWICD IN MATTEROF barrow v mjdai.co no 11-flOF iv; ie /I, ^^Cc/ sy c-... > I West side of Westerberg Valley showing a large c aortiag dump ia the centre foreground. & in 0 f West aide of Wes terberg Valley showing sorting dumps in the foreground and centre and vertical a topes ia the hill in the background. rW'J < ga so?***'* &re pf ^-a <*** f>***`''* c i^aai y^l 1 ny. J|aM,"*~ 'O^M ,. uf ^h-> i-.-* *,,`**>' ..o^'rtf'bA''* y1.11 > PRCCXJCED (N MATTES OF HEYSV M1DAUCO NO 1161 OF S9fl7 PRODUCED IN MATTES OF HARROW V MIDAtCO NO ))4SOF I9S? < i. Miners* in w-'s'-e.-b*'*' V*l hi Ms t'* < PRODUCED IN MATTER Cf MJDA|.c< NO JS48 or j*;- c Fftiw^cpd in Asbestos Farsonai injuryCases: hv<<^ kedanci sootedto Richardr. Scruggs *.;<c. _ Mil_ won Ion- '*br** -.-I Vjfj.l c*OftO<''* 1(3''*' SSSK**^ . . . . .it at Prieska showing dust 1 collecting.rooms in the foreground ind the build! housing the cleaning plant in the rear. M C3S o Cleaning plant at Pricska showing short fibre recovery plant. ir--infTiwrntoii, liTi'f e.i.i in i .iir.r a ... < c Cleaning plant at Prlesi* showing S ci&anlng and tolending of Ions jju fibre. </ Loading iaa tlabar-at Priaska.