Imayini ijula ​​minyaka yonke – ngamamitha angu-30, ngokusho kwemibiko yemboni.
Njengoba ukujula kwanda, nesidingo sokungenisa umoya nokupholisa siyanda, futhi uHowden uyakwazi lokhu ngokuhlangenwe nakho kwakhe kokusebenza nezimayini ezijulile eNingizimu Afrika.
I-Howden yasungulwa ngo-1854 nguJames Howden eScotland njengenkampani yobunjiniyela bezolwandle futhi yangena eNingizimu Afrika ngawo-1950 ukuze ihlinzeke ngezidingo zezimboni zezimayini kanye namandla kagesi. Ngawo-1960, inkampani yasiza ekuhlomiseni izimayini zegolide ezijulile zezwe ngazo zonke izinhlelo zokungenisa umoya kanye nokupholisa ezidingekayo ukuze kukhishwe amamayela ensimbi ngaphansi komhlaba ngokuphepha nangokusebenza kahle.
“Ekuqaleni, imayini yayisebenzisa umoya njengendlela yokupholisa kuphela, kodwa njengoba ukujula kokumba kwanda, kwakudingeka ukupholisa ngomshini ukuze kulungiswe umthwalo wokushisa okhulayo emayini,” kusho uTeunes Wasserman, inhloko yesigaba se-Howden's Mine Cooling and Compressors, etshela i-IM.
Izimayini eziningi zegolide ezijulile eNingizimu Afrika zifake ama-Freon™ centrifugal cooler ngaphezulu nangaphansi komhlaba ukuze kuhlinzekwe ukupholisa okudingekayo kwabasebenzi kanye nemishini engaphansi komhlaba.
Naphezu kokuthuthuka kwesimo samanje, uhlelo lokususa ukushisa lomshini ongaphansi komhlaba lube yinkinga, njengoba amandla okupholisa omshini ayenqunyelwe izinga lokushisa kanye nenani lomoya ophumayo otholakalayo, kusho uWasserman. Ngesikhathi esifanayo, ikhwalithi yamanzi emayini yabangela ukungcola okukhulu kwezishintshi zokushisa zegobolondo ne-tube ezisetshenziswa kulezi zitshizi zokuqala ze-centrifugal.
Ukuze kuxazululwe le nkinga, izimayini zaqala ukupompa umoya obandayo usuka phezulu uye phansi. Nakuba lokhu kwandisa amandla okupholisa, ingqalasizinda edingekayo ithatha isikhala esiseleni futhi inqubo idla amandla amaningi.
Ukuze kuxazululwe lezi zinkinga, izimayini zifuna ukwandisa inani lomoya obandayo olethwa emhlabathini ngamayunithi amanzi abandayo.
Lokhu kwashukumisela uHowden ukuthi angenise ama-amino screw cooler ezimayini eNingizimu Afrika, okokuqala ngokulandelana kwama-surface centrifugal cooler akhona. Lokhu kuholele ekushintsheni kwesinyathelo ngesinyathelo enanini le-coolant enganikezwa kulezi zimayini zegolide ezijulile ezingaphansi komhlaba, okuholele ekwehleni kwezinga lokushisa elimaphakathi lamanzi angaphezulu kusuka ku-6-8°C kuya ku-1°C. Imayini ingasebenzisa ingqalasizinda efanayo yamapayipi emayini, amaningi awo asefakiwe kakade, kuyilapho ikhulisa kakhulu inani lokupholisa elilethwa ezingqimbeni ezijulile.
Cishe eminyakeni engama-20 ngemva kokwethulwa kwe-WRV 510, uHowden, umdlali ohamba phambili emakethe kulo mkhakha, wakha i-WRV 510, i-screw compressor enkulu ene-rotor engu-510 mm. Yayingenye yama-screw compressor amakhulu kunawo wonke emakethe ngaleso sikhathi futhi yayilingana nosayizi we-chiller module owawudingeka ukuze kupholiswe lezo zimayini zaseNingizimu Afrika ezijulile.
“Lokhu kuyashintsha umdlalo ngoba izimayini zingafaka i-chiller eyodwa engu-10-12 MW esikhundleni se-chillers eziningi,” kusho uWasserman. “Phakathi nesikhathi esifanayo, i-ammonia njenge-refrigerant eluhlaza ifaneleka kahle ekuhlanganisweni kwama-screw compressors kanye nama-plate heat exchangers.”
Izinto ezicatshangelwayo nge-ammonia zenziwa zaba semthethweni ngokwezincazelo kanye nezindinganiso zokuphepha ze-ammonia embonini yezimayini, kanti uHowden udlale indima ebalulekile enqubweni yokuklama. Zibuyekeziwe futhi zafakwa emthethweni waseNingizimu Afrika.
Le mpumelelo ifakazelwa ukufakwa kwamandla okuqandisa e-ammonia angaphezu kwama-350 MW yimboni yezimayini yaseNingizimu Afrika, ebhekwa njengenkulu kunazo zonke emhlabeni.
Kodwa ukusungula izinto ezintsha kukaHowden eNingizimu Afrika akuzange kuphelele lapho: ngo-1985 inkampani yanezela umshini weqhwa ongaphezulu kobubanzi bayo obukhulayo bemishini yokupholisa yasezimayini.
Njengoba izinketho zokupholisa ezingaphansi komhlaba kanye nezingaphansi komhlaba zibhekwa njengezibiza kakhulu noma zibiza kakhulu, izimayini zidinga ikhambi elisha lokupholisa ukuze zandise ukumba kuze kube semazingeni ajulile.
I-Howden yafaka isitshalo sayo sokuqala sokwenza iqhwa (isibonelo esingezansi) ngo-1985 e-EPM (i-East Rand Proprietary Mine) empumalanga yeGoli, enekhono lokugcina lokupholisa elicishe libe ngu-40 MW kanye namandla eqhwa angu-4320 t/h.
Isisekelo salo msebenzi ukwakheka kweqhwa phezu komhlaba bese lithuthwa ngemayini liye edamini leqhwa elingaphansi komhlaba, lapho amanzi avela edamini leqhwa abese ejikeleziswa khona eziteshini zokupholisa ezingaphansi komhlaba noma asetshenziswe njengamanzi okucubungula imithombo yokumba. Iqhwa elincibilikisiwe libe seliphonswa libuyiselwe phezulu.
Inzuzo eyinhloko yalolu hlelo lokwakha iqhwa izindleko zokupompa ezincishisiwe, okunciphisa izindleko zokusebenza ezihambisana nezinhlelo zamanzi abandayo ngaphezulu cishe ngo-75-80%. Lokhu kuncike “emandleni okupholisa agcinwe ekushintsheni kwesigaba samanzi,” kusho uWasserman, echaza ukuthi i-1kg/s yeqhwa inamandla okupholisa afanayo namanzi aqandisiwe angu-4.5-5kg/s.
Ngenxa “yokusebenza kahle kokubeka indawo okuphezulu”, idamu elingaphansi komhlaba lingagcinwa ku-2-5°C ukuthuthukisa ukusebenza kokushisa kwesiteshi sokupholisa umoya esingaphansi komhlaba, futhi kwandise umthamo wokupholisa.
Enye inzuzo yokubaluleka okukhethekile kwesitshalo samandla eqhwa eNingizimu Afrika, izwe elaziwa ngegridi yalo yamandla engazinzile, ikhono lesistimu lokusetshenziswa njengendlela yokugcina ukushisa, lapho iqhwa lidalwa futhi liqongelelwa khona emadamini eqhwa angaphansi komhlaba nangezikhathi eziphakeme.
Inzuzo yokugcina iholele ekuthuthukisweni kwephrojekthi yokubambisana kwemboni esekelwa yi-Eskom lapho i-Howden iphenya khona ngokusetshenziswa kwabakhiqizi beqhwa ukunciphisa isidingo sikagesi esiphezulu, kanye namacala okuhlola eMponeng naseMoab Hotsong, izimayini ezingaphansi komhlaba ezijulile kakhulu emhlabeni.
“Siqandisa idamu ebusuku (ngemuva kwamahora okusebenza) futhi sasebenzisa amanzi neqhwa elincibilikisiwe njengomthombo wokupholisa imayini ngezikhathi zomsebenzi omatasa kakhulu,” kuchaza uWasserman. “Amayunithi okupholisa ayisisekelo ayacinywa ngezikhathi zomsebenzi omatasa kakhulu, okunciphisa umthwalo kugridi.”
Lokhu kwaholela ekuthuthukisweni komshini weqhwa osebenza ngokhiye eMponeng, lapho uHowden aqede khona umsebenzi ohlanganisa imishini yokwakha, kagesi kanye neyemishini yomshini weqhwa onamandla angu-12 MW, angu-120 t/h.
Izengezo zakamuva kusu lokupholisa eliyinhloko likaMponeng zifaka phakathi iqhwa elithambile, amanzi abandayo angaphezulu, ama-air cooler angaphezulu (ama-BAC) kanye nohlelo lokupholisa olungaphansi komhlaba, ukuba khona emanzini emigodini kwamazinga aphezulu kasawoti nama-chloride ancibilikisiwe ngesikhathi somsebenzi.
Unolwazi oluningi lwaseNingizimu Afrika kanye nokugxila kwezixazululo, hhayi imikhiqizo kuphela, kuyaqhubeka nokuguqula izinhlelo zokuqandisa emhlabeni jikelele, usho kanje.
Njengoba uWasserman eshilo, njengoba izimayini eziningi ziya ngokuya zijula ​​futhi zingena esikhaleni esikhulu ezimayini, kulula ukubona izixazululo ezinjengalezi ezitholakala kwezinye izingxenye zomhlaba.
UMeinhardt uthe: “I-Howden ibilokhu ithumela ubuchwepheshe bayo bokupholisa imayini ejulile eNingizimu Afrika amashumi eminyaka. Isibonelo, sahlinzeka ngezixazululo zokupholisa imayini zezimayini zegolide ezingaphansi komhlaba eNevada emuva ngawo-1990.
“Ubuchwepheshe obuthakazelisayo obusetshenziswa kwezinye izimayini zaseNingizimu Afrika ukugcina iqhwa elishisayo ukuze kudluliswe umthwalo – amandla okushisa agcinwa emadamini amakhulu eqhwa. Iqhwa likhiqizwa ngezikhathi zomsebenzi omatasa futhi lisetshenziswa ngezikhathi zomsebenzi omatasa,” kusho yena. “Ngokwesiko, amayunithi okuqandisa aklanyelwe izinga lokushisa eliphezulu elingafinyelela emahoreni amathathu ngosuku phakathi nezinyanga zasehlobo. Kodwa-ke, uma unamandla okugcina amandla okupholisa, unganciphisa lowo mthamo.”
“Uma unohlelo olunezinga eliphezulu kakhulu lokukhula futhi ufuna ukuthuthukela emananini ashibhile ngezikhathi ezingezona ezokukhula kakhulu, lezi zixazululo zokwenza iqhwa zingaba yisibonelo esiqinile sebhizinisi,” kusho yena. “Imali yokuqala yesitshalo inganciphisa izindleko zokusebenza eziphansi.”
Ngesikhathi esifanayo, i-BAC, ebilokhu isetshenziswa ezimayini zaseNingizimu Afrika amashumi eminyaka, ithola ukubaluleka okukhulu emhlabeni jikelele.
Uma kuqhathaniswa nemiklamo ye-BAC yendabuko, isizukulwane sakamuva sama-BAC sinokusebenza kahle kokushisa okuphezulu kunezandulelayo, imikhawulo yokushisa komoya wezimayini ephansi kanye nomkhawulo omncane. Ahlanganisa futhi imodyuli yokupholisa-on-demand (CoD) epulatifomu ye-Howden Ventsim CONTROL, elungisa ngokuzenzakalelayo izinga lokushisa lomoya wekhola ukuze lihambisane nezidingo zangaphansi komhlaba.
Ngonyaka odlule, iHowden ilethe ama-BAC amathathu esizukulwane esisha kumakhasimende aseBrazil naseBurkina Faso.
Le nkampani iyakwazi futhi ukukhiqiza izixazululo ezenziwe ngokwezifiso zezimo zokusebenza ezinzima; isibonelo samuva nje ukufakwa 'okuyingqayizivele' kwama-BAC ammonia cooler e-OZ Minerals emayini yaseCarrapateena eNingizimu Australia.
“UHowden ufake ama-dry condenser ane-Howden ammonia compressors kanye nama-closed loop air cooler e-Australia ngaphandle kwamanzi atholakalayo,” kusho uWasserman mayelana nokufakwa. “Njengoba lokhu kufakwe ‘komile’ hhayi ama-open spray cooler afakwe ezinhlelweni zamanzi, la ma-cooler aklanyelwe ukusebenza kahle kakhulu.”
Le nkampani okwamanje ihlola ikhambi lokuqapha isikhathi sokusebenza kwesitshalo se-BAC esingu-8 MW (esithombeni ngezansi) esakhiwe futhi sakhiwa emayini iYaramoko Fortuna Silver (eyayikade iRoxgold) eBurkina Faso.
Lolu hlelo, olulawulwa yisitshalo saseHowden eGoli, luvumela inkampani ukweluleka ngokuthuthukiswa kokusebenza kahle kanye nokugcinwa kwayo ukuze isitshalo siqhubeke sisebenza kahle kakhulu. Iyunithi ye-BAC esikhungweni sezimayini saseCaraiba e-Ero Copper, eBrazil nayo yenzelwe ukusebenzisa lesi sici.
Ipulatifomu ye-Total Mine Ventilation Solutions (TMVS) iyaqhubeka nokwakha ubudlelwano obunenani eliqhubekayo futhi inkampani izokwethula izifundo ezimbili zokuthi kungenzeka yini ukuthi i-Ventilation On Demand (VoD) iyasebenza ezweni ngo-2021.
Emngceleni waseZimbabwe, inkampani isebenza kuphrojekthi ezovumela iminyango ezenzakalelayo etholakala ngevidiyo uma ifunwa ezimayini ezingaphansi komhlaba, ivumele ukuthi ivuleke ngezikhathi ezahlukene futhi inikeze umoya opholile ofanele kuye ngezidingo ezithile zemoto.
Lokhu kuthuthukiswa kobuchwepheshe, kusetshenziswa ingqalasizinda yezimayini ekhona kanye nemithombo yedatha engekho eshalofini, kuzoba yingxenye ebalulekile yemikhiqizo yesikhathi esizayo kaHowden.
Okuhlangenwe nakho kukaHowden eNingizimu Afrika: Funda ukuthi ungaklama kanjani izixazululo zokupholisa ukuze ubhekane nekhwalithi yamanzi ephansi ezimayini zayo zegolide ezijulile, ukuthi ungenza kanjani izixazululo zibe ngcono ngangokunokwenzeka ukuze ugweme izinkinga zegridi, nokuthi ungahlangabezana kanjani nezinye zezidingo zekhwalithi yomoya eziqinile kakhulu. Izinga lokushisa kanye nezidingo zempilo yomsebenzi emhlabeni wonke Umthethonqubo - uzoqhubeka nokukhiqiza izimayini emhlabeni jikelele.
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