SIMULATION OF ROCK TYPES IN COAL DEPOSITS USING THE MULTIPLE-POINTS METHOD CONSTRAINED BY ORIENTED PATHS

Pedro Valenzuela Sepulveda (2010). SIMULATION OF ROCK TYPES IN COAL DEPOSITS USING THE MULTIPLE-POINTS METHOD CONSTRAINED BY ORIENTED PATHS MPhil Thesis, School of Mechanical and Mining Engineering, The University of Queensland.

       
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Author Pedro Valenzuela Sepulveda
Thesis Title SIMULATION OF ROCK TYPES IN COAL DEPOSITS USING THE MULTIPLE-POINTS METHOD CONSTRAINED BY ORIENTED PATHS
School, Centre or Institute School of Mechanical and Mining Engineering
Institution The University of Queensland
Publication date 2010-03
Thesis type MPhil Thesis
Supervisor Dr. Peter Knights
Dr. Shuxing Li
Total pages 97
Total colour pages 28
Total black and white pages 69
Subjects 09 Engineering
Abstract/Summary A critical hazard to identify and manage in modern Longwall coal mines is that of unplanned strong roof conditions and collapse scenarios. This unstable condition is described as an Excessive Periodic Weighting (EPW) which is monitored and measured in the Longwall support equipment. Strong roof conditions are in turn often caused by the presence of sandstone units in the roof rock strata. The uncertainty in the shape of these sandstone bodies is studied through simulations of the rock types. A simulation method that has given good results in reservoirs was tested in a Coal deposit. This method is called Multiple-Points (MP) statistics. Instead of drillholes it borrows information from the geological model directly and delivers simulations which have similar rock type proportions as compared to the targets calculated from the model. The classic MP method applied in 2D was modified, so as to look for information along streamlines within a search ellipse around the block u to simulate, not the whole geological model. The alternative algorithm is named Oriented Paths Multiple Points Simulation (OPMPS) and was tested in a Coal deposit as well. Results show that rock type proportions are quite close to the targets as long as the right search radii are entered by the user. As expected realisations tend to produce sandstone bodies that are elongated and follow the paleoflow direction. The extension of this algorithm in 3D and the use of alternative stochastic methods (Markov Chains, fractals, object-based methods, etc) to determine streamlines are two avenues to continue this research in the future. Addressing the problem in 3D would solve the problems of un-simulated nodes. This, in addition to including the variability of the rock mass discontinuities, would enable the preparation of probabilistic Hazard Maps of Excessive Periodic Weighting in a Longwall mine, which is also suggested as further research.
Keyword Multiple-Points statistics, Streamlines, Paleoflow direction, Sedimentary deposits.
Additional Notes 22, 23, 29, 32, 33, 34, 35, 42, 44, 48, 51, 55, 56, 57, 58, 60, 62, 63, 65, 66, 67, 68, 70, 71, 83, 95, 96, 97.

 
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Created: Thu, 18 Aug 2011, 17:26:27 EST by Mr Pedro Valenzuela Sepulveda on behalf of Library - Information Access Service