In this paper, rock mechanics investigations carried out on the future behaviour and support requirements of a large cavern planned to be utilized as a chamber for ore storage which is under early stages of its construction are presented. This cavern which is to be excavated in weak granodiorite and scarp, will have the dimensions of 15 m width, 40 m height, and 60 m length when completed. To reach the goal, rock mechanical parameters have been extensively studied. In this respect, major geological patterns and their strength characteristics have been established together with the physical and mechanical properties of the ore bearing rock (scarp) and the wall rock (marble and altered granodiorite). Moreover, the state of stress in the area was measured. Large proportion of the data thus obtained was integrated into different rock mass classification systems. Back analysis has been carried out. Stability of ore storage cavern is studied and measures to be taken are suggested.
In der vorliegenden Arbeit werden die felsmechanische Untersuchungsergebnisse ueber das Zukunftsverhalten einer grossen Untertage-Aushöhlung vorgestellt and Abstuetzungserfordernisse fuer dieses Raum festgelegt, welches zum Lagern von Erz bestimmt ist and sich im Anfangsstadium der Herstellung befindet. Diese im minderfesten Granodiorit and Skarn auszuhbhlende Kaverne wird, wenn fertiggestellt, 40 m hoch, 15 m breit and 60 m lang sein Um das Ziel zu erreichen, wurden die felsmechanische Parameter ausfuehrlich untersucht. In diesem Zusammenhang wurden die massgebenden geologischen Formen and deren Festigkeitseigenschaften sowie die mechanischen and physikalischen Eigenschaften des erzhaltigen Gesteins (Skarn) and des Nebengesteins (Marmor and verwittertes Granodiorit) festgelegt. Ausserdem wurden die spannungszustànde in dem Gebirge gemessen. Ein grosser Teil der so erhaltenen Messdaten wurden in die verschicdene Klassifizierungssysteme der Gesteinsmassen hinein integriert and retrograden Analysen wurden duzchgefuehrt. Schliesslich wurde die standfestigkeit des Erzlagerkammersstudiert and die hierzu notwendigen Massnahmen vorgeschlagen.
Dans cet ouvrage, les recherches pour le soutenemant et la tenue d''un large caverne à excaver comme le magasin pour le minerai produit dans la mine de scheelite à Uludağ(Bursa) sont faites. Ce caverne sera excavê dans une roche de faible grano-diorite et scarp, ayant des dimensions nettes de 15 metres de largeur, 40 metres de hauteur et 60 metres de longueur finalement. A fin de pouvoir à accomplire cet oeuvre, les parametres mecaniques ont ete etudiees soigneusement. Dans ce domain, les structures geologiques et les proprietes mecaniques de cettes roches ont ete determinees. De plus, l''etat de contraintes dans cette zône a ete etudie. Graces aux resultats ainsi obtenus on est arrive à un system de classification des masses rocheuse en question. Une analyse est faite et la stabilite de catte chambre est etudiee et les precautions à prendre ont ete suggerees.
Uludağ tungsten deposit is located in the province of Bursa, northwest Turkey. Ore bearing rock, scarp occurs between elevations of 2100 m and 2300 m above sea level. Lengthy and severe winter conditions prevail in the area. Near surface part of the deposit is exploited by open pit mining. Sublevel stoping method is applied to extract the ore underground (Figure 1). Stopes having dimensions of up to 15 m width, 30 m height and 100 m length are created as a result of this mining method. Rock mechanical investigations under a project program covered the whole mine both underground and open pit. The work done to evaluate the future behaviour and support requirements of a large cavern, which is planned to serve as ore storage chamber for the output of open pit mine, will be given here. This cavern which is under early stages of its construction will have the dimensions of 15 m width, 40 m height and 60 m length when completed. The originality of this work is that the storage cavern will be opened up by the sublevel stoping method rather than conventional large excavation opening method.
Geological setting Uludag tungsten mine is situated between marbles of Palaeozoic-aged Metamorphic Series and the younger granodioritic batholith. The Metamorphic series of the Uludag massif are composed of amphibolites, gneisses and marbles at the base overlain by mica-schists,phyllites and semi-marbles. These in turn are overlain by Permian - Carboniferous clastics and limestones (Erk 1942). Tungsten bearing minerals are found in the scarp rocks which are formed as a result of contact metamorphism of marbles by the intrusion of a granodioritic batholith, and also at higher levels in the granodiorite close to the contact zone (Kaaden 1954). Marbles are very poor in tungsten ore and tungsten bearing scheelite mineral is present only in thin vein formations. Two types of scarp have been recognized (İnan 1979):
Endoscarn is formed as a thin band within the magmatic mass of the contact zone and represents the metasomatically altered granodiorite.
Exoscarn is formed within the marbles by contact metamorphism process.
