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Öğe Açık işletmelerde kısa ve orta dönem üretim planlamasında yeni bir yaklaşım(İnönü Üniversitesi, Mühendislik Fakültesi, Maden Mühendisliği Bölümü, Malatya, Türkiye, 1997) Kumral, Mustafa; Onur, A.HakanÖz: Açık işletmelerin kısa, orta ve uzun dönemli üretim planlaması, nihai sınırı bilinen açık işletme içerisinde haftalık, aylık ve yıllık bazda yapılacak üretimin kalite ve miktar bakımından gereksinimleri karşılaması demektir Bu çalışmada, Adana Çimento hammadde ocağı için kısa ve orta vadede istenilen planlamayı yapabilmek için FORTRAN dili kullanılarak yazılmış bir bilgisayar programı tanıtılmaktadır. Tanıtımı yapılan yöntem bir optimizasyon yöntemi değildir. Kullanıcıya mümkün olduğu kadar fazla sayıda alternatifi deneyip içlerinden en iyisini seçme prensibine dayanır. Yöntem ve bu yöntem ile ilgili bir uygulama bu makalede verilmiştir.Öğe Geostatistical modeling of spatial variability of SPT data for a borax stockpile site(Elsevier Science Bv, 2010) Basarir, Hakan; Kumral, Mustafa; Karpuz, Celal; Tutluoglu, LeventThe major borax producer, Eti Mining Co. of Turkey, planned to construct an export stock site located near the Bandirma Harbor in the northwestern of Turkey. During this construction, some stability problems were encountered. To analyze the stability problems and to assess the engineering properties of soil in the stock site geotechnical investigations were started. As a part of geotechnical investigations one of the most common field tests, the standard penetration tests (SPT), was conducted for soil exploration. In this study, the field is geostatistically simulated to assess the uncertainty associated with the spatial variability of SPT results. Multiple probable realizations of SPT values are generated using sequential Gaussian simulation. Using 122 NSPT data in the borax stockpile site, the characteristics observed in the available data are reproduced in a manner that the heterogeneity of SPT within the field is honored. The estimated NSPT data can also be used for other purposes such as determination of bearing capacity, and estimation of soil strength parameters. (C) 2010 Elsevier B.V. All rights reserved.Öğe Mine maintenance time as a non-linear optimization problem under uncertainty(Emerald Group Publishing Ltd, 2009) Kumral, MustafaPurpose - During operation, mines experience safety, reliability, environmental and financial problems. In order to avoid these problems or idle capacities, mining operations should be performed within the specified reliability level of the system. Therefore, mining sub-systems such as drilling, blasting, loading, hauling, ventilation, hoisting and supporting should be designed and maintained carefully. In this context, maintenance time causes a critical optimization problem in mines. The purpose of this paper is to address these issues. Design/methodology/approach - The problem is formulated as a non-linear optimization problem and solved by genetic algorithms. A case study is conducted to demonstrate to the performance of approach for an underground operation. Findings - The results show that the approach can be used to determine the best action time. Practical implications - The approach can be applicable to different mining methods in more sophisticated sub-systems. Originality/value - The paper recommends a genetic algorithmic approach to make a decision on optimal timing of maintenance of a mine.Öğe Production planning of mines: Optimisation of block sequencing and destination(Taylor & Francis Ltd, 2012) Kumral, MustafaMine planning is really about seeking an optimal solution to three coupled problems, namely: mine block sequencing, ore-waste discrimination by cut-off grades and determination of production rates. The key objective of the optimisation model is to maximise net present value (NPV) under the access and capacity constraints. In current practice, mine block sequencing is implemented for pre-defined cut-off grades and production rates determined outside of optimisation process (Model 1). This article takes a further step in improving the optimisation process by enabling ore-waste discrimination and block sequencing to be optimised concurrently through a mixed integer programming (MIP) model for given capacities (Model 2). This optimisation model gives rise to the problem of size in terms of the number of destinations. However, it allows more block configuration in tandem with increases in NPV. To demonstrate the superior attributes of this enhanced model, a case study was implemented using data from a gold mine. The new model generated 5% more NPV. Increasing computer capacity and CPU speed enables mine planners to use Model 2 for solving mine production planning problems efficiently.Öğe Robust stochastic mine production scheduling(Taylor & Francis Ltd, 2010) Kumral, MustafaThe production scheduling of open pit mines aims to determine the extraction sequence of blocks such that the net present value (NPV) of a mining project is maximized under capacity and access constraints. This sequencing has significant effect on the profitability of the mining venture. However, given that the values of coefficients in the optimization procedure are obtained in a medium of sparse data and unknown future events, implementations based on deterministic models may lead to destructive consequences to the company. In this article, a robust stochastic optimization (RSO) approach is used to deal with mine production scheduling in a manner such that the solution is insensitive to changes in input data. The approach seeks a trade off between optimality and feasibility. The model is demonstrated on a case study. The findings showed that the approach can be used in mine production scheduling problems efficiently.
