37 research outputs found

    Production Scheduling and Waste Disposal Planning for Oil Sands Mining Using Goal Programming

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    In oil sands mining, timely provisions of ore and tailings containment with less environmental footprints are the main drivers of profitability and sustainability. The recent Alberta Energy Resources Conservation Board Directive 074 requires oil sands waste disposal planning to be an integral part of mine planning. This requires the development of a well integrated strategy of directional mining and tailings dyke construction for in-pit and ex-pit tailings storage management. The objectives of this paper are to: 1) determine the order and time of extraction of ore, dyke material and waste that maximizes the net present value; 2) determine the destination of dyke material that minimizes construction cost; and 3) minimize deviations from the production goals of the mining operation. We have developed, implemented, and verified a theoretical optimization framework based on mixed integer linear goal programming (MILGP) to address these objectives. This study presents an integration of mixed integer linear programming and goal programming in solving large scale mine planning optimization problems using clustering and pushback techniques. Application of the MILGP model was presented with an oil sands mining case. The MILGP model generated a smooth and uniform mining schedule that generates value and provides a robust framework for effective waste disposal planning. The results show that mining progresses with an ore to waste ratio of 1:1.5 throughout the mine life, generating an overall net present value of $14,237M. This approach improves the sustainable development of oil sands through better waste management

    Aggregate Cost Minimization in Hot-Mix Asphalt Design

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    Hot-mix asphalt is a mixture of aggregates and asphalt binder in appropriate ratios to produce a high-performing material for asphalt pavements. The aggregate structure, which depends on the gradation, is an important factor in determining the volumetric properties of HMA. The design process to determine the optimal aggregate blend is currently iterative and engineers rely almost exclusively on experience. This approach is time consuming and often results in suboptimal HMA mixtures. This study presents linear programming optimization models and attendant solution procedures that minimize HMA aggregate cost and produce high-quality HMA. The models are validated with real-life examples, and results indicate that the models are useful to replicate HMA mixes during field modifications, reduce the aggregate cost in a mixture, and manage stockpile inventory. The application of optimization models will increase the application of the Bailey method in the United States. © 2011 American Society of Civil Engineers

    Linear Programming Optimization of Asphalt Mix Design

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    The objective of asphalt mix design is to produce a mix with optimal performance using available aggregate stockpiles. Often, this process does not take into consideration aggregate plant stockpile inventories or the cost of aggregate in the mix. This is due to the lack of tools that enable the lab technician or the engineer to optimize the mix for good performance while reducing the cost of aggregate and managing the stockpile inventory levels. The Bailey method provides useful guidance on aggregate gradation selection for optimal performance. This work presents a linear programming model of the asphalt mix design problem. The algorithm is implemented in MATLAB as an Asphalt Mix Design Optimization (AMIDO) program. The program is successfully validated with real-life data. The results show that AMIDO can be used to successfully produce any mix design with known Bailey method ratios. Also, RAP can be included in a design easily by making use of the Bailey method ratios and AMIDO. This work improves the state-of-the-art in asphalt mix design for dense graded mixes and could potentially be modified for other mixes

    Asphalt Mix Design Optimization for Efficient Plant Management

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    The role of aggregate gradation in hot-mix asphalt performance is well documented in the literature. Yet the Bailey method is the only tool available for guidance on aggregate gradation selection for optimal performance. Also, there is a lack of tools for design engineers and plant managers of quarry sites to manage stockpile inventory levels and control cost of aggregate used in asphalt mixes. This work presents a linear programming model of the asphalt mix design problem and a numerical algorithm to solve the model. The algorithm is implemented in MATLAB as an asphalt mix design optimization (AMIDO) program. The program is successfully verified with an example. The results show that using the Bailey method alone results in suboptimal results and that cheaper mixes with similar aggregate ratios can be designed with the same aggregate stockpiles. For the specific stockpiles used in the verification, the AMIDO mix design resulted in a 53-cent/ton reduction in aggregate cost. This work improves the state of the art in asphalt mix design for dense-graded mixes and could be modified for other mixes
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