The application of GRP and thin spray liner support products in a typical block cave mining method to enhance safety and productivity

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1 The ppliction of GRP nd thin spy line suppot poducts in typicl block cve mining method to enhnce sfety nd poductivity by P.H. Feei* nd A. Pioddi* J o u n l Synopsis A typicl sub-level block cve mining extction method employs n undecut level to estblish cvity in hd ock, nd s such equies specil suppot methods nd poducts to be instlled duing the development phse. The undecut level development in the block cve oebody is then scificil, nd suppot elements will eventully epot to the cushe nd pehps conveyo belt systems fo tnspottion to sufce. The choice of suppot poducts instlled in the undecut level development should tke cogniznce of the detimentl effect these could hve on the mining system such s cutting of conveyo belts, obstucting cushes, sfety spects, nd poductivity. This wok exploes the pobbility nd pcticlity of mking use of new-genetion suppot poducts to mke the opetion sfe s well s enhnce poductivity in the development phse nd duing the undecut opetion. This ppe will investigte the use of glss einfoced plstic (GRP) ockbolts nd GRP mesh insted of conventionl steel bolts nd mesh long with esin cpsule-filled holes with the GRP bolts. Complementing this with thin spy line (TSL) ppliction s nothe mens of ceting sfe opeting envionment, s well s poductive suppot medium, will lso be ddessed. These poposed items e envisged to educe poduction downtime nd impove the sfety of ou people. These items e ll esy nd light to hndle, cuttble nd cushe fiendly, s they will bek up duing the cushing pocess. Keywods thin spy lines, GRP bolts. Intoduction Pessue to povide wokplce fee fom injuies nd ftlities hs dded to the woldwide mket pessue to impove pofits nd mgins in the mining industy. A ockfll study (Potvin et l. 2001) conducted in 26 Austlin undegound metl mines hs shown tht ove 90% of ockfll injuies involved in ocks smlle thn 1 ton. Futhemoe, studies hve shown tht most injuies in undegound mines hve occued within few mete of the ctive fce. This suggests tht the cuent ppoches in contolling the smll pieces of exposed ocks ne the ctive fce whee minewokes e consistently exposed cn be impoved. The ppoches used nge fom using no sufce suppot to the instlltion of mesh (steel nd fibe), nd in poo gound conditions the instlltion of shotcete. While pplying the cuent methodology ne the fce would likely educe the isks of ockfll injuies, it could negtively impct the opetions with egds to cost nd mining cycle times. Thin spy lines (TSLs) cn ddess the bovementioned poblem. The instlltion of sufce suppot using emote nd pid spying techniques hs the potentil to minimize intefeence with the mining cycle nd educe costs. TSLs cn be pplied essentilly on o t the fce to keep the smll key blocks in plce nd educe the potentil of gvity-induced fllouts of smll pieces of ock. The poducts discussed in this ppe wee ll developed by Minov RSA, the intent being to compe the chcteistics of ech type of poduct ginst the othes, the thn ginst those of competitive poducts. Fo the pupose of this investigtion, Minov RSA hs chosen to evlute thei poducts ginst the following set of citei: Chcteistics of vious TSLs Ese of ppliction Poduct qulity pefomnce Spy bility nd covege Compison to shotcete Scle of intefeence with the mining cycle. The fist pt of this ppe will descibe the chcteistics of Cpcem KT - TSL nge. The second pt of the ppe will descibe the chcteistics of the glss fibe einfoced bolts nd mesh. * Minov, South Afic. The Southen Aficn Institute of Mining nd Metllugy, SA ISSN X/ This ppe ws fist pesented t the, MineSfe Confeence, August 2011, Empeos Plce, Hotel Csino Convention Resot, Johnnesbug. P p e The Jounl of The Southen Aficn Institute of Mining nd Metllugy VOLUME 112 FEBRUARY

2 The ppliction of GRP nd thin spy line suppot poducts Thin spy line chcteistics The technicl chcteistics of Minov RSA s nge of Cpcem KT- TSL poducts e shown in Tble I. The Cpcem KT nge of TSLs povides potective coting to ock, concete, o col sufces tht e susceptible to deteiotion on exposue to mine tmosphee, o e employed s TSL fo suppot. (Figue 1) These poducts e ll popelled by compessed i onto the ock sufce. A full liquid TSL tht does not equie compessed i fo populsion onto the ock sufce is in n dvnced stge of development. Citicl equiements of TSLs hve been identified s follows: Adequte pot life when mixing i.e. moe thn 30 minutes Fctoy pe-mixed poducts fo consistent pefomnce of poduct Fst development of stength fo pid pefomnce fte two hous of ppliction i.e. compessive, tensile, nd she stength Excellent dhesion i.e. bonding to the substte Visibility of the coting (white o light in colou). The suppot pefomnce of TSLs is detemined lgely by the substtes onto which it is ttched. The TSLs cn getly ssist in mintining the initil integity of the ock mss unde genel loding conditions. To ensue effective sufce suppot design, it is impotnt to fully undestnd the equied einfocing cpbilities of the skin suppot. In fible gound conditions, the fist function of TSL is to pevent the unvelling nd loosening of fgments, thus mintining the ock mss integity. If unvelling is not pevented, the suppot esistnce within the ock mss will gdully decese nd the demnd on the sufce suppot will consequently incese. Being in intimte contct with the ock sufce, the coting ction of TSLs bidges joints, effectively penettes fctues, nd bonds the ock mss togethe, thus esticting inteblock movement. Figue 2 illusttes the intection between vious suppot components in suppot system, epesented s einfoced bem loded in n othogonl diection. Pneumtic ppliction equipment Esily pplied by one peson Visibility White TSL poduct Tble I Minov TSL chcteistics summy (t 25 C) Popety Tekflex White Gey Fst Fst 2C Compessive stength (MP) 2 hous A flexible hous poduct dys dys: Tensile stength (MP) 2 hous hous dys dys She stength (MP) 24 hous dys dys Adhesive stength (MP) 28 dys: dys: 3.1 ~ 0.2 ~ 0.2 ~ Figue 1 Undegound pplictions of TSLs Figue 2 TSL block theoy 142 FEBRUARY 2012 VOLUME 112 The Jounl of The Southen Aficn Institute of Mining nd Metllugy

3 The ppliction of GRP nd thin spy line suppot poducts Clssifiction of TSL chcteistics Lbotoy intepettion of TSL technicl chcteistics could be s follows. The clssifiction in Tble II should be ed in conjunction with the geotechnicl equiements fo the specific loding conditions tht my be expected, nd my not ll be eqully impotnt o pplicble. In selecting the most suitble TSL, cognisnce must be tken of the specific equiements nd intended ppliction of the TSL. Fo exmple, in sttic envionment the equiement my be fo TSL with high unixil compessive stength, whee tensile stength cpbilities e less citicl. Undegound ppliction Minov RSA TSLs e cuently being extensively used in pltinum nd chome mines, with eltively limited ppliction in othe hd-ock nd dimond mines. The Cpcem KT nge is used in most pplictions, with specilized Tekflex pplictions in veticl settle dms nd ise boeholes fo seling ginst wte lekge nd in excvtions equiing flexibility. The success of pplictions stems fom ese of mixing nd spying nd ultimtely the clening of equipment fte use. All this leds to quick nd cost-effective spying cycles nd will detemine the success of the TSL ppliction. Good sufce peption is lso essentil fo good bond. Stess-induced fctuing ws obseved in the ock mss suounding the excvtion nd wedge type filue of ock occued t the intesections of these fctues nd lowngled joint sets, ceting vey ough nd uneven ock sufce in the immedite hnging- nd sidewlls of the excvtion. The condition of the ock mss ound tunnel is to lge degee contolled by the ock stength nd the stesses it will be subjected to duing its life cycle. In highstess conditions, sound design nd excvtion techniques e equied to educe ely fctuing dmge nd to pepe the ock wlls fo the instlltion of suppot. In these conditions, the instlltion of suppot t n ely stge fte exposue of the ock sufce cn significntly impove the peviling gound conditions. It hs become common pctice in the deep-level scenio to pply thin lye of shotcete s soon s possible fte the blst to inhibit the dvese effect of stess fctuing nd wetheing, nd to mintin sfe woking conditions till such time tht secondy nd moe pemnent suppot cn be instlled. Tble II Lbotoy intepettion of TSL technicl chcteistics s qulity mesue could be s follows: Tensile stength 1 MP 3 MP 5 MP Wek TSL Avege TSL Stong TSL Mteil She stength 5 MP 10 MP 15 MP Wek TSL Avege TSL Stong TSL Tensile dhesive stength 1 MP 2 MP 4 MP Wek TSL Avege TSL Stong TSL She bond stength 1 MP 3 MP 5 MP Wek TSL Avege TSL Stong TSL Howeve, it is often difficult to mintin the shotcete within esonble distnce fom the dvncing fce, due minly to logisticl constints nd difficulty of fully integting the shotcete into the development cycle. TSLs hve the potentil to educe ccident levels nd incese poductivity, s the pid spying techniques involves miniml intefeence with the mining ctivity. In fible gound conditions, the fist function of TSL is to inhibit the unvelling nd loosening of of fgments, thus mintining the ock mss integity. In eltively lge excvtions, tunnels, nd mechnized poduction envionment, TSLs e vey well suited to obotic m spy system fo fst nd efficient pplictions. If unvelling is not pevented, the suppot esistnce within the ock mss will gdully decese nd the demnd on the sufce suppot will consequently incese. Being in intimte contct with the ock sufce, the coting ction of TSLs bidges joints, effectively penette fctues, nd bonds the ock mss togethe, thus esticting inte-block movement. Moe pemnent stuctul suppot such s thick shotcete cn be pplied on top of the TSLs with good bonding. Cpcem KT Poduct desciption Cpcem KT White nd Gey hve vey simil popeties nd e supplied s single-component powde (pe-mixed in the fctoy) to which wte is dded. The min diffeence between Cpcem KT White nd Gey is the cement used, nd KT White cues to billint white finish, while KT Gey cues to light cement-gey finish. Cpcem KT Fst is poduct developed by Minov RSA with the intention to povide ely eil suppot covege to undegound excvtions, offeing stength fte 2 hous. Cpcem KT Fst 2C nd Tekflex consist of two pcked components pemixed powde nd liquid polyme foming kit. The Cpcem KT nge foms semi-igid suppot membne tht ssists the ock to etin its initil integity by educing the dvese effects of scling, splling, nd wetheing. It is supplied in 25 kg bgs which poduce on vege 15 lites of poduct when mixed with 5.4 lites of wte o polyme. It cn theoeticlly cove 3.4 m2 if pplied 5 mm thick to flt sufce. Howeve, due to the oughness fcto of the undegound ock, it is estimted tht 2.5 m2 cn be coveed by one 25 kg bg o kit. Appliction methodology Typicl mixing ngement The contents of numbe of 25 kg bgs of Cpcem KT White, Gey, o Fst e mixed togethe with clen wte s pe ecipe, fo ppoximtely 4 minutes nd then pumped (using n electic pump o compessed i diven pump), though 25 mm hose to the spy nozzle some 15 m wy, fom whee it is spyed onto the hnging- nd sidewlls eithe by hnd-held o obotic m ngement. The spy tempo is in the egion of 500 to 800 lites pe hou fo effective ppliction. With continuous mixing of the TSL whilst spying, sufce e of some 45 m2 cn be coveed in 30 minutes. The totl cycle time is thus some 35 minutes, mesued fom the time the opetos ente the tunnel until they move out (Figue 3). J o u n l P p e The Jounl of The Southen Aficn Institute of Mining nd Metllugy VOLUME 112 FEBRUARY

4 The ppliction of GRP nd thin spy line suppot poducts Single mix ngement fo vey smll e pplictions Continuous mixing ngement fo lge e pplictions Continuous mixing with obotic m fo lge mechnised nd high e pplictions Figue 3 Lod ppliction on Cpcem KT Fst 2C used with Minov webbing Lod (kn) Displcement (mm) Figue 4 Minov RSA hd done tests with TSLs on numeous pnels to detemine the eltive pefomnce of the poducts. Tests wee done with TSLs only nd lso with combintion of TSLs with eltively thin webbing spyed ove. The esults e illustted in Figues 4 6 nd Tble III One could conclude tht TSLs offe pcticl solution fo limited gound suppot, nd if used in conjunction with ppopite webbing nd followed in exteme cses by lye of shotcete, they offe supeb pcticl nd mechnized solution to gound suppot in scificil o pemnent tunnel o excvtion envionment, with the sfest ppliction method nd with vey few people involved. All pplictions fom the ppliction of webbing to TSL to shotcete cn be done mechnized, emotely nd pidly (Tble IV). 144 FEBRUARY 2012 VOLUME 112 The Jounl of The Southen Aficn Institute of Mining nd Metllugy

5 The ppliction of GRP nd thin spy line suppot poducts J o u n l Defomtion (mm) Figue 5 Lod ppliction on Cpcem KT Fst 2C used with Minov webbing Figue 6 Minov webbing P p e Tble III Thin spy line chcteistics Age (dys) Cpcem KT Fst 2C Enegy bsoption (J) Webbing Tble IV Poduct compisons (typicl cost self-pplied with integted cew) Desciption Shotcete KT 2C KT White KT Gey KT Fst (±25 mm) (±5 mm) 3 m 2 (±5 mm) 3 m 2 (±5 mm) 3 m 2 (±5 mm) 3 m 2 Appoximte ex fctoy poduct cost pe m2 R 85 R 95 R 85 R 65 R 85 Appoximte dedicted lbou cost pe m2 R 125 R 55 R 55 R 55 R 55 * Appoximte totl cost pe m2 R 210 R 150 R 140 R 120 R 140 Rebound Poo (lots of mteil) Hdly ny Hdly ny Hdly ny Hdly ny Bgs pe m kg pe m Ese of Appliction Cumbesome Esy Esy Esy Esy **Time to cove 45 m2 150 Minutes 55 Minutes 55 Minutes 55 Minutes 55 Minutes (conventionl ppliction) Equipment Lge Smll Smll Smll Smll Intefeence with development cycle High Miniml Miniml Miniml Miniml * Poduct cost my vy slightly pe m² fom opetion to opetion due to sufce es. Lbou cost fo ppliction could be vey diffeent fom the numbes quoted bove, especilly if the ppliction cew is not pt of the development cew. **With continuous mixing ngement of the TSL poducts, the ppliction time cn be limited to 30 minutes pe ppliction cycle followed by wshing out the equipment befoe the next use. Minov RSA will ensue ppopite pump nd mixing ngements to llow fo continuous mixing nd spying with the development cycle nd equipment selection fo development. The Jounl of The Southen Aficn Institute of Mining nd Metllugy VOLUME 112 FEBRUARY

6 The ppliction of GRP nd thin spy line suppot poducts Spy equipment The ese of ppliction of TSLs will ensue miniml intefeence with the development cycle nd impove sfety nd poductivity. The equipment equied fo TSLs is smll comped to conventionl shotcete equipment nd cn edily be moved between sites. Thee e vious types of TSL pumping nd mixing equipment vilble; howeve, the use of equipment with independent mixing nd pumping ngements is ecommended to educe ppliction cycle times. Logistics In the cse of 25 mm shotcete, ppoximtely 158 x 25 kg bgs e equied to cove n e of 45 m2, which equtes to ±4 tons of mteil. In the cse of 5 mm TSLs such s Cpcem KT, 23 x 25kg bgs o ½ ton of mteil is equied to cove 45 m2. The use of TSLs cn significntly educe the demnd on the ledy budened logisticl systems of the mine while mintining sfe mining conditions ight t the dvncing fce. A typicl conventionl development cycle might consist of the following: Clening opetions Mking sfe Instlltion of tempoy suppot (jcks nd netting) Mking off suppot holes Dilling nd instlltion of suppot Mking off of the ound Dilling the ound Chging up nd blsting Removing tempoy suppot Re-enty. Depending on the equiements, the ppliction of sufce suppot lines should idelly be integted into the ovell poduction cycle whee it is most pcticl nd cuses the lest intefeence with the development cycle. If it is equied to pply the sufce line fom the lst line of pemnent suppot up to the fce, then idelly this ctivity should tke plce immeditely fte the instlltion of tempoy suppot o even pemnent suppot if esin bolt instlltion is chosen. In bd gound undecut development end, the suppot egime might cll fo the following suppot: A bolting ptten Shotcete t 25 mm thickness Steel mesh nd/o lce instlltion Shotcete t 50 mm thickness. With the new-genetion suppot vilble the following could be poposed: GRP o synthetic netting instlltion with netting instlling unit mounted to fce jumbo 5 mm TSL on wshed nd mde sfe development ock sufce with obotic m pplicto A GRP nd esin cpsule bolting ptten with mechnized bolte. This could be dequte to sfely llow citicl nd inline ctivities to continue t the fce, nd then follow up with 50 mm shotcete ppoximtely 20 m behind the dvncing fce. Wht we ttempt to demonstte is tht combintion of TSLs, ppopite netting, GRP bolts, nd shotcete will offe the sme suppot esistnce but with less mteil, fste development cycles, sfe development methods, nd suppot poducts tht cn be boken up nd destoyed when the undecut level gets blsted wy nd the poduct goes though the cushes. Allownce must be mde in the poduction cycle fo t lest hlf n hou fo the ppliction of the TSL, ssuming the poduct nd equipment is on site. This excludes the time tken to set up the equipment nd the clening ftewds. Futhemoe, it could be dvntgeous to spy thin lye of TSL ove the peviously spyed sufce of the pevious blst to incese the TSL thickness to sy 8 mm nd poduce good nd consistent cove nd potection. Conclusion Rock-elted ccidents e the mjo cuse of injuies nd ftlities in undegound mines, nd most of these ccidents occu ne the ctive fces whee wokes spend most of thei time. One of the mjo cuses of instbility is lck of suppot nd/o covege between suppot units. Suppot tendons lone do not povide sufficient ock einfocement in fible gound conditions nd hence llow the potentil of gvity induced fllout of smll pieces of ock. TSLs hve the potentil to benefit the mine by offeing impoved poductivity, pofitbility, nd sfety. Fom mnufctuing pespective, it is vey unlikely tht ll the chcteistics tht TSL could hve cn be included in one supe poduct. Fo this eson the pope selection nd ppliction of the coect TSL is vey impotnt to be ble to significntly impove gound conditions nd educe elted injuies. Intoduction to glss fibe einfoced plstic bolts nd mesh In 1985 Weidmnn AG, compny in Switzelnd, stted with the development nd mnufctue of nge of glss fibe einfoced plstic (GRP) ockbolts which wee then used fo the fist time in tunnelling pojects in Switzelnd. The GRP bolts wee instlled s pemnent suppot togethe with steel mesh nd shotcete in numeous tunnels constucted by the single-shell method. GRP bolt technology hs since found widesped ppliction in the mining nd civil engineeing industies. Comped to steel, glss fibe einfoced plstics hve dvntges tht cn be tced to the popeties of the composite mteil. It offes high esistnce to coosion, high tensile stength, light weight, nd is esily cut though. The ppliction of glss fibe einfoced plstics offes vious possibilities. In coopetion with Rockbolt Systems (Switzelnd), the Minov goup offes nge of GRP bolts suitble fo vious ock suppot pplictions. Minov RSA hs lso developed nge of TSLs suitble fo use s undegound continment suppot o fo wetheing potection. GRP desciption GRP bolts consist simply of composite of esin nd fibe tht is mnufctued though the pultusion mnufctuing 146 FEBRUARY 2012 VOLUME 112 The Jounl of The Southen Aficn Institute of Mining nd Metllugy

7 The ppliction of GRP nd thin spy line suppot poducts pocess which ws developed in the ely 1970s. The w mteils (fibe nd esin) e pulled though die, which gives the od its shpe nd dimension. The ods consist of ppoximtely 75% glss fibe nd 25% esin. The fibe theds e continuous, nd no dmge o cutting of fibes duing the mnufctuing pocess (Figue 7). GRP popeties Due to the high tensile stength nd eltive high modulus of GRP, the bolt hs high nd immedite lod-being cpcity if pplied with fst setting esin cpsules. The high flexibility is well suited fo ppliction without couplings in confined loctions nd the low weight fcilittes ese of hndling. The high esistnce to coosion of GRP bolts mkes them idel fo use in highly coosive envionments. GRP bolts hve sevel dvntges comped to steel bolts: Coosion esistnt the mteil is duble nd s pt of the finl lining suppots stuctue duing its whole lifespn Cuttbility voids dmge to cutte heds nd does not dely excvtion Continuous thed theding ove the whole length fcilittes coupling High tensile stength ppoximtely double the lod of steel b with the sme dimete (Figue 8, 9 nd Tble V) Flexibility GRP bolts cn bend nd theefoe be used in confined spces without the use of coupling elements Low weight GRP bolt is only qute of the weight of steel bolt of the sme dimension. GRP Mesh FiReP FRP POWERMESH ws developed to comply with stndd gid pplictions while poviding the dded benefits of dubility nd cut bility. High lod cpcity t ech joint, comped to tht of welded mesh, is unique nd mkes the Figue 7 Typicl pultusion pocess used in the mnufctue of GRP bolts Figue 8 Compison of mteil chcteistics of GRP bolts vs. steel bolts J o u n l P p e Types of GRP bolts GRP bolts e well suited to be used s pimy o secondy suppot s stndlone suppot unit o s n integl pt of suppot systems. Thee e fou diffeent types of GRP bolts vilble; nmely, the ll-thed bolt K60 nd J64, the selfdilling tubul od, nd the cble bolt. K60 nd J64 bolt The ll-thed K60 bolt cn esily be instlled using polyeste esin cpsules, thus leding its self vey well towds mechniztion, o it cn be gouted into plce by the use of cement cpsules o pumpble gout. The J64 injection bolt (tube) ws developed to fcilitte the injection of cementitious gout, epoxy, o silicte esin fo gound consolidtion o wte seling pplictions (Figue 10). Self-dilling bolt The self-dilling bolt ws developed fo use in wek ock o soil nd cn be coupled to lengths up to 20 m, depending on ock o soil conditions. The bolts e suitble fo use with oty dilling mchine nd cn effectively penette ock with hdness of ppoximtely 60 MP. The bolts e set in plce with cementitious gout o chemicl gout nd e most suitble fo piling hed of n dvncing fce developed in poo gound conditions (Figue 11). Figue 9 Compison of GRP bolts vs. vious steel bolts tests cied out t the Technicl Univesity of Lule, Sweden Tble V Compison of mteil chcteistics fo Weidmnn GRP bolts GRP Steel Aluminium Specific weight (kg/dm³) Tensile stength (N/mm²) E-modulus (N/mm²) Ultimte stin (%) > 10 > 10 The Jounl of The Southen Aficn Institute of Mining nd Metllugy VOLUME 112 FEBRUARY

8 The ppliction of GRP nd thin spy line suppot poducts the most pessing mteil poblem woldwide. With cpitl, downtime, nd mteil costs ising, coosion pevention is high on mny industies' list of pioities. Evey minute, sevel tons of steel e lost to coosion. The cost of coosion potection is enomous. Even with potection the coosion poblem is only delyed, but not solved. Coectly pplied FiReP FRP ockbolt systems suppot the constuction ove its entie life. Becuse of its nti-coosion concept, the FiReP FRP ockbolt technology is used incesingly fo soil einfocement nd gound nchoing. Figue 10 Typicl exmple of K60 nd J64 injection bolt Figue 11 Typicl exmple of self-dilling bolt design of fibe einfoced polyme (FRP) gid-einfoced RC stuctues vible option fo enginees nd mining suppot stuctues. Exmple Unit stndd 100 x 100 x 6 mm, od dimete 6 mm Beking lod of 6 mm od >28.3 kn. Ultimte stength of 6 mm od >1 000 N/mm² Tensile E-modulus N/mm² nd lod of knot >3 kn nd >5 kn Ovell dimensions x 800 mm. Single-lining suppot systems Becuse of the dubility of the mteils, FiReP FRP ockbolt systems cn be utilized not only s tempoy suppot, s with egul steel ockbolts, but lso integted into the clcultion fo the finl lod-being stuctue. In situ concete shells cn theefoe be educed o even eliminted. This so-clled single-lining tunnel constuction method is widely used in Euope in mility nd civil cvens. The finl suppot consists solely of ockbolts nd einfoced shotcete. With the impovements chieved using those mteils, single-lining tunnels will futhe incese in impotnce. The cost eductions, especilly in the lge-scle coss- Alpine tunnels e enomous. The constuction costs of ilwy tunnel fo low speed o highwy tunnel with modete tffic cn be educed by up to 50%. (Figue 12) Applictions of GRP GRP bolt technology is especilly well suited fo use s tempoy suppot units whee cutte heds e used fo excvtion in hd o soft gound conditions. The cuttbility of GRP llows the cuttes to cut though the bolt without cusing dmge to the cutting heds nd costly delys, nd GRP cn esily be boken in ock cushe educing significntly dmge to equipment (Figue 13). GRP bolts e typiclly used t collieies duing stooping opetions, the coll nd holing positions fo ise boing mchines, o t the coll nd holing position fo tunnel boing mchines, nd in ggessive coosive envionments (Figue 14). Othe options Avilble od size 3 mm 12 mm Othe mesh sizes vilble on equest Polyeste/epoxy/vinyl este esin Non-flmmble Anti-sttic coting Coosion esistnce FiReP FRP ockbolt systems e coosion esistnt nd theefoe the only cuently vilble ockbolt system tht cn be egded s pemnent, even unde difficult conditions with ggessive wte nd ock defomtions. Coosion is Figue 12 Typicl exmple of GRP powe mesh 148 FEBRUARY 2012 VOLUME 112 The Jounl of The Southen Aficn Institute of Mining nd Metllugy

9 The ppliction of GRP nd thin spy line suppot poducts Sevel TSLs suitble fo vious mining envionments nd geotechnicl conditions e vilble nd could be well suited s dditionl suppot o consolidtion medium in the undecut level development in block cve whee this my J o u n l Figue 13 GRP bolts with mesh GRP bolts cn be used s stndlone suppot o in combintion with vious types of suppot medi. In poo o fible gound conditions, GRP cn be used in combintion with webbing, netting, mesh, shotcete, o TSLs (Figue 15). GRP bolts cn lso be used s self-dilling bolts in the ppopite pplictions. Resin is genelly injected though the bolt to consolidte the vey wek o fible ock (Figue 16). The vey ntue of the block cve mining method mkes it idel fo exploing the benefits tht could be deived fom the use of GRP technology. The undecut development is scificil nd the instlled suppot will be destoyed once the undecut blsting nd oe poduction commences. The instlled suppot will eventully epot to the dw points whee it could cuse obstuction; o wose, end up on the conveyo belt systems with the potentil of cutting the belts o cuse obstuctions in the cushe. The inheent popeties of GRP cn ovecome the shotcomings of conventionl steel-type suppot nd enhnce sfety nd poductivity. In es whee poo o fible gound conditions e encounteed, it is often necessy to conside the use of continment suppot in ddition to tendon suppot. Common pctice is to instll wie mesh nd lcing o shotcete o combintion of wie mesh nd shotcete. Although these types of suppot e genelly vey effective in stbilizing vey wek gound conditions, they e time-consuming nd costly, not to mention the logisticl poblems they my cete. Figue 14 Typicl ppliction of GRP bolts whee cutte heds e used Figue 15 Typicl exmple of GRP bolts used in combintion with wie mesh P p e Figue 16 Typicl pplictions of self-dilling bolts The Jounl of The Southen Aficn Institute of Mining nd Metllugy VOLUME 112 FEBRUARY

10 The ppliction of GRP nd thin spy line suppot poducts be equied. TSLs offe cost-effective suppot solution s ltentive o supplementy suppot to shotcete in es whee the building of stuctue is not equiement. The min dvntges of TSLs comped to shotcete is the ese of ppliction, speed of ppliction, ely stength, much educed tnspottion of mteil, less lbou intensiveness, nd cost-effectiveness. TSLs cn be used s tempoy o pemnent suppot, depending on the equiements nd peviling geotechnicl conditions. As tempoy suppot, the TSL cn be incopoted into the dily poduction cycle to mintin sfe mining conditions t the fce. This llows pemnent suppot to be instlled t lte stge without cusing unnecessy poduction delys. Typicl undecut development suppot sttegy nd ltente considetions The suppot sttegy selected fo block cve undecut level is genelly site-specific nd to lge extent depends on the undecut level design nd locl conditions. Dift suppot nd einfocement typiclly consists of polyeste esin cpsulenchoed bolts. Resin bolting offes immedite ctive nd pemnent suppot, nd the suppot egime is enhnced by the ddition of n ppopite TSL pplied diectly t the development fce fte the blst. It is enhnced even futhe by the instlltion of the cutble GRP powe mesh o synthetic webbing long with the TSLs. Mesh cn be instlled mechniclly by mens of mesh instlle unit mounted on the fce jumbo. GRP bolts cn be instlled with dedicted bolte unit mking use of cousel bolting unit. The use of continment suppot such s shotcete o mesh is consideed only if conditions wnt its use. GRP bolts e well suited to be used in the mechnized envionment nd hence cn be used s n ltentive to conventionl steel bolts without compomising poductivity o sfety. They cn lso be used in combintion with TSLs, shotcete, nd mesh. GRP bolts e ppoximtely 20% moe expensive thn esin-nchoed steel bolts of the sme dimete. Howeve, in some mining pplictions the benefits tht e deived fom GRP f outweigh the dditionl cost. Shotcete nd/o wie mesh e commonly used to suppot undecut difts whee the continment of ock suppot my be equied to ensue tht excvtions emin open nd sfe fo thei designed life. Howeve, shotcete o wie mesh does not edily fit in with the development cycle, nd often esult in educed development efficiencies o suppot bcklog. Should the mining conditions pemit, TSLs my be consideed s cost-effective ltentive o ddition to shotcete nd othe types of continment suppot. The min dvntge of TSLs is tht they cn esily be integted into the mining cycle poviding suppot concuent with the fce. A combintion of GRP mesh o synthetic webbing coveed by lye of ppopite TSLs long with GRP bolt instlltions nd followed by stuctul thickness of shotcete mkes much sense in scificil development envionment. Conclusion With ecent technologicl dvncement of suppot poducts nd methodologies tody, we e ble to wok sfe, smte, nd moe poductively with ppopite suppot equiements fo excvtions. The combintion of fully mechnized system of suppot, commencing with the mking sfe of woking development end with scle nd high-pessue wte jetting of the ock sufce to eliminte uncontolled flls of smlle ock pieces, followed by the mechnized instlltion of webbing if equied nd this being coveed with n ppopite thick lye of the coect TSL, llows in-line development ctivities to tke plce t highe tempos nd pehps sfe thn is genelly the cse tody. The ppliction of thinne lye of shotcete on top of the TSL nd webbing nd bolts on the instlled suppot completes well suppoted development end with good qulity suppot instlled sfely. The uthos believe tht thee is much meit in futhe investigting the economicl ppliction nd implementtion of ppopite new technology in mining nd tunneling opetions. Refeences ARCHIBALD, J.F. Assessment of wll coting mteils fo loclized wll suppot in undegound mines. Repot of Phse 4 Investigtions fo the Mining Industy Resech Ogniztion of Cnd (MIROC), pp. ARCHIBALD, J.F. nd DEGAGNE, D.O. Recent Cndin Advnces in the ppliction of spy-on polymeic linings. Mining Helth nd Sfety Confeence, Apil 2000, Sudbuy, Ontio, ARCHIBALD, J.F. Assessing cceptnce citei fo nd cpbilities of lines fo mitigting gound flls. Mining Helth nd Sfety Confeence, Sudbuy, Ontio, BROWN, E.T. Block Cving Geomechnics Hndbook. The Intentionl Cving Study 1, Julius Kuttschnitt Minel Resech Cente, Univesity of Queenslnd, Austli, p ESPLEY, S., TANNANT, D.D., BAIDEN, G., nd KAISER, P.K. Design citei fo thin spy-on membne suppot fo undegound hdock mining. Cndin Institute of Mining nd Metllugy Annul Meeting, Clgy, KUIJPERS, J. Evlution of membne suppot behviou. Sufce Suppot Lines: Membnes, shotcete nd Mesh. Austlin Cente fo Geomechnics, Peth, LEWIS, B. Mondi Rock-HoldTM the development of this stuctul membne suppot. Sufce Suppot Lines: Membnes, shotcete nd Mesh. Austlin Cente fo Geomechnics, Peth, NAISMITH, W.A. nd STEWARD, N.R. Comptive pefomnce testing of ultthin stuctul lines. 2nd Intentionl Semin on Sufce Suppot Lines: Thin Spyed Lines, Shotcete, Mesh. The Southen Aficn Institute of Mining nd Metllugy, Sndton, South Afic, Sect. 18, POTVIN, Y. Towds common undestnding of TSL pplictions in mines. 2nd Intentionl Semin on Sufce Suppot Lines: Thin Spyed Lines, Shotcete, Mesh. The Southen Aficn Institute of Mining nd Metllugy, Sndton, South Afic, SPEARING, A.J.S., OHLER, J., nd ATTOGBE, E. The effective testing of thin suppot membnes fo use in undegound mines. Sufce Suppot Lines: Membnes, Shotcete nd Mesh, Austlin Cente fo Geomechnics, Peth, Austli, STACEY, T.R. Membne suppot mechnics, loding mechnisms, desied membne pefomnce, nd ppopite test methods. Colloquium 2001, Shotcete nd Membne Suppot, The Southen Aficn Institute of Mining nd Metllugy, FEBRUARY 2012 VOLUME 112 The Jounl of The Southen Aficn Institute of Mining nd Metllugy