Assessment of dewatering requirements for Çaldağ nickel mine in Western Turkey


Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Jeoloji Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2011

Öğrenci: ÇİĞDEM CANKARA

Danışman: HASAN YAZICIGİL

Özet:

The purpose of this study is to assess the dewatering requirements of planned open pit nickel mining at Çaldağ Site in Western Turkey. Dewatering is required for safe and efficient working conditions and pit wall stability. With this scope, a groundwater model of the study area is developed and used to predict the dewatering rate. The methodology mainly involves data collection, site hydrogeologic characterization and development of conceptual model, followed by construction and use of a groundwater model to predict the dewatering requirements of the mine site. The groundwater flow modeling is carried out using MODFLOW software and the dewatering simulations are carried out using MODFLOW Drain package. The drain cell configuration is determined by pit boundaries and invert elevations of drains corresponded to the bench elevations that will be achieved with respect to the mining schedule. In the transient model runs, monthly time steps were used. Using the outflow from in-pit drain cells, the v monthly dewatering rates are calculated. In order to assess the impacts of the hydraulic conductivity of the laterite on the pit inflow rates, simulations were carried out for different values of hydraulic conductivity of laterites. The predicted flow rate using the calibrated model is 107.54 L/s. A tenfold reduction in the hydraulic conductivity of laterite resulted in three fourths of decrease in the flow rate (24.42 L/s). Consequently, a wide range of flow rates for different hydraulic conductivity values of laterite was calculated. In order to confirm the hydraulic conductivity of laterites in the area, and to obtain a realistic dewatering rate, further pumping tests are needed.