Journal of Mining and Environement
Volume:5 Issue: 2, Summer 2014

We have applied an automatic interpretation method of potential data called AN-EUL in unexploded ordnance (UXO) prospective which is indeed a combination of the analytic signal and the Euler deconvolution approaches. The method can be applied for both magnetic and gravity data as well for gradient surveys based upon the concept of the structural index (SI) of a potential anomaly which is related to the geometry of the anomaly sources. With AN-EUL method, both the depth and the approximate geometry (or SI) of the causative sources can be deduced. A realistic model for UXO to be simulated by a simple shape body is a prolate spheroid. The method is applied for both synthetic potential data assuming a collection of causative UXO sources replicating various sizes placed at different depths. In both cases, the estimated depth and the SI of the synthetic UXOs approximately correspond to the synthetic model parameters. The location detection of the causative sources is based upon the Blakely automatic picking algorithm. For both data sets, since the anomaly responses of the small UXOs are affected by noise, the estimated SI is a bit disturbed but the locations correspond to the real ones. The Blakely algorithm also identifies weak anomalies that are due to noise in data; thus, a post-processing of the estimated SI of the automatically detected sources may be needed to prevent false alarm sources in UXO exploration. Two field data sets have been provided to demonstrate the capability of the applied methods in UXO detection.

The method of weights of evidence is one of the most important data driven methods for mineral potential mapping in GIS. In this method, considering the characteristics of known mineralized locations, we can prospect new mineralized areas. In this research work, the method of weights of evidence has been used for hydrothermal gold potential mapping in Torbat-e-Heydarieh area, east of Iran. As a relatively large number of gold mineral occurrences (i.e., exactly 27 known gold mineralized locations) have been recognized in the study area, the use of the weights of evidence method for prospecting new gold mineralized zones in the area may be quite efficient. In this study, a combination of the results of the airborne geophysical, geological, argillic, propillitic and iron oxide alteration, geochemical and structural data based on the method of weights of evidence, has been made to determine probable gold mineralization zones in the form of a posteriori map of the survey area. Consequently, four major zones in this area have been identified as high gold mineralization potential zones, in which many vein and veinlet mineralization forms can be found.

Detection of Oil-Water Contacts (OWCs) is one of the primary tasks before evaluation of reservoir’s hydrocarbon in place, determining net pay zones and suitable depths for perforation operation. This paper introduces Bayesian decision making tool as an effective technique in OWC detecting using wire line logs. To compare strengths of the suggested method in detecting OWC with conventional one, the same database was used. Proposed method was applied to wire line logs in three wells of a carbonate reservoir in an oil field of the southwestern Iran and its results have been evaluated by well testing results. Results indicate that the usage of Bayesian method in detecting OWC is more accurate than conventional method and may improve the results about 5% on average. In addition, using this method, any variation of water saturation (Sw) log and reservoir fluid types may be detectable.

Theoretical review of ‘mining pit lakes’ indicates that like natural lakes such lakes display a huge diversity. They are typically in a non-equilibrium state with respect to their surroundings. Hence, at the decommissioning phase of mining operation a detailed technical study are required on different aspects of such created water bodies considering its morphometry, geology, hydrology, water quality (geo-chemistry), rate of filling, and biology. Pit lakes has their value as resources for miscellaneous purposes e.g. recreation, fisheries, water supply, and wildlife habitat which is dependent mostly on their topography, location water use and safety characteristics. Internationally, pit lakes as self sustaining aquatic ecosystems have been developed in the past e.g. Alberata Pit Lake in Canada [1, 2]; Sleeper pit lake [3] and Westfield pit lake, Scotland [4]. In Indian mining industry neither scientific studies nor case record of mining pit lake development are available because ‘closure plans’ are introduced recently. One such attempt in India at Kerendari coal mine in Jharkhand state is a laudable and new attempt which is at the stage of planning. In brief, since the opportunities for development of ‘mining pit lakes’ are immense and company owning it can nurture their ecological and commercial benefits appropriately, this review will be practically useful particularly in those countries which has less number of age old surface mines heading towards the decommissioning phase. The review done here can be practically utilized for evaluation, assessment, new project clearances and statuary compliance purposes.

In this paper, the reliability of powered supports has been discussed utilizing the gathered failure data and failure interval data from Tabas coal mine in two years. The data sets were investigated using statistical procedures and in two levels: the existence of trend and serial correlation. The results show that the powered supports follow the Gamma reliability function. The reliability of the machine decreases to almost zero after 520 operation hours and after 80 hours the probability of failure of powered supports increases to 60 percent.Powered Support’s failure rate shows an improving behavior and therefore decreasing failure rate. In the beginning of the process the failure rate is 0.021 failures per hour, which after a sudden decrease reaches the rate of 0.012, thence forward on a gently decreasing rate and after 100 hours gets to the rate of 0.01.Regarding the maintenance policy and to protect the machine’s operation continuity Preventive maintenance strategy can be chosen. The reliability of the discussed machine can be maintained on a descent level by inspecting and controlling over the parts in short term intervals. With regard to reliability plots of powered supports operation, preventive reliability-based maintenance time intervals for 80% reliability levels for powered supports is 15 hours.

This study investigates the optimization of gold dissolution from Aghdarre ore. Therefore, a laboratory investigation was initiated, to improve the leaching conditions with the objective of maximizing mill capacity with no reduction on gold recovery. It was observed that the time reduction from 25 to 15 hours did not change the gold recovery. In the other words, it indicated that a capacity of 140t/h can be sustained without detrimental effect on gold recovery. The optimum parameters were 700g/t NaCN, 46% solid in pulp, pH=10, and d80=45 microns using the Taguchi method. So, the gold recovery was obtained 90.71%. Also, it was concluded that the NaCN concentration was the most effective parameter and the solid percent plus retention time had the lowest effects on this process.