Numerical modelling of the groundwater inflow to an advancing open pit mine: Kolahdarvazeh pit, Central Iran

The groundwater inflow into a mine during its life and after ceasing operations is one of the most important concerns of the mining industry. This paper presents a hydrogeological assessment of the Irankuh Zn-Pb mine at 20 km south of Esfahan and 1 km northeast of Abnil in west-Central Iran. During mine excavation, the upper impervious bed of a confined aquifer was broken and water at high-pressure flowed into an open pit mine associated with the Kolahdarvazeh deposit. The inflow rates were 6.7 and 1.4 m3/s at the maximum and minimum quantities, respectively. Permeability, storage coefficient, thickness and initial head of the fully saturated confined aquifer were 3.5 x 10−4 m/s, 0.2, 30 m and 60 m, respectively. The hydraulic heads as a function of time were monitored at four observation wells in the vicinity of the pit over 19 weeks and at an observation well near a test well over 21 h. In addition, by measuring the rate of pumping out from the pit sump, at a constant head (usually equal to height of the pit floor), the real inflow rates to the pit were monitored. The main innovations of this work were to make comparison between numerical modelling using a finite element software called SEEP/W and actual data related to inflow and extend the applicability of the numerical model. This model was further used to estimate the hydraulic heads at the observation wells around the pit over 19 weeks during mining operations. Data from a pump-out test and observation wells were used for model calibration and verification. In order to evaluate the model efficiency, the modelling results of inflow quantity and hydraulic heads were compared to those from analytical solutions, as well as the field data. The mean percent error in relation to field data for the inflow quantity was 0.108. It varied between 1.16 and 1.46 for hydraulic head predictions, which are much lower values than the mean percent errors resulted from the analytical solutions (from 1.8 to 5.3 for inflow and from 2.16 to 3.5 for hydraulic head predictions). The analytical solutions underestimated the inflow compared to the numerical model for the time period of 2-19 weeks. The results presented in this paper can be used for developing an effective dewatering program

Value of fine needle aspiration in cytological diagnosis of salivary gland masses

Introduction: Fine needle aspiration (FNA) is one of important diagnostic procedures in evaluation ofmasses of salivary glands which is noteworthy due to its simplicity and cost-effectiveness. This studyaimed at comparing the results of FNA in masses of salivary glands with results of post-excisionalhistological examinations.Materials and Methods: In an analytic-descriptive setting, 51 patients with masses of salivary glandswere recruited during a 30-months period (April 2005- September 2007) in ear, nose and throat andpathology wards of Tabriz Imam Khomeini Hospital (Iran). Firstly, all the patients evaluated with FNAand then, post-excisional histopathological studies were carried out, considering as the final diagnosis.Results: Fifty one patients, 30 females and 21 males with the mean age of 32.87±16.41 (17-80) yearswere enrolled. Forty six masses located in parotid gland, 4 masses in submandibular gland and a mass insublingual gland. Results of FNA were consistent with definite diagnosis in 42 (82.4%) cases. Thisconsistency was 85.2% and 60% for benign and malignant masses, respectively. Sensitivity, specificity,positive predictive value, negative predictive value and accuracy of FNA for diagnosis and discriminationof benign masses from malignant ones were 85.4, 30, 83.3, 33.3 and 74.5 percent, respectively.Conclusion: There is a high consistency between the results of FNA and final histopathologicaldiagnosis in masses of salivary glands. Sensitivity of this procedure is high for diagnosis anddiscrimination of benign masses from malignant ones and the related specificity is low