Umgodi usiba nzulu rhoqo ngonyaka – 30 m, ngokweengxelo zoshishino.
Njengoko ubunzulu bukhula, nesidingo sokungenisa umoya nokupholisa siyanda, kwaye uHowden uyazi oku ngamava akhe okusebenza nemigodi enzulu eMzantsi Afrika.
IHowden yasekwa ngo-1854 nguJames Howden eScotland njengenkampani yobunjineli bezolwandle yaza yangena eMzantsi Afrika ngeminyaka yoo-1950 ukuze incede iimfuno zemizi-mveliso yezemigodi namandla. Ngeminyaka yoo-1960, le nkampani yanceda ekuxhobiseni imigodi yegolide enzulu yelizwe ngeenkqubo zokungenisa umoya kunye nokupholisa ezifunekayo ukuze kukhutshwe iimayile zentsimbi ngokukhuselekileyo nangokufanelekileyo phantsi komhlaba.
“Ekuqaleni, umgodi wawusebenzisa umoya kuphela njengendlela yokupholisa, kodwa njengoko ubunzulu bomgodi bukhula, kwakufuneka ukupholisa ngoomatshini ukuze kulungiswe umthwalo wobushushu okhulayo emgodini,” utshilo uTeunes Wasserman, intloko yecandelo leHowden's Mine Cooling and Compressors, kwi-IM.
Imigodi emininzi yegolide enzulu eMzantsi Afrika ifake ii-Freon™ centrifugal coolers ngaphezulu nangaphantsi komhlaba ukuze zinike ukupholisa okufunekayo kubasebenzi kunye nezixhobo ezingaphantsi komhlaba.
Nangona imeko iphucukile, inkqubo yokukhupha ubushushu yomatshini ongaphantsi komhlaba ibonakalise ingxaki, njengoko amandla okupholisa omatshini ayencitshiswe bubushushu kunye nobungakanani bomoya ophumayo, utshilo uWasserman. Kwangaxeshanye, umgangatho wamanzi emigodini wabangela ukungcoliswa okukhulu kwezitshintshi zobushushu zegobolondo kunye neetyhubhu ezisetyenziswa kwezi zitshizi zokuqala ze-centrifugal.
Ukusombulula le ngxaki, imigodi yaqala ukupompa umoya obandayo ukusuka phezulu ukuya emhlabeni. Nangona oku kwandisa amandla okupholisa, iziseko ezifunekayo zithatha indawo kwisisele kwaye inkqubo ifuna amandla kunye namandla amaninzi.
Ukujongana nale micimbi, imigodi ifuna ukwandisa ubuninzi bomoya obandayo oziswa emhlabeni ngeeyunithi zamanzi abandayo.
Oku kwabangela ukuba uHowden aqalise ii-amino screw coolers kwimigodi eMzantsi Afrika, okokuqala ngokulandelelana emva kwee-surface centrifugal coolers ezikhoyo. Oku kukhokelele kutshintsho oluncinci kubungakanani be-coolant enokunikezelwa kwezi migodi zegolide ezinzulu ezingaphantsi komhlaba, nto leyo ebangele ukwehla kobushushu obuqhelekileyo bamanzi angaphezulu ukusuka kwi-6-8°C ukuya kwi-1°C. Imigodi ingasebenzisa iziseko ezifanayo zemibhobho yemigodi, uninzi lwazo esele zifakiwe, ngelixa inyusa kakhulu ubungakanani be-coolant ethunyelwa kwiindawo ezinzulu.
Kwiminyaka emalunga nama-20 emva kokwaziswa kwe-WRV 510, uHowden, umdlali ophambili kwezorhwebo kweli candelo, waphuhlisa i-WRV 510, i-compressor yesikrufu esikhulu esine-rotor engama-510 mm. Yayiyenye yezona compressors zesikrufu zinkulu kwimarike ngelo xesha kwaye yayilingana nobukhulu be-chiller module efunekayo ukupholisa loo migodi inzulu yaseMzantsi Afrika.
“Oku kuyatshintsha umdlalo kuba imigodi ingafaka i-chiller enye ye-10-12 MW endaweni ye-chillers ezininzi,” utshilo uWasserman. “Kwangaxeshanye, i-ammonia njenge-refrigerant eluhlaza ifanelekile kwiindibaniselwano ze-screw compressors kunye ne-plate heat exchangers.”
Izinto eziqwalaselweyo malunga ne-ammonia zenziwe ngokweenkcukacha kunye nemigangatho yokhuseleko lwe-ammonia kwishishini lezemigodi, uHowden edlala indima ebalulekileyo kwinkqubo yoyilo. Zihlaziyiwe kwaye zafakwa kumthetho waseMzantsi Afrika.
Le mpumelelo ibonakaliswa kukufakelwa kwamandla okukhenkceza e-ammonia angaphezu kwama-350 MW lishishini lezemigodi laseMzantsi Afrika, elithathwa njengelona likhulu kwihlabathi.
Kodwa ubuchule bukaHowden eMzantsi Afrika abuzange buphelele apho: ngo-1985 inkampani yongeza umatshini womkhenkce ongaphezulu kuluhlu olukhulayo lwee-cooler zasemigodini.
Njengoko iindlela zokupholisa ngaphezulu nangaphantsi komhlaba zithathwa njengezibiza kakhulu okanye zibiza kakhulu, imigodi ifuna isisombululo esitsha sokupholisa ukuze kwandiswe ngakumbi ukwembiwa ukuya kumanqanaba anzulu.
IHowden yafaka isityalo sayo sokuqala sokwenza umkhenkce (umzekelo ongezantsi) ngo-1985 kwi-EPM (i-East Rand Proprietary Mine) empuma yeGoli, enomthamo wokugqibela wokupholisa omalunga ne-40 MW kunye nomthamo womkhenkce oyi-4320 t/h.
Isiseko salo msebenzi kukwenziwa komkhenkce phezu komhlaba uze uwuthuthe ngomgodi ukuya kwidama lomkhenkce elingaphantsi komhlaba, apho amanzi avela kwidama lomkhenkce ajikeleziswa kwiindawo zokupholisa ezingaphantsi komhlaba okanye asetyenziswe njengamanzi okucubungula amaqula okumba. Umkhenkce onyibilikisiweyo emva koko uphonswa ubuyiselwe kumphezulu.
Inzuzo ephambili yale nkqubo yokwenza umkhenkce kukunciphisa iindleko zokupompa, nto leyo enciphisa iindleko zokusebenza ezinxulumene neenkqubo zamanzi abandayo ngaphezulu malunga nama-75-80%. Oku kuxhomekeke "kumandla okupholisa agcinwe kwiinguqu zamanzi," utshilo uWasserman, echaza ukuba i-1kg/s yomkhenkce inomthamo ofanayo wokupholisa njenge-4.5-5kg/s yamanzi aqandisiweyo.
Ngenxa "yokusebenza kakuhle kokubeka indawo", idama elingaphantsi komhlaba linokugcinwa kwi-2-5°C ukuphucula ukusebenza kobushushu besikhululo sokupholisa umoya esingaphantsi komhlaba, kwakhona ukwandisa amandla okupholisa.
Enye inzuzo yokubaluleka kwesikhululo samandla omkhenkce eMzantsi Afrika, ilizwe elaziwa ngegridi yalo yamandla engaguqukiyo, kukukwazi kwenkqubo ukusetyenziswa njengendlela yokugcina ubushushu, apho umkhenkce wenziwa kwaye uqokeleleke kumadama omkhenkce angaphantsi komhlaba nangamaxesha exesha elixakekileyo.
Le nzuzo yokugqibela ikhokelele ekuphuhlisweni kweprojekthi yobudlelwane kushishino exhaswa yi-Eskom apho uHowden ephanda ukusetyenziswa kwabenzi bomkhenkce ukunciphisa imfuno ephezulu yombane, kunye namatyala ovavanyo eMponeng naseMoab Hotsong, iimayini ezingaphantsi komhlaba ezinzulu kakhulu emhlabeni.
“Siyikhenkceza idama ebusuku (emva kweeyure zomsebenzi) saza sasebenzisa amanzi nomkhenkce onyibilikisiweyo njengomthombo wokupholisa umgodi ngexesha leeyure zomsebenzi oxakekileyo,” ucacisa uWasserman. “Iiyunithi zokupholisa ezisisiseko ziyacinywa ngexesha leeyure zomsebenzi oxakekileyo, nto leyo enciphisa umthwalo kwigridi.”
Oku kukhokelele ekuphuhlisweni komatshini womkhenkce ojikajikayo eMponeng, apho uHowden wagqiba khona umsebenzi oquka izixhobo zokwakha, zombane nezoomatshini zomatshini womkhenkce onama-12 MW, i-120 t/h.
Izinto ezongeziweyo zakutshanje kwicebo eliphambili lokupholisa likaMponeng ziquka umkhenkce othambileyo, amanzi abandayo angaphezulu, ii-air coolers (ii-BAC) kunye nenkqubo yokupholisa engaphantsi komhlaba, ubukho emanzini emigodini bamanqanaba aphezulu eetyuwa ezinyibilikisiweyo kunye neekloride ngexesha lomsebenzi.
Ubutyebi bamava aseMzantsi Afrika kunye nokugxila kwizisombululo, kungekuphela nje kwiimveliso, kuyaqhubeka nokutshintsha iinkqubo zokukhenkceza kwihlabathi liphela, utshilo.
Njengoko uWasserman ekhankanyile, njengoko imigodi emininzi isiya ingena nzulu kwaye inendawo enkulu kwimigodi, kulula ukubona izisombululo ezifana nezi zifumaneka kwezinye iindawo zehlabathi.
UMeinhardt uthe: “IHowden ibithumela ubuchwepheshe bayo bokupholisa imigodi enzulu eMzantsi Afrika kangangeminyaka emininzi. Umzekelo, besinikezela ngezisombululo zokupholisa imigodi kwimigodi yegolide engaphantsi komhlaba eNevada kwiminyaka yoo-1990.
“Iteknoloji enomdla esetyenziswa kwezinye iimigodi zaseMzantsi Afrika kukugcina umkhenkce oshushu ukuze kuhanjiswe umthwalo – amandla obushushu agcinwa kumadama amakhulu omkhenkce. Umkhenkce uveliswa ngexesha leeyure ezixakekileyo kwaye usetyenziswa ngexesha leeyure ezixakekileyo,” utshilo. “Ngokwesiko, iiyunithi zokukhenkceza zenzelwe ubushushu obuphezulu obunokufikelela kwiiyure ezintathu ngosuku ngexesha leenyanga zasehlotyeni. Nangona kunjalo, ukuba unako ukugcina amandla okupholisa, unganciphisa loo mandla.”
“Ukuba unesicwangciso esinezinga eliphezulu kakhulu lokunyuka kwaye ufuna ukuphucula ukuya kumaxabiso aphantsi ngexesha elingengonyaka, ezi zisombululo zokwenza umkhenkce zinokuba ngumzekelo oqinileyo weshishini,” utshilo. “Imali yokuqala yesityalo inokunciphisa iindleko zokusebenza eziphantsi.”
Kwangaxeshanye, i-BAC, ebisetyenziswa kwimigodi yaseMzantsi Afrika amashumi eminyaka, ifumana ukubaluleka okukhulu kwihlabathi liphela.
Xa kuthelekiswa noyilo lwe-BAC lwendabuko, isizukulwana samva nje se-BACs sisebenza kakuhle kakhulu kubushushu kunezangaphambili, sinciphisa imida yobushushu bomoya kunye nomlinganiselo omncinci. Zikwadibanisa imodyuli yokupholisa-ngokufunekayo (CoD) kwiqonga le-Howden Ventsim CONTROL, elilungisa ngokuzenzekelayo ubushushu bomoya wekhola ukuze buhambelane neemfuno zangaphantsi komhlaba.
Kunyaka ophelileyo, iHowden inikezele nge-BACs ezintathu zesizukulwana esitsha kubathengi baseBrazil naseBurkina Faso.
Le nkampani ikwazi ukuvelisa izisombululo ezenzelwe wena kwiimeko ezinzima zokusebenza; umzekelo wakutshanje kukufakelwa 'okukhethekileyo' kwe-BAC ammonia coolers ze-OZ Minerals kumgodi weCarrapateena eMzantsi Australia.
“UHowden ufake ii-dry condenser ezine-Howden ammonia compressors kunye nee-closed loop dry air coolers e-Australia xa kungekho manzi afumanekayo,” utshilo uWasserman malunga nokufakelwa. “Njengoko olu lufakelo ‘olumileyo’ kwaye kungekhona ii-open spray coolers ezifakwe kwiinkqubo zamanzi, ezi coolers zenzelwe ukusebenza kakuhle kakhulu.”
Le nkampani okwangoku ivavanya isisombululo sokujonga ixesha lokusebenza kwesityalo se-BAC esingama-8 MW (esiboniswe ngezantsi) esiyilwe saza sakhiwa kwimayini yeYaramoko Fortuna Silver (eyayisakuba yiRoxgold) eBurkina Faso.
Le nkqubo, elawulwa sisityalo saseHowden eGoli, ivumela inkampani ukuba inike iingcebiso malunga nokuphuculwa kokusebenza kakuhle kunye nokugcinwa kwayo ukuze isityalo siqhubeke sisebenza ngokugqibeleleyo. Iyunithi ye-BAC kwindawo yokumba imigodi yaseCaraiba e-Ero Copper, eBrazil nayo yenzelwe ukusebenzisa olu phawu.
Iqonga leTotal Mine Ventilation Solutions (TMVS) liyaqhubeka nokwakha ubudlelwane obuzinzileyo obunexabiso elongezelelekileyo kwaye inkampani iza kuqalisa izifundo ezimbini zobuchule bokungenisa umoya ococekileyo (VoD) kweli lizwe ngo-2021.
Kanye kumda waseZimbabwe, inkampani isebenza kwiprojekthi eza kuvumela iingcango ezizenzekelayo ezisebenza ngevidiyo xa zifunwa kwimigodi engaphantsi komhlaba, nto leyo evumela ukuba zivuleke ngamaxesha ahlukeneyo kwaye zibonelele ngomlinganiselo ofanelekileyo womoya opholileyo ngokuxhomekeke kwiimfuno ezithile zesithuthi.
Olu phuhliso lobuchwepheshe, kusetyenziswa iziseko zophuhliso lwemigodi ezikhoyo kunye nemithombo yedatha efumanekayo, luya kuba yinxalenye ebalulekileyo yeemveliso zexesha elizayo zikaHowden.
Amava kaHowden eMzantsi Afrika: Funda indlela yokuyila izisombululo zokupholisa ukujongana nomgangatho ophantsi wamanzi kwimigodi yayo yegolide enzulu, indlela yokwenza izisombululo zibe nobuchule bokusebenzisa umbane kangangoko kunokwenzeka ukuze kuthintelwe iingxaki zegridi, kunye nendlela yokuhlangabezana nezinye zeemfuno zomgangatho womoya ezingqongqo. Ulawulo lobushushu kunye neemfuno zempilo yomsebenzi kwihlabathi liphela Umgaqo-nkqubo - uya kuqhubeka nokuhlawula imigodi kwihlabathi liphela.
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