An investigtion on undegound tnspot ods nd influence on sfety nd poductivity t Khutl Colliey by L. Lehs* Ppe witten on poject wok cied out in ptil fulfilment of B. Eng (Mining Engineeing) J o u n l Synopsis The pupose of the poject ws to investigte the chllenges fced by Khutl Colliey petining to undegound od constuction nd mintennce. Futhemoe the influence of these chllenges on poductivity nd sfety equiements wee tken into considetion. The opeting stndds equied fo the constuction nd mintennce of the 2 sem od tnspot infstuctue ws investigted, togethe with esons why the stndds of opeting pocedue e not met. The Code of Pctice put in plce by Khutl Colliey ws used to view the stndd opeting pocedues. Leding pctices on undegound od constuction wee eseched. The poject ims to discove the gps tht Khutl Colliey must bidge to implement enhnced pctices with egds to undegound od constuction. Duing the peiod of study, obsevtions wee cied out to detemine whethe the od constuction stndds of opeting pocedue wee being dheed to t ll times fo both od constuction nd od mintennce. Khutl Colliey hs put in plce tffic mngement pln, which includes sfety pctices nd wok policies tht must be dheed to while tvelling on undegound tnspot ods. Keywods od constuction, mintennce, sttegic od design. Mine bckgound Khutl Colliey is bod nd pill mine locted in Mpumlng 50 km west of Witbnk nd 100 km est of Johnnesbug. The mine is owned by BHP Billiton Enegy Col Division. The site peption fo the opetion of this mine stted in 1984. The initil design ws imed t chieving 13.3 Mt un of mine pe nnum. Col ws fist mined in 1986 nd supplied to Kendl powe sttion. In 2004 the life of mine of Khutl Colliey ws pedicted to extend to 2033. Khutl Colliey opetes both undegound nd sufce mining sections. The totl eseves s mesued in 2004 wee 601 Mt, 511 Mt of which wee ttibuted to undegound opetions nd 90 Mt to sufce opetions. Sfe pctices e high pioity t Khutl Colliey. Khutl Colliey utilizes the bod nd pill mining method. Single pss continuous mines e used fo col extction. This mining method is commonly used to extct nehoizontl col sems in South Afic. Duing col extction, oof boltes instll pemnent oof suppot. Shuttle cs nd bttey hules e used to tnspot col to the feede beke. The col is then tnspoted to 1050 mm tunk conveyos. Fom the tunk conveyos the col is tnsfeed to lge 1350 mm conveyo belts in the min development. The col is then tipped into undegound bins nd tnspoted to inclined conveyos, nd finlly conveyed to sufce silos. An intoduction to od constuction Duing the od building pocess fou mchines e equied nmely the: Too/LHD nd tcto Rod building mteil is stockpiled t sufce mine btch silos. The mteil is fed down boehole fom the on- sufce silo into the undegound wokings using font- end lode Gde The second step is to sped the od building mteil ound the od constuction e nd to gde ove the e. Rod gdes e the pimy mchines used fo new od constuction nd od mintennce. Gdes e used fo od levelling nd to cete smooth ods. Gdes e lso used fo pothole mintennce Compcto A compcto is used to compess the mteil on the newly constucted od. The pupose of compcting is to ensue tht the mteil pticles stick fimly togethe, esulting in tight dheence between the pticles of the mteil. Compcting stbilizes the od stbility nd pevents od building mteil fom moving * Deptment of Mining Engineeing, Univesity of Petoi. The Southen Aficn Institute of Mining nd Metllugy, 2012. SA ISSN 0038 223X/3.00 + 0.00. Ppe eceived Feb. 2012; evised ppe eceived M. 2012. P p e The Jounl of The Southen Aficn Institute of Mining nd Metllugy VOLUME 112 APRIL 2012 267
An investigtion on undegound tnspot ods nd influence on sfety nd poductivity Spy tnke nd tcto Once the od hs been built it is spyed with dust suppession poduct utilizing spy tnke which is huled by tcto. The od building pocess consists of intedependent sevices. If one of the bovementioned mchines is unvilble the entie pocess is delyed. At Khutl Colliey, the 2 Sem est mine nd west mine utilize single set of od building equipment. Fo peiod of 2 weeks the mchines e llocted to est mine nd fo the following two weeks to west mine. An intoduction to od mintennce Rod mintennce includes gding nd pothole mintennce. Potholes (Figue 1) must be filled with ocks o snd-gvel mix when necessy. Duing od mintennce the od must lso be compcted nd gded. It is the duty of the mine to pefom od inspection nd to obseve the seveity of potholes nd wte ccumultion on ods. It is lso the duty of the mine to epot the od condition to the shift boss nd to futhe delegte wok to the tem to mintin the equied sections. Rods must be constucted with due considetion fo wte dmge, which is the min cuse of od dmge in Khutl 2 Sem est nd west mine. A common poblem tht ws obseved is tht of wte ccumultion t the splits (Figue 2) nd wte flooding into ods. The sitution leds to slippey sufces nd this cetes the isk of slips nd flls nd vehicle ccidents. Poblem sttement The chllenges expeienced by Khutl Colliey with egds to undegound tnspot od constuction wee investigted. The poject ims to identify the vious spects of undegound tnspot od infstuctue tht influence poductivity nd sfety. Poject objectives To esech nd benchmk leding pctices in od constuction. To undestnd how undegound od constuction nd od mintennce pocesses influence sfety nd poductivity. To estblish whethe Khutl Colliey is cuently pcticing the coect pocedues with egds to building nd mintining undegound tnspot ods. To mke ecommendtions on how Khutl Colliey cn impove thei pocedues with the im of chieving leding pctices with egds to undegound tnspot ods, sfety nd poductivity. Methodology The following method ws followed to cquie the dt necessy to indicte the pimy poblems tht e fced by Khutl Colliey with egds to od constuction nd od mintennce. Rod constuction/mintennce nd the influence on sfety Anlyse how Khutl Colliey hs incopoted the fou steps of sfety to identify nd minimize ccidents on undegound tnspot ods Anlyse the tffic mngement pln nd the dheence thee to. Rod constuction/mintennce nd the influence on poductivity Compe the od constuction pocess to the od building stndd opeting pocedue (SOP) Anlyse the sttistics tht e ecoded by the mine plnning deptment on od building mchine utiliztion Collect nd compe dily field epots to the MES (mine electonic system) dt Resech nd popose possible solutions to the chllenges fced by Khutl colliey with egds to undegound tnspot ods nd thei influence on poductivity nd sfety. Results Khutl hs focused ll employees nd contctos on being let to ll hzds nd isks ound them. The fist nd most citicl step is ecognising these hzds nd isks nd instituting the necessy contols to eliminte them. This is in line with the HIRA tining cuently being undetken t the opetion. Hzd identifiction is impotnt becuse it is fundmentl to pesonl sfety. Employees nd contctos e continuously uged to be let to the things tht cn hut them, nd eithe void them completely o institute the necessy contols. At the end of the dy, employees nd contctos need to get home sfe, helthy, nd hppy to Figue 1 Pothole on undegound tnspot od Figue 2 Wte Accumultion t split 300 mm by 300 mm pothole Wte Accumultion t Splits: Mini ponds e +/-2 m dimete Depths of 1.2 m 268 APRIL 2012 VOLUME 112 The Jounl of The Southen Aficn Institute of Mining nd Metllugy
An investigtion on undegound tnspot ods nd influence on sfety nd poductivity those who need nd love them. An individul s Pesonl Big 5, o PB5 e the five people, things o esons impotnt to ech nd evey employee o contcto. Poductivity Figues 3 to Figue 5 indicte the od building mchine vilbility nd utiliztion s ecoded by the mine Mine Electonic dt System (MES) s comped to the esults collected duing the peiod of study. The conditions of the ods with egds to wte nd potholes ffects the deteiotion of the equipment tht tvels on the ods. Tble I indictes the od building mchiney mintennce histoy. Equipment hs technologicl life cycle. It is impotnt tht od building mchines e seviced nd ovehuled ccoding to the mintennce pln in ode to sustin the mchine pefomnce. Tble II indictes the equiements of the mines od building mteil SOP nd the ctul field pctices. The mine supplies sndstone mix s od building mteil t Khutl Colliey. The od building cews undegound use duff ( muddy wste mteil) fo od constuction. Duff is used becuse of the low vilbility of the LHD. When the LHD is on bekdown the od building mteil cnnot be tnspoted fom the undegound silo. Duff is esily vilble in the old woking es. Figue 6 indictes the equied time nd the ctul time tken to tvel to section 23. The lost time is ppoximtely 6 minutes. Section 23 is ppoximtely 9 km fom the shft. The od egultion speed t Khutl Colliey undegound is 30 km/h (Mkgl, 2010). Tons win = (minutes sved) * (50%)* 7.5 t/min = 6 min*50%*7.5 = 22.5 t. 50% chnce of the clcultion being ccute nd tht the CM cutting te is idelly 7.5 t/min, the 6 minutes tht is lost while tvelling towds sections cn esult in tons win of 22.5 t pe shift. J o u n l P p e Figue 5 Field vilbility nd utiliztion (Khutl Colliey MES) Figue 3 LHD 25 MES vilbility (Khutl Colliey MES) Tble I Rod building mchine mintennce histoy (Khutl Colliey ovehul sttegy) Mchine no Puchse dte Replcement Mjo ovehul Tcto 21 06/06/2001 2017 1st MO not done Tcto 23 03/07/2001 2017 1st MO not done LHD 25 01/08/97 2013 All MO done Gde 3 05/21/1996 2012 All MO done Compcto 1 01/04/1991 Replced 2007 All MO done Tble II Diffeence between duff nd SOP sndstone mix povided fo od building Figue 4 Tcto 21 MES vilbility (Khutl Colliey MES) Duff Clyey Seveely dmged by wte Incesed numbe of potholes Difficult to mintin Results in sticky nd bumpy ods when dmged. Wet uneven ods e chllenging to level Sndstone mix (gvel mix) Hd nd stble Cpble of esisting wte dmge Fewe of potholes Esie to mintin Results in bumpy ods when dmged but cn esily be leveled by gding nd compcting The Jounl of The Southen Aficn Institute of Mining nd Metllugy VOLUME 112 APRIL 2012 269
An investigtion on undegound tnspot ods nd influence on sfety nd poductivity Actul time tvelled pe dy comped to mine stndds (section 23) Tvel/time (min) Actul tvelling time (min) Minimum equied tvelling time (min) Dys Figue 6 Dt indicting time tvelled to section 23 Evlution of esults Complince to the od building SOP could be impoved. Duff is used to build nd mintin ods insted of the sndstone mix povided by the mine The numeous od building mchine bekdowns tht e cuently expeienced t the mine ffect poduction dvesely Wte ccumultion in the tnspot ods esults in hzdous woking envionments Loss time while tvelling to poduction sections ffects poductivity negtively. Conclusion The is lck of dheence to the od building SOP Numeous fctos ffects od constuction negtively: Rod flooding The lck of foml od design Rod defects e.g. potholes nd wte ccumultion esults in unsfe woking conditions Shift time lost on tvelling to sections ffects poductivity nd esults in poduction losses. Recommendtions Wte mngement Khutl should monito nd ensue good housekeeping. Wte sevices should be closed t the end of shift usge i.e. close conveyo belt wte spys Dms must be well mintined to minimize lekges Pumps should be instlled t poblem es s poctive wte mngement pln Wte-contining fissues nd veins should be seled to educe wte ccumultion on ods fom ntul wte-being souces. This is usully done by concete lining of shft wlls o though cementtion. Cementtion is pocess wheeby concete is pumped into boehole tht intesect wte-being vein o fissue. Rod design Rods must be built with the sndstone mix supplied s stted in the od building SOP. Two od designs options e suggested fo futue wok. Suggestions fo futhe wok The im of extenl benchmking is to esech two od designs tht my be pplied t Khutl Colliey. The od design must offe high wte esistnce nd level nd stble od sufces. The od designs e flexible, nd Khutl Colliey cn opt to modify od designs to best suit the chllenges expeienced in od constuction. Hyson Cell Tyson cells, lso known s geocells, e lge connected pttens of moulded concete slbs. The fmewok fo csting the concete is mde fom thin-wlled plstic films. The cell fom wok emins in the concete cst duing instlltion, which seves s jointing. The stndd cell sizes nge fom 150 mm x 150 mm to 400 mm x 400 mm. Minimum cell depth is 50 mm, while mximum depth is 4 m. The cells my contin gnul fill fo the constuction of wlls. The cells hve wide ppliction, nd cn be used to line dms o stems nd fo the pevention of slope eosion. The Hyson Cell is lso used s the pvement stuctue in the constuction of sufce mine ods, undegound tnspot ods, nd ipot unwys (Hyson Cells). The side fces of the hyson cell e not stight flt plnes, but e slightly cuved nd hve smll dome-shped potusions tht fit into hollow on the djcent concete cell. This design pevents she movement between the cells nd Figue 7 Hyson Cell vilbility (www.hysoncell.co.z) 270 APRIL 2012 VOLUME 112 The Jounl of The Southen Aficn Institute of Mining nd Metllugy
An investigtion on undegound tnspot ods nd influence on sfety nd poductivity Rod din Weing couse Bse lye Figue 8 Pvement stuctue od design (Thompson nd Visse, 1999b) Sub-bse lye Not to scle 2% typicl cossfll Numbe of pvement lyes my vy ccoding to specific design dopted Sub-gde (fill) Sub-gde (in situ) J o u n l P p e Tble III Advntges nd disdvntges of the Hyson Cell Advntges Completely wte esistnt Zeo mintennce Withstnd hevy lods Disdvntges High implementtion cost Fo usge on both the no. 2 nd 4 sems new oof suppot system would hve to be designed s the tibuty e nd the lod suppoted by the pills my incese Tble IV Advntges nd disdvntges of pvement stuctue od design (L. Lehs 2011) Advntges Moe stble stuctue s comped to duff Chepe thn Hyson Cell pvement Disdvntges Not highly wte esistnt The tnspottion of the concete mix to undegound envionment my equie moe stuctul design e.g. boeholes My cuse difficulty when tvelling below i cossings due to od thickness cetes n intelocking effect. The Hyson Cell pvement cn withstnd hevy (600 t mchines) lods without defomtion. The Hyson Cell hs poved to be effective t: Phlbow Mining Compny, fo the eloction of w nd potble wte esevois. Hvecoft Dm Leblelo Wte Scheme. The dm ws epoted to be completely lek-fee 7 yes fte constuction Finsch Mine undegound ods. Kimbelite is wek ock tht is esily wetheed by wte. The Hyson pvement stuctue ws used to stbilize the undegound infstuctue t Finsch nd to pevent futhe wte dmge in cetin es. Pvement stuctul design The pvement od design is method of developing the most economicl combintion of pvement tht is comptible with the undelying in situ mteil. The bse lye, subbse lye, nd the sub-gde lye detemine the stuctul stength of the od. The weing couse mteil ffects the functionl design of the od. Poo weing couse mteil esults in poo ide qulity, excessive dust, incesed tye dmge, nd incesed vehicle dmge. Thompson nd Visse (1988, 1999,b) hve estblished suitble guidelines to select the coect type of od building mteil. The following e fctos tht ffect the selection of mteil types: The od geometics The envionmentl climte Tffic volumes. Accoding to Thompson nd Visse (1999b)3 the plcement of od sufce ove ny mteil tht cnnot dequtely suppot the weight of the tffic using the od nd cnnot pevent dmge of the od sufce to wte will hmpe the mobility nd contollbility of the vehicles. The od design depicted in Figue 8 consists of 2% cossfll gdient. The cossfll (gdient) ssists with wte unoff. Thus wte flows to the odside wee it ccumultes nd cn be dined o pumped out of the mine. The pvement stuctul design is flexible design nd cn be modified to suit the envionment of od constuction. The pvement stuctul design is extensively used on sufce mines, but with the coect design nd knowledge it cn be pplicble to undegound tnspot ods (Thompson nd Visse, 1999b) The Jounl of The Southen Aficn Institute of Mining nd Metllugy VOLUME 112 APRIL 2012 271
An investigtion on undegound tnspot ods nd influence on sfety nd poductivity Acknowledgements M. Feddie Hunte nd the 2# sem tem A specil thnks to: 1. My mentos M Clive Knobbs nd M John Steyn fo thei guidnce nd constnt suppot 2. The Mining Deptment of the Univesity of Petoi nd the stff fo thei ssistnce 3. BHP Billiton fo gnting me the oppotunity nd lening expeience. My getest gtitude to the men nd women woking t Khutl Colliey 2 sem est nd west fo thei help nd suppot. Refeences HYSON CELLS. http://www.hysoncells.co.z [ccessed 21 Apil 2011] THOMPSON, R.J., VISSER, A.T. et l. 1998. http://www.docstoc.com/docs/ 71353427/Designing-nd-benchmking-mine-ods-fo-sfe-ndefficient-hulingBenchmking hul Rod Design Stndds to Reduce Tnspottion Accidents.[ccessed 21 Apil 2011]. THOMPSON, R.J. nd VISSER, A.T. 1999. https://mining.cutin.edu.u/people/ stff_pofiles/oge_thompson_pofile.cfmdesigning nd Mintining Open CstMine Hul Rods. THOMPSON, R.J. AND VISSER, A.T. 1999b. UnivesityofPetoihttp://envionmentl.heculesselcot.com/ResouseFolde/13Integted_Asset_Mnge ment_sttegies.pdfdesigning nd Mnging Unpved Mine Hul Rods fo Optimum Pefomnce.[ccessed 21 Apil 2011]. THOMPSON, R.J. 2008. https://mining.cutin.edu.u/people/stff_pofiles/ oge_thompson_pofile.cfmhul Rod Design Considetion.[ccessed 21 Apil 2011]. THOMPSON, R.J. 1995. http://minevi.com/summy of Agencies tht Attibute to Tnspot ndtmming Accidents. [ccessed 21 Apil 2011]. http://www.bhpbilliton.com/bbcontentepositoy/epots/khutl2004sitehsecepot.pdf [ccessed5/01/2011]. http://www.bhpbilliton.com. k. dive [ccessed 5/01/2011]. http://www.emgold.com/s/ldho-mylnd_poject.sp [ccessed 7/01/2011]. http://www.eskom.co.z/live/content.php [ccessed 12/01/2011]. http://www.homelndenegygoup.com/i/pdf/techepotp09.pdf [ccessed 6/04/2011]. http://www,infomine.com.publicltions/docs [ccessed 7/01/2011]. http://www.ketonenegy.co.z/im/files/cp_2_geology_01p08.pdf [ccessed 6/04/2011]. http://www.mqdt.com/dt/show_minel.spfcol [ccessed 5/01/2011]. http://onlinewebstudio.co.z/online_epoets_/muob [ccessed 7/01/2011]. http://www.qpoject.og/methods/esglossy.html[ccessed 5/01/2011]. http://sechsoftwequlity.techtget.com/definition/best-pctice [ccessed 5/01/2011]. http://www.diectminingsevices.com/wpcontent/uplods/2010/06/sme_mine_ Hul_Rods_99-090.pdf [ccessed 7/04/2011]. http://www.cps11.co.z/cps07/cpsdocs/powepoints/st8s%20don%20 Ross%20opt.pdf [Accessed 6/04/11]. http://www.e-mj.com/index.php/fetues/659-hul-od-design-considetions.pdf [ccessed7/04/2011]. http://pdfseve.infomwold.com/93696_751309423_777785684.pdf [ccessed 7/04/2011]. http://www.engineeingnews.co.z/ticle/mintennce-system-is-beingdeveloped-t-gootegeluknd-jwneng-2004-03-05[ccessed 6/04/11]. http://www.exxo.com/pdf/icp/ip/mining/col.htm [ccessed 7/04/2011]. http://pdfseve.infomwold.com/93696_751309423_777785684.pdf[ccesse d 7/04/2011]. http://www.womp-int.com/stoy/2009vol05/stoy024.htm[ccessed 7/04/2011]. http://www.minesub.nsw.gov.u/sitefiles/minesubnswgovu/msbguidlines [cessesd7/04/2011]. http://www.sentul.co.z/pdf/koonfontein_mine_site_visit_pesenttion_08_s eptembe_2009.pdf[ccessed 10/01/2011]. http://tuto2u.net/business/sttegy/benchmking.htm10/01/2011. http://upetd.up.c.z/thesis/vilble/etd-02142011-170102/unesticted/01chpte1-3.pdf [Accessed 7/04/2011]. JACKSON, A. 2008.Khutl Rod building Stndd of Opeting Pocedue. MAKGALA, C. 2010. Khutl Tffic Mngement Pln. Khutl Colliey. 272 APRIL 2012 VOLUME 112 The Jounl of The Southen Aficn Institute of Mining nd Metllugy