For rational and realistic numerical simulation of behaviour of jointed rock mass around cut-&-fill stopes at great depth in Mosaboni copper mine, India, extensive geotechnical studies were conducted using various rock mechanics approaches. Due to differences in philosophy of these approaches and complex characteristics of the rock mass under study, its properties, determined by these approaches, differed widely. Different combinations of values of these parameters were tried in numerical models of stopes and their findings were compared with field observations to select the standard value of each parameter. Methodology, approaches and findings of this investigation have been briefly narrated in this paper.
Pour une simulation numerique rationnelle et realiste du comportement de la masse de roche jointoyee autour du gradins coupes - et - remplis a une grande profondeur dans la mine de cuivre a Mosaboni en Inde, des etudes geotechniques approfondies ont ete realisees en utilisant des methodes diverses de Ie mecanique de roche. En raison de differences dans la philosophie de ces methodes et les caracteristiques complexes de la masse de roche etudiee, ses proprietes, evaluees par ces methodes ont montre une grande difference. De differentes combinaisons des valeurs de ces paramèteres ont ete essayees dans des modèles numeriques des gradins. Lea resultats ont ete compares aux observations de champ afin de selectionner la valeur normalisae de chaque paramètre. Cettè communication donne en resume la methodologie, les methodes et les resultats de cette etude.
Es wurden mit Hilfe von verschiedenen Ahnnăhrungsversuchen des Gesteinmechanismus eingehenden geotechnischen Untersuchungen gemacht, zum rationalen und realitischen numerisch Simulierung von Defassen der gegliderten Gesteinmasse um Hieb-und-Fulle herum Stopes im Tiefbaukupferbergwerk in Mosaboni, Indien. Wegen Verschiendenheit zwischen den Begriff diesen Ahnnă hrungsversuchen und auch die komplex Eigenschaften der untergesuchten Gesteinmasse gingen die Eigenschaften wie bestimmt mit Hilfe von diesen Ahnnahrungsversuchen sehr einander aus. Verschiedene Kombinationen von Nutzen diesen Parametem wurden im numerischen Modelieren von Stopes wurden versucht. Die ergebnisse wurden vergleicht mit Feldresultat, um normaler Wert von jedem Parameter auszuwăhlen. Nachfolgend sind die Methode, die Ahnnăhrungsversuchen und die Ergebnisse dieser Untersuchung ebenfalls kurz erŏrtert.
Mosaboni copper mine of Hindustan Copper Ltd., is in south-east Singhbhum Thrust Belt in Bihar, India, and is the deepest (being worked at a depth of 1014 m) underground non-auriferous mine in India. Host rocks comprise of biotite-chlorite and hronblende schists, phyllite, and quartzite, and belong to Precambrian iron ore series. Mineable width of the chalcopyrite orebody varies from 1.5 to 30 m with 30°aVerage dip. Thinner parts of the deposit are worked by room-and-pillar method with post-filling, and thicker parts are mined by horizontal cut-&-fill (HCF) stoping, with or without post-pillars. Unstable ground conditions result at places due to great depth, large excavation areas and prolonged exposure. To optimise stope geometry and design the support system, HCF stopes between 25th and 28th levels in this mine were numerically modelled. Thorough knowledge of rock mass properties were essential for accurate simulation. Extensive geotechnical studies were conducted and various empirical approaches were used for this purpose.
The findings of geotechnical studies, conducted in HCF stoping areas between 26th and 28th levels, are as follows (Ghosh et al, 1991; Rao et al, 1992; Rao & Jain, 1993): 1. Rock mass is jointed with five sets of well developed discontinuities.
