An assessment of the classification of limestone rock slopes in surface mining: a case study in South Africa

Abstract

Slopes in surface mines are usually designed from the geotechnical data. The important geotechnical parameters include geology, rock strength and groundwater. In designing the most optimum slopes, each geotechnical parameter is evaluated individually before restructuring them in their appropriate spatial association with each other. To examine each parameter’s input to the rate, magnitude and direction of slope movement during the commodity extraction process, it is possible to simulate the results of the individual parameters. In surface mining, the frequency and magnitude of slope failure analysis is critical if it occurs in the area of an entree ramp or above an area of higher ore grade. These areas of potential failure require regular monitoring and suitable remedial measures to be implemented without delay. Mining of limestone in South Africa is important in the cement industry, however, surface mining of carbonate rock may result in slope failures. Limestone is carbonaceous, which reacts when exposed to changes in water and temperature. Slope stability methods have primarily been designed for surface mining using a hard rock datum. These slope stability methods have ignored the environmental factors which are important aspects for the steadiness of carbonaceous rock. The drive of this study is to use the designed rock slope stability methods on soft rock to assess which methods can be used to ensure safe and economic mining operations. Using rock mass classification schemes is helpful in determining the slope steadiness in surface mining but limitations exist. The systems require additional parameters that look at support structures for slopes taking into consideration slope material that is susceptible to solubility when exposed to environmental agents. In utilising rock mass categorisation, one is able to find rock mass properties such has cohesion and internal frictional angel in a safe working condition with limited laboratory work. Rock mass properties help determine the slope condition with regards to stability and safety

Imithambeka ezimayini zomhlaba yakhiwe ngokwe mininingwane ye-geotechnical. Imingcele ebalulekile ye-geotechnical ifaka i-geology (isayensi ebhekene nokwakheka komhlaba, umlando wawo, nezinqubo ezisebenza kuwo), namandla edwala namanzi angaphansi komhlaba. Ekwakheni imithambeka engcono kakhulu, ipharamitha ngayinye ye-geotechnical ihlolwa ngokuhlukana ngaphambi kokuyakha kabusha ebudlelwaneni bayo bendawo efanele. Imiphumela yepharamitha ngayinye ingenzelwa ukuthola ukusebenza kwayo okumayelana nobukhulu, isilinganiso kanye nokuqondiswa kokufuduka kwemithambeka ngesikhathi sokukhishwa kwempahla. Ezimayini zomhlaba, isilinganiso nobukhulu bokuhlaziywa kokuhluleka kwemithambeka kubalulekile uma kwenzeka eduze kommango wokungena noma ngaphezulu kwendawo esebangeni eliphakeme. Lezi zindawo ezibuye zibe nokuhluleka zidinga ukuqashwa njalo kanti futhi izinyathelo ezifanele zokulungisa zingathathwa ngaphandle kokubambezeleka. Ukumbiwa kwamatshe eNingizimu Afrika kubalulekile embonini kasimende, kodwa-ke, ukumbiwa komhlaba okungaphezulu kwedwala le-carbonate kungaholela ekuhlulekeni kwemithambeka. I-limestone ibhekwa njenge mpahla e-carbonaceous, eshintshayo uma ivezwa kuzinguquko ezisemanzini nasezingeni lokushisa. Izindlela zokuqina kwemithambeka zenzelwe kakhulu ukumba phansi kusetshenziswa ucezu lolwazi ngedwala eliqinile. Lezi zindlela zokuzinza kwemithambeka azizinakanga izici zemvelo okuyizinto ezibucayi ekusimameni kwedwala lekhaboni. Inhloso yalolu cwaningo ukusebenzisa izindlela eziklanyelwe ukuqina kwemithambeka yedwala elithambile ukuze kuhlolwe ukuthi yiziphi izindlela ezingasetshenziswa ukuqinisekisa ukusebenza kwezimayini eziphephile nezomnotho

Amathambeka kumphezulu wemigodi ayilwe ngokubanzi ngokwe datha yofundo ngezobugcisa. Ukubaluleka kweparemeters zemfundo ngezobugcisa kuquka ukwakheka komhlaba, amandla eliwa kunye namanzi aphantsi komhlaba. Ekuyilweni kwelona lilungileyo ithambeka iparemeter yofundo ngezobugcisa nganye iyavavanywa ngokwahlukana phambi kokuba zakhiwe kabutsha umphandle wazo ofanelekileyo ngokusondelelana kwazo, enye kwenye. Iziphumo zeparemeter nganye zinokuboniswa ukuze kumiselwe ukusebenza ngokujoliswe kubukhulu,ixabiso nesikhokelo sokufuduswa kwethambeka ngexesha lokumbiwa kwezorhwebo emigodini. Kulwambiwo lwemigodi rhoqo nobukhulu bethambeka uhlalutyo lokuwa lubalulekile xa kunokuthi kwenzeke kwindawo yokungena okanye ngaphezulu komgangatho wexabiso ophezulu. Ezi ndawo zamathuba amakhulu okuwa kwethambeka kudinga ingqwalasela kunye namanyathelo osasazo afanelekileyo, anokuthi asetyenziswe ngaphandle kolibaziseko. Ukumbiwa kwelitye lekalika eMzansi Afrika kubalulekile kwicandelo lesamente nangona kunjalo ukumbiwa kwelitye lekhabhonathi kungabangela ukuwa kwethambeka. Ilitye lekalika lithathwa njengezinye zezinto ze-corbonaceous, zivakalelwa xa zithe zadibana nenguqulelo yamanzi namaqondo obushushu. Iindlela zokuzinziswa kwethambeka ziyilwe kwasekuqaleni kulwambiwo lwemigodi kusetyenziswa idwala elinzima kwaye eliluqilima. Ezi ndlela zokuzinzisa ithambeka azizange ziyijonge imeko yendalo esingqongileyo nekuzizo izinto ezibalulekilyo kuzinzo lweliwa leCarbonaceous. Injongo yolufundon kuku sebenzisa iindlela eziyiliweyo zoqilimo kwidwala lethambeka. Kumadwala athambileyo ukujonga ukuba zeziphi iindlela ezinokusetyenziswa ukuqinisekisa ukuphepha kuqoqosho nemisebenzi yezemigodi