Report on a quarterly inspection of the South Alligator Uranium field
Transcription
Report on a quarterly inspection of the South Alligator Uranium field
BMR Record C. 1961/8 COMMONWEALTH OF AUSTRALIA. DEPARTMENT OF NATIONAL DEVELOPMENT. BUREAU'OF MINERAL RESOURCES GEOLOGY AND GEOPHYSICS, RECORDS. ~" ~ ,/c 8 )Yld"~ q11/Ltf'""Z- ~ 4-· q 1961 3. REPORT ON A QUARTERLY INSPECTION ... . ~ of the SOUTH ALLIGATOR URANIUM FIELD for S;BPTEMBER 1 1961 by C. E , I '' P,r i char.~ The informaton contained in this report has been obtained by the Department of National Development, as part of the policy of the Commonwealth Government, to assist in the exploration and develop• ment of mineral resources. It may not be published in any form or used in a company prospectus without the permission in writing of the Director, Bureau of Mineral Resources, Geology and Geophysics. f; Mf<. Re co-ra C , (qbI\~ ' REPORT ON A RUARTER LY INSPECTION of the SOUTH ALLI GATOR UR NI UM F IELD for by c. E. Prichard Conten ts Page I NTRODUCTION 1 UNITED URANIUM Nc L. Saddl e Ridge Scinto No.5 El Sherana Skull Prospect Palette Area Coronation Hill 1 1 1· 1 2 3 SOUTH ALLIGATOR URANIUM ti. L. Roekhole Mine ~ ORE RESERVES 4 5 ORE RESERVES .. South Alligator Uranium Field 6 Airstrip Pros pect ,INTRODUCTION An inspection of uranium company operations on the South Alligator Uranium :B'ield was made from 11 th to 1 5th September, 1961. The previous inspection was in June, 1961, The road to the Field was receiving maintenance and remains in good order. UNITED URANIUM N.L, Major underground exploration near Palette cont.i nued throughout the quarter • The programme of underground exploration has been completed at Coronation Hill and temporarily suspended at El Sherana , Mos.t of the ore produced during the quarter came from the Coronation Hill open cut. Saddle Ridgj Cleaning up t he open eut was completed, Six hundred tons of ore 9ontaining 44oo lbs. of u3o8were obtained. No ore remains in sight. Scinto No.J: Twenty-three wagon drill holes· were drilled north of the open eut without proving ore. Wagon drilling in front of and at the southern end of t he open cut was mor~ suecessf'Ul and located 1100 tons of ore estimated to contain 6ooo lbs. of u3 oa. The 57 foot level Adit from t he open cut has been extended lfO feet, the north-east crosscut extenq,ed 37 teet , and t he south-ea st crosscut extended 1lf. feet. Development ore, including stripplng about 5 feet from the backs in the sou'th-east crosscut, totalled 30 tons containing 14<:> lbs._. of oxideo Work has ceased temporari.l y but will be re.sumed when miners. are available. SkJilll prgspegt A joint cont aining seeondary uranium minerals had beenfound in Upper Proterozoic sandstone which outcrops as a cliff at Skull Prospect. Scree was removed from below this find to a dept h of 5o feet over a length of about 1 50 feet . Secondary urani urn minerals are present in the original joint and in several others. They also occur in the deeper scree and in weathered Lower Proterozoic shale which ean now be seen abutting the· Upper Proterozoic s andstone. No pitchblende wa s seen in .... 2 these exposees ao:r was arJ.7 located ill 16 wag&n d.r ill hele:a d;r.Uled at the base o.f t h e cliff. t !he comp3n1 intend!.a to remove tJt. little more se:ree before ueoiding on the best method ef exploriJ18 f .o r a posf!ihlt, pi tcablende lens. Pale'tte uea - thictergrounti expl6rat1oll was eoncatrated in t.bia fa.'ea tllnushout the ql181"ter. The south drive frcom No.2 Ad.i t is now 2)5 feet in length and t h. e.·_.·. ~or"th d:rive ~ 42 f.eet. sunk t o 4 t et depth at 21:0~ Winze·s . have been: and to 73 .f eet at 65B and a rise at TON ertend.s twelve :teet above t he backs. A weet eroseeut at 325N was dri'Ven ll teet in Upper Proterozoic sandstone ami a north ~os1Jc:ttt at 435J' extdda 22 .t eet also in. san~stene., · Ore wu pr<n'e4 ollly in tb.e 65N _ winz• and the 70N rise :from which 73 t0'ns containing 4500 lbs. of oxide were recovered. No.• 6 Adi t wu driven 66 :teet through Lower Pr()tero:ao1o shale to No.2 Adit to improve ve:nt1latio~ in 'the North Dr ive. No. 5 Ad-it .wW bee-n extendea to a total l ,e agth of 404 fe.et. !:be Eas.t Drive is 37 feet i n length along the contact. hom 21 feet to 37 feet assays indicate o;ne fifth of a pound of' oxide per ·tGn"" The West Drive has laeen extended t o 60 feet alan~; the conta.e't. Only scattered low r.adioaetivity was 1oeated. N&,.2 West llr1v~ ad No. 2 East Drive were t hen co-mmenced from the Adit in .Lower Prot r ozoic shale about 60 feet fron1 the eontaet with Upper Pr ot-e rozoic s811dstone. I ·t was intended t o drive parallel with and aeeut 60 feet from the eon:t&et and explore it h:r lo-n g hole drill.ing every twenty- feet.. Ne.2 West Drive is 140 feet in length and Upper Prot erozoic sandstone appeared in the face.. Long holes had been drilled from only two chambers when i r.spected. fh.ese loca't·e d no ore and ind.ieated the co.r:rtac-t continuing about 60 feet from the drive. Drilling is eo:nt 1nu.1ng. No. 2 East Drive is 53 feet long in bleached. shale throughout. No. 7 A4it had bee.:n commenced t ,owaraa the end of the period., The portal, in Lower Prot erozoic shale, is below that of No. 3 Adit. Only about 70 feet bad be,e n driven when inspeeted and the Upper Proter ozoic had not yet been reached. ExtEtns1 ve unde,.:ogro.und ,ex:plo:ration of th.e Upper Proterozoic/Lower Proter ozoic contact between Palette No.1 Adit area Cliff- face has been un:sueeessful so 'far as only a fe• -tc~ e:t ore· have bee!l located. However, long hole drilling has not been completed f'rom the exi&ting openings . - 3 "" co.ronat1gn Hill The Noo 2 Adit at RL900 has been driven to 511 feet. The North Drive, eommP.ncing 460 feet from the portal of the Adi ~' has been driven 250 feet. Rocks exposed i.n . the world.ngs are altered and unusual types. Typical Upper Proterozoic angular conglomerate with a sandstone matrix . occurs at the end of the North Drive . A dark sheared and altered roek1 possibly originally - volcanic; is common. A little carbonaceous shale in irregular bands up to several t'eet thick occurs within t he altered volcanic . This exploration did not locate ore as had been expected from the previous underground work which had explored from RL1025 to RL975. . Open cut mini!}lg has continued at Coronation Hill. The design of the cut was amended to allow its .deepening by 10 feet to R11000. When inspected the RL10lto bench was almost completed. To 19th August ,, 1·961 , 66lt2 tons of ore containing 32,800 lbs . of oxide have been produced from the open cut. - lt .. S.OUTH ALLIGATOR UR.AN'Iffi-1. N, L. Explora tion and development ceased at t he end of July a s sufficient ore had been developed t o complete the existing contra ct. It is expected t hat this ore will be mined and stockpiled before the Christmas elosedown. Treatment of the ore will continue probably till March, 1962. Rockhole !Ant In the ~To. 3 Adi t area stoping and development pr?dueed 385 tons of' ore containi ng 11,500 lbs. dhJ.efly from 1 5'00E to 1550E, in this area. U~OR No developed ore relfia.Ins From t he 1A Level between 1632E ~nd 1665E ~35 tons of ore cont aining 19t500 lbs. u,oa .were obtained from development and stopl.ng above tl1e levelo From 1'7801 to 1860E 270 tons o:f ore containing 5~. 700 lbs. u~oa were obtained also :£'rom above the level. From a winze at 1980E lt4o tons of ore containing 11,500 .lbs. U308 were raised from belo:w the level. From 623E in No. 2 Adit 20 tons of ore containing 1,300 lbs. U:;08 were raised from below Adit level. Developed or partly developed ore near 1630Et· 1800E, 1980E, and 2000E. is s till to be mined. Airstrip Proanee~ A shaft at Airstrip Prospect was sunk to a total depth o£ 75- feet·. From collar to 62 feet was in Upper Proterozoie sandstone and from 62 feet to 75 feet in Lower Proterozoie shale with the sandstone hanging \vall adjacent. Slight radioaetivi ty was pre sent in t he shale but a drive east from the bottom of t he shaft was in barren sandstone for its tota.l length of six fee to Work has stopped and e quipment has been removed. -'ORE RESERVES Un;t.t~g Ur aniWA N.L. Ore reserves have been r educed by 4,o6o tons cont ai ni ng 39,4oO lbso of oxide trea ted during the quarter. From Saddle Ridge 6oo . t ons not i ncluded in the previous .estimate were mined. Palette area ore reserve has not been al tared as t he 73 tons mined are development ore • Wagon drilling at Scinto 5 has proved 1100 tons of ore·. The ore reserve a t Scinto VI has been re-examined. Open cutting at El Sherana . Saddle Ridge Scinto v, and Coronation Hill ha s s~ovm consistently ·tha t ore mined from the hi gher benches has been less t han ore estimated. An -allowance has been made for this in the recalculated figure for Scinto VI ., and for Cor onation Hill .• Sout h AJ.l~g a tor Ur sm.ium N.Jd. A reappreci a tion of the ore re serves in the Rockhole Mine wa s made. As most lenses of ore are only partly developed and as grade is estimated from Phillips Pocket Monitor r eadings of r adioactivity (controlled by recent results fr,om mining similar ore occurrences) the results are approximate only. Hm~eve r 1 care was t aken t hat they are not unduly optimistic. All t he ore remaining i n situ is in the 1A. level where 900 tons containing 30,000 lbs. of oxide are estimated. In addition 1500 tons cont aining 43,000 lbso of oxide are s tockpiJ.ed. During t he quarter 1250 tons containing 36 1 600 l'bs. of oxide i!Tere treated. It is pr obable t hat extraction of the partly developed ore will r eveal extensions of t he l enses and again i ncrea se ore reserves. - 6 ORE f\EeERVE§ as at §eptember . 196] UNITED URANIUM N.• lj. Jwe ,J:£61 lbs,u3 o8 ~ El Sherana 2100 Coronation Hill 19000 ... Saddle Ridge Scinto v Scinto VI 4ooo Palette 300 Koolpin Creek 1800 stockpile 2800 10000 150000 30000 314100 - ... - 23300 10000 10000 110800 Mines s~~tem}2er al ~21 ~ ~· tons 30 14o 2100 14ooo 4900 600 28000 44oo -73 ... -- -... ... 4500 ~.u3o8 10000 100000 1100 -6000 300 1800 44-?0 14oOO 10000 10000 98000 27770 238000 4ooo SOUTH ALLJ:G TOR UR§.NIUI:f N, L. Jttn@al<£61 · Rockhole Mine Stockpile HLn~si Septembe.r ., 1961 ~ ~. u3o8 ton§ lbs . tons lbs .u3o8 4300 81700 1550 lf9500 900 1 500 30000 43000 4300 81700 24oo 73000 TOTAL ORE RESERVES - September, 1961 South Alligator Uranium Field .. - 30 , 170 tons containing 311 ,ooo lbs. u3o8 •